| /* |
| * jdpostct.c |
| * |
| * This file was part of the Independent JPEG Group's software: |
| * Copyright (C) 1994-1996, Thomas G. Lane. |
| * libjpeg-turbo Modifications: |
| * Copyright (C) 2022, D. R. Commander. |
| * For conditions of distribution and use, see the accompanying README.ijg |
| * file. |
| * |
| * This file contains the decompression postprocessing controller. |
| * This controller manages the upsampling, color conversion, and color |
| * quantization/reduction steps; specifically, it controls the buffering |
| * between upsample/color conversion and color quantization/reduction. |
| * |
| * If no color quantization/reduction is required, then this module has no |
| * work to do, and it just hands off to the upsample/color conversion code. |
| * An integrated upsample/convert/quantize process would replace this module |
| * entirely. |
| */ |
| |
| #define JPEG_INTERNALS |
| #include "jinclude.h" |
| #include "jpeglib.h" |
| #include "jsamplecomp.h" |
| |
| |
| #if BITS_IN_JSAMPLE != 16 || defined(D_LOSSLESS_SUPPORTED) |
| |
| /* Private buffer controller object */ |
| |
| typedef struct { |
| struct jpeg_d_post_controller pub; /* public fields */ |
| |
| /* Color quantization source buffer: this holds output data from |
| * the upsample/color conversion step to be passed to the quantizer. |
| * For two-pass color quantization, we need a full-image buffer; |
| * for one-pass operation, a strip buffer is sufficient. |
| */ |
| jvirt_sarray_ptr whole_image; /* virtual array, or NULL if one-pass */ |
| _JSAMPARRAY buffer; /* strip buffer, or current strip of virtual */ |
| JDIMENSION strip_height; /* buffer size in rows */ |
| /* for two-pass mode only: */ |
| JDIMENSION starting_row; /* row # of first row in current strip */ |
| JDIMENSION next_row; /* index of next row to fill/empty in strip */ |
| } my_post_controller; |
| |
| typedef my_post_controller *my_post_ptr; |
| |
| |
| /* Forward declarations */ |
| METHODDEF(void) post_process_1pass(j_decompress_ptr cinfo, |
| _JSAMPIMAGE input_buf, |
| JDIMENSION *in_row_group_ctr, |
| JDIMENSION in_row_groups_avail, |
| _JSAMPARRAY output_buf, |
| JDIMENSION *out_row_ctr, |
| JDIMENSION out_rows_avail); |
| #ifdef QUANT_2PASS_SUPPORTED |
| METHODDEF(void) post_process_prepass(j_decompress_ptr cinfo, |
| _JSAMPIMAGE input_buf, |
| JDIMENSION *in_row_group_ctr, |
| JDIMENSION in_row_groups_avail, |
| _JSAMPARRAY output_buf, |
| JDIMENSION *out_row_ctr, |
| JDIMENSION out_rows_avail); |
| METHODDEF(void) post_process_2pass(j_decompress_ptr cinfo, |
| _JSAMPIMAGE input_buf, |
| JDIMENSION *in_row_group_ctr, |
| JDIMENSION in_row_groups_avail, |
| _JSAMPARRAY output_buf, |
| JDIMENSION *out_row_ctr, |
| JDIMENSION out_rows_avail); |
| #endif |
| |
| |
| /* |
| * Initialize for a processing pass. |
| */ |
| |
| METHODDEF(void) |
| start_pass_dpost(j_decompress_ptr cinfo, J_BUF_MODE pass_mode) |
| { |
| my_post_ptr post = (my_post_ptr)cinfo->post; |
| |
| switch (pass_mode) { |
| case JBUF_PASS_THRU: |
| if (cinfo->quantize_colors) { |
| /* Single-pass processing with color quantization. */ |
| post->pub._post_process_data = post_process_1pass; |
| /* We could be doing buffered-image output before starting a 2-pass |
| * color quantization; in that case, jinit_d_post_controller did not |
| * allocate a strip buffer. Use the virtual-array buffer as workspace. |
| */ |
| if (post->buffer == NULL) { |
| post->buffer = (_JSAMPARRAY)(*cinfo->mem->access_virt_sarray) |
| ((j_common_ptr)cinfo, post->whole_image, |
| (JDIMENSION)0, post->strip_height, TRUE); |
| } |
| } else { |
| /* For single-pass processing without color quantization, |
| * I have no work to do; just call the upsampler directly. |
| */ |
| post->pub._post_process_data = cinfo->upsample->_upsample; |
| } |
| break; |
| #ifdef QUANT_2PASS_SUPPORTED |
| case JBUF_SAVE_AND_PASS: |
| /* First pass of 2-pass quantization */ |
| if (post->whole_image == NULL) |
| ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); |
| post->pub._post_process_data = post_process_prepass; |
| break; |
| case JBUF_CRANK_DEST: |
| /* Second pass of 2-pass quantization */ |
| if (post->whole_image == NULL) |
| ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); |
| post->pub._post_process_data = post_process_2pass; |
| break; |
| #endif /* QUANT_2PASS_SUPPORTED */ |
| default: |
| ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); |
| break; |
| } |
| post->starting_row = post->next_row = 0; |
| } |
| |
| |
| /* |
| * Process some data in the one-pass (strip buffer) case. |
| * This is used for color precision reduction as well as one-pass quantization. |
| */ |
| |
| METHODDEF(void) |
| post_process_1pass(j_decompress_ptr cinfo, _JSAMPIMAGE input_buf, |
| JDIMENSION *in_row_group_ctr, |
| JDIMENSION in_row_groups_avail, _JSAMPARRAY output_buf, |
| JDIMENSION *out_row_ctr, JDIMENSION out_rows_avail) |
| { |
| my_post_ptr post = (my_post_ptr)cinfo->post; |
| JDIMENSION num_rows, max_rows; |
| |
| /* Fill the buffer, but not more than what we can dump out in one go. */ |
| /* Note we rely on the upsampler to detect bottom of image. */ |
| max_rows = out_rows_avail - *out_row_ctr; |
| if (max_rows > post->strip_height) |
| max_rows = post->strip_height; |
| num_rows = 0; |
| (*cinfo->upsample->_upsample) (cinfo, input_buf, in_row_group_ctr, |
| in_row_groups_avail, post->buffer, &num_rows, |
| max_rows); |
| /* Quantize and emit data. */ |
| (*cinfo->cquantize->_color_quantize) (cinfo, post->buffer, |
| output_buf + *out_row_ctr, |
| (int)num_rows); |
| *out_row_ctr += num_rows; |
| } |
| |
| |
| #ifdef QUANT_2PASS_SUPPORTED |
| |
| /* |
| * Process some data in the first pass of 2-pass quantization. |
| */ |
| |
| METHODDEF(void) |
| post_process_prepass(j_decompress_ptr cinfo, _JSAMPIMAGE input_buf, |
| JDIMENSION *in_row_group_ctr, |
| JDIMENSION in_row_groups_avail, _JSAMPARRAY output_buf, |
| JDIMENSION *out_row_ctr, JDIMENSION out_rows_avail) |
| { |
| my_post_ptr post = (my_post_ptr)cinfo->post; |
| JDIMENSION old_next_row, num_rows; |
| |
| /* Reposition virtual buffer if at start of strip. */ |
| if (post->next_row == 0) { |
| post->buffer = (_JSAMPARRAY)(*cinfo->mem->access_virt_sarray) |
| ((j_common_ptr)cinfo, post->whole_image, |
| post->starting_row, post->strip_height, TRUE); |
| } |
| |
| /* Upsample some data (up to a strip height's worth). */ |
| old_next_row = post->next_row; |
| (*cinfo->upsample->_upsample) (cinfo, input_buf, in_row_group_ctr, |
| in_row_groups_avail, post->buffer, |
| &post->next_row, post->strip_height); |
| |
| /* Allow quantizer to scan new data. No data is emitted, */ |
| /* but we advance out_row_ctr so outer loop can tell when we're done. */ |
| if (post->next_row > old_next_row) { |
| num_rows = post->next_row - old_next_row; |
| (*cinfo->cquantize->_color_quantize) (cinfo, post->buffer + old_next_row, |
| (_JSAMPARRAY)NULL, (int)num_rows); |
| *out_row_ctr += num_rows; |
| } |
| |
| /* Advance if we filled the strip. */ |
| if (post->next_row >= post->strip_height) { |
| post->starting_row += post->strip_height; |
| post->next_row = 0; |
| } |
| } |
| |
| |
| /* |
| * Process some data in the second pass of 2-pass quantization. |
| */ |
| |
| METHODDEF(void) |
| post_process_2pass(j_decompress_ptr cinfo, _JSAMPIMAGE input_buf, |
| JDIMENSION *in_row_group_ctr, |
| JDIMENSION in_row_groups_avail, _JSAMPARRAY output_buf, |
| JDIMENSION *out_row_ctr, JDIMENSION out_rows_avail) |
| { |
| my_post_ptr post = (my_post_ptr)cinfo->post; |
| JDIMENSION num_rows, max_rows; |
| |
| /* Reposition virtual buffer if at start of strip. */ |
| if (post->next_row == 0) { |
| post->buffer = (_JSAMPARRAY)(*cinfo->mem->access_virt_sarray) |
| ((j_common_ptr)cinfo, post->whole_image, |
| post->starting_row, post->strip_height, FALSE); |
| } |
| |
| /* Determine number of rows to emit. */ |
| num_rows = post->strip_height - post->next_row; /* available in strip */ |
| max_rows = out_rows_avail - *out_row_ctr; /* available in output area */ |
| if (num_rows > max_rows) |
| num_rows = max_rows; |
| /* We have to check bottom of image here, can't depend on upsampler. */ |
| max_rows = cinfo->output_height - post->starting_row; |
| if (num_rows > max_rows) |
| num_rows = max_rows; |
| |
| /* Quantize and emit data. */ |
| (*cinfo->cquantize->_color_quantize) (cinfo, post->buffer + post->next_row, |
| output_buf + *out_row_ctr, |
| (int)num_rows); |
| *out_row_ctr += num_rows; |
| |
| /* Advance if we filled the strip. */ |
| post->next_row += num_rows; |
| if (post->next_row >= post->strip_height) { |
| post->starting_row += post->strip_height; |
| post->next_row = 0; |
| } |
| } |
| |
| #endif /* QUANT_2PASS_SUPPORTED */ |
| |
| |
| /* |
| * Initialize postprocessing controller. |
| */ |
| |
| GLOBAL(void) |
| _jinit_d_post_controller(j_decompress_ptr cinfo, boolean need_full_buffer) |
| { |
| my_post_ptr post; |
| |
| if (cinfo->data_precision != BITS_IN_JSAMPLE) |
| ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision); |
| |
| post = (my_post_ptr) |
| (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE, |
| sizeof(my_post_controller)); |
| cinfo->post = (struct jpeg_d_post_controller *)post; |
| post->pub.start_pass = start_pass_dpost; |
| post->whole_image = NULL; /* flag for no virtual arrays */ |
| post->buffer = NULL; /* flag for no strip buffer */ |
| |
| /* Create the quantization buffer, if needed */ |
| if (cinfo->quantize_colors) { |
| /* The buffer strip height is max_v_samp_factor, which is typically |
| * an efficient number of rows for upsampling to return. |
| * (In the presence of output rescaling, we might want to be smarter?) |
| */ |
| post->strip_height = (JDIMENSION)cinfo->max_v_samp_factor; |
| if (need_full_buffer) { |
| /* Two-pass color quantization: need full-image storage. */ |
| /* We round up the number of rows to a multiple of the strip height. */ |
| #ifdef QUANT_2PASS_SUPPORTED |
| post->whole_image = (*cinfo->mem->request_virt_sarray) |
| ((j_common_ptr)cinfo, JPOOL_IMAGE, FALSE, |
| cinfo->output_width * cinfo->out_color_components, |
| (JDIMENSION)jround_up((long)cinfo->output_height, |
| (long)post->strip_height), |
| post->strip_height); |
| #else |
| ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); |
| #endif /* QUANT_2PASS_SUPPORTED */ |
| } else { |
| /* One-pass color quantization: just make a strip buffer. */ |
| post->buffer = (_JSAMPARRAY)(*cinfo->mem->alloc_sarray) |
| ((j_common_ptr)cinfo, JPOOL_IMAGE, |
| cinfo->output_width * cinfo->out_color_components, |
| post->strip_height); |
| } |
| } |
| } |
| |
| #endif /* BITS_IN_JSAMPLE != 16 || defined(D_LOSSLESS_SUPPORTED) */ |