| /* pngwutil.c - utilities to write a PNG file |
| * |
| * Last changed in libpng 1.7.0 [(PENDING RELEASE)] |
| * Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson |
| * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) |
| * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) |
| * |
| * This code is released under the libpng license. |
| * For conditions of distribution and use, see the disclaimer |
| * and license in png.h |
| */ |
| |
| #include "pngpriv.h" |
| #define PNG_SRC_FILE PNG_SRC_FILE_pngwutil |
| |
| #ifdef PNG_WRITE_SUPPORTED |
| |
| #ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED |
| /* Place a 32-bit number into a buffer in PNG byte order. We work |
| * with unsigned numbers for convenience, although one supported |
| * ancillary chunk uses signed (two's complement) numbers. |
| */ |
| void PNGAPI |
| png_save_uint_32(png_bytep buf, png_uint_32 i) |
| { |
| buf[0] = PNG_BYTE(i >> 24); |
| buf[1] = PNG_BYTE(i >> 16); |
| buf[2] = PNG_BYTE(i >> 8); |
| buf[3] = PNG_BYTE(i); |
| } |
| |
| /* Place a 16-bit number into a buffer in PNG byte order. |
| * The parameter is declared unsigned int, not png_uint_16, |
| * just to avoid potential problems on pre-ANSI C compilers. |
| */ |
| void PNGAPI |
| png_save_uint_16(png_bytep buf, unsigned int i) |
| { |
| buf[0] = PNG_BYTE(i >> 8); |
| buf[1] = PNG_BYTE(i); |
| } |
| #endif /* WRITE_INT_FUNCTIONS */ |
| |
| /* Simple function to write the signature. If we have already written |
| * the magic bytes of the signature, or more likely, the PNG stream is |
| * being embedded into another stream and doesn't need its own signature, |
| * we should call png_set_sig_bytes() to tell libpng how many of the |
| * bytes have already been written. |
| */ |
| void PNGAPI |
| png_write_sig(png_structrp png_ptr) |
| { |
| png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10}; |
| |
| #ifdef PNG_IO_STATE_SUPPORTED |
| /* Inform the I/O callback that the signature is being written */ |
| png_ptr->io_state = PNG_IO_WRITING | PNG_IO_SIGNATURE; |
| #endif |
| |
| /* Write the rest of the 8 byte signature */ |
| png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes], |
| (png_size_t)(8 - png_ptr->sig_bytes)); |
| |
| if (png_ptr->sig_bytes < 3) |
| png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE; |
| } |
| |
| /* Write the start of a PNG chunk. The type is the chunk type. |
| * The total_length is the sum of the lengths of all the data you will be |
| * passing in png_write_chunk_data(). |
| */ |
| static void |
| png_write_chunk_header(png_structrp png_ptr, png_uint_32 chunk_name, |
| png_uint_32 length) |
| { |
| png_byte buf[8]; |
| |
| #if defined(PNG_DEBUG) && (PNG_DEBUG > 0) |
| PNG_CSTRING_FROM_CHUNK(buf, chunk_name); |
| png_debug2(0, "Writing %s chunk, length = %lu", buf, (unsigned long)length); |
| #endif |
| |
| if (png_ptr == NULL) |
| return; |
| |
| #ifdef PNG_IO_STATE_SUPPORTED |
| /* Inform the I/O callback that the chunk header is being written. |
| * PNG_IO_CHUNK_HDR requires a single I/O call. |
| */ |
| png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_HDR; |
| #endif |
| |
| /* Write the length and the chunk name */ |
| png_save_uint_32(buf, length); |
| png_save_uint_32(buf + 4, chunk_name); |
| png_write_data(png_ptr, buf, 8); |
| |
| /* Put the chunk name into png_ptr->chunk_name */ |
| png_ptr->chunk_name = chunk_name; |
| |
| /* Reset the crc and run it over the chunk name */ |
| png_reset_crc(png_ptr, buf+4); |
| |
| #ifdef PNG_IO_STATE_SUPPORTED |
| /* Inform the I/O callback that chunk data will (possibly) be written. |
| * PNG_IO_CHUNK_DATA does NOT require a specific number of I/O calls. |
| */ |
| png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_DATA; |
| #endif |
| } |
| |
| void PNGAPI |
| png_write_chunk_start(png_structrp png_ptr, png_const_bytep chunk_string, |
| png_uint_32 length) |
| { |
| png_write_chunk_header(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), length); |
| } |
| |
| /* Write the data of a PNG chunk started with png_write_chunk_header(). |
| * Note that multiple calls to this function are allowed, and that the |
| * sum of the lengths from these calls *must* add up to the total_length |
| * given to png_write_chunk_header(). |
| */ |
| void PNGAPI |
| png_write_chunk_data(png_structrp png_ptr, png_const_voidp data, |
| png_size_t length) |
| { |
| /* Write the data, and run the CRC over it */ |
| if (png_ptr == NULL) |
| return; |
| |
| if (data != NULL && length > 0) |
| { |
| png_write_data(png_ptr, data, length); |
| |
| /* Update the CRC after writing the data, |
| * in case the user I/O routine alters it. |
| */ |
| png_calculate_crc(png_ptr, data, length); |
| } |
| } |
| |
| /* Finish a chunk started with png_write_chunk_header(). */ |
| void PNGAPI |
| png_write_chunk_end(png_structrp png_ptr) |
| { |
| png_byte buf[4]; |
| |
| if (png_ptr == NULL) return; |
| |
| #ifdef PNG_IO_STATE_SUPPORTED |
| /* Inform the I/O callback that the chunk CRC is being written. |
| * PNG_IO_CHUNK_CRC requires a single I/O function call. |
| */ |
| png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_CRC; |
| #endif |
| |
| /* Write the crc in a single operation */ |
| png_save_uint_32(buf, png_ptr->crc); |
| |
| png_write_data(png_ptr, buf, (png_size_t)4); |
| } |
| |
| /* Write a PNG chunk all at once. The type is an array of ASCII characters |
| * representing the chunk name. The array must be at least 4 bytes in |
| * length, and does not need to be null terminated. To be safe, pass the |
| * pre-defined chunk names here, and if you need a new one, define it |
| * where the others are defined. The length is the length of the data. |
| * All the data must be present. If that is not possible, use the |
| * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end() |
| * functions instead. |
| */ |
| static void |
| png_write_complete_chunk(png_structrp png_ptr, png_uint_32 chunk_name, |
| png_const_voidp data, png_size_t length) |
| { |
| if (png_ptr == NULL) |
| return; |
| |
| /* On 64 bit architectures 'length' may not fit in a png_uint_32. */ |
| if (length > PNG_UINT_31_MAX) |
| png_error(png_ptr, "length exceeds PNG maximum"); |
| |
| png_write_chunk_header(png_ptr, chunk_name, (png_uint_32)/*SAFE*/length); |
| png_write_chunk_data(png_ptr, data, length); |
| png_write_chunk_end(png_ptr); |
| } |
| |
| /* This is the API that calls the internal function above. */ |
| void PNGAPI |
| png_write_chunk(png_structrp png_ptr, png_const_bytep chunk_string, |
| png_const_voidp data, png_size_t length) |
| { |
| png_write_complete_chunk(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), data, |
| length); |
| } |
| |
| static png_alloc_size_t |
| png_write_row_buffer_size(png_const_structrp png_ptr) |
| /* Returns the width of the widest pass in the first row of an interlaced |
| * image. Passes in the first row are: 0.5.3.5.1.5.3.5, so the widest row is |
| * normally the one from pass 5. The only exception is if the image is only |
| * one pixel wide, so: |
| */ |
| #define PNG_FIRST_ROW_MAX_WIDTH(w) (w > 1U ? PNG_PASS_COLS(w, 5U) : 1U) |
| |
| /* For interlaced images the count of pixels is rounded up to a the number of |
| * pixels in the first pass (numbered 0). This ensures that passes before |
| * the last can be packed in the buffer without overflow. |
| */ |
| { |
| png_alloc_size_t w; |
| |
| /* If the image is interlaced adjust 'w' for the interlacing: */ |
| if (png_ptr->interlaced != PNG_INTERLACE_NONE) |
| { |
| /* Take advantage of the fact that 1-row interlaced PNGs require half the |
| * normal row width: |
| */ |
| if (png_ptr->height == 1U) /* no pass 6 */ |
| w = PNG_FIRST_ROW_MAX_WIDTH(png_ptr->width); |
| |
| /* Otherwise round up to a multiple of 8. This may waste a few (less |
| * than 8) bytes for PNGs with a height less than 57 but this hardly |
| * matters. |
| */ |
| else |
| w = (png_ptr->width + 7U) & ~7U; |
| } |
| |
| else |
| w = png_ptr->width; |
| |
| /* The rounding above may leave 'w' exactly 2^31 */ |
| debug(w <= 0x80000000U); |
| |
| switch (png_ptr->row_output_pixel_depth) |
| { |
| /* This would happen if the function is called before png_write_IHDR. */ |
| default: NOT_REACHED; return 0; |
| |
| case 1: w = (w+7) >> 3; break; |
| case 2: w = (w+3) >> 2; break; |
| case 4: w = (w+1) >> 1; break; |
| case 8: break; |
| case 16: w <<= 1; break; /* overflow: w is set to 0, which is OK */ |
| |
| /* For the remaining cases the answer is w*bytes; where bytes is 3,4,6 |
| * or 8. This may overflow 32 bits. There is no way to compute the |
| * result on an arbitrary platform, so test the maximum of a (size_t) |
| * against w for each possible byte depth: |
| */ |
| # define CASE(b)\ |
| case b*8:\ |
| if (w <= (PNG_SIZE_MAX/b)/*compile-time constant*/)\ |
| return w * b;\ |
| return 0; |
| |
| CASE(3) |
| CASE(4) |
| CASE(6) |
| CASE(8) |
| |
| # undef CASE |
| } |
| |
| /* This is the low bit depth case. The following can never be false on |
| * systems with a 32-bit or greater size_t: |
| */ |
| if (w <= PNG_SIZE_MAX) |
| return w; |
| |
| return 0U; |
| } |
| |
| /* Release memory used by the deflate mechanism */ |
| static void |
| png_deflateEnd(png_const_structrp png_ptr, z_stream *zs, int check) |
| { |
| if (zs->state != NULL) |
| { |
| int ret = deflateEnd(zs); |
| |
| /* Z_DATA_ERROR means there was pending output. */ |
| if ((ret != Z_OK && (check || ret != Z_DATA_ERROR)) || zs->state != NULL) |
| { |
| png_zstream_error(zs, ret); |
| |
| if (check) |
| png_error(png_ptr, zs->msg); |
| |
| else |
| png_warning(png_ptr, zs->msg); |
| |
| zs->state = NULL; |
| } |
| } |
| } |
| |
| /* compression_buffer (new in 1.6.0) is just a linked list of temporary buffers. * From 1.6.0 it is retained in png_struct so that it will be correctly freed in |
| * the event of a write error (previous implementations just leaked memory.) |
| * |
| * From 1.7.0 the size is fixed to the same as the (uncompressed) row buffer |
| * size. This avoids allocating a large chunk of memory when compressing small |
| * images. This type is also opaque outside this file. |
| */ |
| typedef struct png_compression_buffer |
| { |
| struct png_compression_buffer *next; |
| png_byte output[PNG_ROW_BUFFER_SIZE]; |
| } png_compression_buffer, *png_compression_bufferp; |
| |
| /* png_compression_buffer methods */ |
| /* Deleting a compression buffer deletes the whole list: */ |
| static void |
| png_free_compression_buffer(png_const_structrp png_ptr, |
| png_compression_bufferp *listp) |
| { |
| png_compression_bufferp list = *listp; |
| |
| if (list != NULL) |
| { |
| *listp = NULL; |
| |
| do |
| { |
| png_compression_bufferp next = list->next; |
| |
| png_free(png_ptr, list); |
| list = next; |
| } |
| while (list != NULL); |
| } |
| } |
| |
| /* Return the next compression buffer in the list, allocating it if necessary. |
| * The caller must update 'end' if required; this just moves down the list. |
| */ |
| static png_compression_bufferp |
| png_get_compression_buffer(png_const_structrp png_ptr, |
| png_compression_bufferp *end) |
| { |
| png_compression_bufferp next = *end; |
| |
| if (next == NULL) |
| { |
| next = png_voidcast(png_compression_bufferp, png_malloc_base(png_ptr, |
| sizeof *next)); |
| |
| /* Check for OOM: this is a recoverable error for non-critical chunks, let |
| * the caller decide what to do rather than issuing a png_error here. |
| */ |
| if (next != NULL) |
| { |
| next->next = NULL; /* initialize the buffer */ |
| *end = next; |
| } |
| } |
| |
| return next; /* may still be NULL on OOM */ |
| } |
| |
| /* This structure is used to hold all the data for zlib compression of a single |
| * stream of data. It may be re-used, it stores the compressed data internally |
| * and can handle arbitrary input and output. |
| * |
| * 'list' is the output data contained in compression buffers, 'end' points to |
| * list at the start and is advanced down the compression buffer list (extending |
| * it as required) as the data is written. If 'end' points into a compression |
| * buffer (does not point to 'list') that is the buffer in use in |
| * z_stream::{next,avail}_out. |
| * |
| * Compression may be performed in multiple steps, '*end' always points to the |
| * compression buffer *after* the one that is in use, so 'end' is pointing |
| * *into* the one in use. |
| * |
| * end(on entry) .... end ....... end(on exit) |
| * | | | |
| * | | | |
| * V +----V-----+ +-----V----+ +----------+ |
| * list ---> | next --+--> | next --+--> | next | |
| * | output[] | | output[] | | output[] | |
| * +----------+ +----------+ +----------+ |
| * [in use] [unused] |
| * |
| * These invariants should always hold: |
| * |
| * 1) If zs.state is NULL decompression is not in progress, list may be non-NULL |
| * but end could be anything; |
| * |
| * 2) Otherwise if zs.next_out is NULL list will be NULL and end will point at |
| * list, len, overflow and start will be 0; |
| * |
| * 3) Otherwise list is non-NULL and end points at the 'next' element of an |
| * in-use compression buffer. zs.next_out points into the 'output' element |
| * of the same buffer. {overflow, len} is the amount of compressed data, len |
| * being the low 31 bits, overflow being the higher bits. start is used for |
| * writing and is the index of the first byte in list->output to write, |
| * {overflow, len} does not include start. |
| */ |
| typedef struct |
| { |
| z_stream zs; /* zlib compression data */ |
| png_compression_bufferp list; /* Head of the buffer list */ |
| png_compression_bufferp *end; /* Pointer to last 'next' pointer */ |
| png_uint_32 len; /* Bottom 31 bits of data length */ |
| unsigned int overflow; /* Top bits of data length */ |
| unsigned int start; /* Start of data in first block */ |
| } png_zlib_compress, *png_zlib_compressp; |
| |
| /* png_zlib_compress methods */ |
| /* Initialize the compress structure. The z_stream itself is not initialized, |
| * however the the 'user' fields are set, including {next,avail}_{in,out}. The |
| * initialization does not change 'list', however it does set 'end' to point to |
| * it, effectively truncating the list. |
| */ |
| static void |
| png_zlib_compress_init(png_structrp png_ptr, png_zlib_compressp pz) |
| { |
| /* png_zlib_compress z_stream: */ |
| pz->zs.zalloc = png_zalloc; |
| pz->zs.zfree = png_zfree; |
| /* NOTE: this does not destroy 'restrict' because in all the functions herein |
| * *png_ptr is only ever accessed via *either* pz->zs.opaque *or* a passed in |
| * png_ptr. |
| */ |
| pz->zs.opaque = png_ptr; |
| |
| pz->zs.next_in = NULL; |
| pz->zs.avail_in = 0U; |
| pz->zs.total_in = 0U; |
| |
| pz->zs.next_out = NULL; |
| pz->zs.avail_out = 0U; |
| pz->zs.total_out = 0U; |
| |
| pz->zs.msg = PNGZ_MSG_CAST("zlib success"); /* safety */ |
| |
| /* pz->list preserved */ |
| pz->end = &pz->list; |
| pz->len = 0U; |
| pz->overflow = 0U; |
| pz->start = 0U; |
| } |
| |
| /* Return the png_ptr: this is defined here for all the remaining |
| * png_zlib_compress methods because they are only ever called with zs |
| * initialized. |
| */ |
| #define png_ptr png_voidcast(png_const_structrp, pz->zs.opaque) |
| |
| #if PNG_RELEASE_BUILD |
| # define png_zlib_compress_validate(pz, in_use) ((void)0) |
| #else /* !RELEASE_BUILD */ |
| static void |
| png_zlib_compress_validate(png_zlib_compressp pz, int in_use) |
| { |
| const uInt o_size = sizeof pz->list->output; |
| |
| affirm(pz->end != NULL && (in_use || (pz->zs.next_in == NULL && |
| pz->zs.avail_in == 0U && *pz->end == NULL))); |
| |
| if (pz->overflow == 0U && pz->len == 0U && pz->start == 0U) /* empty */ |
| { |
| affirm((pz->end == &pz->list && pz->zs.next_out == NULL |
| && pz->zs.avail_out == 0U) || |
| (pz->list != NULL && pz->end == &pz->list->next && |
| pz->zs.next_out == pz->list->output && |
| pz->zs.avail_out == o_size)); |
| } |
| |
| else /* not empty */ |
| { |
| png_compression_bufferp *ep = &pz->list, list; |
| png_uint_32 o, l; |
| |
| affirm(*ep != NULL && pz->zs.next_out != NULL); |
| |
| /* Check the list length: */ |
| o = pz->overflow; |
| l = pz->len; |
| affirm((l & 0x80000000U) == 0U && (o & 0x80000000U) == 0U); |
| |
| do |
| { |
| list = *ep; |
| l -= o_size; |
| if (l & 0x80000000U) --o, l &= 0x7FFFFFFFU; |
| ep = &list->next; |
| } |
| while (ep != pz->end); |
| |
| l += pz->start; |
| l += pz->zs.avail_out; |
| if (l & 0x80000000U) ++o, l &= 0x7FFFFFFFU; |
| |
| affirm(o == 0U && l == 0U && pz->zs.next_out >= list->output && |
| pz->zs.next_out + pz->zs.avail_out == list->output + o_size); |
| } |
| } |
| #endif /* !RELEASE_BUILD */ |
| |
| /* Destroy one zlib compress structure. */ |
| static void |
| png_zlib_compress_destroy(png_zlib_compressp pz, int check) |
| { |
| /* If the 'opaque' pointer is NULL this png_zlib_compress was never |
| * initialized, so do nothing. |
| */ |
| if (png_ptr != NULL) |
| { |
| if (pz->zs.state != NULL) |
| { |
| if (check) |
| png_zlib_compress_validate(pz, 0/*in_use*/); |
| |
| png_deflateEnd(png_ptr, &pz->zs, check); |
| } |
| |
| pz->end = &pz->list; /* safety */ |
| png_free_compression_buffer(png_ptr, &pz->list); |
| } |
| } |
| |
| /* Ensure that space is available for output, returns the amount of space |
| * available, 0 on OOM. This updates pz->zs.avail_out (etc) as required. |
| */ |
| static uInt |
| png_zlib_compress_avail_out(png_zlib_compressp pz) |
| { |
| uInt avail_out = pz->zs.avail_out; |
| |
| png_zlib_compress_validate(pz, 1/*in_use*/); |
| |
| if (avail_out == 0U) |
| { |
| png_compression_bufferp next; |
| |
| affirm(pz->end == &pz->list || (pz->end != NULL && pz->list != NULL)); |
| next = png_get_compression_buffer(png_ptr, pz->end); |
| |
| if (next != NULL) |
| { |
| pz->zs.next_out = next->output; |
| pz->zs.avail_out = avail_out = sizeof next->output; |
| pz->end = &next->next; |
| } |
| |
| /* else return 0: OOM */ |
| } |
| |
| else |
| affirm(pz->end != NULL && pz->list != NULL); |
| |
| return avail_out; |
| } |
| |
| /* Compress the given data given an initialized png_zlib_compress structure. |
| * This may be called multiple times, interleaved with writes as required. |
| * |
| * The input data is passed in in pz->zs.next_in, however the length of the data |
| * is in 'input_len' (to avoid the zlib uInt limit) and pz->zs.avail_in is |
| * overwritten (and left at 0). |
| * |
| * The output information is used and the amount of compressed data is added on |
| * to pz->{overflow,len}. |
| * |
| * If 'limit' is a limit on the amount of data to add to the output (not the |
| * total amount). The function will retun Z_BUF_ERROR if the limit is reached |
| * and the function will never produce more (additional) compressed data than |
| * the limit. |
| * |
| * All of zstream::next_in[input] is consumed if a success code is returned |
| * (Z_OK or Z_STREAM_END if flush is Z_FINISH), otherwise next_in may be used to |
| * determine how much was compressed. |
| * |
| * pz->overflow is not checked for overflow, so if 'limit' is not set overflow |
| * is possible. The caller must guard against this when supplying a limit of 0. |
| */ |
| static int |
| png_compress( |
| png_zlib_compressp pz, |
| png_alloc_size_t input_len, /* Length of data to be compressed */ |
| png_uint_32 limit, /* Limit on amount of compressed data made */ |
| int flush) /* Flush parameter at end of input */ |
| { |
| const int unlimited = (limit == 0U); |
| |
| /* Sanity checking: */ |
| affirm(pz->zs.state != NULL && |
| (pz->zs.next_out == NULL |
| ? pz->end == &pz->list && pz->len == 0U && pz->overflow == 0U |
| : pz->list != NULL && pz->end != NULL)); |
| implies(pz->zs.next_out == NULL, pz->zs.avail_out == 0); |
| |
| for (;;) |
| { |
| uInt extra; |
| |
| /* OUTPUT: make sure some space is available: */ |
| if (png_zlib_compress_avail_out(pz) == 0U) |
| return Z_MEM_ERROR; |
| |
| /* INPUT: limit the deflate call input to ZLIB_IO_MAX: */ |
| /* Adjust the input counters: */ |
| { |
| uInt avail_in = ZLIB_IO_MAX; |
| |
| if (avail_in > input_len) |
| avail_in = (uInt)/*SAFE*/input_len; |
| |
| input_len -= avail_in; |
| pz->zs.avail_in = avail_in; |
| } |
| |
| if (!unlimited && pz->zs.avail_out > limit) |
| { |
| extra = (uInt)/*SAFE*/(pz->zs.avail_out - limit); /* unused bytes */ |
| pz->zs.avail_out = (uInt)/*SAFE*/limit; |
| limit = 0U; |
| } |
| |
| else |
| { |
| extra = 0U; |
| limit -= pz->zs.avail_out; /* limit >= 0U */ |
| } |
| |
| pz->len += pz->zs.avail_out; /* maximum that can be produced */ |
| |
| /* Compress the data */ |
| { |
| int ret = deflate(&pz->zs, input_len > 0U ? Z_NO_FLUSH : flush); |
| |
| /* Claw back input data that was not consumed (because avail_in is |
| * reset above every time round the loop) and correct the output |
| * length. |
| */ |
| input_len += pz->zs.avail_in; |
| pz->zs.avail_in = 0; /* safety */ |
| pz->len -= pz->zs.avail_out; |
| |
| if (pz->len & 0x80000000U) |
| ++pz->overflow, pz->len &= 0x7FFFFFFFU; |
| |
| limit += pz->zs.avail_out; |
| pz->zs.avail_out += extra; |
| |
| /* Check the error code: */ |
| switch (ret) |
| { |
| case Z_OK: |
| if (pz->zs.avail_out > extra) |
| { |
| /* zlib had output space, so all the input should have been |
| * consumed: |
| */ |
| affirm(input_len == 0U /* else unexpected stop */ && |
| flush != Z_FINISH/* ret != Z_STREAM_END */); |
| return Z_OK; |
| } |
| |
| else |
| { |
| /* zlib ran out of output space, produce some more. If the |
| * limit is 0 at this point, however, no more space is |
| * available. |
| */ |
| if (unlimited || limit > 0U) |
| break; /* Allocate more output */ |
| |
| /* No more output space available, but the input may have all |
| * been consumed. |
| */ |
| if (input_len == 0U && flush != Z_FINISH) |
| return Z_OK; |
| |
| /* Input all consumed, but insufficient space to flush the |
| * output; this is the Z_BUF_ERROR case. |
| */ |
| return Z_BUF_ERROR; |
| } |
| |
| case Z_STREAM_END: |
| affirm(input_len == 0U && flush == Z_FINISH); |
| return Z_STREAM_END; |
| |
| case Z_BUF_ERROR: |
| /* This means that we are flushing all the output; expect |
| * avail_out and input_len to be 0. |
| * |
| * NOTE: if png_compress is called with input_len 0 and flush set |
| * to Z_NO_FLUSH this affirm will fire because zlib will have no |
| * work to do. |
| */ |
| affirm(input_len == 0U && pz->zs.avail_out == extra); |
| /* Allocate another buffer */ |
| break; |
| |
| default: |
| /* An error */ |
| return ret; |
| } |
| } |
| } |
| } |
| |
| #undef png_ptr /* remove definition using a png_zlib_compressp */ |
| |
| /* All the compression state is held here, it is allocated when required. This |
| * ensures that the read code doesn't carry the overhead of the much less |
| * frequently used write stuff. |
| * |
| * TODO: make png_create_write_struct allocate this stuff after the main |
| * png_struct. |
| */ |
| struct filter_selector; /* Used only for filter selection */ |
| |
| typedef struct png_zlib_state |
| { |
| png_zlib_compress s; /* Primary compression state */ |
| png_compression_bufferp stash; /* Unused compression buffers */ |
| |
| # define ps_png_ptr(ps) png_upcast(png_const_structrp, (ps)->s.zs.opaque) |
| /* A png_ptr, used below in functions that only have a png_zlib_state. |
| * NOTE: the png_zlib_compress must have been initialized! |
| */ |
| |
| png_uint_32 zlib_max_pixels; |
| /* Maximum number of pixels that zlib can handle at once; the lesser of |
| * the PNG maximum and the maximum that will fit in (uInt)-1 bytes. This |
| * number of pixels may not be byte aligned. |
| */ |
| png_uint_32 zlib_max_aligned_pixels; |
| /* The maximum number of pixels that zlib can handle while maintaining a |
| * buffer byte alignment of PNG_ROW_BUFFER_BYTE_ALIGN; <= the previous |
| * value. |
| */ |
| |
| png_alloc_size_t write_row_size; |
| /* Size of the PNG row (without the filter byte) in bytes or 0 if it is |
| * too large to be cached. |
| */ |
| |
| # ifdef PNG_WRITE_FILTER_SUPPORTED |
| /* During write libpng needs the previous row when writing a new row with |
| * up, avg or paeth and one or more image rows when performing filter |
| * selection. So if performing filter selection typically two or more |
| * rows are required while if no filter selection is to be done only the |
| * previous row pointer is required. |
| */ |
| png_bytep previous_write_row; /* Last row written, if any */ |
| # ifdef PNG_SELECT_FILTER_SUPPORTED |
| png_bytep current_write_row; /* Row being written */ |
| struct filter_selector *selector; /* Data for filter selection */ |
| png_uint_32 filter_select_window; |
| /* The number of bytes of uncompressed PNG data which are assumed to |
| * be relevant when doing filter selection. Limited to 8453377 |
| * (about 2^23); the maximum number of bytes that can be encoded in |
| * the largest deflate window. |
| */ |
| # define PNG_FILTER_SELECT_WINDOW_MAX 8453377U |
| png_byte filter_select_threshold; |
| /* If the number of distinct codes seen in the PNG data are below |
| * this threshold the PNG data will not be filtered (if the 'none' |
| * filter is allowed). If this is still true and a particular |
| * filter does not add new codes that filter will be used. |
| */ |
| png_byte filter_select_threshold2; |
| /* If the number of distinct codes that result by using a particular |
| * filter is below this second threshold that filter will be used. |
| * (When multiple filters pass this criterion the lowest numbered |
| * one producing the lowest number of new codes will be |
| * chosen.) |
| */ |
| # endif /* SELECT_FILTER */ |
| |
| unsigned int row_buffer_max_pixels; |
| /* The maximum number of pixels that can fit in PNG_ROW_BUFFER_SIZE |
| * bytes; not necessary a whole number of bytes. |
| */ |
| unsigned int row_buffer_max_aligned_pixels; |
| /* The maximum number of pixels that can fit in PNG_ROW_BUFFER_SIZE |
| * bytes while maintaining PNG_ROW_BUFFER_BYTE_ALIGN alignment. |
| */ |
| |
| unsigned int filter_mask :8; /* mask of filters to consider on NEXT row */ |
| # define PREVIOUS_ROW_FILTERS\ |
| (PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH) |
| unsigned int filters :8; /* Filters for current row */ |
| unsigned int save_row :2; /* As below: */ |
| # define SAVE_ROW_UNSET 0U |
| # define SAVE_ROW_OFF 1U /* Previous-row filters will be ignored */ |
| # define SAVE_ROW_DEFAULT 2U /* Default to save rows set by libpng */ |
| # define SAVE_ROW_ON 3U /* Force rows to be saved */ |
| # define SAVE_ROW(ps) ((ps)->save_row >= SAVE_ROW_DEFAULT) |
| # endif /* WRITE_FILTER */ |
| |
| /* Compression settings: see below for how these are encoded. */ |
| png_uint_32 pz_IDAT; /* Settings for the image */ |
| png_uint_32 pz_iCCP; /* Settings for iCCP chunks */ |
| png_uint_32 pz_text; /* Settings for text chunks */ |
| png_uint_32 pz_current; /* Last set settings */ |
| |
| # ifdef PNG_WRITE_FLUSH_SUPPORTED |
| png_uint_32 flush_dist; /* how many rows apart to flush, 0 - no flush */ |
| png_uint_32 flush_rows; /* number of rows written since last flush */ |
| # endif /* WRITE_FLUSH */ |
| } png_zlib_state; |
| |
| /* Create the zlib state: */ |
| static void |
| png_create_zlib_state(png_structrp png_ptr) |
| { |
| png_zlib_statep ps = png_voidcast(png_zlib_state*, |
| png_malloc(png_ptr, sizeof *ps)); |
| |
| /* Clear to NULL/0: */ |
| memset(ps, 0, sizeof *ps); |
| |
| debug(png_ptr->zlib_state == NULL); |
| png_ptr->zlib_state = ps; |
| png_zlib_compress_init(png_ptr, &ps->s); |
| |
| # ifdef PNG_WRITE_FILTER_SUPPORTED |
| ps->previous_write_row = NULL; |
| # ifdef PNG_SELECT_FILTER_SUPPORTED |
| ps->current_write_row = NULL; |
| ps->selector = NULL; |
| # endif /* SELECT_FILTER */ |
| # endif /* WRITE_FILTER */ |
| # ifdef PNG_WRITE_FLUSH_SUPPORTED |
| /* Set this to prevent flushing by making it larger than the number |
| * of rows in the largest interlaced PNG; PNG_UINT_31_MAX times |
| * (1/8+1/8+1/8+1/4+1/4+1/2+1/2); 1.875, or 15/8 |
| */ |
| ps->flush_dist = 0xEFFFFFFFU; |
| # endif /* WRITE_FLUSH */ |
| } |
| |
| static void |
| png_zlib_state_set_buffer_limits(png_const_structrp png_ptr, png_zlib_statep ps) |
| /* Delayed initialization of the zlib state maxima; this is not done above in |
| * case the zlib_state is created before the IHDR has been written, which |
| * would lead to the various png_struct fields used below being |
| * uninitialized. |
| */ |
| { |
| /* Initialization of the buffer size constants. */ |
| const unsigned int bpp = PNG_PIXEL_DEPTH(*png_ptr); |
| const unsigned int byte_pp = bpp >> 3; /* May be 0 */ |
| const unsigned int pixel_block = |
| /* Number of pixels required to maintain PNG_ROW_BUFFER_BYTE_ALIGN |
| * alignment. For multi-byte pixels use the first set bit to determine |
| * if the pixels have a greater alignment already. |
| */ |
| bpp < 8U ? |
| PNG_ROW_BUFFER_BYTE_ALIGN * (8U/bpp) : |
| PNG_ROW_BUFFER_BYTE_ALIGN <= (byte_pp & -byte_pp) ? |
| 1U : |
| PNG_ROW_BUFFER_BYTE_ALIGN / (byte_pp & -byte_pp); |
| |
| /* pixel_block must always be a power of two: */ |
| debug(bpp > 0 && pixel_block > 0 && |
| (pixel_block & -pixel_block) == pixel_block && |
| ((8U*PNG_ROW_BUFFER_BYTE_ALIGN-1U) & (pixel_block*bpp)) == 0U); |
| |
| /* Zlib maxima */ |
| { |
| png_uint_32 max = (uInt)-1; /* max bytes */ |
| |
| if (bpp <= 8U) |
| { |
| /* Maximum number of bytes PNG can generate in the lower bit depth |
| * cases: |
| */ |
| png_uint_32 png_max = |
| (0x7FFFFFFF + PNG_ADDOF(bpp)) >> PNG_SHIFTOF(bpp); |
| |
| if (png_max < max) |
| max = 0x7FFFFFFF; |
| } |
| |
| else /* bpp > 8U */ |
| { |
| max /= byte_pp; |
| if (max > 0x7FFFFFFF) |
| max = 0x7FFFFFFF; |
| } |
| |
| /* So this is the maximum number of pixels regardless of alignment: */ |
| ps->zlib_max_pixels = max; |
| |
| /* For byte alignment the value has to be a multiple of pixel_block and |
| * that is a power of 2, so: |
| */ |
| ps->zlib_max_aligned_pixels = max & ~(pixel_block-1U); |
| } |
| |
| # ifdef PNG_WRITE_FILTER_SUPPORTED |
| /* PNG_ROW_BUFFER maxima; this is easier because PNG_ROW_BUFFER_SIZE is |
| * limited so that the number of bits fits in any ANSI-C (unsigned int). |
| */ |
| { |
| const unsigned int max = (8U * PNG_ROW_BUFFER_SIZE) / bpp; |
| |
| ps->row_buffer_max_pixels = max; |
| ps->row_buffer_max_aligned_pixels = max & ~(pixel_block-1U); |
| } |
| # endif /* WRITE_FILTER */ |
| |
| /* NOTE: this will be 0 for very long rows on 32-bit or less systems */ |
| ps->write_row_size = png_write_row_buffer_size(png_ptr); |
| } |
| |
| static png_zlib_statep |
| get_zlib_state(png_structrp png_ptr) |
| { |
| if (png_ptr->zlib_state == NULL) |
| png_create_zlib_state(png_ptr); |
| |
| return png_ptr->zlib_state; |
| } |
| |
| /* Internal API to clean up all the deflate related stuff, including the buffer |
| * lists. |
| */ |
| static void /* PRIVATE */ |
| png_deflate_release(png_structrp png_ptr, png_zlib_statep ps, int check) |
| { |
| # ifdef PNG_WRITE_FILTER_SUPPORTED |
| /* Free any mode-specific data that is owned here: */ |
| if (ps->previous_write_row != NULL) |
| { |
| png_bytep p = ps->previous_write_row; |
| ps->previous_write_row = NULL; |
| png_free(png_ptr, p); |
| } |
| |
| # ifdef PNG_SELECT_FILTER_SUPPORTED |
| if (ps->current_write_row != NULL) |
| { |
| png_bytep p = ps->current_write_row; |
| ps->current_write_row = NULL; |
| png_free(png_ptr, p); |
| } |
| |
| if (ps->selector != NULL) |
| { |
| struct filter_selector *s = ps->selector; |
| ps->selector = NULL; |
| png_free(png_ptr, s); |
| } |
| # endif /* SELECT_FILTER */ |
| # endif /* WRITE_FILTER */ |
| |
| /* The main z_stream opaque pointer needs to remain set to png_ptr; it is |
| * only set once. |
| */ |
| png_zlib_compress_destroy(&ps->s, check); |
| png_free_compression_buffer(png_ptr, &ps->stash); |
| } |
| |
| void /* PRIVATE */ |
| png_deflate_destroy(png_structrp png_ptr) |
| { |
| png_zlib_statep ps = png_ptr->zlib_state; |
| |
| if (ps != NULL) |
| { |
| png_deflate_release(png_ptr, ps, 0/*check*/); |
| png_ptr->zlib_state = NULL; |
| png_free(png_ptr, ps); |
| } |
| } |
| |
| /* Compression settings. |
| * |
| * These are stored packed into a png_uint_32 to make comparison with the |
| * current setting quick. The packing method uses four bits for each setting |
| * and reserves '0' for unset. |
| * |
| * ps_<setting>_base: The lowest valid value (encoded as 1). |
| * ps_<setting>_max: The highest valid value. |
| * ps_<setting>_pos: The position in the range 0..3 (shift of 0..12). |
| * |
| * The low 16 bits are the zlib compression parameters: |
| */ |
| #define pz_level_base (-1) |
| #define pz_level_max 9 |
| #define pz_level_pos 0 |
| #define pz_windowBits_base 8 |
| #define pz_windowBits_max 15 |
| #define pz_windowBits_pos 1 |
| #define pz_memLevel_base 1 |
| #define pz_memLevel_max 9 |
| #define pz_memLevel_pos 2 |
| #define pz_strategy_base 0 |
| #define pz_strategy_max 4 |
| #define pz_strategy_pos 3 |
| #define pz_zlib_bits 0xFFFFU |
| /* Anything below this is not used directly by zlib: */ |
| #define pz_png_level_base 0 |
| #define pz_png_level_max 6 |
| #define pz_png_level_pos 4 |
| |
| #define pz_offset(name) (pz_ ## name ## _base - 1) |
| /* setting_value == pz_offset(setting)+encoded_value */ |
| #define pz_min(name) pz_ ## name ## _base |
| #define pz_max(name) pz_ ## name ## _max |
| #define pz_shift(name) (4 * pz_ ## name ## _pos) |
| |
| #define pz_bits(name,x) ((int)(((x)>>pz_shift(name))&0xF)) |
| /* the encoded value, or 0 if unset */ |
| |
| /* Enquiries: */ |
| #define pz_isset(name,x) (pz_bits(name,x) != 0) |
| #define pz_value(name,x) (pz_bits(name,x)+pz_offset(name)) |
| |
| /* Assignments: */ |
| #define pz_clear(name,x) ((x)&~((png_uint_32)0xFU<<pz_shift(name))) |
| #define pz_encode(name,v) ((png_uint_32)((v)-pz_offset(name))<<pz_shift(name)) |
| #define pz_change(name,x,v) (pz_clear(name,x) | pz_encode(name, v)) |
| |
| /* Direct use/modification: */ |
| #define pz_var(ps, type) ((ps)->pz_ ## type) |
| #define pz_get(ps, type, name, def)\ |
| (pz_isset(name, pz_var(ps, type)) ? pz_value(name, pz_var(ps, type)) : (def)) |
| /* pz_assign checks for out-of-range values and clears the setting if these are |
| * given. No warning or error is generated. |
| */ |
| #define pz_assign(ps, type, name, value)\ |
| (pz_var(ps, type) = pz_clear(name, pz_var(ps, type)) |\ |
| ((value) >= pz_min(name) && (value) <= pz_max(name) ?\ |
| pz_encode(name, value) : 0)) |
| |
| static png_int_32 |
| pz_compression_setting(png_structrp png_ptr, png_uint_32 owner, |
| int min, int max, int shift, png_int_32 value, int only_get, int unset) |
| /* This is a support function for png_write_setting below. */ |
| { |
| png_zlib_statep ps; |
| png_uint_32p psettings; |
| |
| /* The value is only required for a 'set', eliminate out-of-range values |
| * first: |
| */ |
| if (!only_get && (value < min || value > max)) |
| return PNG_EDOM; |
| |
| /* If setting a value make sure the state exists: */ |
| if (!only_get) |
| ps = get_zlib_state(png_ptr); |
| |
| else if (owner != 0U) /* ps may be NULL */ |
| ps = png_ptr->zlib_state; |
| |
| else /* get and owner is 0U */ |
| return 0; /* supported */ |
| |
| psettings = NULL; |
| switch (owner) |
| { |
| png_int_32 res; |
| |
| case png_IDAT: |
| if (ps != NULL) psettings = &ps->pz_IDAT; |
| break; |
| |
| case png_iCCP: |
| if (ps != NULL) psettings = &ps->pz_iCCP; |
| break; |
| |
| case 0U: |
| /* All the settings. At this point the 'get' case has returned 0 |
| * above, the value has been checked and the paramter is 0, therefore |
| * valid. Each of the following calls should succeed and it would be |
| * reasonable to eliminate the PNG_FAILED tests in a world where |
| * software engineers never made mistakes. |
| */ |
| res = pz_compression_setting(png_ptr, png_IDAT, min, max, shift, |
| value, 0/*set*/, 1/*iff unset*/); |
| |
| if (PNG_FAILED(res)) |
| return res; |
| |
| res = pz_compression_setting(png_ptr, png_iCCP, min, max, shift, |
| value, 0/*set*/, 1/*iff unset*/); |
| |
| if (PNG_FAILED(res)) |
| return res; |
| |
| /* The text settings are changed regardless of the customize support |
| * because if WRITE_CUSTOMIZE_ZTXT_COMPRESSION is not supported the old |
| * behavior was to use the WRITE_CUSTOMIZE_COMPRESSION setting. |
| * |
| * However, when we get png_zTXt directly (from png_write_setting) and |
| * the support is not compiled in return PNG_ENOSYS. |
| */ |
| unset = 1; /* i.e. only if not already set */ |
| |
| # ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED |
| case png_zTXt: |
| case png_iTXt: |
| # endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */ |
| if (ps != NULL) psettings = &ps->pz_text; |
| break; |
| |
| default: |
| /* Return PNG_ENOSYS, not PNG_EINVAL, to support future addition of new |
| * compressed chunks and the fact that zTXt and iTXt customization can |
| * be disabled. |
| */ |
| return PNG_ENOSYS; |
| } |
| |
| if (psettings == NULL) |
| return PNG_UNSET; /* valid setting that is not set */ |
| |
| { |
| png_uint_32 settings = *psettings; |
| png_uint_32 mask = 0xFU << shift; |
| |
| /* Do not set it if 'only_get' was passed in or if 'unset' is true and the |
| * setting is not currently set: |
| */ |
| if (!only_get && ((settings & mask) == 0U || !unset)) |
| *psettings = (settings & ~mask) + |
| ((png_uint_32)/*SAFE*/(value-min+1) << shift); |
| |
| settings &= mask; |
| |
| if (settings == 0U) |
| return PNG_UNSET; |
| |
| else |
| return (int)/*SAFE*/((settings >> shift)-1U) + min; |
| } |
| } |
| |
| #define compression_setting(pp, owner, setting, value, get)\ |
| pz_compression_setting(pp, owner, pz_min(setting), pz_max(setting),\ |
| pz_shift(setting), value, get, 0/*always*/) |
| |
| /* There is (as of zlib 1.2.8) a bug in the implementation of compression with a |
| * window size of 256 which zlib works round by resetting windowBits from 8 to 9 |
| * whenever deflateInit2 is called with that value. Fix this up here. |
| */ |
| static void |
| fix_cinfo(png_zlib_statep ps, png_bytep data, png_alloc_size_t data_size) |
| { |
| /* Do this if the CINFO field is '1', meaning windowBits of 9. The first |
| * byte of the stream is the CMF value, CINFO is in the upper four bits. |
| * |
| * If zlib didn't futz with the value then it should match the value in |
| * pz_current; check this is debug. (See below for why this works in the |
| * pz_default_settings call.) |
| */ |
| # define png_ptr png_voidcast(png_const_structrp, ps->s.zs.opaque) |
| if (data[0] == 0x18U && |
| pz_get(ps, current, windowBits, 0) == 8 /* i.e. it was requested */) |
| { |
| /* Double check this here; the fixup only works if the data was 256 bytes |
| * or shorter *or* the window is never used. For safety repeat the checks |
| * done in pz_default_settings; technically we should be able to just skip |
| * this test. |
| * |
| * TODO: set a 'fixup' flag in zlib_state to make this quicker? |
| */ |
| if (data_size <= 256U || |
| pz_get(ps, current, strategy, Z_RLE) == Z_HUFFMAN_ONLY || |
| pz_get(ps, current, level, 1) == Z_NO_COMPRESSION) |
| { |
| unsigned int d1; |
| |
| data[0] = 0x08U; |
| /* The header checksum must be fixed too. The FCHECK (low 5 bits) make |
| * CMF.FLG a multiple of 31: |
| */ |
| d1 = data[1] & 0xE0U; /* top three bits */ |
| d1 += 31U - (0x0800U + d1) % 31U; |
| data[1] = PNG_BYTE(d1); |
| } |
| |
| else /* pz_default_settings is expected to guarantee the above */ |
| NOT_REACHED; |
| } |
| |
| else if (data_size > 0U) |
| { |
| /* Prior to 1.7.0 libpng would shrink the windowBits even if the |
| * application requested a particular value, so: |
| */ |
| unsigned int z_cinfo = data[0] >> 4; |
| unsigned int half_z_window_size = 1U << (z_cinfo + 7); |
| |
| if (data_size <= half_z_window_size && z_cinfo > 0) |
| { |
| unsigned int tmp; |
| |
| do |
| { |
| half_z_window_size >>= 1; |
| --z_cinfo; |
| } |
| while (z_cinfo > 0 && data_size <= half_z_window_size); |
| |
| data[0] = PNG_BYTE((z_cinfo << 4) + 0x8U); |
| tmp = data[1] & 0xE0U; /* top three bits */ |
| tmp += 31U - ((data[0] << 8) + tmp) % 31U; |
| data[1] = PNG_BYTE(tmp); |
| } |
| } |
| |
| else |
| NOT_REACHED; /* invalid data size (0) */ |
| # undef png_ptr |
| } |
| |
| static png_uint_32 |
| pz_default_settings(png_uint_32 settings, const png_uint_32 owner, |
| const png_alloc_size_t data_size, const unsigned int filters/*for IDAT*/) |
| { |
| int png_level, strategy, zlib_level, windowBits; |
| |
| /* The png 'level' parameter controls the defaults below. It uses the same |
| * numbering scheme as the Zlib compression level except that -1 invokes the |
| * set of options and, in some cases, libpng behavior of libpng 1.6 and |
| * earlier. |
| * |
| * In the comments below reference is made to the differences beteen the |
| * legacy compression sizes from libpng 1.6 and earlier and the result of |
| * using the various options. These are quoted as an overall size change in |
| * the compression of 147323 PNG test files. The set of test files is |
| * slightly restricted because pre-1.7 versions of png_read_png leave random |
| * bits into the final byte of a row which ends with a partial byte. This |
| * affects the compression unpredictably so such files were omitted from the |
| * measurements. |
| */ |
| if (!pz_isset(png_level, settings)) |
| { |
| png_level = PNG_DEFAULT_COMPRESSION_LEVEL; |
| settings |= pz_encode(png_level, png_level); |
| } |
| |
| else |
| png_level = pz_value(png_level, settings); |
| |
| /* First default the strategy. At lower data sizes other strategies do as |
| * well as the zlib default compression strategy but they never seem to |
| * improve on it with the 1.7 filtering. |
| */ |
| if (!pz_isset(strategy, settings)) |
| { |
| switch (png_level) |
| { |
| case PNG_COMPRESSION_COMPAT: /* Legacy setting */ |
| /* The pre-1.7 code used Z_FILTERED normally but uses |
| * Z_DEFAULT_STRATEGY for palette or low-bit-depth images. |
| * |
| * In fact Z_DEFAULT_STRATEGY works best for filtered images as |
| * well, however the change in results is small: |
| * |
| * Z_DEFAULT_STRATEGY: -0.1% |
| * Z_FILTERED: +0.1% |
| * |
| * NOTE: this happened even if WRITE_FILTER was *not* supported. |
| */ |
| if (owner != png_IDAT || filters == PNG_FILTER_NONE) |
| strategy = Z_DEFAULT_STRATEGY; |
| |
| else |
| strategy = Z_FILTERED; |
| break; |
| |
| case PNG_COMPRESSION_HIGH_SPEED: |
| /* RLE is as fast as HUFFMAN_ONLY and can reduce size a lot in a few |
| * cases. |
| */ |
| strategy = Z_RLE; |
| break; |
| |
| default: /* For GCC */ |
| case PNG_COMPRESSION_LOW: |
| case PNG_COMPRESSION_MEDIUM: |
| /* Z_FILTERED is almost as good as the default and can be |
| * significantly faster. It biases the algorithm towards smaller |
| * byte values. |
| * |
| * Using Z_DEFAULT_STRATEGY here, rather than Z_FILTERED, benefits |
| * smaller 8 and 16-bit gray and larger 8 and 16-bit RGB images, |
| * however the overall gain is only 0.1% because it is offset by |
| * losses in larger 8-bit gray and alpha images. It is extremely |
| * difficult to deduce a pattern other than biases in the test set |
| * of images. |
| * |
| * Looking at the pattern of behavior with the 1.6 filter selection |
| * algorithm (none of palette or low-bit-depth, else all) produces |
| * results as follows: |
| */ |
| if (owner == png_IDAT) |
| { |
| if (filters == PNG_FILTER_NONE) |
| strategy = Z_DEFAULT_STRATEGY; |
| |
| else |
| strategy = Z_FILTERED; |
| } |
| |
| else if (owner == png_iCCP) |
| strategy = Z_DEFAULT_STRATEGY; |
| |
| /* TODO: investigate this, the observed behavior is suspicious: */ |
| else /* text chunk */ |
| strategy = Z_FILTERED; /* Always better for some reason */ |
| break; |
| |
| case PNG_COMPRESSION_LOW_MEMORY: |
| /* Reduce memory at all costs, speed doesn't matter. */ |
| case PNG_COMPRESSION_HIGH_READ_SPEED: |
| case PNG_COMPRESSION_HIGH: |
| if (owner == png_IDAT || owner == png_iCCP) |
| strategy = Z_DEFAULT_STRATEGY; |
| |
| else |
| strategy = Z_FILTERED; |
| break; |
| } |
| |
| settings |= pz_encode(strategy, strategy); |
| } |
| |
| else |
| strategy = pz_value(strategy, settings); |
| |
| /* Next the zlib level; this just defaults to the png level, except that for |
| * Huffman or RLE encoding the level setting for Zlib doesn't matter. |
| */ |
| if (!pz_isset(level, settings)) |
| { |
| switch (strategy) |
| { |
| case Z_HUFFMAN_ONLY: |
| case Z_RLE: |
| /* The 'level' doesn't make any significant difference to the |
| * compression with these strategies; in a test set of about 3GByte |
| * of PNG files the total compressed size changed under 20 bytes |
| * with libpng 1.6! |
| */ |
| zlib_level = 1; |
| break; |
| |
| default: /* Z_FIXED, Z_FILTERED, Z_DEFAULT_STRATEGY */ |
| /* Everything that uses the window seems to show rapidly diminishing |
| * returns above level 6 (at least with libpng 1.6). |
| * Z_DEFAULT_COMPRESSION is, in fact, level 6 so Mark seems to |
| * concur. With libpng 1.6 the following results were obtained |
| * using the full test set of files (including those with a partial |
| * byte at the end of the row) and just varying the zlib level: |
| * |
| * LEVEL SIZE(bytes) CHANGE TIME(s) CHANGE METRIC |
| * 9 2550246600 -1.19% 1972 +227% -77% |
| * 8 2556675866 -0.94% 1215 +101% -59% |
| * 7 2572685552 -0.32% 679 +12% -15% |
| * 6 2581196708 0% 604 0% 0% |
| * 5 2602831249 +0.84% 414 -30% +87% |
| * 4 2625206800 +1.71% 358 -40% +153% |
| * 3 2674752349 +3.62% 298 -50% +303% |
| * 2 2716261483 +5.23% 262 -56% +537% |
| * 1 2749875805 +6.53% 251 -57% +662% |
| * 0 7174488347 202 -66% |
| * |
| * The CHANGE columns express the change in compressed size |
| * (positive is an increase; a decrease in compression) and time |
| * (positive is an increase; an increase in time) relative to level |
| * 6. The METRIC column is a measure of the compression-per-second |
| * relative to level 6; positive is an increase in |
| * compression-per-second. |
| * |
| * The metric is derived by assuming the difference in time between |
| * level 0 (which does no compression) and the level being |
| * considered is spent doing the compression. (Reasonable, since |
| * only the level changed). Just the inverse of the product of the |
| * size and the time difference is a measure of compression per |
| * second. It can be seen that time dominates the metric; |
| * compression only varies slightly (under 8%) across the level |
| * range. |
| */ |
| switch (png_level) |
| { |
| case PNG_COMPRESSION_COMPAT: |
| zlib_level = Z_DEFAULT_COMPRESSION; /* NOTE: -1 */ |
| break; |
| |
| case PNG_COMPRESSION_HIGH_SPEED: |
| zlib_level = 1; |
| break; |
| |
| default: /* For GCC */ |
| case PNG_COMPRESSION_LOW: |
| zlib_level = 3; |
| break; |
| |
| case PNG_COMPRESSION_MEDIUM: |
| zlib_level = 6; /* Old default! */ |
| break; |
| |
| case PNG_COMPRESSION_LOW_MEMORY: |
| case PNG_COMPRESSION_HIGH_READ_SPEED: |
| case PNG_COMPRESSION_HIGH: |
| zlib_level = 9; |
| break; |
| } |
| break; |
| } |
| |
| settings |= pz_encode(level, zlib_level); |
| } |
| |
| else |
| zlib_level = pz_value(level, settings); |
| |
| /* Now default windowBits. This is probably the most important of the |
| * settings because it is pretty much the only one that affects decode |
| * performance. The smaller the better: |
| */ |
| if (!pz_isset(windowBits, settings)) |
| { |
| if (png_level == PNG_COMPRESSION_COMPAT/* Legacy */) |
| { |
| /* This is the libpng16 calculation (it is wrong; a misunderstanding of |
| * what zlib actually requires!) |
| * |
| * Using the code below with the legacy choice of Z_FILTERED or |
| * Z_DEFAULT_STRATEGY increases the size of the test files by only |
| * 0.04%, however the settings below considerably reduce the windowBits |
| * used potentially benefitting read code a lot. |
| * |
| * NOTE: the algorithm below was determined by experiment and |
| * observation with the same set of test files; there is some |
| * considerable possibility that a different set might show different |
| * results. Obtaining large, representative, test sets is both a |
| * considerable amount of work and very error prone. [JB 20160518] |
| */ |
| windowBits = 15; |
| |
| if (data_size <= 16384U) |
| { |
| unsigned int half_window_size = 1U << (windowBits-1); |
| |
| while (data_size + 262U <= half_window_size) |
| { |
| half_window_size >>= 1; |
| --windowBits; |
| } |
| } |
| } |
| |
| /* The window size affects the memory used on both read and write but also |
| * the time on write (but not normally read). Handle the low memory |
| * requirement first: |
| */ |
| else if (zlib_level == Z_NO_COMPRESSION || |
| png_level == PNG_COMPRESSION_LOW_MEMORY) |
| windowBits = 8; |
| |
| /* If the strategy has been set to something that doesn't benefit from |
| * higher windowBits values take advantage of this. Note that pz_value |
| * returns an invalid value if pz_isset is false. |
| * |
| * The only png_level that affects this decision is HIGH_SPEED, because |
| * a smaller windowBits should speed up the search, however the code above |
| * chose zlib_level based on this so ignore that consideration and just |
| * use zlib_level below. |
| */ |
| else switch (strategy) |
| { |
| png_alloc_size_t test_size; |
| |
| case Z_HUFFMAN_ONLY: |
| /* Use the minimum; the window doesn't get used */ |
| windowBits = 8; |
| break; |
| |
| case Z_RLE: |
| /* The longest length code is 258 bytes, the shortest string that |
| * can achieve this is 259 bytes long; 259 copies of the same byte |
| * which can be encoded as a code for the byte value then a string |
| * of length 258 starting at the first byte. So if the data is |
| * longer than 256 bytes use '9' for the windowBits, otherwise use |
| * 8: |
| */ |
| if (data_size <= 256U) |
| windowBits = 8; |
| |
| else |
| windowBits = 9; |
| break; |
| |
| /* By experiment using about 150,000 files the optimal windowBits |
| * value across a range of files is somewhat less than implied by |
| * the data size and depends on the zlib level and the strategy |
| * used, the following values were determined by experiment using |
| * those files: |
| */ |
| case Z_FILTERED: |
| /* The Z_FILTERED case changes suddenly at (zlib) level 4 to |
| * benefit from looking at all the data: |
| */ |
| if (zlib_level < 4 && zlib_level != Z_DEFAULT_COMPRESSION/*-1: 6*/) |
| test_size = data_size / 8U; |
| |
| else |
| test_size = data_size; |
| |
| goto check_test_size; |
| |
| case Z_FIXED: |
| /* With the fixed Huffman tables better compression only ever comes |
| * from looking for matches, so, logically: |
| */ |
| test_size = data_size; |
| goto check_test_size; |
| |
| default: |
| /* The default algorithm always does better with a window smaller |
| * than all the data and shows jumps at level 4 and level 8. The |
| * net effect with the test set of images is a very minor overall |
| * improvement compared to the pre-1.7 calculation (data size + |
| * 262). The benefit is less than 0.01%, however smaller window |
| * sizes reduce the memory zlib has to allocate in the decoder. |
| */ |
| switch (zlib_level) |
| { |
| case 1: case 2: case 3: |
| test_size = data_size / 8U; |
| break; |
| |
| default: /* -1(Z_DEFAULT_COMPRESSION) == 6, 4..7 */ |
| /* This includes, implicitly, ZLIB_NO_COMPRESSION, but that |
| * was eliminated in the 'if' above. |
| */ |
| test_size = data_size / 4U; |
| break; |
| |
| case 8: case 9: |
| test_size = data_size / 3U; |
| break; |
| } |
| |
| goto check_test_size; |
| |
| check_test_size: |
| /* Find the smallest window that covers 'test_size' bytes, subject |
| * to the constraint that if the actual data size is more than 256 |
| * bytes the minimum windowBits that can be supported is 9: |
| */ |
| if (data_size <= 256U) |
| windowBits = 8; |
| |
| else |
| windowBits = 9; |
| |
| while (windowBits < 15 && (1U << windowBits) < test_size) |
| ++windowBits; |
| |
| break; |
| } |
| |
| settings |= pz_encode(windowBits, windowBits); |
| } |
| |
| else |
| windowBits = pz_value(windowBits, settings); |
| |
| /* zlib has a problem with 256 byte windows; 512 is used instead. |
| * We can't work round this if the data size is more than 256 bytes and |
| * the strategy actually uses the window (everything except huffman-only) |
| * so fix the problem here. |
| */ |
| if (windowBits == 8 && data_size > 256U && strategy != Z_HUFFMAN_ONLY && |
| zlib_level != Z_NO_COMPRESSION) |
| settings = pz_change(windowBits, settings, 9); |
| |
| /* For memLevel this just increases the memory used but can help with the |
| * Huffman code generation even to level 9 (the maximum), so just set the |
| * max. This affects memory used, not (apparently) compression speed so |
| * the only relevant png_level is LOW_MEMORY. |
| * |
| * The legacy setting is '8'; this is the level that Zlib defaults to because |
| * 16-bit iAPX86 systems could not handle '9'. Because MAX_MEM_LEVEL is used |
| * below this does not matter; zconf.h selects 8 or 9 as appropriate. |
| * |
| * In fact using '9' with the legacy settings increases the size of the test |
| * set minutely; +0.007%. This is hardly significant; 0.007% of the test |
| * images equals 10 images. (Nevertheless it is interesting, just as the |
| * observation that decreasing windowBits can result in smaller compressed |
| * sizes is interesting.) |
| */ |
| if (!pz_isset(memLevel, settings)) |
| { |
| int memLevel; |
| |
| switch (png_level) |
| { |
| case PNG_COMPRESSION_COMPAT: |
| memLevel = 8; |
| break; |
| |
| case PNG_COMPRESSION_LOW_MEMORY: |
| memLevel = 1; |
| break; |
| |
| default: |
| memLevel = MAX_MEM_LEVEL/*from zconf.h*/; |
| break; |
| } |
| |
| settings |= pz_encode(memLevel, memLevel); |
| } |
| |
| return settings; |
| } |
| |
| /* This is used below to find the size of an image to pass to png_deflate_claim. |
| * It returns 0 for images whose size would overflow a 32-bit integer or have |
| * rows which cannot be allocated. |
| */ |
| static png_alloc_size_t |
| png_image_size(png_const_structrp png_ptr) |
| { |
| /* The size returned here is limited to PNG_SIZE_MAX, if the size would |
| * exceed that (or is close to exceeding that) 0 is returned. See below for |
| * a variant that limits the size of 0xFFFFFFFFU. |
| */ |
| const png_alloc_size_t rowbytes = png_ptr->zlib_state->write_row_size; |
| |
| /* NON-INTERLACED: (1+rowbytes) * h |
| * INTERLACED: Each pixel is transmitted exactly once, so the size is |
| * (rowbytes * h) + the count of filter bytes. Each complete |
| * block of 8 image rows generates at most 15 output rows |
| * (less for narrow images), so the filter byte count is |
| * at most (15*h/8)+14. Because the original rows are split |
| * extra byte passing may be introduced. Account for this by |
| * allowing an extra 1 byte per output row; that's two bytes |
| * including the filer byte. |
| * |
| * So: |
| * NON-INTERLACED: (rowbytes * h) + h |
| * INTERLACED: < (rowbytes * h) + 2*(15 * h/8) + 2*15 |
| * |
| * Hence: |
| */ |
| if (rowbytes != 0) |
| { |
| const png_uint_32 h = png_ptr->height; |
| |
| if (png_ptr->interlaced == PNG_INTERLACE_NONE) |
| { |
| const png_alloc_size_t limit = PNG_SIZE_MAX / h; |
| |
| /* On 16-bit systems the above might be 0, so: */ |
| if (rowbytes </*allow 1 for filter byte*/ limit) |
| return (rowbytes+1U) * h; |
| } |
| |
| else /* INTERLACED */ |
| { |
| const png_uint_32 w = png_ptr->width; |
| |
| /* Interlacing makes the image larger because of the replication of |
| * both the filter byte and the padding to a byte boundary. |
| */ |
| png_alloc_size_t cb_base; |
| int pass; |
| |
| for (cb_base=0, pass=0; pass<PNG_INTERLACE_ADAM7_PASSES; ++pass) |
| { |
| const png_uint_32 pass_w = PNG_PASS_COLS(w, pass); |
| |
| if (pass_w > 0) |
| { |
| const png_uint_32 pass_h = PNG_PASS_ROWS(h, pass); |
| |
| if (pass_h > 0) |
| { |
| /* This is the number of bytes available for each row of this |
| * pass: |
| */ |
| const png_alloc_size_t limit = (PNG_SIZE_MAX - cb_base)/pass_h; |
| /* This cannot overflow because if it did rowbytes would |
| * have been 0 above. |
| */ |
| const png_alloc_size_t pass_bytes = |
| PNG_ROWBYTES(png_ptr->row_output_pixel_depth, pass_w); |
| |
| if (pass_bytes </*allow 1 for filter byte*/ limit) |
| cb_base += (pass_bytes+1U) * pass_h; |
| |
| else |
| return 0U; /* insufficient address space left */ |
| } |
| } |
| } |
| |
| return cb_base; |
| } |
| } |
| |
| /* Failure case: */ |
| return 0U; |
| } |
| |
| /* Initialize the compressor for the appropriate type of compression. */ |
| static png_zlib_statep |
| png_deflate_claim(png_structrp png_ptr, png_uint_32 owner, |
| png_alloc_size_t data_size) |
| { |
| png_zlib_statep ps = get_zlib_state(png_ptr); |
| |
| affirm(png_ptr->zowner == 0); |
| |
| { |
| int ret; /* zlib return code */ |
| unsigned int filters = 0U; |
| png_uint_32 settings; |
| |
| switch (owner) |
| { |
| case png_IDAT: |
| debug(data_size == 0U); |
| data_size = png_image_size(png_ptr); |
| |
| if (data_size == 0U) |
| data_size = PNG_SIZE_MAX; |
| |
| settings = ps->pz_IDAT; |
| # ifdef PNG_WRITE_FILTER_SUPPORTED |
| filters = ps->filter_mask; |
| debug(filters != 0U); |
| # else /* !WRITE_FILTER */ |
| filters = PNG_FILTER_NONE; |
| # endif /* !WRITE_FILTER */ |
| break; |
| |
| case png_iCCP: |
| settings = ps->pz_iCCP; |
| break; |
| |
| default: /* text chunk */ |
| settings = ps->pz_text; |
| break; |
| } |
| |
| settings = pz_default_settings(settings, owner, data_size, filters); |
| |
| /* Check against the previous initialized values, if any. The relevant |
| * settings are in the low 16 bits. |
| */ |
| if (ps->s.zs.state != NULL && |
| ((settings ^ ps->pz_current) & pz_zlib_bits) != 0U) |
| png_deflateEnd(png_ptr, &ps->s.zs, 0/*check*/); |
| |
| /* For safety clear out the input and output pointers (currently zlib |
| * doesn't use them on Init, but it might in the future). |
| */ |
| ps->s.zs.next_in = NULL; |
| ps->s.zs.avail_in = 0; |
| ps->s.zs.next_out = NULL; |
| ps->s.zs.avail_out = 0; |
| |
| /* The length fields must be cleared too and the lists reset: */ |
| ps->s.overflow = ps->s.len = ps->s.start = 0U; |
| |
| if (ps->s.list != NULL) /* error in prior chunk writing */ |
| { |
| debug(ps->stash == NULL); |
| ps->stash = ps->s.list; |
| ps->s.list = NULL; |
| } |
| |
| ps->s.end = &ps->s.list; |
| |
| /* Now initialize if required, setting the new parameters, otherwise just |
| * do a simple reset to the previous parameters. |
| */ |
| if (ps->s.zs.state != NULL) |
| ret = deflateReset(&ps->s.zs); |
| |
| else |
| ret = deflateInit2(&ps->s.zs, pz_value(level, settings), Z_DEFLATED, |
| pz_value(windowBits, settings), pz_value(memLevel, settings), |
| pz_value(strategy, settings)); |
| |
| ps->pz_current = settings; |
| |
| /* The return code is from either deflateReset or deflateInit2; they have |
| * pretty much the same set of error codes. |
| */ |
| if (ret == Z_OK && ps->s.zs.state != NULL) |
| png_ptr->zowner = owner; |
| |
| else |
| { |
| png_zstream_error(&ps->s.zs, ret); |
| png_error(png_ptr, ps->s.zs.msg); |
| } |
| } |
| |
| return ps; |
| } |
| |
| #ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED /* includes iCCP */ |
| /* Compress the block of data at the end of a chunk. This claims and releases |
| * png_struct::z_stream. It returns the amount of data in the chunk list or |
| * zero on error (a zlib stream always contains some bytes!) |
| * |
| * prefix_len is the amount of (uncompressed) data before the start of the |
| * compressed data. The routine will return 0 if the total of the compressed |
| * data and the prefix exceeds PNG_UINT_MAX_31. |
| * |
| * NOTE: this function may not return; it only returns 0 if |
| * png_chunk_report(PNG_CHUNK_WRITE_ERROR) returns (not the default). |
| */ |
| static int /* success */ |
| png_compress_chunk_data(png_structrp png_ptr, png_uint_32 chunk_name, |
| png_uint_32 prefix_len, png_const_voidp input, png_alloc_size_t input_len) |
| { |
| /* To find the length of the output it is necessary to first compress the |
| * input. The result is buffered rather than using the two-pass algorithm |
| * that is used on the inflate side; deflate is assumed to be slower and a |
| * PNG writer is assumed to have more memory available than a PNG reader. |
| * |
| * IMPLEMENTATION NOTE: the zlib API deflateBound() can be used to find an |
| * upper limit on the output size, but it is always bigger than the input |
| * size so it is likely to be more efficient to use this linked-list |
| * approach. |
| */ |
| png_zlib_statep ps = png_deflate_claim(png_ptr, chunk_name, input_len); |
| |
| affirm(ps != NULL); |
| |
| /* The data compression function always returns so that we can clean up. */ |
| ps->s.zs.next_in = PNGZ_INPUT_CAST(png_voidcast(const Bytef*, input)); |
| |
| /* Use the stash, if available: */ |
| debug(ps->s.list == NULL); |
| ps->s.list = ps->stash; |
| ps->stash = NULL; |
| |
| { |
| int ret = png_compress(&ps->s, input_len, PNG_UINT_31_MAX-prefix_len, |
| Z_FINISH); |
| |
| ps->s.zs.next_out = NULL; /* safety */ |
| ps->s.zs.avail_out = 0; |
| ps->s.zs.next_in = NULL; |
| ps->s.zs.avail_in = 0; |
| png_ptr->zowner = 0; /* release png_ptr::zstream */ |
| |
| /* Since Z_FINISH was passed as the flush parameter any result other than |
| * Z_STREAM_END is an error. In any case in the event of an error free |
| * the whole compression state; the only expected error is Z_MEM_ERROR. |
| */ |
| if (ret != Z_STREAM_END) |
| { |
| png_zlib_compress_destroy(&ps->s, 0/*check*/); |
| |
| /* This is not very likely given the PNG_UINT_31_MAX limit above, but |
| * if code is added to limit the size of the chunks produced it can |
| * start to happen. |
| */ |
| if (ret == Z_BUF_ERROR) |
| ps->s.zs.msg = PNGZ_MSG_CAST("compressed chunk too long"); |
| |
| else |
| png_zstream_error(&ps->s.zs, ret); |
| |
| png_chunk_report(png_ptr, ps->s.zs.msg, PNG_CHUNK_WRITE_ERROR); |
| return 0; |
| } |
| } |
| |
| /* png_compress is meant to guarantee this on a successful return: */ |
| affirm(ps->s.overflow == 0U && ps->s.len <= PNG_UINT_31_MAX - prefix_len); |
| |
| /* Correct the zlib CINFO field: */ |
| if (ps->s.len >= 2U) |
| fix_cinfo(ps, ps->s.list->output, input_len); |
| |
| return 1; |
| } |
| |
| /* Return the length of the compressed data; this is effectively a debug |
| * function to catch inconsistencies caused by internal errors. It will |
| * disappear in a release build. |
| */ |
| #if PNG_RELEASE_BUILD |
| # define png_length_compressed_chunk_data(pp, p) ((pp)->zlib_state->s.len) |
| #else /* !RELEASE_BUILD */ |
| static png_uint_32 |
| png_length_compressed_chunk_data(png_structrp png_ptr, png_uint_32 p) |
| { |
| png_zlib_statep ps = png_ptr->zlib_state; |
| |
| debug(ps != NULL && ps->s.overflow == 0U && ps->s.len <= PNG_UINT_31_MAX-p); |
| return ps->s.len; |
| } |
| #endif /* !RELEASE_BUILD */ |
| |
| /* Write all the data produced by the above function; the caller must write the |
| * prefix and chunk header. |
| */ |
| static void |
| png_write_compressed_chunk_data(png_structrp png_ptr) |
| { |
| png_zlib_statep ps = png_ptr->zlib_state; |
| png_compression_bufferp next; |
| png_uint_32 output_len; |
| |
| affirm(ps != NULL && ps->s.overflow == 0U); |
| next = ps->s.list; |
| |
| for (output_len = ps->s.len; output_len > 0U; next = next->next) |
| { |
| png_uint_32 size = PNG_ROW_BUFFER_SIZE; |
| |
| /* If this affirm fails there is a bug in the calculation of |
| * output_length above, or in the buffer_limit code in png_compress. |
| */ |
| affirm(next != NULL && output_len > 0U); |
| |
| if (size > output_len) |
| size = output_len; |
| |
| png_write_chunk_data(png_ptr, next->output, size); |
| |
| output_len -= size; |
| } |
| |
| /* Release the list back to the stash. */ |
| debug(ps->stash == NULL); |
| ps->stash = ps->s.list; |
| ps->s.list = NULL; |
| ps->s.end = &ps->s.list; |
| } |
| #endif /* WRITE_COMPRESSED_TEXT */ |
| |
| #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \ |
| defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED) |
| /* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification, |
| * and if invalid, correct the keyword rather than discarding the entire |
| * chunk. The PNG 1.0 specification requires keywords 1-79 characters in |
| * length, forbids leading or trailing whitespace, multiple internal spaces, |
| * and the non-break space (0x80) from ISO 8859-1. Returns keyword length. |
| * |
| * The 'new_key' buffer must be at least 80 characters in size (for the keyword |
| * plus a trailing '\0'). If this routine returns 0 then there was no keyword, |
| * or a valid one could not be generated, and the caller must CHUNK_WRITE_ERROR. |
| */ |
| static unsigned int |
| png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key) |
| { |
| png_const_charp orig_key = key; |
| unsigned int key_len = 0; |
| int bad_character = 0; |
| int space = 1; |
| |
| png_debug(1, "in png_check_keyword"); |
| |
| if (key == NULL) |
| { |
| *new_key = 0; |
| return 0; |
| } |
| |
| while (*key && key_len < 79) |
| { |
| png_byte ch = (png_byte)(0xff & *key++); |
| |
| if ((ch > 32 && ch <= 126) || (ch >= 161 /*&& ch <= 255*/)) |
| *new_key++ = ch, ++key_len, space = 0; |
| |
| else if (space == 0) |
| { |
| /* A space or an invalid character when one wasn't seen immediately |
| * before; output just a space. |
| */ |
| *new_key++ = 32, ++key_len, space = 1; |
| |
| /* If the character was not a space then it is invalid. */ |
| if (ch != 32) |
| bad_character = ch; |
| } |
| |
| else if (bad_character == 0) |
| bad_character = ch; /* just skip it, record the first error */ |
| } |
| |
| if (key_len > 0 && space != 0) /* trailing space */ |
| { |
| --key_len, --new_key; |
| if (bad_character == 0) |
| bad_character = 32; |
| } |
| |
| /* Terminate the keyword */ |
| *new_key = 0; |
| |
| if (key_len == 0) |
| return 0; |
| |
| #ifdef PNG_WARNINGS_SUPPORTED |
| /* Try to only output one warning per keyword: */ |
| if (*key != 0) /* keyword too long */ |
| png_app_warning(png_ptr, "keyword truncated"); |
| |
| else if (bad_character != 0) |
| { |
| PNG_WARNING_PARAMETERS(p) |
| |
| png_warning_parameter(p, 1, orig_key); |
| png_warning_parameter_signed(p, 2, PNG_NUMBER_FORMAT_02x, bad_character); |
| |
| png_formatted_warning(png_ptr, p, "keyword \"@1\": bad character '0x@2'"); |
| } |
| #endif /* WARNINGS */ |
| |
| return key_len; |
| } |
| #endif /* WRITE_TEXT || WRITE_pCAL || WRITE_iCCP || WRITE_sPLT */ |
| |
| /* Write the IHDR chunk, and update the png_struct with the necessary |
| * information. Note that the rest of this code depends upon this |
| * information being correct. |
| */ |
| void /* PRIVATE */ |
| png_write_IHDR(png_structrp png_ptr, png_uint_32 width, png_uint_32 height, |
| int bit_depth, int color_type, int compression_type, int filter_method, |
| int interlace_type) |
| { |
| png_byte buf[13]; /* Buffer to store the IHDR info */ |
| |
| png_debug(1, "in png_write_IHDR"); |
| |
| /* Check that we have valid input data from the application info */ |
| switch (color_type) |
| { |
| case PNG_COLOR_TYPE_GRAY: |
| switch (bit_depth) |
| { |
| case 1: |
| case 2: |
| case 4: |
| case 8: |
| #ifdef PNG_WRITE_16BIT_SUPPORTED |
| case 16: |
| #endif |
| break; |
| |
| default: |
| png_error(png_ptr, "Invalid bit depth for grayscale image"); |
| } |
| break; |
| |
| case PNG_COLOR_TYPE_RGB: |
| #ifdef PNG_WRITE_16BIT_SUPPORTED |
| if (bit_depth != 8 && bit_depth != 16) |
| #else |
| if (bit_depth != 8) |
| #endif |
| png_error(png_ptr, "Invalid bit depth for RGB image"); |
| |
| break; |
| |
| case PNG_COLOR_TYPE_PALETTE: |
| switch (bit_depth) |
| { |
| case 1: |
| case 2: |
| case 4: |
| case 8: |
| break; |
| |
| default: |
| png_error(png_ptr, "Invalid bit depth for paletted image"); |
| } |
| break; |
| |
| case PNG_COLOR_TYPE_GRAY_ALPHA: |
| if (bit_depth != 8 && bit_depth != 16) |
| png_error(png_ptr, "Invalid bit depth for grayscale+alpha image"); |
| |
| break; |
| |
| case PNG_COLOR_TYPE_RGB_ALPHA: |
| #ifdef PNG_WRITE_16BIT_SUPPORTED |
| if (bit_depth != 8 && bit_depth != 16) |
| #else |
| if (bit_depth != 8) |
| #endif |
| png_error(png_ptr, "Invalid bit depth for RGBA image"); |
| |
| break; |
| |
| default: |
| png_error(png_ptr, "Invalid image color type specified"); |
| } |
| |
| if (compression_type != PNG_COMPRESSION_TYPE_BASE) |
| { |
| png_app_error(png_ptr, "Invalid compression type specified"); |
| compression_type = PNG_COMPRESSION_TYPE_BASE; |
| } |
| |
| /* Write filter_method 64 (intrapixel differencing) only if |
| * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and |
| * 2. Libpng did not write a PNG signature (this filter_method is only |
| * used in PNG datastreams that are embedded in MNG datastreams) and |
| * 3. The application called png_permit_mng_features with a mask that |
| * included PNG_FLAG_MNG_FILTER_64 and |
| * 4. The filter_method is 64 and |
| * 5. The color_type is RGB or RGBA |
| */ |
| if ( |
| # ifdef PNG_MNG_FEATURES_SUPPORTED |
| !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 && |
| ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) && |
| (color_type == PNG_COLOR_TYPE_RGB || |
| color_type == PNG_COLOR_TYPE_RGB_ALPHA) && |
| (filter_method == PNG_INTRAPIXEL_DIFFERENCING)) && |
| # endif /* MNG_FEATURES */ |
| filter_method != PNG_FILTER_TYPE_BASE) |
| { |
| png_app_error(png_ptr, "Invalid filter type specified"); |
| filter_method = PNG_FILTER_TYPE_BASE; |
| } |
| |
| if (interlace_type != PNG_INTERLACE_NONE && |
| interlace_type != PNG_INTERLACE_ADAM7) |
| { |
| png_app_error(png_ptr, "Invalid interlace type specified"); |
| interlace_type = PNG_INTERLACE_ADAM7; |
| } |
| |
| /* Save the relevant information */ |
| png_ptr->bit_depth = png_check_byte(png_ptr, bit_depth); |
| png_ptr->color_type = png_check_byte(png_ptr, color_type); |
| png_ptr->interlaced = png_check_byte(png_ptr, interlace_type); |
| png_ptr->filter_method = png_check_byte(png_ptr, filter_method); |
| png_ptr->compression_type = png_check_byte(png_ptr, compression_type); |
| png_ptr->width = width; |
| png_ptr->height = height; |
| |
| /* Pack the header information into the buffer */ |
| png_save_uint_32(buf, width); |
| png_save_uint_32(buf + 4, height); |
| buf[8] = png_check_byte(png_ptr, bit_depth); |
| buf[9] = png_check_byte(png_ptr, color_type); |
| buf[10] = png_check_byte(png_ptr, compression_type); |
| buf[11] = png_check_byte(png_ptr, filter_method); |
| buf[12] = png_check_byte(png_ptr, interlace_type); |
| |
| /* Write the chunk */ |
| png_write_complete_chunk(png_ptr, png_IHDR, buf, (png_size_t)13); |
| png_ptr->mode |= PNG_HAVE_IHDR; |
| } |
| |
| /* Write the palette. We are careful not to trust png_color to be in the |
| * correct order for PNG, so people can redefine it to any convenient |
| * structure. |
| */ |
| void /* PRIVATE */ |
| png_write_PLTE(png_structrp png_ptr, png_const_colorp palette, |
| unsigned int num_pal) |
| { |
| png_uint_32 max_palette_length, i; |
| png_const_colorp pal_ptr; |
| png_byte buf[3]; |
| |
| png_debug(1, "in png_write_PLTE"); |
| |
| max_palette_length = (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ? |
| (1 << png_ptr->bit_depth) : PNG_MAX_PALETTE_LENGTH; |
| |
| if (( |
| # ifdef PNG_MNG_FEATURES_SUPPORTED |
| (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0 && |
| # endif /* MNG_FEATURES */ |
| num_pal == 0) || num_pal > max_palette_length) |
| { |
| if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) |
| { |
| png_error(png_ptr, "Invalid number of colors in palette"); |
| } |
| |
| else |
| { |
| png_warning(png_ptr, "Invalid number of colors in palette"); |
| return; |
| } |
| } |
| |
| if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0) |
| { |
| png_warning(png_ptr, |
| "Ignoring request to write a PLTE chunk in grayscale PNG"); |
| |
| return; |
| } |
| |
| png_ptr->num_palette = png_check_bits(png_ptr, num_pal, 9); |
| png_debug1(3, "num_palette = %d", png_ptr->num_palette); |
| |
| png_write_chunk_header(png_ptr, png_PLTE, num_pal * 3U); |
| |
| for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++) |
| { |
| buf[0] = pal_ptr->red; |
| buf[1] = pal_ptr->green; |
| buf[2] = pal_ptr->blue; |
| png_write_chunk_data(png_ptr, buf, 3U); |
| } |
| |
| png_write_chunk_end(png_ptr); |
| png_ptr->mode |= PNG_HAVE_PLTE; |
| } |
| |
| /* Write an IEND chunk */ |
| void /* PRIVATE */ |
| png_write_IEND(png_structrp png_ptr) |
| { |
| png_debug(1, "in png_write_IEND"); |
| |
| png_write_complete_chunk(png_ptr, png_IEND, NULL, (png_size_t)0); |
| png_ptr->mode |= PNG_HAVE_IEND; |
| } |
| |
| #if defined(PNG_WRITE_gAMA_SUPPORTED) || defined(PNG_WRITE_cHRM_SUPPORTED) |
| static int |
| png_save_int_31(png_structrp png_ptr, png_bytep buf, png_int_32 i) |
| /* Save a signed value as a PNG unsigned value; the argument is required to |
| * be in the range 0..0x7FFFFFFFU. If not a *warning* is produced and false |
| * is returned. Because this is only called from png_write_cHRM_fixed and |
| * png_write_gAMA_fixed below this is safe (we don't need either chunk, |
| * particularly if the value is bogus.) |
| * |
| * The warning is png_app_error; it may return if the app tells it to but the |
| * app can have it error out. JB 20150821: I believe the checking in png.c |
| * actually makes this error impossible, but this is safe. |
| */ |
| { |
| #ifndef __COVERITY__ |
| if (i >= 0 && i <= 0x7FFFFFFF) |
| #else |
| /* Supress bogus Coverity complaint */ |
| if (i >= 0) |
| #endif |
| { |
| png_save_uint_32(buf, (png_uint_32)/*SAFE*/i); |
| return 1; |
| } |
| |
| else |
| { |
| png_chunk_report(png_ptr, "negative value in cHRM or gAMA", |
| PNG_CHUNK_WRITE_ERROR); |
| return 0; |
| } |
| } |
| #endif /* WRITE_gAMA || WRITE_cHRM */ |
| |
| #ifdef PNG_WRITE_gAMA_SUPPORTED |
| /* Write a gAMA chunk */ |
| void /* PRIVATE */ |
| png_write_gAMA_fixed(png_structrp png_ptr, png_fixed_point file_gamma) |
| { |
| png_byte buf[4]; |
| |
| png_debug(1, "in png_write_gAMA"); |
| |
| /* file_gamma is saved in 1/100,000ths */ |
| if (png_save_int_31(png_ptr, buf, file_gamma)) |
| png_write_complete_chunk(png_ptr, png_gAMA, buf, (png_size_t)4); |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_sRGB_SUPPORTED |
| /* Write a sRGB chunk */ |
| void /* PRIVATE */ |
| png_write_sRGB(png_structrp png_ptr, int srgb_intent) |
| { |
| png_byte buf[1]; |
| |
| png_debug(1, "in png_write_sRGB"); |
| |
| if (srgb_intent >= PNG_sRGB_INTENT_LAST) |
| png_chunk_report(png_ptr, "Invalid sRGB rendering intent specified", |
| PNG_CHUNK_WRITE_ERROR); |
| |
| buf[0] = png_check_byte(png_ptr, srgb_intent); |
| png_write_complete_chunk(png_ptr, png_sRGB, buf, (png_size_t)1); |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_iCCP_SUPPORTED |
| /* Write an iCCP chunk */ |
| void /* PRIVATE */ |
| png_write_iCCP(png_structrp png_ptr, png_const_charp name, |
| png_const_voidp profile) |
| { |
| png_uint_32 name_len; |
| png_uint_32 profile_len; |
| png_byte new_name[81]; /* 1 byte for the compression byte */ |
| |
| png_debug(1, "in png_write_iCCP"); |
| |
| affirm(profile != NULL); |
| |
| profile_len = png_get_uint_32(profile); |
| name_len = png_check_keyword(png_ptr, name, new_name); |
| |
| if (name_len == 0) |
| { |
| png_chunk_report(png_ptr, "iCCP: invalid keyword", PNG_CHUNK_WRITE_ERROR); |
| return; |
| } |
| |
| ++name_len; /* trailing '\0' */ |
| new_name[name_len++] = PNG_COMPRESSION_TYPE_BASE; |
| |
| if (png_compress_chunk_data(png_ptr, png_iCCP, name_len, profile, |
| profile_len)) |
| { |
| png_write_chunk_header(png_ptr, png_iCCP, |
| name_len+png_length_compressed_chunk_data(png_ptr, name_len)); |
| png_write_chunk_data(png_ptr, new_name, name_len); |
| png_write_compressed_chunk_data(png_ptr); |
| png_write_chunk_end(png_ptr); |
| } |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_sPLT_SUPPORTED |
| /* Write a sPLT chunk */ |
| void /* PRIVATE */ |
| png_write_sPLT(png_structrp png_ptr, png_const_sPLT_tp spalette) |
| { |
| png_uint_32 name_len; |
| png_byte new_name[80]; |
| png_byte entrybuf[10]; |
| png_size_t entry_size = (spalette->depth == 8 ? 6 : 10); |
| png_size_t palette_size = entry_size * spalette->nentries; |
| png_sPLT_entryp ep; |
| |
| png_debug(1, "in png_write_sPLT"); |
| |
| name_len = png_check_keyword(png_ptr, spalette->name, new_name); |
| |
| if (name_len == 0) |
| png_error(png_ptr, "sPLT: invalid keyword"); |
| |
| /* Make sure we include the NULL after the name */ |
| png_write_chunk_header(png_ptr, png_sPLT, |
| (png_uint_32)(name_len + 2 + palette_size)); |
| |
| png_write_chunk_data(png_ptr, new_name, name_len + 1); |
| |
| png_write_chunk_data(png_ptr, &spalette->depth, 1); |
| |
| /* Loop through each palette entry, writing appropriately */ |
| for (ep = spalette->entries; ep<spalette->entries + spalette->nentries; ep++) |
| { |
| if (spalette->depth == 8) |
| { |
| entrybuf[0] = png_check_byte(png_ptr, ep->red); |
| entrybuf[1] = png_check_byte(png_ptr, ep->green); |
| entrybuf[2] = png_check_byte(png_ptr, ep->blue); |
| entrybuf[3] = png_check_byte(png_ptr, ep->alpha); |
| png_save_uint_16(entrybuf + 4, ep->frequency); |
| } |
| |
| else |
| { |
| png_save_uint_16(entrybuf + 0, ep->red); |
| png_save_uint_16(entrybuf + 2, ep->green); |
| png_save_uint_16(entrybuf + 4, ep->blue); |
| png_save_uint_16(entrybuf + 6, ep->alpha); |
| png_save_uint_16(entrybuf + 8, ep->frequency); |
| } |
| |
| png_write_chunk_data(png_ptr, entrybuf, entry_size); |
| } |
| |
| png_write_chunk_end(png_ptr); |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_sBIT_SUPPORTED |
| /* Write the sBIT chunk */ |
| void /* PRIVATE */ |
| png_write_sBIT(png_structrp png_ptr, png_const_color_8p sbit, int color_type) |
| { |
| png_byte buf[4]; |
| png_size_t size; |
| |
| png_debug(1, "in png_write_sBIT"); |
| |
| /* Make sure we don't depend upon the order of PNG_COLOR_8 */ |
| if ((color_type & PNG_COLOR_MASK_COLOR) != 0) |
| { |
| unsigned int maxbits; |
| |
| maxbits = color_type==PNG_COLOR_TYPE_PALETTE ? 8 : png_ptr->bit_depth; |
| |
| if (sbit->red == 0 || sbit->red > maxbits || |
| sbit->green == 0 || sbit->green > maxbits || |
| sbit->blue == 0 || sbit->blue > maxbits) |
| { |
| png_app_error(png_ptr, "Invalid sBIT depth specified"); |
| return; |
| } |
| |
| buf[0] = sbit->red; |
| buf[1] = sbit->green; |
| buf[2] = sbit->blue; |
| size = 3; |
| } |
| |
| else |
| { |
| if (sbit->gray == 0 || sbit->gray > png_ptr->bit_depth) |
| { |
| png_app_error(png_ptr, "Invalid sBIT depth specified"); |
| return; |
| } |
| |
| buf[0] = sbit->gray; |
| size = 1; |
| } |
| |
| if ((color_type & PNG_COLOR_MASK_ALPHA) != 0) |
| { |
| if (sbit->alpha == 0 || sbit->alpha > png_ptr->bit_depth) |
| { |
| png_app_error(png_ptr, "Invalid sBIT depth specified"); |
| return; |
| } |
| |
| buf[size++] = sbit->alpha; |
| } |
| |
| png_write_complete_chunk(png_ptr, png_sBIT, buf, size); |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_cHRM_SUPPORTED |
| /* Write the cHRM chunk */ |
| void /* PRIVATE */ |
| png_write_cHRM_fixed(png_structrp png_ptr, const png_xy *xy) |
| { |
| png_byte buf[32]; |
| |
| png_debug(1, "in png_write_cHRM"); |
| |
| /* Each value is saved in 1/100,000ths */ |
| if (png_save_int_31(png_ptr, buf, xy->whitex) && |
| png_save_int_31(png_ptr, buf + 4, xy->whitey) && |
| png_save_int_31(png_ptr, buf + 8, xy->redx) && |
| png_save_int_31(png_ptr, buf + 12, xy->redy) && |
| png_save_int_31(png_ptr, buf + 16, xy->greenx) && |
| png_save_int_31(png_ptr, buf + 20, xy->greeny) && |
| png_save_int_31(png_ptr, buf + 24, xy->bluex) && |
| png_save_int_31(png_ptr, buf + 28, xy->bluey)) |
| png_write_complete_chunk(png_ptr, png_cHRM, buf, 32); |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_tRNS_SUPPORTED |
| /* Write the tRNS chunk */ |
| void /* PRIVATE */ |
| png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha, |
| png_const_color_16p tran, int num_trans, int color_type) |
| { |
| png_byte buf[6]; |
| |
| png_debug(1, "in png_write_tRNS"); |
| |
| if (color_type == PNG_COLOR_TYPE_PALETTE) |
| { |
| affirm(num_trans > 0 && num_trans <= PNG_MAX_PALETTE_LENGTH); |
| { |
| # ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED |
| union |
| { |
| png_uint_32 u32[1]; |
| png_byte b8[PNG_MAX_PALETTE_LENGTH]; |
| } inverted_alpha; |
| |
| /* Invert the alpha channel (in tRNS) if required */ |
| if (png_ptr->write_invert_alpha) |
| { |
| int i; |
| |
| memcpy(inverted_alpha.b8, trans_alpha, num_trans); |
| |
| for (i=0; 4*i<num_trans; ++i) |
| inverted_alpha.u32[i] = ~inverted_alpha.u32[i]; |
| |
| trans_alpha = inverted_alpha.b8; |
| } |
| # endif /* WRITE_INVERT_ALPHA */ |
| |
| png_write_complete_chunk(png_ptr, png_tRNS, trans_alpha, num_trans); |
| } |
| } |
| |
| else if (color_type == PNG_COLOR_TYPE_GRAY) |
| { |
| /* One 16 bit value */ |
| affirm(tran->gray < (1 << png_ptr->bit_depth)); |
| png_save_uint_16(buf, tran->gray); |
| png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)2); |
| } |
| |
| else if (color_type == PNG_COLOR_TYPE_RGB) |
| { |
| /* Three 16 bit values */ |
| png_save_uint_16(buf, tran->red); |
| png_save_uint_16(buf + 2, tran->green); |
| png_save_uint_16(buf + 4, tran->blue); |
| affirm(png_ptr->bit_depth == 8 || (buf[0] | buf[2] | buf[4]) == 0); |
| png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)6); |
| } |
| |
| else /* Already checked in png_set_tRNS */ |
| impossible("invalid tRNS"); |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_bKGD_SUPPORTED |
| /* Write the background chunk */ |
| void /* PRIVATE */ |
| png_write_bKGD(png_structrp png_ptr, png_const_color_16p back, int color_type) |
| { |
| png_byte buf[6]; |
| |
| png_debug(1, "in png_write_bKGD"); |
| |
| if (color_type == PNG_COLOR_TYPE_PALETTE) |
| { |
| if ( |
| # ifdef PNG_MNG_FEATURES_SUPPORTED |
| (png_ptr->num_palette != 0 || |
| (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0) && |
| # endif /* MNG_FEATURES */ |
| back->index >= png_ptr->num_palette) |
| { |
| png_app_error(png_ptr, "Invalid background palette index"); |
| return; |
| } |
| |
| buf[0] = back->index; |
| png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)1); |
| } |
| |
| else if ((color_type & PNG_COLOR_MASK_COLOR) != 0) |
| { |
| png_save_uint_16(buf, back->red); |
| png_save_uint_16(buf + 2, back->green); |
| png_save_uint_16(buf + 4, back->blue); |
| #ifdef PNG_WRITE_16BIT_SUPPORTED |
| if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]) != 0) |
| #else |
| if ((buf[0] | buf[2] | buf[4]) != 0) |
| #endif |
| { |
| png_app_error(png_ptr, |
| "Ignoring attempt to write 16-bit bKGD chunk when bit_depth is 8"); |
| |
| return; |
| } |
| |
| png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)6); |
| } |
| |
| else |
| { |
| if (back->gray >= (1 << png_ptr->bit_depth)) |
| { |
| png_app_error(png_ptr, |
| "Ignoring attempt to write bKGD chunk out-of-range for bit_depth"); |
| |
| return; |
| } |
| |
| png_save_uint_16(buf, back->gray); |
| png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)2); |
| } |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_hIST_SUPPORTED |
| /* Write the histogram */ |
| void /* PRIVATE */ |
| png_write_hIST(png_structrp png_ptr, png_const_uint_16p hist, int num_hist) |
| { |
| int i; |
| png_byte buf[3]; |
| |
| png_debug(1, "in png_write_hIST"); |
| |
| if (num_hist > (int)png_ptr->num_palette) |
| { |
| png_debug2(3, "num_hist = %d, num_palette = %d", num_hist, |
| png_ptr->num_palette); |
| |
| png_warning(png_ptr, "Invalid number of histogram entries specified"); |
| return; |
| } |
| |
| png_write_chunk_header(png_ptr, png_hIST, (png_uint_32)(num_hist * 2)); |
| |
| for (i = 0; i < num_hist; i++) |
| { |
| png_save_uint_16(buf, hist[i]); |
| png_write_chunk_data(png_ptr, buf, (png_size_t)2); |
| } |
| |
| png_write_chunk_end(png_ptr); |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_tEXt_SUPPORTED |
| /* Write a tEXt chunk */ |
| void /* PRIVATE */ |
| png_write_tEXt(png_structrp png_ptr, png_const_charp key, png_const_charp text, |
| png_size_t text_len) |
| { |
| unsigned int key_len; |
| png_byte new_key[80]; |
| |
| png_debug(1, "in png_write_tEXt"); |
| |
| key_len = png_check_keyword(png_ptr, key, new_key); |
| |
| if (key_len == 0) |
| { |
| png_chunk_report(png_ptr, "tEXt: invalid keyword", PNG_CHUNK_WRITE_ERROR); |
| return; |
| } |
| |
| if (text == NULL || *text == '\0') |
| text_len = 0; |
| |
| else |
| text_len = strlen(text); |
| |
| if (text_len > PNG_UINT_31_MAX - (key_len+1)) |
| { |
| png_chunk_report(png_ptr, "tEXt: text too long", PNG_CHUNK_WRITE_ERROR); |
| return; |
| } |
| |
| /* Make sure we include the 0 after the key */ |
| png_write_chunk_header(png_ptr, png_tEXt, |
| (png_uint_32)/*checked above*/(key_len + text_len + 1)); |
| /* |
| * We leave it to the application to meet PNG-1.0 requirements on the |
| * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of |
| * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them. |
| * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG. |
| */ |
| png_write_chunk_data(png_ptr, new_key, key_len + 1); |
| |
| if (text_len != 0) |
| png_write_chunk_data(png_ptr, (png_const_bytep)text, text_len); |
| |
| png_write_chunk_end(png_ptr); |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_zTXt_SUPPORTED |
| /* Write a compressed text chunk */ |
| void /* PRIVATE */ |
| png_write_zTXt(png_structrp png_ptr, png_const_charp key, png_const_charp text, |
| int compression) |
| { |
| unsigned int key_len; |
| png_byte new_key[81]; |
| |
| png_debug(1, "in png_write_zTXt"); |
| |
| if (compression != PNG_TEXT_COMPRESSION_zTXt) |
| png_app_warning(png_ptr, "zTXt: invalid compression type ignored"); |
| |
| key_len = png_check_keyword(png_ptr, key, new_key); |
| |
| if (key_len == 0) |
| { |
| png_chunk_report(png_ptr, "zTXt: invalid keyword", PNG_CHUNK_WRITE_ERROR); |
| return; |
| } |
| |
| /* Add the compression method and 1 for the keyword separator. */ |
| ++key_len; |
| new_key[key_len++] = PNG_COMPRESSION_TYPE_BASE; |
| |
| if (png_compress_chunk_data(png_ptr, png_zTXt, key_len, text, strlen(text))) |
| { |
| png_write_chunk_header(png_ptr, png_zTXt, |
| key_len+png_length_compressed_chunk_data(png_ptr, key_len)); |
| png_write_chunk_data(png_ptr, new_key, key_len); |
| png_write_compressed_chunk_data(png_ptr); |
| png_write_chunk_end(png_ptr); |
| } |
| |
| /* else chunk report already issued and ignored */ |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_iTXt_SUPPORTED |
| /* Write an iTXt chunk */ |
| void /* PRIVATE */ |
| png_write_iTXt(png_structrp png_ptr, int compression, png_const_charp key, |
| png_const_charp lang, png_const_charp lang_key, png_const_charp text) |
| { |
| png_uint_32 key_len, prefix_len, data_len; |
| png_size_t lang_len, lang_key_len, text_len; |
| png_byte new_key[82]; /* 80 bytes for the key, 2 byte compression info */ |
| |
| png_debug(1, "in png_write_iTXt"); |
| |
| key_len = png_check_keyword(png_ptr, key, new_key); |
| |
| if (key_len == 0) |
| { |
| png_chunk_report(png_ptr, "iTXt: invalid keyword", PNG_CHUNK_WRITE_ERROR); |
| return; |
| } |
| |
| debug(new_key[key_len] == 0); |
| ++key_len; /* terminating 0 added by png_check_keyword */ |
| |
| /* Set the compression flag */ |
| switch (compression) |
| { |
| case PNG_ITXT_COMPRESSION_NONE: |
| case PNG_TEXT_COMPRESSION_NONE: |
| compression = new_key[key_len++] = 0; /* no compression */ |
| break; |
| |
| case PNG_TEXT_COMPRESSION_zTXt: |
| case PNG_ITXT_COMPRESSION_zTXt: |
| compression = new_key[key_len++] = 1; /* compressed */ |
| break; |
| |
| default: |
| png_chunk_report(png_ptr, "iTXt: invalid compression", |
| PNG_CHUNK_WRITE_ERROR); |
| return; |
| } |
| |
| new_key[key_len++] = PNG_COMPRESSION_TYPE_BASE; |
| |
| /* We leave it to the application to meet PNG-1.0 requirements on the |
| * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of |
| * any non-Latin-1 characters except for NEWLINE (yes, this is really weird |
| * in an 'international' text string. ISO PNG, however, specifies that the |
| * text is UTF-8 and this *IS NOT YET CHECKED*, so invalid sequences may be |
| * present. |
| * |
| * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG. |
| * |
| * TODO: validate the language tag correctly (see the spec.) |
| */ |
| if (lang == NULL) lang = ""; /* empty language is valid */ |
| lang_len = strlen(lang)+1U; |
| if (lang_key == NULL) lang_key = ""; /* may be empty */ |
| lang_key_len = strlen(lang_key)+1U; |
| if (text == NULL) text = ""; /* may be empty */ |
| |
| if (lang_len > PNG_UINT_31_MAX-key_len || |
| lang_key_len > PNG_UINT_31_MAX-key_len-lang_len) |
| { |
| png_chunk_report(png_ptr, "iTXt: prefix too long", PNG_CHUNK_WRITE_ERROR); |
| return; |
| } |
| |
| prefix_len = (png_uint_32)/*SAFE*/(key_len+lang_len+lang_key_len); |
| text_len = strlen(text); /* no trailing '\0' */ |
| |
| if (compression != 0) |
| { |
| if (png_compress_chunk_data(png_ptr, png_iTXt, prefix_len, text, |
| text_len)) |
| data_len = png_length_compressed_chunk_data(png_ptr, prefix_len); |
| |
| else |
| return; /* chunk report already issued and ignored */ |
| } |
| |
| else |
| { |
| if (text_len > PNG_UINT_31_MAX-prefix_len) |
| { |
| png_chunk_report(png_ptr, "iTXt: text too long", |
| PNG_CHUNK_WRITE_ERROR); |
| return; |
| } |
| |
| data_len = (png_uint_32)/*SAFE*/text_len; |
| } |
| |
| png_write_chunk_header(png_ptr, png_iTXt, prefix_len+data_len); |
| png_write_chunk_data(png_ptr, new_key, key_len); |
| png_write_chunk_data(png_ptr, lang, lang_len); |
| png_write_chunk_data(png_ptr, lang_key, lang_key_len); |
| |
| if (compression != 0) |
| png_write_compressed_chunk_data(png_ptr); |
| |
| else |
| png_write_chunk_data(png_ptr, text, data_len); |
| |
| png_write_chunk_end(png_ptr); |
| } |
| #endif /* WRITE_iTXt */ |
| |
| #if defined(PNG_WRITE_oFFs_SUPPORTED) ||\ |
| defined(PNG_WRITE_pCAL_SUPPORTED) |
| /* PNG signed integers are saved in 32-bit 2's complement format. ANSI C-90 |
| * defines a cast of a signed integer to an unsigned integer either to preserve |
| * the value, if it is positive, or to calculate: |
| * |
| * (UNSIGNED_MAX+1) + integer |
| * |
| * Where UNSIGNED_MAX is the appropriate maximum unsigned value, so when the |
| * negative integral value is added the result will be an unsigned value |
| * correspnding to the 2's complement representation. |
| */ |
| static int |
| save_int_32(png_structrp png_ptr, png_bytep buf, png_int_32 j) |
| { |
| png_uint_32 i = 0xFFFFFFFFU & (png_uint_32)/*SAFE & CORRECT*/j; |
| |
| if (i != 0x80000000U/*value not permitted*/) |
| { |
| png_save_uint_32(buf, i); |
| return 1; |
| } |
| |
| else |
| { |
| png_chunk_report(png_ptr, "invalid value in oFFS or pCAL", |
| PNG_CHUNK_WRITE_ERROR); |
| return 0; |
| } |
| } |
| #endif /* WRITE_oFFs || WRITE_pCAL */ |
| |
| #ifdef PNG_WRITE_oFFs_SUPPORTED |
| /* Write the oFFs chunk */ |
| void /* PRIVATE */ |
| png_write_oFFs(png_structrp png_ptr, png_int_32 x_offset, png_int_32 y_offset, |
| int unit_type) |
| { |
| png_byte buf[9]; |
| |
| png_debug(1, "in png_write_oFFs"); |
| |
| if (unit_type >= PNG_OFFSET_LAST) |
| png_warning(png_ptr, "Unrecognized unit type for oFFs chunk"); |
| |
| if (save_int_32(png_ptr, buf, x_offset) && |
| save_int_32(png_ptr, buf + 4, y_offset)) |
| { |
| /* unit type is 0 or 1, this has been checked already so the following |
| * is safe: |
| */ |
| buf[8] = unit_type != 0; |
| png_write_complete_chunk(png_ptr, png_oFFs, buf, (png_size_t)9); |
| } |
| } |
| #endif /* WRITE_oFFs */ |
| |
| #ifdef PNG_WRITE_pCAL_SUPPORTED |
| /* Write the pCAL chunk (described in the PNG extensions document) */ |
| void /* PRIVATE */ |
| png_write_pCAL(png_structrp png_ptr, png_charp purpose, png_int_32 X0, |
| png_int_32 X1, int type, int nparams, png_const_charp units, |
| png_charpp params) |
| { |
| png_uint_32 purpose_len; |
| size_t units_len; |
| png_byte buf[10]; |
| png_byte new_purpose[80]; |
| |
| png_debug1(1, "in png_write_pCAL (%d parameters)", nparams); |
| |
| if (type >= PNG_EQUATION_LAST) |
| png_error(png_ptr, "Unrecognized equation type for pCAL chunk"); |
| |
| purpose_len = png_check_keyword(png_ptr, purpose, new_purpose); |
| |
| if (purpose_len == 0) |
| png_error(png_ptr, "pCAL: invalid keyword"); |
| |
| ++purpose_len; /* terminator */ |
| |
| png_debug1(3, "pCAL purpose length = %d", (int)purpose_len); |
| units_len = strlen(units) + (nparams == 0 ? 0 : 1); |
| png_debug1(3, "pCAL units length = %d", (int)units_len); |
| |
| if (save_int_32(png_ptr, buf, X0) && |
| save_int_32(png_ptr, buf + 4, X1)) |
| { |
| png_size_tp params_len = png_voidcast(png_size_tp, |
| png_malloc(png_ptr, nparams * sizeof (png_size_t))); |
| int i; |
| size_t total_len = purpose_len + units_len + 10; |
| |
| /* Find the length of each parameter, making sure we don't count the |
| * null terminator for the last parameter. |
| */ |
| for (i = 0; i < nparams; i++) |
| { |
| params_len[i] = strlen(params[i]) + (i == nparams - 1 ? 0 : 1); |
| png_debug2(3, "pCAL parameter %d length = %lu", i, |
| (unsigned long)params_len[i]); |
| total_len += params_len[i]; |
| } |
| |
| png_debug1(3, "pCAL total length = %d", (int)total_len); |
| png_write_chunk_header(png_ptr, png_pCAL, (png_uint_32)total_len); |
| png_write_chunk_data(png_ptr, new_purpose, purpose_len); |
| buf[8] = png_check_byte(png_ptr, type); |
| buf[9] = png_check_byte(png_ptr, nparams); |
| png_write_chunk_data(png_ptr, buf, (png_size_t)10); |
| png_write_chunk_data(png_ptr, (png_const_bytep)units, |
| (png_size_t)units_len); |
| |
| for (i = 0; i < nparams; i++) |
| png_write_chunk_data(png_ptr, (png_const_bytep)params[i], |
| params_len[i]); |
| |
| png_free(png_ptr, params_len); |
| png_write_chunk_end(png_ptr); |
| } |
| } |
| #endif /* WRITE_pCAL */ |
| |
| #ifdef PNG_WRITE_sCAL_SUPPORTED |
| /* Write the sCAL chunk */ |
| void /* PRIVATE */ |
| png_write_sCAL_s(png_structrp png_ptr, int unit, png_const_charp width, |
| png_const_charp height) |
| { |
| png_byte buf[64]; |
| png_size_t wlen, hlen, total_len; |
| |
| png_debug(1, "in png_write_sCAL_s"); |
| |
| wlen = strlen(width); |
| hlen = strlen(height); |
| total_len = wlen + hlen + 2; |
| |
| if (total_len > 64) |
| { |
| png_warning(png_ptr, "Can't write sCAL (buffer too small)"); |
| return; |
| } |
| |
| buf[0] = png_check_byte(png_ptr, unit); |
| memcpy(buf + 1, width, wlen + 1); /* Append the '\0' here */ |
| memcpy(buf + wlen + 2, height, hlen); /* Do NOT append the '\0' here */ |
| |
| png_debug1(3, "sCAL total length = %u", (unsigned int)total_len); |
| png_write_complete_chunk(png_ptr, png_sCAL, buf, total_len); |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_pHYs_SUPPORTED |
| /* Write the pHYs chunk */ |
| void /* PRIVATE */ |
| png_write_pHYs(png_structrp png_ptr, png_uint_32 x_pixels_per_unit, |
| png_uint_32 y_pixels_per_unit, |
| int unit_type) |
| { |
| png_byte buf[9]; |
| |
| png_debug(1, "in png_write_pHYs"); |
| |
| if (unit_type >= PNG_RESOLUTION_LAST) |
| png_warning(png_ptr, "Unrecognized unit type for pHYs chunk"); |
| |
| png_save_uint_32(buf, x_pixels_per_unit); |
| png_save_uint_32(buf + 4, y_pixels_per_unit); |
| buf[8] = png_check_byte(png_ptr, unit_type); |
| |
| png_write_complete_chunk(png_ptr, png_pHYs, buf, (png_size_t)9); |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_tIME_SUPPORTED |
| /* Write the tIME chunk. Use either png_convert_from_struct_tm() |
| * or png_convert_from_time_t(), or fill in the structure yourself. |
| */ |
| void /* PRIVATE */ |
| png_write_tIME(png_structrp png_ptr, png_const_timep mod_time) |
| { |
| png_byte buf[7]; |
| |
| png_debug(1, "in png_write_tIME"); |
| |
| if (mod_time->month > 12 || mod_time->month < 1 || |
| mod_time->day > 31 || mod_time->day < 1 || |
| mod_time->hour > 23 || mod_time->second > 60) |
| { |
| png_warning(png_ptr, "Invalid time specified for tIME chunk"); |
| return; |
| } |
| |
| png_save_uint_16(buf, mod_time->year); |
| buf[2] = mod_time->month; |
| buf[3] = mod_time->day; |
| buf[4] = mod_time->hour; |
| buf[5] = mod_time->minute; |
| buf[6] = mod_time->second; |
| |
| png_write_complete_chunk(png_ptr, png_tIME, buf, (png_size_t)7); |
| } |
| #endif |
| |
| static void |
| png_end_IDAT(png_structrp png_ptr) |
| { |
| png_zlib_statep ps = png_ptr->zlib_state; |
| |
| png_ptr->zowner = 0U; /* release the stream */ |
| |
| if (ps != NULL) |
| png_deflate_release(png_ptr, ps, 1/*check*/); |
| } |
| |
| static void |
| png_write_IDAT(png_structrp png_ptr, int flush) |
| { |
| png_zlib_statep ps = png_ptr->zlib_state; |
| png_uint_32 IDAT_size; |
| |
| /* Check for a correctly initialized list, the requirement that the end |
| * pointer is NULL means that the end of the list can be easily detected. |
| */ |
| affirm(ps != NULL && ps->s.end != NULL && *ps->s.end == NULL); |
| png_zlib_compress_validate(&png_ptr->zlib_state->s, 0/*in_use*/); |
| |
| IDAT_size = png_ptr->IDAT_size; |
| if (IDAT_size == 0U) |
| { |
| switch (pz_get(ps, IDAT, png_level, PNG_DEFAULT_COMPRESSION_LEVEL)) |
| { |
| case PNG_COMPRESSION_COMPAT: /* Legacy */ |
| IDAT_size = 8192U; |
| break; |
| |
| case PNG_COMPRESSION_LOW_MEMORY: |
| case PNG_COMPRESSION_HIGH_SPEED: |
| case PNG_COMPRESSION_LOW: |
| /* png_compress uses PNG_ROW_BUFFER_SIZE buffers for the compressed |
| * data. Optimize to allocate only one of these: |
| */ |
| IDAT_size = PNG_ROW_BUFFER_SIZE; |
| break; |
| |
| default: |
| case PNG_COMPRESSION_MEDIUM: |
| IDAT_size = PNG_ZBUF_SIZE; |
| break; |
| |
| case PNG_COMPRESSION_HIGH_READ_SPEED: |
| /* Assume the reader reads partial IDAT chunks (pretty much a |
| * requirement given that some PNG encoders produce just one IDAT) |
| */ |
| case PNG_COMPRESSION_HIGH: |
| /* This doesn't control the amount of memory allocated unless the |
| * PNG IDAT data really is this big. |
| * |
| * TODO: review handling out-of-memory from png_compress() by |
| * flushing an IDAT. |
| */ |
| IDAT_size = PNG_UINT_31_MAX; |
| break; |
| } |
| } |
| |
| /* Write IDAT chunks while either 'flush' is true or there are at |
| * least png_ptr->IDAT_size bytes available to be written. |
| */ |
| for (;;) |
| { |
| png_uint_32 len = IDAT_size; |
| |
| if (ps->s.overflow == 0U) |
| { |
| png_uint_32 avail = ps->s.len; |
| |
| if (avail < len) |
| { |
| /* When end_of_image is true everything gets written, otherwise |
| * there must be at least IDAT_size bytes available. |
| */ |
| if (!flush) |
| return; |
| |
| if (avail == 0U) |
| break; |
| |
| len = avail; |
| } |
| } |
| |
| png_write_chunk_header(png_ptr, png_IDAT, len); |
| |
| /* Write bytes from the buffer list, adjusting {overflow,len} as they are |
| * written. |
| */ |
| do |
| { |
| png_compression_bufferp next = ps->s.list; |
| unsigned int avail = sizeof next->output; |
| unsigned int start = ps->s.start; |
| unsigned int written; |
| |
| affirm(next != NULL); |
| |
| if (next->next == NULL) /* end of list */ |
| { |
| /* The z_stream should always be pointing into this output buffer, |
| * the buffer may not be full: |
| */ |
| debug(ps->s.zs.next_out + ps->s.zs.avail_out == |
| next->output + sizeof next->output); |
| avail -= ps->s.zs.avail_out; |
| } |
| |
| else /* not end of list */ |
| debug((ps->s.zs.next_out < next->output || |
| ps->s.zs.next_out > next->output + sizeof next->output) && |
| (ps->s.overflow > 0 || |
| ps->s.start + ps->s.len >= sizeof next->output)); |
| |
| /* First, if this is the very first IDAT (PNG_HAVE_IDAT not set) |
| * fix the Zlib CINFO field if required: |
| */ |
| if ((png_ptr->mode & PNG_HAVE_IDAT) == 0U && |
| avail >= start+2U /* enough for the zlib header */) |
| { |
| debug(start == 0U); |
| fix_cinfo(ps, next->output+start, png_image_size(png_ptr)); |
| } |
| |
| else /* always expect to see at least 2 bytes: */ |
| debug((png_ptr->mode & PNG_HAVE_IDAT) != 0U); |
| |
| /* Set this now to prevent the above happening again second time round |
| * the loop: |
| */ |
| png_ptr->mode |= PNG_HAVE_IDAT; |
| |
| if (avail <= start+len) |
| { |
| /* Write all of this buffer: */ |
| affirm(avail > start); /* else overflow on the subtract */ |
| written = avail-start; |
| png_write_chunk_data(png_ptr, next->output+start, written); |
| |
| /* At the end there are no buffers in the list but the z_stream |
| * still points into the old (just released) buffer. This can |
| * happen when the old buffer is not full if the compressed bytes |
| * exactly match the IDAT length; it should always happen when |
| * end_of_image is set. |
| */ |
| ps->s.list = next->next; |
| |
| if (next->next == NULL) |
| { |
| debug(avail == start+len); |
| ps->s.end = &ps->s.list; |
| ps->s.zs.next_out = NULL; |
| ps->s.zs.avail_out = 0U; |
| } |
| |
| next->next = ps->stash; |
| ps->stash = next; |
| ps->s.start = 0U; |
| } |
| |
| else /* write only part of this buffer */ |
| { |
| written = len; |
| png_write_chunk_data(png_ptr, next->output+start, written); |
| ps->s.start = (unsigned int)/*SAFE*/(start + written); |
| } |
| |
| /* 'written' bytes were written: */ |
| len -= written; |
| |
| if (written <= ps->s.len) |
| ps->s.len -= written; |
| |
| else |
| { |
| affirm(ps->s.overflow > 0U); |
| --ps->s.overflow; |
| ps->s.len += 0x80000000U - written; |
| UNTESTED |
| } |
| } |
| while (len > 0U); |
| |
| png_write_chunk_end(png_ptr); |
| } |
| |
| /* avail == 0 && flush */ |
| png_end_IDAT(png_ptr); |
| png_ptr->mode |= PNG_AFTER_IDAT; |
| } |
| |
| /* This is is a convenience wrapper to handle IDAT compression; it takes a |
| * pointer to the input data and places no limit on the size of the output but |
| * is otherwise the same as png_compress(). It also handles the use of the |
| * stash (only used for IDAT compression.) |
| */ |
| static int |
| png_compress_IDAT_data(png_structrp png_ptr, png_zlib_statep ps, |
| png_zlib_compressp pz, png_const_voidp input, uInt input_len, int flush) |
| { |
| /* Delay initialize the z_stream. */ |
| if (png_ptr->zowner != png_IDAT) |
| png_deflate_claim(png_ptr, png_IDAT, 0U); |
| |
| affirm(png_ptr->zowner == png_IDAT && pz->end != NULL && *pz->end == NULL); |
| |
| /* z_stream::{next,avail}_out are set by png_compress to point into the |
| * buffer list. next_in must be set here, avail_in comes from the input_len |
| * parameter: |
| */ |
| pz->zs.next_in = PNGZ_INPUT_CAST(png_voidcast(const Bytef*, input)); |
| *pz->end = ps->stash; /* May be NULL */ |
| ps->stash = NULL; |
| |
| /* zlib buffers the output, the maximum amount of compressed data that can be |
| * produced here is governed by the amount of buffering. |
| */ |
| { |
| int ret = png_compress(pz, input_len, 0U/*unlimited*/, flush); |
| |
| affirm(pz->end != NULL && ps->stash == NULL); |
| ps->stash = *pz->end; /* May be NULL */ |
| *pz->end = NULL; |
| |
| /* Z_FINISH should give Z_STREAM_END, everything else should give Z_OK, in |
| * either case all the input should have been consumed: |
| */ |
| implies(ret == Z_OK || ret == Z_FINISH, pz->zs.avail_in == 0U && |
| (ret == Z_STREAM_END) == (flush == Z_FINISH)); |
| pz->zs.next_in = NULL; |
| pz->zs.avail_in = 0U; /* safety */ |
| png_zlib_compress_validate(pz, 0/*in_use*/); |
| |
| return ret; |
| } |
| } |
| |
| /* Compress some image data using the main png_zlib_compress. Write the result |
| * out if there is sufficient data. |
| */ |
| static void |
| png_compress_IDAT(png_structrp png_ptr, png_const_voidp input, uInt input_len, |
| int flush) |
| { |
| png_zlib_statep ps = png_ptr->zlib_state; |
| int ret = png_compress_IDAT_data(png_ptr, ps, &ps->s, input, input_len, |
| flush); |
| |
| /* Check the return code. */ |
| if (ret == Z_OK || ret == Z_STREAM_END) |
| png_write_IDAT(png_ptr, flush == Z_FINISH); |
| |
| else /* ret != Z_OK && ret != Z_STREAM_END */ |
| { |
| /* This is an error condition. It is fatal. */ |
| png_end_IDAT(png_ptr); |
| png_zstream_error(&ps->s.zs, ret); |
| png_error(png_ptr, ps->s.zs.msg); |
| } |
| } |
| |
| /* This is called at the end of every row to handle the required callbacks and |
| * advance png_struct::row_number and png_struct::pass. |
| */ |
| static void |
| png_write_end_row(png_structrp png_ptr, int flush) |
| { |
| png_uint_32 row_number = png_ptr->row_number; |
| unsigned int pass = png_ptr->pass; |
| |
| debug(pass < 7U); |
| implies(flush == Z_FINISH, png_ptr->zowner == 0U); |
| |
| /* API NOTE: the write callback is made before any changes to the row number |
| * or pass however, in 1.7.0, the zlib stream can be closed before the |
| * callback is made (this is new). The application flush function happens |
| * afterward as was the case before. In 1.7.0 this is solely determined by |
| * the order of the code that follows. |
| */ |
| if (png_ptr->write_row_fn != NULL) |
| png_ptr->write_row_fn(png_ptr, row_number, pass); |
| |
| # ifdef PNG_WRITE_FLUSH_SUPPORTED |
| if (flush == Z_SYNC_FLUSH) |
| { |
| if (png_ptr->output_flush_fn != NULL) |
| png_ptr->output_flush_fn(png_ptr); |
| png_ptr->zlib_state->flush_rows = 0U; |
| } |
| # else /* !WRITE_FLUSH */ |
| PNG_UNUSED(flush) |
| # endif /* !WRITE_FLUSH */ |
| |
| /* Finally advance to the next row/pass: */ |
| if (png_ptr->interlaced == PNG_INTERLACE_NONE) |
| { |
| debug(row_number < png_ptr->height); |
| |
| if (++row_number == png_ptr->height) /* last row */ |
| { |
| row_number = 0U; |
| debug(flush == Z_FINISH); |
| png_ptr->pass = 7U; |
| } |
| } |
| |
| # ifdef PNG_WRITE_INTERLACING_SUPPORTED |
| else /* interlaced */ if (png_ptr->do_interlace) |
| { |
| /* This gets called only for rows that are processed; i.e. rows that |
| * are in the pass of a pass which is itself in the output. |
| */ |
| debug(row_number < png_ptr->height && |
| PNG_PASS_IN_IMAGE(png_ptr->width, png_ptr->height, pass) && |
| pass <= PNG_LAST_PASS(png_ptr->width, png_ptr->height) && |
| PNG_ROW_IN_INTERLACE_PASS(row_number, pass)); |
| |
| /* NOTE: the last row of the original image may not be in the pass, in |
| * this case the code which skipped the row must do the increment |
| * below! See 'interlace_row' in pngwrite.c and the code in |
| * png_write_png_rows below. |
| * |
| * In that case an earlier row will be the last one in the pass (if the |
| * pass is in the output), check this here: |
| */ |
| implies(pass == PNG_LAST_PASS(png_ptr->width, png_ptr->height) && |
| PNG_LAST_PASS_ROW(row_number, pass, png_ptr->height), |
| flush == Z_FINISH); |
| |
| if (++row_number == png_ptr->height) /* last row */ |
| { |
| row_number = 0U; |
| png_ptr->pass = 0x7U & ++pass; |
| } |
| } |
| # endif /* WRITE_INTERLACING */ |
| |
| else /* application does interlace */ |
| { |
| implies(png_ptr->height == 1U, pass != 6U); |
| debug(PNG_PASS_IN_IMAGE(png_ptr->width, png_ptr->height, pass) && |
| row_number < PNG_PASS_ROWS(png_ptr->height, pass)); |
| |
| if (++row_number == PNG_PASS_ROWS(png_ptr->height, pass)) |
| { |
| /* last row in this pass, next one may be empty. */ |
| row_number = 0U; |
| |
| do |
| ++pass; |
| while (pass < 7U && |
| !PNG_PASS_IN_IMAGE(png_ptr->width, png_ptr->height, pass)); |
| |
| implies(png_ptr->height == 1U, pass != 6U); |
| implies(pass == 7U, flush == Z_FINISH); |
| png_ptr->pass = 0x7U & pass; |
| } |
| } |
| |
| png_ptr->row_number = row_number; |
| } |
| |
| #ifdef PNG_WRITE_FLUSH_SUPPORTED |
| /* Flush the current output buffers now */ |
| void PNGAPI |
| png_write_flush(png_structrp png_ptr) |
| { |
| png_debug(1, "in png_write_flush"); |
| |
| /* Force a flush at the end of the current row by setting 'flush_rows' to the |
| * maximum: |
| */ |
| if (png_ptr != NULL && png_ptr->zlib_state != NULL) |
| png_ptr->zlib_state->flush_rows = 0xEFFFFFFF; |
| } |
| |
| /* Return the correct flush to use */ |
| static int |
| row_flush(png_zlib_statep ps, unsigned int row_info_flags) |
| { |
| if (PNG_IDAT_END(row_info_flags)) |
| return Z_FINISH; |
| |
| else if ((row_info_flags & png_row_end) != 0 && |
| ++ps->flush_rows >= ps->flush_dist) |
| return Z_SYNC_FLUSH; |
| |
| else |
| return Z_NO_FLUSH; |
| } |
| #else /* !WRITE_FLUSH */ |
| # define row_flush(ps, ri) (PNG_IDAT_END(ri) ? Z_FINISH : Z_NO_FLUSH) |
| #endif /* !WRITE_FLUSH */ |
| |
| static void |
| write_filtered_row(png_structrp png_ptr, png_const_voidp filtered_row, |
| unsigned int row_bytes, unsigned int filter /*if at start of row*/, |
| int flush) |
| { |
| /* This handles writing a row that has been filtered, or did not need to be |
| * filtered. If the data row has a partial pixel it must have been handled |
| * correctly in the caller; filters generate a full 8 bits even if the pixel |
| * only has one significant bit! |
| */ |
| debug(row_bytes > 0); |
| affirm(row_bytes <= ZLIB_IO_MAX); /* I.e. it fits in a uInt */ |
| |
| if (filter < PNG_FILTER_VALUE_LAST) /* start of row */ |
| { |
| png_byte buffer[1]; |
| |
| buffer[0] = PNG_BYTE(filter); |
| png_compress_IDAT(png_ptr, buffer, 1U/*len*/, Z_NO_FLUSH); |
| } |
| |
| png_compress_IDAT(png_ptr, filtered_row, row_bytes, flush); |
| } |
| |
| static void |
| write_unfiltered_rowbits(png_structrp png_ptr, png_const_bytep filtered_row, |
| unsigned int row_bits, png_byte filter /*if at start of row*/, |
| int flush) |
| { |
| /* Same as above, but it correctly clears the unused bits in a partial |
| * byte. |
| */ |
| const png_uint_32 row_bytes = row_bits >> 3; |
| |
| debug(filter == PNG_FILTER_VALUE_NONE || filter == PNG_FILTER_VALUE_LAST); |
| |
| if (row_bytes > 0U) |
| { |
| row_bits -= row_bytes << 3; |
| write_filtered_row(png_ptr, filtered_row, row_bytes, filter, |
| row_bits == 0U ? flush : Z_NO_FLUSH); |
| filter = PNG_FILTER_VALUE_LAST; /* written */ |
| } |
| |
| /* Handle a partial byte. */ |
| if (row_bits > 0U) |
| { |
| png_byte buffer[1]; |
| |
| buffer[0] = PNG_BYTE(filtered_row[row_bytes] & ~(0xFFU >> row_bits)); |
| write_filtered_row(png_ptr, buffer, 1U, filter, flush); |
| } |
| } |
| |
| #ifdef PNG_WRITE_FILTER_SUPPORTED |
| static void |
| filter_block_singlebyte(unsigned int row_bytes, png_bytep sub_row, |
| png_bytep up_row, png_bytep avg_row, png_bytep paeth_row, |
| png_const_bytep row, png_const_bytep prev_row, png_bytep prev_pixels) |
| { |
| /* Calculate rows for all four filters where the input has one byte per pixel |
| * (more accurately per filter-unit). |
| */ |
| png_byte a = prev_pixels[0]; |
| png_byte c = prev_pixels[1]; |
| |
| while (row_bytes-- > 0U) |
| { |
| const png_byte x = *row++; |
| const png_byte b = prev_row == NULL ? 0U : *prev_row++; |
| |
| /* Calculate each filtered byte in turn: */ |
| if (sub_row != NULL) *sub_row++ = 0xFFU & (x - a); |
| if (up_row != NULL) *up_row++ = 0xFFU & (x - b); |
| if (avg_row != NULL) *avg_row++ = 0xFFU & (x - (a+b)/2U); |
| |
| /* Paeth is a little more difficult: */ |
| if (paeth_row != NULL) |
| { |
| int pa = b-c; /* a+b-c - a */ |
| int pb = a-c; /* a+b-c - b */ |
| int pc = pa+pb; /* a+b-c - c = b-c + a-c */ |
| png_byte p = a; |
| |
| pa = abs(pa); |
| pb = abs(pb); |
| if (pa > pb) pa = pb, p = b; |
| if (pa > abs(pc)) p = c; |
| |
| *paeth_row++ = 0xFFU & (x - p); |
| } |
| |
| /* And set a and c for the next pixel: */ |
| a = x; |
| c = b; |
| } |
| |
| /* Store a and c for the next block: */ |
| prev_pixels[0] = a; |
| prev_pixels[1] = c; |
| } |
| |
| static void |
| filter_block_multibyte(unsigned int row_bytes, |
| const unsigned int bpp, png_bytep sub_row, png_bytep up_row, |
| png_bytep avg_row, png_bytep paeth_row, png_const_bytep row, |
| png_const_bytep prev_row, png_bytep prev_pixels) |
| { |
| /* Calculate rows for all four filters, the input is a block of bytes such |
| * that row_bytes is a multiple of bpp. bpp can be 2, 3, 4, 6 or 8. |
| * prev_pixels will be updated to the last pixels processed. |
| */ |
| while (row_bytes >= bpp) |
| { |
| unsigned int i; |
| |
| for (i=0; i<bpp; ++i) |
| { |
| const png_byte a = prev_pixels[i]; |
| const png_byte c = prev_pixels[i+bpp]; |
| const png_byte b = prev_row == NULL ? 0U : *prev_row++; |
| const png_byte x = *row++; |
| |
| /* Save for the next pixel: */ |
| prev_pixels[i] = x; |
| prev_pixels[i+bpp] = b; |
| |
| /* Calculate each filtered byte in turn: */ |
| if (sub_row != NULL) *sub_row++ = 0xFFU & (x - a); |
| if (up_row != NULL) *up_row++ = 0xFFU & (x - b); |
| if (avg_row != NULL) *avg_row++ = 0xFFU & (x - (a+b)/2U); |
| |
| /* Paeth is a little more difficult: */ |
| if (paeth_row != NULL) |
| { |
| int pa = b-c; /* a+b-c - a */ |
| int pb = a-c; /* a+b-c - b */ |
| int pc = pa+pb; /* a+b-c - c = b-c + a-c */ |
| png_byte p = a; |
| |
| pa = abs(pa); |
| pb = abs(pb); |
| if (pa > pb) pa = pb, p = b; |
| if (pa > abs(pc)) p = c; |
| |
| *paeth_row++ = 0xFFU & (x - p); |
| } |
| } |
| |
| row_bytes -= i; |
| } |
| } |
| |
| static void |
| filter_block(png_const_bytep prev_row, png_bytep prev_pixels, |
| png_const_bytep unfiltered_row, unsigned int row_bits, |
| const unsigned int bpp, png_bytep sub_row, png_bytep up_row, |
| png_bytep avg_row, png_bytep paeth_row) |
| { |
| const unsigned int row_bytes = row_bits >> 3; /* complete bytes */ |
| |
| if (bpp <= 8U) |
| { |
| /* There may be a partial byte at the end. */ |
| if (row_bytes > 0) |
| filter_block_singlebyte(row_bytes, sub_row, up_row, avg_row, paeth_row, |
| unfiltered_row, prev_row, prev_pixels); |
| |
| /* The partial byte must be handled correctly here; both the previous row |
| * value and the current value need to have non-present bits cleared. |
| */ |
| if ((row_bits & 7U) != 0) |
| { |
| const png_byte mask = PNG_BYTE(~(0xFFU >> (row_bits & 7U))); |
| png_byte buffer[2]; |
| |
| buffer[0] = unfiltered_row[row_bytes] & mask; |
| |
| if (prev_row != NULL) |
| buffer[1U] = prev_row[row_bytes] & mask; |
| |
| else |
| buffer[1U] = 0U; |
| |
| filter_block_singlebyte(1U, |
| sub_row == NULL ? NULL : sub_row+row_bytes, |
| up_row == NULL ? NULL : up_row+row_bytes, |
| avg_row == NULL ? NULL : avg_row+row_bytes, |
| paeth_row == NULL ? NULL : paeth_row+row_bytes, |
| buffer, buffer+1U, prev_pixels); |
| } |
| } |
| |
| else |
| filter_block_multibyte(row_bytes, bpp >> 3, |
| sub_row, up_row, avg_row, paeth_row, |
| unfiltered_row, prev_row, prev_pixels); |
| } |
| |
| static void |
| filter_row(png_structrp png_ptr, png_const_bytep prev_row, |
| png_bytep prev_pixels, png_const_bytep unfiltered_row, |
| unsigned int row_bits, unsigned int bpp, unsigned int filter, |
| int start_of_row, int flush) |
| { |
| /* filters_to_try identifies a single filter and it is not PNG_FILTER_NONE. |
| */ |
| png_byte filtered_row[PNG_ROW_BUFFER_SIZE]; |
| |
| affirm((row_bits+7U) >> 3 <= PNG_ROW_BUFFER_SIZE && |
| filter >= PNG_FILTER_VALUE_SUB && filter <= PNG_FILTER_VALUE_PAETH); |
| debug((row_bits % bpp) == 0U); |
| |
| filter_block(prev_row, prev_pixels, unfiltered_row, row_bits, bpp, |
| filter == PNG_FILTER_VALUE_SUB ? filtered_row : NULL, |
| filter == PNG_FILTER_VALUE_UP ? filtered_row : NULL, |
| filter == PNG_FILTER_VALUE_AVG ? filtered_row : NULL, |
| filter == PNG_FILTER_VALUE_PAETH ? filtered_row : NULL); |
| |
| write_filtered_row(png_ptr, filtered_row, (row_bits+7U)>>3, |
| start_of_row ? filter : PNG_FILTER_VALUE_LAST, flush); |
| } |
| |
| /* Allow the application to select one or more row filters to use. */ |
| static png_int_32 |
| set_filter(png_zlib_statep ps, unsigned int filtersIn) |
| { |
| /* Notice that PNG_NO_FILTERS is 0 and passes this test; this is OK because |
| * filters then gets set to PNG_FILTER_NONE, as is required. |
| * |
| * The argument to this routine is actually an (int), but conversion to |
| * (unsigned int) is safe because it leaves the top bits set which results in |
| * PNG_EDOM below. |
| */ |
| if (filtersIn < PNG_FILTER_NONE) |
| filtersIn = PNG_FILTER_MASK(filtersIn); |
| |
| /* PNG_ALL_FILTERS is a constant, unfortunately it is nominally signed, for |
| * historical reasons, hence the PNG_BIC_MASK here. |
| */ |
| if ((filtersIn & PNG_BIC_MASK(PNG_ALL_FILTERS)) == 0U) |
| { |
| # ifndef PNG_SELECT_FILTER_SUPPORTED |
| filtersIn &= -filtersIn; /* Use lowest set bit */ |
| # endif /* !SELECT_FILTER */ |
| |
| return ps->filter_mask = filtersIn & PNG_ALL_FILTERS; |
| } |
| |
| else /* Out-of-range filtersIn: */ |
| return PNG_EDOM; |
| } |
| #endif /* WRITE_FILTER */ |
| |
| #ifdef PNG_WRITE_FILTER_SUPPORTED |
| void /* PRIVATE */ |
| png_write_start_IDAT(png_structrp png_ptr) |
| { |
| png_zlib_statep ps = get_zlib_state(png_ptr); |
| |
| /* Set up the IDAT compression state. Expect the state to have been released |
| * by the previous owner, but it doesn't much matter if there was an error. |
| * Note that the stream is not claimed yet. |
| */ |
| debug(png_ptr->zowner == 0U); |
| |
| /* This sets the buffer limits and write_row_size, which is used below. */ |
| png_zlib_state_set_buffer_limits(png_ptr, ps); |
| |
| if (ps->filter_mask == 0) |
| { |
| # ifdef PNG_SELECT_FILTER_SUPPORTED |
| /* Now default the filter mask if it hasn't been set already: */ |
| int png_level = |
| pz_get(ps, IDAT, png_level, PNG_DEFAULT_COMPRESSION_LEVEL); |
| |
| /* If the bit depth is less than 8, so pixels are not byte aligned, PNG |
| * filtering hardly ever helps because there is no correlation between |
| * the bytes on which the filter works and the actual pixel values. |
| * Note that GIF is a whole lot better at this because it uses LZW to |
| * compress a bit-stream, not a byte stream as in the deflate |
| * implementation of LZ77. |
| * |
| * If the row size is less than 256 bytes filter selection algorithms |
| * are flakey because the restricted range of codes in each row can |
| * lead to poor selection of filters, particularly if the bytes in the |
| * image are themselves limited. (This happens when a low bit-depth |
| * image is encoded with 8-bit channels.) |
| * |
| * By experiment with the test set of images the breakpoint between |
| * not filtering and filtering based on which gives best compression by |
| * row size is as follows: |
| * |
| * NONE FAST ALL |
| * PAL <=anything [even 8-bit palette images larger if filtered] |
| * G<8 <=anything [low bit depth gray images] |
| * G8 <=16 [+~1%] >16 |
| * G16 <=128 [+~1%] >128 |
| * GA8 <=64 [+~1%] >64 |
| * GA16 <=anything [always better without filtering!] |
| * RGB8 <=32 [+0-2%(1)] >32 |
| * RGB16 <=1024 [+~1%] >1024 |
| * RGBA8 <=64 [+~~1%] >64 |
| * RGBA16 <=128 {+~0.5%] >128 |
| * |
| * (1) The largest 24-bit RGB image (RGB8) faired better, by 1.3%, |
| * with 'fast' filters. This is assumed to be random. |
| * |
| * Aggregated across all color types and bit depths the breakpoint for |
| * filtering is >16 bytes, but the size increase only exceeds 0.5% for |
| * images with rows between 64 and 128 bytes, hence the choices below. |
| * |
| * Across all the test images that change (not including selecting just |
| * the 'fast' filters by default) does not change the compressed size |
| * significantly (+0.06% across the whole test set), however it does |
| * substantially increase the number of images without filtering. |
| * |
| * Using just none and sub filters results in overall compressed sizes |
| * somewhere around the geometric mean of no filtering and 'fast'. |
| * |
| * The image size also plays a part. Filtering is not an advantage for |
| * images of size <= 512 bytes. This is also reflected below. |
| * |
| * NOTE: the libpng 1.6 (and earlier) algorithm seems to work |
| * because it biases the byte codes in the output towards 0 and 255. |
| * Zlib doesn't care what the codes are, but Huffman encoding always |
| * benefits from a biased distribution and the filters themselves were |
| * designed to produce values in this range. |
| * |
| * In a raw comparison with the legacy code selection of specific sets |
| * of filters always increased the compressed size of the test set, as |
| * follows: |
| * |
| * PNG_ALL_FILTERS: +0.26% |
| * PNG_FAST_FILTERS: +1.9% |
| * NONE+SUB: +5.8% |
| * PNG_NO_FILTERS: +14% |
| * |
| * This mainly proves that a static selection of filters (without |
| * considering the PNG format) is always worse than the legacy |
| * algorithm below. |
| * |
| * NOTE: ps->filter_mask must be set to a mask value, not a simple |
| * PNG_FILTER_VALUE_ number. |
| */ |
| if (ps->write_row_size == 0U /* row cannot be buffered */) |
| ps->filter_mask = PNG_FILTER_NONE; |
| |
| else if (png_level == PNG_COMPRESSION_COMPAT/* Legacy */) |
| { |
| if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE || |
| png_ptr->bit_depth < 8U) |
| ps->filter_mask = PNG_FILTER_NONE; |
| |
| else |
| ps->filter_mask = PNG_ALL_FILTERS; |
| } |
| |
| /* NOTE: overall with the following size tests (row and image size) the |
| * test set of images end up 0.06% larger, however some color types are |
| * smaller and some larger; the differences are minute. If the test is |
| * <=128 (which means <=129 bytes per row with the filter byte) the |
| * resultant inclusion of 32x32 RGBA images results in significantly |
| * increased compressed size. |
| * |
| * The test on png_level captures the following settings: |
| * |
| * PNG_COMPRESSION_LOW_MEMORY |
| * PNG_COMPRESSION_HIGH_SPEED |
| * PNG_COMPRESSION_HIGH_READ_SPEED |
| * |
| * NOTE: this relies on the exact values in png.h! |
| */ |
| else if (png_level <= PNG_COMPRESSION_HIGH_READ_SPEED |
| || png_ptr->color_type == PNG_COLOR_TYPE_PALETTE |
| || png_ptr->bit_depth < 8U |
| || ps->write_row_size/*does not include filter*/ < 128U |
| || png_image_size(png_ptr) <= 512U) |
| ps->filter_mask = PNG_FILTER_NONE; |
| |
| /* ELSE: there are at least 128 bytes in every row and the pixels |
| * are multiples of a byte. |
| */ |
| else switch (png_level) |
| { |
| default: /* For GCC */ |
| case PNG_COMPRESSION_LOW: |
| ps->filter_mask = PNG_FILTER_NONE+PNG_FILTER_SUB; |
| break; |
| |
| case PNG_COMPRESSION_MEDIUM: |
| ps->filter_mask = PNG_FAST_FILTERS; |
| break; |
| |
| case PNG_COMPRESSION_HIGH: |
| ps->filter_mask = PNG_ALL_FILTERS; |
| break; |
| } |
| # else /* !SELECT_FILTER */ |
| ps->filter_mask = PNG_FILTER_NONE; |
| # endif /* !SELECT_FILTER */ |
| } |
| } |
| |
| static png_byte |
| png_write_start_row(png_zlib_statep ps, int start_of_pass, int no_previous_row) |
| /* Called at the start of a row to set up anything required for filter |
| * handling in the row. Sets png_zlib_state::filters to a single filter. |
| */ |
| { |
| unsigned int mask = ps->filter_mask; |
| |
| /* If we see a previous-row filter in mask and png_zlib_state::save_row is |
| * still unset set it. This means that the first time a previous-row filter |
| * is seen row-saving gets turned on. |
| */ |
| if (ps->save_row == SAVE_ROW_UNSET && (mask & PREVIOUS_ROW_FILTERS) != 0U) |
| ps->save_row = SAVE_ROW_DEFAULT; |
| |
| if ((no_previous_row /* row not stored */ && !start_of_pass) || |
| ps->save_row == SAVE_ROW_OFF /* disabled by app */ || |
| ps->write_row_size == 0U /* row too large to buffer */) |
| mask &= PNG_BIC_MASK(PREVIOUS_ROW_FILTERS); |
| |
| /* On the first row of a pass Paeth is equivalent to sub and up is equivalent |
| * to none, so try to simplify the mask in in this case. |
| */ |
| else if (start_of_pass) { |
| # define MATCH(flags) ((mask & (flags)) == (flags)) |
| if (MATCH(PNG_FILTER_NONE|PNG_FILTER_UP)) |
| mask &= PNG_BIC_MASK(PNG_FILTER_UP); |
| |
| if (MATCH(PNG_FILTER_SUB|PNG_FILTER_PAETH)) |
| mask &= PNG_BIC_MASK(PNG_FILTER_PAETH); |
| # undef MATCH |
| } |
| |
| # ifdef PNG_SELECT_FILTER_SUPPORTED |
| if ((mask & (mask-1U)) == 0U /* single bit set */ || |
| ps->write_row_size == 0U /* row cannot be buffered */) |
| # endif /* SELECT_FILTER */ |
| /* Convert the lowest set bit into the corresponding value. If no bits |
| * are set select NONE. After this switch statement the value of |
| * ps->filters is guaranteed to just be a single filter. |
| */ |
| switch (mask & -mask) |
| { |
| default: mask = PNG_FILTER_VALUE_NONE; break; |
| case PNG_FILTER_SUB: mask = PNG_FILTER_VALUE_SUB; break; |
| case PNG_FILTER_UP: mask = PNG_FILTER_VALUE_UP; break; |
| case PNG_FILTER_AVG: mask = PNG_FILTER_VALUE_AVG; break; |
| case PNG_FILTER_PAETH: mask = PNG_FILTER_VALUE_PAETH; break; |
| } |
| |
| return ps->filters = PNG_BYTE(mask); |
| } |
| |
| static png_bytep |
| allocate_row(png_structrp png_ptr, png_const_bytep data, png_alloc_size_t size) |
| /* Utility to allocate and save some row bytes. If the result is NULL the |
| * allocation failed and the png_zlib_struct will have been updated to |
| * prevent further allocation attempts. |
| */ |
| { |
| const png_zlib_statep ps = png_ptr->zlib_state; |
| png_bytep buffer; |
| |
| debug(ps->write_row_size > 0U); |
| |
| /* OOM is handled silently, as is the case where the row is too large to |
| * buffer. |
| */ |
| buffer = png_voidcast(png_bytep, |
| png_malloc_base(png_ptr, ps->write_row_size)); |
| |
| /* Setting write_row_size to 0 switches on the code for handling a row that |
| * is too large to buffer. This will kick in next time round, i.e. on the |
| * next row. |
| */ |
| if (buffer == NULL) |
| ps->write_row_size = 0U; |
| |
| else |
| memcpy(buffer, data, size); |
| |
| return buffer; |
| } |
| #endif /* WRITE_FILTER */ |
| |
| #ifdef PNG_SELECT_FILTER_SUPPORTED |
| /* Bit set operations. Not in ANSI C-90 but commonly available in highly |
| * optimized versions, hence the ifndef. These operations just work on bitsets |
| * of size 256. The second argument (the code index) may be evaluated multiple |
| * times. |
| */ |
| #ifndef PNG_CODE_SET /* Can be set in pngpriv.h */ |
| typedef png_uint_32 png_codeset[8]; |
| # define PNG_CODE_MASK(i) (((png_uint_32)1U) << ((i) & 0x1FU)) |
| # define PNG_CODE_IS_SET(c,i) (((c)[(i) >> 5] & PNG_CODE_MASK(i))) |
| # define PNG_CODE_SET(c,i) (((c)[(i) >> 5] |= PNG_CODE_MASK(i))) |
| # define PNG_CODE_CLEAR(c,i) (((c)[(i) >> 5] &= ~PNG_CODE_MASK(i))) |
| #endif /* !PNG_CODE_SET */ |
| |
| typedef struct filter_selector |
| { |
| /* Persistent filter selection information (stored across row boundaries). |
| * A code is not considered if it last occured more than 'window' bytes ago. |
| * The deflate algorithm means that 'window' cannot exceed 8453377, however |
| * practical versions may be far less. When 'distance' reaches 'window' any |
| * code where: |
| * |
| * distance - code_distance[code] > window |
| * |
| * at the end of a row 'code' is removed from codeset. Otherwise |
| * (rearranging the above): |
| * |
| * distance - window <= code_distance[code] |
| * |
| * and so the distances of the still active codes can be reduced: |
| * |
| * code_distance[code] -= distance-window |
| * distance = window |
| * |
| * This prevents any wrap of 'distance' on a row which is shorter than |
| * 2^32-window. |
| * |
| * However when then row is 2^32-window or more bytes long (the row can be up |
| * to just under 2^34 bytes long) this algorithm doesn't work; 'distance' |
| * will overflow in the middle of the row and all codes are relevant. This |
| * is handled below simply by reseting the set of present codes at the start |
| * of the row and ignoring the overflow. |
| */ |
| unsigned int code_count; /* Number of distinct codes seen */ |
| int png_level; /* Cached compression level */ |
| png_uint_32 filter_select_max_width; |
| /* The maximum number of pixels which can be fitted in the window without |
| * filling the entire window (i.e. the maximum number that can be fitted |
| * in (window-1) bytes). |
| */ |
| png_uint_32 sum_bias[PNG_FILTER_VALUE_LAST]; |
| /* For each filter a measure of its cost in the filter sum calculation. |
| * This allows filter selection based on the sum-of-absolute-dfferences |
| * method to be biased to favour particular filters. There was no such |
| * bias before 1.7 and the filter byte was ignored. |
| */ |
| png_uint_32 distance; /* Distance from beginning */ |
| png_codeset codeset; /* Set of seen codes */ |
| png_uint_32 code_distance[256]; /* Distance at last occurence */ |
| } filter_selector; |
| |
| static const filter_selector * |
| png_start_filter_select(png_zlib_statep ps, unsigned int bpp) |
| { |
| # define png_ptr ps_png_ptr(ps) |
| filter_selector *fs = ps->selector; |
| |
| if (fs == NULL) |
| { |
| fs = png_voidcast(filter_selector*, png_malloc_base(png_ptr, sizeof *fs)); |
| |
| if (fs != NULL) |
| { |
| png_uint_32 window = ps->filter_select_window; |
| fs->png_level = pz_get(ps, IDAT, png_level, |
| PNG_DEFAULT_COMPRESSION_LEVEL); |
| |
| /* Delay initialize this here: */ |
| if (window < 3U || window > PNG_FILTER_SELECT_WINDOW_MAX) |
| ps->filter_select_window = window = PNG_FILTER_SELECT_WINDOW_MAX; |
| |
| fs->code_count = 0; |
| |
| switch (fs->png_level) |
| { |
| default: |
| /* TODO: investigate other settings */ |
| { |
| unsigned int f; |
| |
| for (f=0; f<PNG_FILTER_VALUE_LAST; ++f) |
| fs->sum_bias[f] = f; |
| } |
| ps->filter_select_threshold = 64U; /* 6bit RGB */ |
| ps->filter_select_threshold2 = 50U; /* TODO: experiment! */ |
| break; |
| |
| case PNG_COMPRESSION_COMPAT: /* Legacy */ |
| memset(fs->sum_bias, 0U, sizeof fs->sum_bias); |
| ps->filter_select_threshold = 1U; /* disabled */ |
| ps->filter_select_threshold2 = 1U; |
| break; |
| } |
| |
| /* This is the maximum row width, in pixels, of a row which fits and |
| * leaves 1 byte free in the window. For any bigger row filter |
| * selection ignores the previous rows. |
| */ |
| fs->filter_select_max_width = ((window-2U/*filter+last byte*/)*8U)/bpp; |
| fs->distance = 0U; |
| memset(fs->codeset, 0U, sizeof fs->codeset); |
| /* fs->code_distance is left uninitialized because fs->codeset says |
| * whether or not each entry has been initialized. |
| */ |
| ps->selector = fs; |
| } |
| |
| else |
| ps->write_row_size = 0U; /* OOM */ |
| } |
| # undef png_ptr |
| |
| return fs; |
| } |
| |
| typedef struct |
| { |
| /* Per-filter data. This remains separate from the above until the filter |
| * selection has been made. It reflects the above however the codeset only |
| * records codes present in this row. |
| * |
| * The 'sum' fields are the sum of the absolute deviation of each code from |
| * 0, the algorithm from 1.6 and earlier. In other words: |
| * |
| * if (code >= 128) |
| * sum += code; |
| * else |
| * sum += 256-code; |
| */ |
| unsigned int code_count; /* Number of distinct codes seen in row */ |
| unsigned int new_code_count; /* Number of new codes seen in row */ |
| png_uint_32 sum_low; /* Low 31 bits of code sum */ |
| png_uint_32 sum_high; /* High 32 bits of code sum */ |
| png_codeset codeset; /* Set of codes seen in this row */ |
| png_uint_32 code_distance[256]; /* Distance at last occurence in this row */ |
| } filter_data; |
| |
| static void |
| filter_data_init(filter_data *fd, png_uint_32 distance, unsigned int filter, |
| unsigned int code_is_set, png_uint_32 bias) |
| { |
| fd->code_count = 1U; |
| fd->new_code_count = !code_is_set; |
| fd->sum_low = bias; |
| fd->sum_high = 0U; |
| memset(&fd->codeset, 0U, sizeof fd->codeset); |
| PNG_CODE_SET(fd->codeset, filter); |
| fd->code_distance[filter] = distance; |
| } |
| |
| static void |
| add_code(const filter_selector *fs, filter_data *fd, png_uint_32 distance, |
| unsigned int code) |
| { |
| if (!PNG_CODE_IS_SET(fd->codeset, code)) |
| { |
| PNG_CODE_SET(fd->codeset, code); |
| ++(fd->code_count); |
| fd->code_distance[code] = distance; |
| if (!PNG_CODE_IS_SET(fs->codeset, code)) |
| ++(fd->new_code_count); |
| } |
| |
| { |
| png_uint_32 low = fd->sum_low; |
| |
| if (code <= 128U) |
| low += code; |
| |
| else |
| low += 256U-code; |
| |
| /* Handle overflow into the top bit: */ |
| if (low & 0x80000000U) |
| fd->sum_low = low & 0x7FFFFFFFU, ++fd->sum_high; |
| |
| else |
| fd->sum_low = low; |
| } |
| } |
| |
| static png_byte |
| filter_data_select(png_zlib_statep ps, filter_data fd[PNG_FILTER_VALUE_LAST], |
| unsigned int filter, png_uint_32 distance, png_uint_32 w) |
| { |
| # define png_ptr ps_png_ptr(ps) |
| /* Choose how to do this depending on the row and window size. */ |
| filter_selector *fs = ps->selector; |
| png_uint_32 window = ps->filter_select_window; |
| |
| affirm(fs != NULL); |
| |
| /* Check the width against the maximum number of pixels that can fit in a |
| * window without filling it: |
| */ |
| if (w > fs->filter_select_max_width) |
| { |
| /* The cache is not used */ |
| fs->distance = 0U; /* for next row */ |
| fs->code_count = 0U; |
| memset(fs->codeset, 0U, sizeof fs->codeset); |
| } |
| |
| else |
| { |
| /* Merge the two code sets, discounting codes that last occurred before |
| * the start of the window. |
| */ |
| png_uint_32 adjust, code_count; |
| unsigned int code; |
| |
| /* filter_selector::distance is the distance of the first byte in the row |
| * (the filter byte), but 'distance' can wrap on long rows. The above |
| * test is meant to exclude the wrap case by excluding any case where the |
| * row has as many bytes as the window, so: |
| */ |
| affirm(distance > fs->distance && distance - fs->distance < window); |
| |
| /* Set 'adjust' to the current distance of the start of the window. I.e: |
| * |
| * +---------------+--------+ |
| * | before window | window | future data |
| * +---------------+--------+ |
| * A A |
| * | | |
| * adjust + + distance |
| * |
| * If the window isn't full yet 'adjust' will be zero, otherwise all the |
| * distances will be reduced by 'adjust' so that the first byte of the |
| * window has distance 0. |
| */ |
| if (distance > window) |
| adjust = distance-window; |
| |
| else |
| adjust = 0; |
| |
| |
| /* This may be decreased below if some old codes only occured before the |
| * start of the window. |
| */ |
| code_count = fs->code_count + fd->new_code_count; |
| |
| for (code=0U; code<256U; ++code) |
| { |
| if (PNG_CODE_IS_SET(fd[filter].codeset, code)) |
| { |
| PNG_CODE_SET(fs->codeset, code); |
| debug(fd[filter].code_distance[code] >= adjust); |
| fs->code_distance[code] = fd[filter].code_distance[code] - adjust; |
| } |
| |
| else if (PNG_CODE_IS_SET(fs->codeset, code) && adjust > 0) |
| { |
| /* The code did not occur in this row, the old distance may now be |
| * outside the window (because adjust is non-zero). |
| */ |
| const png_uint_32 d = fs->code_distance[code]; |
| |
| if (d >= adjust) |
| fs->code_distance[code] = d-adjust; |
| |
| else |
| PNG_CODE_CLEAR(fs->codeset, code), --code_count; |
| } |
| } |
| |
| fs->code_count = code_count; |
| fs->distance = distance - adjust; /* I.e. either distance or window! */ |
| } |
| |
| return ps->filters = PNG_BYTE(filter); |
| # undef png_ptr |
| } |
| |
| static png_byte |
| select_filter(png_zlib_statep ps, png_const_bytep row, |
| png_const_bytep prev, unsigned int bpp, png_uint_32 width, int start_of_pass) |
| /* Select a filter from the list provided by png_write_start_row. */ |
| { |
| png_byte filters = png_write_start_row(ps, start_of_pass, prev == NULL); |
| |
| # define png_ptr ps_png_ptr(ps) |
| if (filters >= PNG_FILTER_NONE) /* multiple filters to test */ |
| { |
| const png_uint_32 max_pixels = ps->row_buffer_max_pixels; |
| const png_uint_32 block_pixels = ps->row_buffer_max_aligned_pixels; |
| const filter_selector *fs = ps->selector; |
| png_uint_32 pixels_to_go = width; |
| png_uint_32 distance; |
| unsigned int bits_at_end = 0U; |
| png_byte prev_pixels[4*2*2]; /* 2 pixels up to 4x2-bytes each */ |
| filter_data fd[PNG_FILTER_VALUE_LAST]; |
| |
| debug((filters & (filters-1)) != 0U); /* Expect more than one bit! */ |
| |
| if (fs == NULL) |
| { |
| /* Delay initialize with a quiet OOM handler */ |
| fs = png_start_filter_select(ps, bpp); |
| if (fs == NULL) |
| { |
| ps->filters = PNG_FILTER_VALUE_NONE; |
| return PNG_FILTER_VALUE_NONE; |
| } |
| } |
| |
| /* If PNG_FILTER_NONE is in the list check it first. */ |
| if (filters & PNG_FILTER_NONE) |
| { |
| png_const_bytep rp = row; |
| png_uint_32 w = width; |
| |
| distance = fs->distance; |
| filter_data_init(fd+PNG_FILTER_VALUE_NONE, distance++, |
| PNG_FILTER_VALUE_NONE, |
| PNG_CODE_IS_SET(fs->codeset, PNG_FILTER_VALUE_NONE), |
| fs->sum_bias[PNG_FILTER_VALUE_NONE]); |
| |
| if (bpp >= 8) /* complete bytes */ |
| { |
| const unsigned int bytes = bpp/8U; |
| |
| while (w > 0) |
| { |
| unsigned int b; |
| for (b=0; b<bytes; ++b) |
| add_code(fs, fd+PNG_FILTER_VALUE_NONE, distance++, *rp++); |
| --w; |
| } |
| } |
| |
| else /* multiple pixels per byte */ |
| { |
| const unsigned int ppb = 8U/bpp; |
| |
| debug(ppb * bpp == 8U); /* Expect bpp to be a power of 2 */ |
| |
| while (w >= ppb) |
| { |
| add_code(fs, fd+PNG_FILTER_VALUE_NONE, distance++, *rp++); |
| w -= ppb; |
| } |
| |
| if (w > 0) /* partial byte at end */ |
| add_code(fs, fd+PNG_FILTER_VALUE_NONE, distance++, |
| *rp & (0xFFU >> (w*bpp) /* zero unused bits */)); |
| } |
| |
| /* For PNG data with a small number of codes it is worth skipping the |
| * filtering because it almost always increases the code count |
| * significantly. This is controlled by |
| * png_zlib_state::filter_select_threshold and causes an early return |
| * here. |
| */ |
| if (fd[PNG_FILTER_VALUE_NONE].new_code_count + |
| fs->code_count < ps->filter_select_threshold) |
| return filter_data_select(ps, fd, PNG_FILTER_VALUE_NONE, distance, |
| width); |
| } /* PNG_FILTER_NONE */ |
| |
| memset(prev_pixels, 0U, sizeof prev_pixels); |
| distance = fs->distance; |
| |
| { |
| unsigned int i; |
| |
| for (i=PNG_FILTER_VALUE_NONE+1U; i<PNG_FILTER_VALUE_LAST; ++i) |
| if (PNG_FILTER_MASK(i) & filters) |
| filter_data_init(fd+i, distance, i, |
| PNG_CODE_IS_SET(fs->codeset, i), fs->sum_bias[i]); |
| } |
| |
| ++distance; |
| |
| while (pixels_to_go || bits_at_end) |
| { |
| unsigned int bits, i; |
| union |
| { |
| PNG_ROW_BUFFER_ALIGN_TYPE force_buffer_alignment; |
| png_byte row[4][PNG_ROW_BUFFER_SIZE]; |
| } filtered; |
| union |
| { |
| PNG_ROW_BUFFER_ALIGN_TYPE force_buffer_alignment; |
| png_byte byte; |
| } last; |
| |
| if (pixels_to_go) |
| { |
| if (pixels_to_go > max_pixels) |
| { |
| /* Maintain alignment by consuming on block_pixels at once */ |
| bits = block_pixels * bpp; |
| pixels_to_go -= block_pixels; /* May be 0 */ |
| } |
| |
| else |
| { |
| bits = pixels_to_go * bpp; |
| bits_at_end = bits & 0x7U; |
| bits -= bits_at_end; |
| pixels_to_go = 0U; /* +bits_at_end */ |
| } |
| } |
| |
| else /* incomplete byte at the end of the pixel */ |
| { |
| /* Make sure the unused bits are cleared (to zero, although this is |
| * an arbitrary choice): |
| */ |
| last.byte = PNG_BYTE(*row & ~(0xFFU >> bits_at_end)); |
| row = &last.byte; |
| bits = bits_at_end; |
| bits_at_end = 0U; |
| } |
| |
| filter_block(prev, prev_pixels, row, bits, bpp, |
| filtered.row[0/*sub*/], filtered.row[1/*up*/], |
| filtered.row[2/*avg*/], filtered.row[3/*Paeth*/]); |
| |
| /* A block of (bits+7)/8 bytes is now available to process. */ |
| for (i=0; 8U*i < bits; ++i, ++distance) |
| { |
| unsigned int f; |
| |
| for (f=PNG_FILTER_VALUE_NONE+1U; f<PNG_FILTER_VALUE_LAST; ++f) |
| if (PNG_FILTER_MASK(f) & filters) |
| add_code(fs, fd+f, distance, filtered.row[f-1U][i]); |
| } |
| |
| if (prev != NULL) |
| prev += bits >> 3; |
| |
| row += bits >> 3; |
| } |
| |
| /* Now look at the candidate filters, including 'none' and select the |
| * best. We know that 'none' increases the code count beyond the |
| * threshold, so if the old code count is below the threshold and there is |
| * a filter which does not increase the code count select it; doing so |
| * should do no harm to the overall compression. |
| */ |
| if (fs->code_count < ps->filter_select_threshold) |
| { |
| unsigned int f, min_new_count = 257U, min_f = PNG_FILTER_VALUE_NONE; |
| |
| for (f=PNG_FILTER_VALUE_NONE+1U; f<PNG_FILTER_VALUE_LAST; ++f) |
| if ((PNG_FILTER_MASK(f) & filters) != 0) |
| { |
| unsigned int new_code_count = fd[f].new_code_count; |
| |
| if (new_code_count == 0U) |
| return filter_data_select(ps, fd, f, distance, width); |
| |
| else if (new_code_count < min_new_count) |
| min_new_count = new_code_count, min_f = f; |
| } |
| |
| /* Use the second threshold to decide whether to select the best filter |
| * on this basis alone: |
| */ |
| if (min_f != PNG_FILTER_VALUE_NONE && |
| fs->code_count + min_new_count < ps->filter_select_threshold2) |
| return filter_data_select(ps, fd, min_f, distance, width); |
| } |
| |
| /* Now fall back to the libpng 1.6 and earlier algorithm. This favours |
| * the filter which produces least deviation in the codes from 0. When |
| * this works it does so by reducing the distribution of code values. The |
| * filters implicitly encode the difference between a predictor based on |
| * adjacent values, the assumption is that this will result in values |
| * close to 0. |
| */ |
| { |
| png_uint_32 high = -1; |
| png_uint_32 low = -1; |
| unsigned int min_f = 0 /*unset, but safe*/; |
| unsigned int f; |
| |
| for (f=PNG_FILTER_VALUE_NONE; f<PNG_FILTER_VALUE_LAST; ++f) |
| if ((PNG_FILTER_MASK(f) & filters) != 0 && |
| (fd[f].sum_high < high || |
| (fd[f].sum_high == high && fd[f].sum_low < low))) |
| { |
| high = fd[f].sum_high; |
| low = fd[f].sum_low; |
| |
| if (low & 0x80000000U) |
| { |
| low &= 0x7FFFFFFFU, --high; |
| if (high & 0x80000000U) |
| low = high = 0U; |
| } |
| |
| min_f = f; |
| } |
| |
| return filter_data_select(ps, fd, min_f, distance, width); |
| } |
| } |
| |
| debug(filters < PNG_FILTER_VALUE_LAST); |
| return ps->filters = filters; |
| # undef png_ptr |
| } |
| #else /* !SELECT_FILTER */ |
| /* Filter selection not being done, just call png_write_start_row: */ |
| # define select_filter(ps, rp, pp, bpp, width, start_of_pass)\ |
| png_write_start_row((ps), (start_of_pass), (pp) == NULL) |
| #endif /* !SELECT_FILTER */ |
| |
| /* This is the common function to write multiple rows of PNG data. The data is |
| * in the relevant PNG format but has had no filtering done. |
| */ |
| void /* PRIVATE */ |
| png_write_png_rows(png_structrp png_ptr, png_const_bytep *rows, |
| png_uint_32 num_rows) |
| { |
| const png_zlib_statep ps = png_ptr->zlib_state; |
| const unsigned int bpp = png_ptr->row_output_pixel_depth; |
| # ifdef PNG_WRITE_FILTER_SUPPORTED |
| png_const_bytep previous_row = ps->previous_write_row; |
| # else /* !WRITE_FILTER */ |
| /* These are constant in the no-filer case: */ |
| const png_byte filter = PNG_FILTER_VALUE_NONE; |
| const png_uint_32 max_pixels = ps->zlib_max_pixels; |
| const png_uint_32 block_pixels = ps->zlib_max_aligned_pixels; |
| # endif /* !WRITE_FILTER */ |
| /* Write the given rows handling the png_compress_IDAT argument limitations |
| * (uInt) and any valid row width. |
| */ |
| png_uint_32 last_row_in_pass = 0U; /* Actual last, not last+1! */ |
| png_uint_32 pixels_in_pass = 0U; |
| unsigned int first_row_in_pass = 0U; /* For do_interlace */ |
| unsigned int pixels_at_end = 0U; /* for a partial byte at the end */ |
| unsigned int base_info_flags = png_row_end; |
| int pass = -1; /* Invalid: force calculation first time round */ |
| |
| debug(png_ptr->row_output_pixel_depth == PNG_PIXEL_DEPTH(*png_ptr)); |
| |
| while (num_rows-- > 0U) |
| { |
| if (png_ptr->pass != pass) |
| { |
| /* Recalcuate the row bytes and partial bits */ |
| pass = png_ptr->pass; |
| pixels_in_pass = png_ptr->width; |
| |
| if (png_ptr->interlaced == PNG_INTERLACE_NONE) |
| { |
| debug(pass == 0); |
| last_row_in_pass = png_ptr->height - 1U; |
| base_info_flags |= png_pass_last; /* there is only one */ |
| } |
| |
| else |
| { |
| const png_uint_32 height = png_ptr->height; |
| |
| last_row_in_pass = PNG_PASS_ROWS(height, pass); |
| debug(pass >= 0 && pass < 7); |
| |
| # ifdef PNG_WRITE_INTERLACING_SUPPORTED |
| if (png_ptr->do_interlace) |
| { |
| /* libpng is doing the interlace handling, the row number is |
| * actually the row in the image. |
| * |
| * This overflows when the PNG height is such that the are no |
| * rows in this pass. This does not matter; because there are |
| * no rows the value doesn't get used. |
| */ |
| last_row_in_pass = |
| PNG_ROW_FROM_PASS_ROW(last_row_in_pass-1U, pass); |
| first_row_in_pass = PNG_PASS_START_ROW(pass); |
| } |
| |
| else /* Application handles the interlace */ |
| # endif /* WRITE_INTERLACING */ |
| { |
| /* The row does exist, so this works without checking the column |
| * count. |
| */ |
| debug(last_row_in_pass > 0U); |
| last_row_in_pass -= 1U; |
| } |
| |
| if (pass == PNG_LAST_PASS(pixels_in_pass/*PNG width*/, height)) |
| base_info_flags |= png_pass_last; |
| |
| /* Finally, adjust pixels_in_pass for the interlacing (skip the |
| * final pass; it is full width). |
| */ |
| if (pass < 6) |
| pixels_in_pass = PNG_PASS_COLS(pixels_in_pass, pass); |
| } |
| |
| /* Mask out the bits in a partial byte. */ |
| pixels_at_end = pixels_in_pass & PNG_ADDOF(bpp); |
| |
| # ifdef PNG_WRITE_FILTER_SUPPORTED |
| /* Reset the previous_row pointer correctly; NULL at the start of |
| * the pass. If row_number is not 0 then a previous write_rows was |
| * interrupted in mid-pass and any required buffer should be in |
| * previous_write_row (set in the initializer). |
| */ |
| if (png_ptr->row_number == first_row_in_pass) |
| previous_row = NULL; |
| # endif /* WRITE_FILTER */ |
| } |
| |
| # ifdef PNG_WRITE_INTERLACING_SUPPORTED |
| /* When libpng is handling the interlace we see rows that must be |
| * skipped. |
| */ |
| if (!png_ptr->do_interlace || |
| PNG_ROW_IN_INTERLACE_PASS(png_ptr->row_number, pass)) |
| # endif /* WRITE_INTERLACING */ |
| { |
| const unsigned int row_info_flags = base_info_flags | |
| (png_ptr->row_number == |
| first_row_in_pass ? png_pass_first_row : 0) | |
| (png_ptr->row_number == last_row_in_pass ? png_pass_last_row : 0); |
| const int flush = row_flush(ps, row_info_flags); |
| png_const_bytep row = *rows; |
| png_uint_32 pixels_to_go = pixels_in_pass; |
| # ifdef PNG_WRITE_FILTER_SUPPORTED |
| /* The filter can change each time round. Call png_write_start_row |
| * to resolve any changes. Note that when this function is used to |
| * do filter selection from png_write_png_data on the first row |
| * png_write_start_row will get called twice. |
| */ |
| const png_byte filter = select_filter(ps, row, previous_row, bpp, |
| pixels_in_pass, png_ptr->row_number == first_row_in_pass); |
| const png_uint_32 max_pixels = filter == PNG_FILTER_VALUE_NONE ? |
| ps->zlib_max_pixels : ps->row_buffer_max_pixels; |
| const png_uint_32 block_pixels = filter == PNG_FILTER_VALUE_NONE ? |
| ps->zlib_max_aligned_pixels : ps->row_buffer_max_aligned_pixels; |
| |
| /* The row handling uses png_compress_IDAT directly if there is no |
| * filter to be applied, otherwise it uses filter_row. |
| */ |
| if (filter != PNG_FILTER_VALUE_NONE) |
| { |
| int start_of_row = 1; |
| png_byte prev_pixels[4*2*2]; /* 2 pixels up to 4x2-bytes each */ |
| |
| memset(prev_pixels, 0U, sizeof prev_pixels); |
| |
| while (pixels_to_go > max_pixels) |
| { |
| /* Write a block at once to maintain alignment */ |
| filter_row(png_ptr, previous_row, prev_pixels, row, |
| bpp * block_pixels, bpp, filter, start_of_row, |
| Z_NO_FLUSH); |
| |
| if (previous_row != NULL) |
| previous_row += (block_pixels * bpp) >> 3; |
| |
| row += (block_pixels * bpp) >> 3; |
| pixels_to_go -= block_pixels; |
| start_of_row = 0; |
| } |
| |
| /* The filter code handles the partial byte at the end correctly, |
| * so this is all that is required: |
| */ |
| if (pixels_to_go > 0) |
| filter_row(png_ptr, previous_row, prev_pixels, row, |
| bpp * pixels_to_go, bpp, filter, start_of_row, flush); |
| } |
| |
| else |
| # endif /* WRITE_FILTER */ |
| |
| { |
| /* The no-filter case. */ |
| const uInt block_bytes = (uInt)/*SAFE*/( |
| bpp <= 8U ? |
| block_pixels >> PNG_SHIFTOF(bpp) : |
| block_pixels * (bpp >> 3)); |
| |
| /* png_write_start_IDAT guarantees this, but double check for |
| * overflow above in debug: |
| */ |
| debug((block_bytes & (PNG_ROW_BUFFER_BYTE_ALIGN-1U)) == 0U); |
| |
| /* The filter has to be written here: */ |
| png_compress_IDAT(png_ptr, &filter, 1U/*len*/, Z_NO_FLUSH); |
| |
| /* Process blocks of pixels up to the limit. */ |
| while (pixels_to_go > max_pixels) |
| { |
| png_compress_IDAT(png_ptr, row, block_bytes, Z_NO_FLUSH); |
| row += block_bytes; |
| pixels_to_go -= block_pixels; |
| } |
| |
| /* Now compress the remainder; pixels_to_go <= max_pixels so it will |
| * fit in a uInt. |
| */ |
| { |
| const png_uint_32 remainder = |
| bpp <= 8U |
| ? (pixels_to_go-pixels_at_end) >> PNG_SHIFTOF(bpp) |
| : (pixels_to_go-pixels_at_end) * (bpp >> 3); |
| |
| if (remainder > 0U) |
| png_compress_IDAT(png_ptr, row, remainder, |
| pixels_at_end > 0U ? Z_NO_FLUSH : flush); |
| |
| else |
| debug(pixels_at_end > 0U); |
| |
| if (pixels_at_end > 0U) |
| { |
| /* There is a final partial byte. This is PNG format so the |
| * left-most bits are the most significant. |
| */ |
| const png_byte last = PNG_BYTE(row[remainder] & |
| ~(0xFFU >> (pixels_at_end * bpp))); |
| |
| png_compress_IDAT(png_ptr, &last, 1U, flush); |
| } |
| } |
| } |
| |
| png_write_end_row(png_ptr, flush); |
| |
| # ifdef PNG_WRITE_FILTER_SUPPORTED |
| previous_row = *rows; |
| # endif /* WRITE_FILTER */ |
| # undef HANDLE |
| } /* row in pass */ |
| |
| # ifdef PNG_WRITE_INTERLACING_SUPPORTED |
| else /* row not in pass; just skip it */ |
| { |
| if (++png_ptr->row_number >= png_ptr->height) |
| { |
| debug(png_ptr->row_number == png_ptr->height); |
| |
| png_ptr->row_number = 0U; |
| png_ptr->pass = 0x7U & (pass+1U); |
| } |
| } |
| # endif /* WRITE_INTERLACING */ |
| |
| ++rows; |
| } /* while num_rows */ |
| |
| # ifdef PNG_WRITE_FILTER_SUPPORTED |
| /* previous_row must be copied back unless we don't need it because the |
| * next row is the first one in the pass (this relies on png_write_end_row |
| * setting row_number to 0 at the end!) |
| */ |
| if (png_ptr->row_number != 0U && previous_row != NULL && SAVE_ROW(ps) && |
| ps->previous_write_row != previous_row/*all rows skipped*/) |
| { |
| # ifdef PNG_SELECT_FILTER_SUPPORTED |
| /* We might be able to avoid any copy. */ |
| if (ps->current_write_row == previous_row) |
| { |
| png_bytep old = ps->previous_write_row; |
| ps->previous_write_row = ps->current_write_row; |
| ps->current_write_row = old; /* may be NULL */ |
| } |
| |
| else |
| # endif /* SELECT_FILTER */ |
| |
| if (ps->previous_write_row != NULL) |
| memcpy(ps->previous_write_row, previous_row, |
| png_calc_rowbytes(png_ptr, bpp, pixels_in_pass)); |
| |
| else |
| ps->previous_write_row = allocate_row(png_ptr, previous_row, |
| png_calc_rowbytes(png_ptr, bpp, pixels_in_pass)); |
| } |
| # endif /* WRITE_FILTER */ |
| } |
| |
| #ifdef PNG_WRITE_FILTER_SUPPORTED |
| /* This filters the row, chooses which filter to use, if it has not already |
| * been specified by the application, and then writes the row out with the |
| * chosen filter. |
| */ |
| static void |
| write_png_data(png_structrp png_ptr, png_const_bytep prev_row, |
| png_bytep prev_pixels, png_const_bytep unfiltered_row, png_uint_32 x, |
| unsigned int row_bits, unsigned int row_info_flags) |
| /* This filters the row appropriately and returns an updated prev_row |
| * (updated for 'x'). |
| */ |
| { |
| const png_zlib_statep ps = png_ptr->zlib_state; |
| const unsigned int bpp = png_ptr->row_output_pixel_depth; |
| const int flush = row_flush(ps, row_info_flags); |
| const png_byte filter = ps->filters; /* just one */ |
| |
| /* These invariants are expected from the caller: */ |
| affirm(row_bits <= 8U*PNG_ROW_BUFFER_SIZE); |
| debug(filter < PNG_FILTER_VALUE_LAST/*sic: last+1*/); |
| |
| /* Now choose the correct filter implementation according to the number of |
| * filters in the filters_to_try list. The prev_row parameter is made |
| * NULL on the first row because it is uninitialized at that point. |
| */ |
| if (filter == PNG_FILTER_VALUE_NONE) |
| write_unfiltered_rowbits(png_ptr, unfiltered_row, row_bits, |
| x == 0 ? PNG_FILTER_VALUE_NONE : PNG_FILTER_VALUE_LAST, flush); |
| |
| else |
| filter_row(png_ptr, |
| (row_info_flags & png_pass_first_row) ? NULL : prev_row, |
| prev_pixels, unfiltered_row, row_bits, bpp, filter, x == 0, flush); |
| |
| /* Handle end of row: */ |
| if ((row_info_flags & png_row_end) != 0) |
| png_write_end_row(png_ptr, flush); |
| } |
| |
| void /* PRIVATE */ |
| png_write_png_data(png_structrp png_ptr, png_bytep prev_pixels, |
| png_const_bytep unfiltered_row, png_uint_32 x, |
| unsigned int width/*pixels*/, unsigned int row_info_flags) |
| { |
| const png_zlib_statep ps = png_ptr->zlib_state; |
| |
| affirm(ps != NULL); |
| |
| { |
| const unsigned int bpp = png_ptr->row_output_pixel_depth; |
| const unsigned int row_bits = width * bpp; |
| png_bytep prev_row = ps->previous_write_row; |
| |
| debug(bpp <= 64U && width <= 65535U && |
| width < 65535U/bpp); /* Expensive: only matters on 16-bit */ |
| |
| /* This is called once before starting a new row here, but below it is |
| * only called once between starting a new list of rows. |
| */ |
| if (x == 0) |
| png_write_start_row(ps, (row_info_flags & png_pass_first_row) != 0, |
| prev_row == NULL); |
| |
| /* If filter selection is required the filter will have at least one mask |
| * bit set. |
| */ |
| # ifdef PNG_SELECT_FILTER_SUPPORTED |
| if (ps->filters >= PNG_FILTER_NONE/*lowest mask bit*/) |
| { |
| /* If the entire row is passed in the input process it via |
| * immediately, otherwise the row must be buffered for later |
| * analysis. |
| */ |
| png_const_bytep row; |
| |
| if (x > 0 || (row_info_flags & png_row_end) == 0) |
| { |
| /* The row must be saved for later. */ |
| png_bytep buffer = ps->current_write_row; |
| |
| /* png_write_start row should always check this: */ |
| debug(ps->write_row_size > 0U); |
| |
| if (buffer != NULL) |
| memcpy(buffer + png_calc_rowbytes(png_ptr, bpp, x), |
| unfiltered_row, (row_bits + 7U) >> 3); |
| |
| |
| else if (x == 0U) |
| ps->current_write_row = buffer = allocate_row(png_ptr, |
| unfiltered_row, (row_bits + 7U) >> 3); |
| |
| row = buffer; |
| } |
| |
| else |
| row = unfiltered_row; |
| |
| if (row != NULL) /* else out of memory */ |
| { |
| /* At row end, process the save buffer. */ |
| if ((row_info_flags & png_row_end) != 0) |
| png_write_png_rows(png_ptr, &row, 1U); |
| |
| /* Early return to skip the single-filter code */ |
| return; |
| } |
| |
| /* Caching the row failed, so process the row using the lowest set |
| * filter. The allocation error should only ever happen at the |
| * start of the row. If this goes wrong the output will have been |
| * damaged. |
| */ |
| affirm(x == 0U); |
| } |
| # endif /* SELECT_FILTER */ |
| |
| /* prev_row is either NULL or the position in the previous row buffer */ |
| if (prev_row != NULL && x > 0) |
| prev_row += png_calc_rowbytes(png_ptr, bpp, x); |
| |
| /* This is the single filter case (no selection): */ |
| write_png_data(png_ptr, prev_row, prev_pixels, unfiltered_row, x, |
| row_bits, row_info_flags); |
| |
| /* Copy the current row into the previous row buffer, if available, unless |
| * this is the last row in the pass, when there is no point. Note that |
| * write_previous_row may have garbage in a partial byte at the end as a |
| * result of this memcpy. |
| */ |
| if (!(row_info_flags & png_pass_last_row) && SAVE_ROW(ps)) { |
| if (prev_row != NULL) |
| memcpy(prev_row, unfiltered_row, (row_bits + 7U) >> 3); |
| |
| /* NOTE: if the application sets png_zlib_state::save_row in a callback |
| * it isn't possible to do the save until the next row. allocate_row |
| * handles OOM silently by turning off the save. |
| */ |
| else if (x == 0) /* can allocate the save buffer */ |
| ps->previous_write_row = |
| allocate_row(png_ptr, unfiltered_row, (row_bits + 7U) >> 3); |
| } |
| } |
| } |
| #else /* !WRITE_FILTER */ |
| void /* PRIVATE */ |
| png_write_start_IDAT(png_structrp png_ptr) |
| { |
| png_zlib_statep ps = get_zlib_state(png_ptr); |
| |
| /* Set up the IDAT compression state. Expect the state to have been released |
| * by the previous owner, but it doesn't much matter if there was an error. |
| * Note that the stream is not claimed yet. |
| */ |
| debug(png_ptr->zowner == 0U); |
| |
| /* This sets the buffer limits and write_row_size, which is used below. */ |
| png_zlib_state_set_buffer_limits(png_ptr, ps); |
| } |
| |
| void /* PRIVATE */ |
| png_write_png_data(png_structrp png_ptr, png_bytep prev_pixels, |
| png_const_bytep unfiltered_row, png_uint_32 x, |
| unsigned int width/*pixels*/, unsigned int row_info_flags) |
| { |
| const unsigned int bpp = png_ptr->row_output_pixel_depth; |
| int flush; |
| png_uint_32 row_bits; |
| |
| row_bits = width; |
| row_bits *= bpp; |
| /* These invariants are expected from the caller: */ |
| affirm(width < 65536U && bpp <= 64U && width < 65536U/bpp && |
| row_bits <= 8U*PNG_ROW_BUFFER_SIZE); |
| |
| affirm(png_ptr->zlib_state != NULL); |
| flush = row_flush(png_ptr->zlib_state, row_info_flags); |
| |
| write_unfiltered_rowbits(png_ptr, unfiltered_row, row_bits, |
| x == 0 ? PNG_FILTER_VALUE_NONE : PNG_FILTER_VALUE_LAST, flush); |
| |
| PNG_UNUSED(prev_pixels); |
| |
| /* Handle end of row: */ |
| if ((row_info_flags & png_row_end) != 0) |
| png_write_end_row(png_ptr, flush); |
| } |
| #endif /* !WRITE_FILTER */ |
| |
| png_int_32 /* PRIVATE */ |
| png_write_setting(png_structrp png_ptr, png_uint_32 setting, |
| png_uint_32 parameter, png_int_32 value) |
| { |
| /* Caller checks the arguments for basic validity */ |
| int only_get = (setting & PNG_SF_GET) != 0U; |
| |
| setting &= ~PNG_SF_GET; |
| |
| switch (setting) |
| { |
| /* Settings in png_struct: */ |
| case PNG_SW_IDAT_size: |
| if (parameter > 0 && parameter <= PNG_UINT_31_MAX) |
| { |
| if (!only_get) |
| png_ptr->IDAT_size = parameter; |
| |
| return 0; /* set ok */ |
| } |
| |
| else |
| return PNG_EINVAL; |
| |
| /* Settings in zlib_state: */ |
| case PNG_SW_COMPRESS_png_level: |
| return compression_setting(png_ptr, parameter, png_level, value, |
| only_get); |
| |
| # ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED |
| case PNG_SW_COMPRESS_zlib_level: |
| return compression_setting(png_ptr, parameter, level, value, |
| only_get); |
| |
| case PNG_SW_COMPRESS_windowBits: |
| return compression_setting(png_ptr, parameter, windowBits, value, |
| only_get); |
| |
| case PNG_SW_COMPRESS_memLevel: |
| return compression_setting(png_ptr, parameter, memLevel, value, |
| only_get); |
| |
| case PNG_SW_COMPRESS_strategy: |
| return compression_setting(png_ptr, parameter, strategy, value, |
| only_get); |
| |
| case PNG_SW_COMPRESS_method: |
| if (value != 8) /* Only supported method */ |
| return PNG_EINVAL; |
| return 8; /* old method */ |
| # endif /* WRITE_CUSTOMIZE_COMPRESSION */ |
| |
| # ifdef PNG_WRITE_FILTER_SUPPORTED |
| case PNG_SW_COMPRESS_filters: |
| /* The method must match that in the IHDR: */ |
| if (parameter == png_ptr->filter_method) |
| { |
| if (!only_get) |
| return set_filter(get_zlib_state(png_ptr), value); |
| |
| else if (png_ptr->zlib_state != NULL && |
| png_ptr->zlib_state->filter_mask != 0U/*unset*/) |
| return png_ptr->zlib_state->filter_mask; |
| |
| else |
| return PNG_UNSET; |
| } |
| |
| else /* Invalid filter method */ |
| return PNG_EINVAL; |
| |
| case PNG_SW_COMPRESS_row_buffers: |
| /* New in 1.7.0: direct control of the buffering. */ |
| switch (parameter) |
| { |
| case 0: |
| if (!only_get) |
| get_zlib_state(png_ptr)->save_row = SAVE_ROW_OFF; |
| return 0; |
| |
| case 1: |
| if (!only_get) |
| get_zlib_state(png_ptr)->save_row = SAVE_ROW_ON; |
| return 1; |
| |
| default: |
| return PNG_ENOSYS; /* no support for bigger values */ |
| } |
| # endif /* WRITE_FILTER */ |
| |
| # ifdef PNG_WRITE_FLUSH_SUPPORTED |
| case PNG_SW_FLUSH: |
| /* Set the automatic flush interval or 0 to turn flushing off */ |
| if (!only_get) |
| get_zlib_state(png_ptr)->flush_dist = |
| value <= 0 ? 0xEFFFFFFFU : (png_uint_32)/*SAFE*/value; |
| |
| return 0; |
| # endif /* WRITE_FLUSH */ |
| |
| # ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED |
| case PNG_SRW_CHECK_FOR_INVALID_INDEX: |
| /* The 'enabled' value is a FORTRAN style three-state: */ |
| if (value > 0) |
| png_ptr->palette_index_check = PNG_PALETTE_CHECK_ON; |
| |
| else if (value < 0) |
| png_ptr->palette_index_check = PNG_PALETTE_CHECK_OFF; |
| |
| else |
| png_ptr->palette_index_check = PNG_PALETTE_CHECK_DEFAULT; |
| |
| return 0; |
| # endif /* WRITE_CHECK_FOR_INVALID_INDEX */ |
| |
| # ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED |
| case PNG_SRW_ERROR_HANDLING: |
| /* The parameter is a bit mask of what to set, the value is what to |
| * set it to. PNG_IDAT_ERRORS is ignored on write. |
| */ |
| if (value >= PNG_IGNORE && value <= PNG_ERROR && |
| parameter <= PNG_ALL_ERRORS) |
| { |
| if ((parameter & PNG_BENIGN_ERRORS) != 0U) |
| png_ptr->benign_error_action = value & 0x3U; |
| |
| if ((parameter & PNG_APP_WARNINGS) != 0U) |
| png_ptr->app_warning_action = value & 0x3U; |
| |
| if ((parameter & PNG_APP_ERRORS) != 0U) |
| png_ptr->app_error_action = value & 0x3U; |
| |
| return 0; |
| } |
| |
| return PNG_EINVAL; |
| # endif /* BENIGN_WRITE_ERRORS */ |
| |
| default: |
| return PNG_ENOSYS; /* not supported (whatever it is) */ |
| } |
| } |
| #endif /* WRITE */ |