| /* |
| * jdinput.c |
| * |
| * This file was part of the Independent JPEG Group's software: |
| * Copyright (C) 1991-1997, Thomas G. Lane. |
| * libjpeg-turbo Modifications: |
| * Copyright (C) 2010, 2016, 2018, 2022, D. R. Commander. |
| * Copyright (C) 2015, Google, Inc. |
| * For conditions of distribution and use, see the accompanying README.ijg |
| * file. |
| * |
| * This file contains input control logic for the JPEG decompressor. |
| * These routines are concerned with controlling the decompressor's input |
| * processing (marker reading and coefficient decoding). The actual input |
| * reading is done in jdmarker.c, jdhuff.c, and jdphuff.c. |
| */ |
| |
| #define JPEG_INTERNALS |
| #include "jinclude.h" |
| #include "jpeglib.h" |
| #include "jpegcomp.h" |
| |
| |
| /* Private state */ |
| |
| typedef struct { |
| struct jpeg_input_controller pub; /* public fields */ |
| |
| boolean inheaders; /* TRUE until first SOS is reached */ |
| } my_input_controller; |
| |
| typedef my_input_controller *my_inputctl_ptr; |
| |
| |
| /* Forward declarations */ |
| METHODDEF(int) consume_markers(j_decompress_ptr cinfo); |
| |
| |
| /* |
| * Routines to calculate various quantities related to the size of the image. |
| */ |
| |
| LOCAL(void) |
| initial_setup(j_decompress_ptr cinfo) |
| /* Called once, when first SOS marker is reached */ |
| { |
| int ci; |
| jpeg_component_info *compptr; |
| |
| /* Make sure image isn't bigger than I can handle */ |
| if ((long)cinfo->image_height > (long)JPEG_MAX_DIMENSION || |
| (long)cinfo->image_width > (long)JPEG_MAX_DIMENSION) |
| ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int)JPEG_MAX_DIMENSION); |
| |
| /* For now, precision must match compiled-in value... */ |
| if (cinfo->data_precision != BITS_IN_JSAMPLE) |
| ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision); |
| |
| /* Check that number of components won't exceed internal array sizes */ |
| if (cinfo->num_components > MAX_COMPONENTS) |
| ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components, |
| MAX_COMPONENTS); |
| |
| /* Compute maximum sampling factors; check factor validity */ |
| cinfo->max_h_samp_factor = 1; |
| cinfo->max_v_samp_factor = 1; |
| for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; |
| ci++, compptr++) { |
| if (compptr->h_samp_factor <= 0 || |
| compptr->h_samp_factor > MAX_SAMP_FACTOR || |
| compptr->v_samp_factor <= 0 || |
| compptr->v_samp_factor > MAX_SAMP_FACTOR) |
| ERREXIT(cinfo, JERR_BAD_SAMPLING); |
| cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor, |
| compptr->h_samp_factor); |
| cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor, |
| compptr->v_samp_factor); |
| } |
| |
| #if JPEG_LIB_VERSION >= 80 |
| cinfo->block_size = DCTSIZE; |
| cinfo->natural_order = jpeg_natural_order; |
| cinfo->lim_Se = DCTSIZE2 - 1; |
| #endif |
| |
| /* We initialize DCT_scaled_size and min_DCT_scaled_size to DCTSIZE. |
| * In the full decompressor, this will be overridden by jdmaster.c; |
| * but in the transcoder, jdmaster.c is not used, so we must do it here. |
| */ |
| #if JPEG_LIB_VERSION >= 70 |
| cinfo->min_DCT_h_scaled_size = cinfo->min_DCT_v_scaled_size = DCTSIZE; |
| #else |
| cinfo->min_DCT_scaled_size = DCTSIZE; |
| #endif |
| |
| /* Compute dimensions of components */ |
| for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; |
| ci++, compptr++) { |
| #if JPEG_LIB_VERSION >= 70 |
| compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size = DCTSIZE; |
| #else |
| compptr->DCT_scaled_size = DCTSIZE; |
| #endif |
| /* Size in DCT blocks */ |
| compptr->width_in_blocks = (JDIMENSION) |
| jdiv_round_up((long)cinfo->image_width * (long)compptr->h_samp_factor, |
| (long)(cinfo->max_h_samp_factor * DCTSIZE)); |
| compptr->height_in_blocks = (JDIMENSION) |
| jdiv_round_up((long)cinfo->image_height * (long)compptr->v_samp_factor, |
| (long)(cinfo->max_v_samp_factor * DCTSIZE)); |
| /* Set the first and last MCU columns to decompress from multi-scan images. |
| * By default, decompress all of the MCU columns. |
| */ |
| cinfo->master->first_MCU_col[ci] = 0; |
| cinfo->master->last_MCU_col[ci] = compptr->width_in_blocks - 1; |
| /* downsampled_width and downsampled_height will also be overridden by |
| * jdmaster.c if we are doing full decompression. The transcoder library |
| * doesn't use these values, but the calling application might. |
| */ |
| /* Size in samples */ |
| compptr->downsampled_width = (JDIMENSION) |
| jdiv_round_up((long)cinfo->image_width * (long)compptr->h_samp_factor, |
| (long)cinfo->max_h_samp_factor); |
| compptr->downsampled_height = (JDIMENSION) |
| jdiv_round_up((long)cinfo->image_height * (long)compptr->v_samp_factor, |
| (long)cinfo->max_v_samp_factor); |
| /* Mark component needed, until color conversion says otherwise */ |
| compptr->component_needed = TRUE; |
| /* Mark no quantization table yet saved for component */ |
| compptr->quant_table = NULL; |
| } |
| |
| /* Compute number of fully interleaved MCU rows. */ |
| cinfo->total_iMCU_rows = (JDIMENSION) |
| jdiv_round_up((long)cinfo->image_height, |
| (long)(cinfo->max_v_samp_factor * DCTSIZE)); |
| |
| /* Decide whether file contains multiple scans */ |
| if (cinfo->comps_in_scan < cinfo->num_components || cinfo->progressive_mode) |
| cinfo->inputctl->has_multiple_scans = TRUE; |
| else |
| cinfo->inputctl->has_multiple_scans = FALSE; |
| } |
| |
| |
| LOCAL(void) |
| per_scan_setup(j_decompress_ptr cinfo) |
| /* Do computations that are needed before processing a JPEG scan */ |
| /* cinfo->comps_in_scan and cinfo->cur_comp_info[] were set from SOS marker */ |
| { |
| int ci, mcublks, tmp; |
| jpeg_component_info *compptr; |
| |
| if (cinfo->comps_in_scan == 1) { |
| |
| /* Noninterleaved (single-component) scan */ |
| compptr = cinfo->cur_comp_info[0]; |
| |
| /* Overall image size in MCUs */ |
| cinfo->MCUs_per_row = compptr->width_in_blocks; |
| cinfo->MCU_rows_in_scan = compptr->height_in_blocks; |
| |
| /* For noninterleaved scan, always one block per MCU */ |
| compptr->MCU_width = 1; |
| compptr->MCU_height = 1; |
| compptr->MCU_blocks = 1; |
| compptr->MCU_sample_width = compptr->_DCT_scaled_size; |
| compptr->last_col_width = 1; |
| /* For noninterleaved scans, it is convenient to define last_row_height |
| * as the number of block rows present in the last iMCU row. |
| */ |
| tmp = (int)(compptr->height_in_blocks % compptr->v_samp_factor); |
| if (tmp == 0) tmp = compptr->v_samp_factor; |
| compptr->last_row_height = tmp; |
| |
| /* Prepare array describing MCU composition */ |
| cinfo->blocks_in_MCU = 1; |
| cinfo->MCU_membership[0] = 0; |
| |
| } else { |
| |
| /* Interleaved (multi-component) scan */ |
| if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN) |
| ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan, |
| MAX_COMPS_IN_SCAN); |
| |
| /* Overall image size in MCUs */ |
| cinfo->MCUs_per_row = (JDIMENSION) |
| jdiv_round_up((long)cinfo->image_width, |
| (long)(cinfo->max_h_samp_factor * DCTSIZE)); |
| cinfo->MCU_rows_in_scan = (JDIMENSION) |
| jdiv_round_up((long)cinfo->image_height, |
| (long)(cinfo->max_v_samp_factor * DCTSIZE)); |
| |
| cinfo->blocks_in_MCU = 0; |
| |
| for (ci = 0; ci < cinfo->comps_in_scan; ci++) { |
| compptr = cinfo->cur_comp_info[ci]; |
| /* Sampling factors give # of blocks of component in each MCU */ |
| compptr->MCU_width = compptr->h_samp_factor; |
| compptr->MCU_height = compptr->v_samp_factor; |
| compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height; |
| compptr->MCU_sample_width = compptr->MCU_width * |
| compptr->_DCT_scaled_size; |
| /* Figure number of non-dummy blocks in last MCU column & row */ |
| tmp = (int)(compptr->width_in_blocks % compptr->MCU_width); |
| if (tmp == 0) tmp = compptr->MCU_width; |
| compptr->last_col_width = tmp; |
| tmp = (int)(compptr->height_in_blocks % compptr->MCU_height); |
| if (tmp == 0) tmp = compptr->MCU_height; |
| compptr->last_row_height = tmp; |
| /* Prepare array describing MCU composition */ |
| mcublks = compptr->MCU_blocks; |
| if (cinfo->blocks_in_MCU + mcublks > D_MAX_BLOCKS_IN_MCU) |
| ERREXIT(cinfo, JERR_BAD_MCU_SIZE); |
| while (mcublks-- > 0) { |
| cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci; |
| } |
| } |
| |
| } |
| } |
| |
| |
| /* |
| * Save away a copy of the Q-table referenced by each component present |
| * in the current scan, unless already saved during a prior scan. |
| * |
| * In a multiple-scan JPEG file, the encoder could assign different components |
| * the same Q-table slot number, but change table definitions between scans |
| * so that each component uses a different Q-table. (The IJG encoder is not |
| * currently capable of doing this, but other encoders might.) Since we want |
| * to be able to dequantize all the components at the end of the file, this |
| * means that we have to save away the table actually used for each component. |
| * We do this by copying the table at the start of the first scan containing |
| * the component. |
| * Rec. ITU-T T.81 | ISO/IEC 10918-1 prohibits the encoder from changing the |
| * contents of a Q-table slot between scans of a component using that slot. If |
| * the encoder does so anyway, this decoder will simply use the Q-table values |
| * that were current at the start of the first scan for the component. |
| * |
| * The decompressor output side looks only at the saved quant tables, |
| * not at the current Q-table slots. |
| */ |
| |
| LOCAL(void) |
| latch_quant_tables(j_decompress_ptr cinfo) |
| { |
| int ci, qtblno; |
| jpeg_component_info *compptr; |
| JQUANT_TBL *qtbl; |
| |
| for (ci = 0; ci < cinfo->comps_in_scan; ci++) { |
| compptr = cinfo->cur_comp_info[ci]; |
| /* No work if we already saved Q-table for this component */ |
| if (compptr->quant_table != NULL) |
| continue; |
| /* Make sure specified quantization table is present */ |
| qtblno = compptr->quant_tbl_no; |
| if (qtblno < 0 || qtblno >= NUM_QUANT_TBLS || |
| cinfo->quant_tbl_ptrs[qtblno] == NULL) |
| ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, qtblno); |
| /* OK, save away the quantization table */ |
| qtbl = (JQUANT_TBL *) |
| (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE, |
| sizeof(JQUANT_TBL)); |
| memcpy(qtbl, cinfo->quant_tbl_ptrs[qtblno], sizeof(JQUANT_TBL)); |
| compptr->quant_table = qtbl; |
| } |
| } |
| |
| |
| /* |
| * Initialize the input modules to read a scan of compressed data. |
| * The first call to this is done by jdmaster.c after initializing |
| * the entire decompressor (during jpeg_start_decompress). |
| * Subsequent calls come from consume_markers, below. |
| */ |
| |
| METHODDEF(void) |
| start_input_pass(j_decompress_ptr cinfo) |
| { |
| per_scan_setup(cinfo); |
| latch_quant_tables(cinfo); |
| (*cinfo->entropy->start_pass) (cinfo); |
| (*cinfo->coef->start_input_pass) (cinfo); |
| cinfo->inputctl->consume_input = cinfo->coef->consume_data; |
| } |
| |
| |
| /* |
| * Finish up after inputting a compressed-data scan. |
| * This is called by the coefficient controller after it's read all |
| * the expected data of the scan. |
| */ |
| |
| METHODDEF(void) |
| finish_input_pass(j_decompress_ptr cinfo) |
| { |
| cinfo->inputctl->consume_input = consume_markers; |
| } |
| |
| |
| /* |
| * Read JPEG markers before, between, or after compressed-data scans. |
| * Change state as necessary when a new scan is reached. |
| * Return value is JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI. |
| * |
| * The consume_input method pointer points either here or to the |
| * coefficient controller's consume_data routine, depending on whether |
| * we are reading a compressed data segment or inter-segment markers. |
| */ |
| |
| METHODDEF(int) |
| consume_markers(j_decompress_ptr cinfo) |
| { |
| my_inputctl_ptr inputctl = (my_inputctl_ptr)cinfo->inputctl; |
| int val; |
| |
| if (inputctl->pub.eoi_reached) /* After hitting EOI, read no further */ |
| return JPEG_REACHED_EOI; |
| |
| val = (*cinfo->marker->read_markers) (cinfo); |
| |
| switch (val) { |
| case JPEG_REACHED_SOS: /* Found SOS */ |
| if (inputctl->inheaders) { /* 1st SOS */ |
| initial_setup(cinfo); |
| inputctl->inheaders = FALSE; |
| /* Note: start_input_pass must be called by jdmaster.c |
| * before any more input can be consumed. jdapimin.c is |
| * responsible for enforcing this sequencing. |
| */ |
| } else { /* 2nd or later SOS marker */ |
| if (!inputctl->pub.has_multiple_scans) |
| ERREXIT(cinfo, JERR_EOI_EXPECTED); /* Oops, I wasn't expecting this! */ |
| start_input_pass(cinfo); |
| } |
| break; |
| case JPEG_REACHED_EOI: /* Found EOI */ |
| inputctl->pub.eoi_reached = TRUE; |
| if (inputctl->inheaders) { /* Tables-only datastream, apparently */ |
| if (cinfo->marker->saw_SOF) |
| ERREXIT(cinfo, JERR_SOF_NO_SOS); |
| } else { |
| /* Prevent infinite loop in coef ctlr's decompress_data routine |
| * if user set output_scan_number larger than number of scans. |
| */ |
| if (cinfo->output_scan_number > cinfo->input_scan_number) |
| cinfo->output_scan_number = cinfo->input_scan_number; |
| } |
| break; |
| case JPEG_SUSPENDED: |
| break; |
| } |
| |
| return val; |
| } |
| |
| |
| /* |
| * Reset state to begin a fresh datastream. |
| */ |
| |
| METHODDEF(void) |
| reset_input_controller(j_decompress_ptr cinfo) |
| { |
| my_inputctl_ptr inputctl = (my_inputctl_ptr)cinfo->inputctl; |
| |
| inputctl->pub.consume_input = consume_markers; |
| inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */ |
| inputctl->pub.eoi_reached = FALSE; |
| inputctl->inheaders = TRUE; |
| /* Reset other modules */ |
| (*cinfo->err->reset_error_mgr) ((j_common_ptr)cinfo); |
| (*cinfo->marker->reset_marker_reader) (cinfo); |
| /* Reset progression state -- would be cleaner if entropy decoder did this */ |
| cinfo->coef_bits = NULL; |
| } |
| |
| |
| /* |
| * Initialize the input controller module. |
| * This is called only once, when the decompression object is created. |
| */ |
| |
| GLOBAL(void) |
| jinit_input_controller(j_decompress_ptr cinfo) |
| { |
| my_inputctl_ptr inputctl; |
| |
| /* Create subobject in permanent pool */ |
| inputctl = (my_inputctl_ptr) |
| (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_PERMANENT, |
| sizeof(my_input_controller)); |
| cinfo->inputctl = (struct jpeg_input_controller *)inputctl; |
| /* Initialize method pointers */ |
| inputctl->pub.consume_input = consume_markers; |
| inputctl->pub.reset_input_controller = reset_input_controller; |
| inputctl->pub.start_input_pass = start_input_pass; |
| inputctl->pub.finish_input_pass = finish_input_pass; |
| /* Initialize state: can't use reset_input_controller since we don't |
| * want to try to reset other modules yet. |
| */ |
| inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */ |
| inputctl->pub.eoi_reached = FALSE; |
| inputctl->inheaders = TRUE; |
| } |