737 lines
25 KiB
C
Executable File
737 lines
25 KiB
C
Executable File
/*
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* jdcoefct.c
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*
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* Copyright (C) 1994-1997, Thomas G. Lane.
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* This file is part of the Independent JPEG Group's software.
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* For conditions of distribution and use, see the accompanying README file.
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*
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* This file contains the coefficient buffer controller for decompression.
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* This controller is the top level of the JPEG decompressor proper.
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* The coefficient buffer lies between entropy decoding and inverse-DCT steps.
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*
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* In buffered-image mode, this controller is the interface between
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* input-oriented processing and output-oriented processing.
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* Also, the input side (only) is used when reading a file for transcoding.
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*/
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#define JPEG_INTERNALS
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#include "jinclude.h"
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#include "jpeglib.h"
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/* Block smoothing is only applicable for progressive JPEG, so: */
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#ifndef D_PROGRESSIVE_SUPPORTED
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#undef BLOCK_SMOOTHING_SUPPORTED
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#endif
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/* Private buffer controller object */
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typedef struct {
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struct jpeg_d_coef_controller pub; /* public fields */
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/* These variables keep track of the current location of the input side. */
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/* cinfo->input_iMCU_row is also used for this. */
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JDIMENSION MCU_ctr; /* counts MCUs processed in current row */
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int MCU_vert_offset; /* counts MCU rows within iMCU row */
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int MCU_rows_per_iMCU_row; /* number of such rows needed */
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/* The output side's location is represented by cinfo->output_iMCU_row. */
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/* In single-pass modes, it's sufficient to buffer just one MCU.
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* We allocate a workspace of D_MAX_BLOCKS_IN_MCU coefficient blocks,
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* and let the entropy decoder write into that workspace each time.
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* (On 80x86, the workspace is FAR even though it's not really very big;
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* this is to keep the module interfaces unchanged when a large coefficient
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* buffer is necessary.)
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* In multi-pass modes, this array points to the current MCU's blocks
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* within the virtual arrays; it is used only by the input side.
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*/
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JBLOCKROW MCU_buffer[D_MAX_BLOCKS_IN_MCU];
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#ifdef D_MULTISCAN_FILES_SUPPORTED
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/* In multi-pass modes, we need a virtual block array for each component. */
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jvirt_barray_ptr whole_image[MAX_COMPONENTS];
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#endif
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#ifdef BLOCK_SMOOTHING_SUPPORTED
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/* When doing block smoothing, we latch coefficient Al values here */
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int * coef_bits_latch;
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#define SAVED_COEFS 6 /* we save coef_bits[0..5] */
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#endif
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} my_coef_controller;
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typedef my_coef_controller * my_coef_ptr;
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/* Forward declarations */
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METHODDEF(int) decompress_onepass
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JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf));
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#ifdef D_MULTISCAN_FILES_SUPPORTED
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METHODDEF(int) decompress_data
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JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf));
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#endif
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#ifdef BLOCK_SMOOTHING_SUPPORTED
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LOCAL(boolean) smoothing_ok JPP((j_decompress_ptr cinfo));
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METHODDEF(int) decompress_smooth_data
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JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf));
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#endif
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LOCAL(void)
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start_iMCU_row (j_decompress_ptr cinfo)
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/* Reset within-iMCU-row counters for a new row (input side) */
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{
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my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
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/* In an interleaved scan, an MCU row is the same as an iMCU row.
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* In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
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* But at the bottom of the image, process only what's left.
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*/
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if (cinfo->comps_in_scan > 1) {
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coef->MCU_rows_per_iMCU_row = 1;
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} else {
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if (cinfo->input_iMCU_row < (cinfo->total_iMCU_rows-1))
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coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;
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else
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coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
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}
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coef->MCU_ctr = 0;
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coef->MCU_vert_offset = 0;
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}
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/*
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* Initialize for an input processing pass.
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*/
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METHODDEF(void)
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start_input_pass (j_decompress_ptr cinfo)
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{
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cinfo->input_iMCU_row = 0;
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start_iMCU_row(cinfo);
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}
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/*
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* Initialize for an output processing pass.
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*/
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METHODDEF(void)
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start_output_pass (j_decompress_ptr cinfo)
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{
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#ifdef BLOCK_SMOOTHING_SUPPORTED
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my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
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/* If multipass, check to see whether to use block smoothing on this pass */
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if (coef->pub.coef_arrays != NULL) {
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if (cinfo->do_block_smoothing && smoothing_ok(cinfo))
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coef->pub.decompress_data = decompress_smooth_data;
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else
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coef->pub.decompress_data = decompress_data;
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}
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#endif
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cinfo->output_iMCU_row = 0;
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}
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/*
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* Decompress and return some data in the single-pass case.
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* Always attempts to emit one fully interleaved MCU row ("iMCU" row).
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* Input and output must run in lockstep since we have only a one-MCU buffer.
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* Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
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*
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* NB: output_buf contains a plane for each component in image,
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* which we index according to the component's SOF position.
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*/
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METHODDEF(int)
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decompress_onepass (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
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{
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my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
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JDIMENSION MCU_col_num; /* index of current MCU within row */
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JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1;
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JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
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int blkn, ci, xindex, yindex, yoffset, useful_width;
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JSAMPARRAY output_ptr;
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JDIMENSION start_col, output_col;
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jpeg_component_info *compptr;
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inverse_DCT_method_ptr inverse_DCT;
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/* Loop to process as much as one whole iMCU row */
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for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
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yoffset++) {
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for (MCU_col_num = coef->MCU_ctr; MCU_col_num <= last_MCU_col;
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MCU_col_num++) {
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/* Try to fetch an MCU. Entropy decoder expects buffer to be zeroed. */
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jzero_far((void FAR *) coef->MCU_buffer[0],
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(size_t) (cinfo->blocks_in_MCU * SIZEOF(JBLOCK)));
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if (! (*cinfo->entropy->decode_mcu) (cinfo, coef->MCU_buffer)) {
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/* Suspension forced; update state counters and exit */
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coef->MCU_vert_offset = yoffset;
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coef->MCU_ctr = MCU_col_num;
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return JPEG_SUSPENDED;
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}
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/* Determine where data should go in output_buf and do the IDCT thing.
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* We skip dummy blocks at the right and bottom edges (but blkn gets
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* incremented past them!). Note the inner loop relies on having
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* allocated the MCU_buffer[] blocks sequentially.
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*/
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blkn = 0; /* index of current DCT block within MCU */
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for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
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compptr = cinfo->cur_comp_info[ci];
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/* Don't bother to IDCT an uninteresting component. */
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if (! compptr->component_needed) {
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blkn += compptr->MCU_blocks;
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continue;
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}
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inverse_DCT = cinfo->idct->inverse_DCT[compptr->component_index];
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useful_width = (MCU_col_num < last_MCU_col) ? compptr->MCU_width
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: compptr->last_col_width;
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output_ptr = output_buf[compptr->component_index] +
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yoffset * compptr->DCT_scaled_size;
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start_col = MCU_col_num * compptr->MCU_sample_width;
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for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
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if (cinfo->input_iMCU_row < last_iMCU_row ||
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yoffset+yindex < compptr->last_row_height) {
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output_col = start_col;
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for (xindex = 0; xindex < useful_width; xindex++) {
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(*inverse_DCT) (cinfo, compptr,
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(JCOEFPTR) coef->MCU_buffer[blkn+xindex],
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output_ptr, output_col);
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output_col += compptr->DCT_scaled_size;
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}
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}
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blkn += compptr->MCU_width;
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output_ptr += compptr->DCT_scaled_size;
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}
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}
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}
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/* Completed an MCU row, but perhaps not an iMCU row */
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coef->MCU_ctr = 0;
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}
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/* Completed the iMCU row, advance counters for next one */
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cinfo->output_iMCU_row++;
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if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) {
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start_iMCU_row(cinfo);
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return JPEG_ROW_COMPLETED;
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}
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/* Completed the scan */
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(*cinfo->inputctl->finish_input_pass) (cinfo);
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return JPEG_SCAN_COMPLETED;
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}
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/*
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* Dummy consume-input routine for single-pass operation.
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*/
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METHODDEF(int)
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dummy_consume_data (j_decompress_ptr cinfo)
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{
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return JPEG_SUSPENDED; /* Always indicate nothing was done */
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}
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#ifdef D_MULTISCAN_FILES_SUPPORTED
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/*
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* Consume input data and store it in the full-image coefficient buffer.
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* We read as much as one fully interleaved MCU row ("iMCU" row) per call,
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* ie, v_samp_factor block rows for each component in the scan.
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* Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
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*/
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METHODDEF(int)
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consume_data (j_decompress_ptr cinfo)
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{
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my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
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JDIMENSION MCU_col_num; /* index of current MCU within row */
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int blkn, ci, xindex, yindex, yoffset;
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JDIMENSION start_col;
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JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN];
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JBLOCKROW buffer_ptr;
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jpeg_component_info *compptr;
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/* Align the virtual buffers for the components used in this scan. */
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for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
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compptr = cinfo->cur_comp_info[ci];
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buffer[ci] = (*cinfo->mem->access_virt_barray)
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((j_common_ptr) cinfo, coef->whole_image[compptr->component_index],
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cinfo->input_iMCU_row * compptr->v_samp_factor,
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(JDIMENSION) compptr->v_samp_factor, TRUE);
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/* Note: entropy decoder expects buffer to be zeroed,
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* but this is handled automatically by the memory manager
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* because we requested a pre-zeroed array.
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*/
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}
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/* Loop to process one whole iMCU row */
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for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
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yoffset++) {
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for (MCU_col_num = coef->MCU_ctr; MCU_col_num < cinfo->MCUs_per_row;
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MCU_col_num++) {
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/* Construct list of pointers to DCT blocks belonging to this MCU */
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blkn = 0; /* index of current DCT block within MCU */
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for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
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compptr = cinfo->cur_comp_info[ci];
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start_col = MCU_col_num * compptr->MCU_width;
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for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
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buffer_ptr = buffer[ci][yindex+yoffset] + start_col;
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for (xindex = 0; xindex < compptr->MCU_width; xindex++) {
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coef->MCU_buffer[blkn++] = buffer_ptr++;
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}
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}
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}
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/* Try to fetch the MCU. */
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if (! (*cinfo->entropy->decode_mcu) (cinfo, coef->MCU_buffer)) {
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/* Suspension forced; update state counters and exit */
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coef->MCU_vert_offset = yoffset;
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coef->MCU_ctr = MCU_col_num;
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return JPEG_SUSPENDED;
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}
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}
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/* Completed an MCU row, but perhaps not an iMCU row */
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coef->MCU_ctr = 0;
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}
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/* Completed the iMCU row, advance counters for next one */
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if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) {
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start_iMCU_row(cinfo);
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return JPEG_ROW_COMPLETED;
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}
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/* Completed the scan */
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(*cinfo->inputctl->finish_input_pass) (cinfo);
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return JPEG_SCAN_COMPLETED;
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}
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/*
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* Decompress and return some data in the multi-pass case.
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* Always attempts to emit one fully interleaved MCU row ("iMCU" row).
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* Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
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*
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* NB: output_buf contains a plane for each component in image.
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*/
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METHODDEF(int)
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decompress_data (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
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{
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my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
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JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
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JDIMENSION block_num;
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int ci, block_row, block_rows;
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JBLOCKARRAY buffer;
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JBLOCKROW buffer_ptr;
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JSAMPARRAY output_ptr;
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JDIMENSION output_col;
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jpeg_component_info *compptr;
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inverse_DCT_method_ptr inverse_DCT;
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/* Force some input to be done if we are getting ahead of the input. */
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while (cinfo->input_scan_number < cinfo->output_scan_number ||
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(cinfo->input_scan_number == cinfo->output_scan_number &&
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cinfo->input_iMCU_row <= cinfo->output_iMCU_row)) {
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if ((*cinfo->inputctl->consume_input)(cinfo) == JPEG_SUSPENDED)
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return JPEG_SUSPENDED;
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}
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/* OK, output from the virtual arrays. */
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for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
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ci++, compptr++) {
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/* Don't bother to IDCT an uninteresting component. */
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if (! compptr->component_needed)
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continue;
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/* Align the virtual buffer for this component. */
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buffer = (*cinfo->mem->access_virt_barray)
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((j_common_ptr) cinfo, coef->whole_image[ci],
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cinfo->output_iMCU_row * compptr->v_samp_factor,
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(JDIMENSION) compptr->v_samp_factor, FALSE);
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/* Count non-dummy DCT block rows in this iMCU row. */
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if (cinfo->output_iMCU_row < last_iMCU_row)
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block_rows = compptr->v_samp_factor;
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else {
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/* NB: can't use last_row_height here; it is input-side-dependent! */
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block_rows = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
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if (block_rows == 0) block_rows = compptr->v_samp_factor;
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}
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inverse_DCT = cinfo->idct->inverse_DCT[ci];
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output_ptr = output_buf[ci];
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/* Loop over all DCT blocks to be processed. */
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for (block_row = 0; block_row < block_rows; block_row++) {
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buffer_ptr = buffer[block_row];
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output_col = 0;
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for (block_num = 0; block_num < compptr->width_in_blocks; block_num++) {
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(*inverse_DCT) (cinfo, compptr, (JCOEFPTR) buffer_ptr,
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output_ptr, output_col);
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buffer_ptr++;
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output_col += compptr->DCT_scaled_size;
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}
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output_ptr += compptr->DCT_scaled_size;
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}
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}
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if (++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows)
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return JPEG_ROW_COMPLETED;
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return JPEG_SCAN_COMPLETED;
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}
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#endif /* D_MULTISCAN_FILES_SUPPORTED */
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#ifdef BLOCK_SMOOTHING_SUPPORTED
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/*
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* This code applies interblock smoothing as described by section K.8
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* of the JPEG standard: the first 5 AC coefficients are estimated from
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* the DC values of a DCT block and its 8 neighboring blocks.
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* We apply smoothing only for progressive JPEG decoding, and only if
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* the coefficients it can estimate are not yet known to full precision.
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*/
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/* Natural-order array positions of the first 5 zigzag-order coefficients */
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#define Q01_POS 1
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#define Q10_POS 8
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#define Q20_POS 16
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#define Q11_POS 9
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#define Q02_POS 2
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/*
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* Determine whether block smoothing is applicable and safe.
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* We also latch the current states of the coef_bits[] entries for the
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* AC coefficients; otherwise, if the input side of the decompressor
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* advances into a new scan, we might think the coefficients are known
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* more accurately than they really are.
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*/
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LOCAL(boolean)
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smoothing_ok (j_decompress_ptr cinfo)
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{
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my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
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boolean smoothing_useful = FALSE;
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int ci, coefi;
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jpeg_component_info *compptr;
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JQUANT_TBL * qtable;
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int * coef_bits;
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int * coef_bits_latch;
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if (! cinfo->progressive_mode || cinfo->coef_bits == NULL)
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return FALSE;
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/* Allocate latch area if not already done */
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if (coef->coef_bits_latch == NULL)
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coef->coef_bits_latch = (int *)
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(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
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cinfo->num_components *
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(SAVED_COEFS * SIZEOF(int)));
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coef_bits_latch = coef->coef_bits_latch;
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for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
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ci++, compptr++) {
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/* All components' quantization values must already be latched. */
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if ((qtable = compptr->quant_table) == NULL)
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return FALSE;
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/* Verify DC & first 5 AC quantizers are nonzero to avoid zero-divide. */
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if (qtable->quantval[0] == 0 ||
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qtable->quantval[Q01_POS] == 0 ||
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qtable->quantval[Q10_POS] == 0 ||
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qtable->quantval[Q20_POS] == 0 ||
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qtable->quantval[Q11_POS] == 0 ||
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qtable->quantval[Q02_POS] == 0)
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|
return FALSE;
|
|
/* DC values must be at least partly known for all components. */
|
|
coef_bits = cinfo->coef_bits[ci];
|
|
if (coef_bits[0] < 0)
|
|
return FALSE;
|
|
/* Block smoothing is helpful if some AC coefficients remain inaccurate. */
|
|
for (coefi = 1; coefi <= 5; coefi++) {
|
|
coef_bits_latch[coefi] = coef_bits[coefi];
|
|
if (coef_bits[coefi] != 0)
|
|
smoothing_useful = TRUE;
|
|
}
|
|
coef_bits_latch += SAVED_COEFS;
|
|
}
|
|
|
|
return smoothing_useful;
|
|
}
|
|
|
|
|
|
/*
|
|
* Variant of decompress_data for use when doing block smoothing.
|
|
*/
|
|
|
|
METHODDEF(int)
|
|
decompress_smooth_data (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
|
|
{
|
|
my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
|
|
JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
|
|
JDIMENSION block_num, last_block_column;
|
|
int ci, block_row, block_rows, access_rows;
|
|
JBLOCKARRAY buffer;
|
|
JBLOCKROW buffer_ptr, prev_block_row, next_block_row;
|
|
JSAMPARRAY output_ptr;
|
|
JDIMENSION output_col;
|
|
jpeg_component_info *compptr;
|
|
inverse_DCT_method_ptr inverse_DCT;
|
|
boolean first_row, last_row;
|
|
JBLOCK workspace;
|
|
int *coef_bits;
|
|
JQUANT_TBL *quanttbl;
|
|
INT32 Q00,Q01,Q02,Q10,Q11,Q20, num;
|
|
int DC1,DC2,DC3,DC4,DC5,DC6,DC7,DC8,DC9;
|
|
int Al, pred;
|
|
|
|
/* Force some input to be done if we are getting ahead of the input. */
|
|
while (cinfo->input_scan_number <= cinfo->output_scan_number &&
|
|
! cinfo->inputctl->eoi_reached) {
|
|
if (cinfo->input_scan_number == cinfo->output_scan_number) {
|
|
/* If input is working on current scan, we ordinarily want it to
|
|
* have completed the current row. But if input scan is DC,
|
|
* we want it to keep one row ahead so that next block row's DC
|
|
* values are up to date.
|
|
*/
|
|
JDIMENSION delta = (cinfo->Ss == 0) ? 1 : 0;
|
|
if (cinfo->input_iMCU_row > cinfo->output_iMCU_row+delta)
|
|
break;
|
|
}
|
|
if ((*cinfo->inputctl->consume_input)(cinfo) == JPEG_SUSPENDED)
|
|
return JPEG_SUSPENDED;
|
|
}
|
|
|
|
/* OK, output from the virtual arrays. */
|
|
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
|
|
ci++, compptr++) {
|
|
/* Don't bother to IDCT an uninteresting component. */
|
|
if (! compptr->component_needed)
|
|
continue;
|
|
/* Count non-dummy DCT block rows in this iMCU row. */
|
|
if (cinfo->output_iMCU_row < last_iMCU_row) {
|
|
block_rows = compptr->v_samp_factor;
|
|
access_rows = block_rows * 2; /* this and next iMCU row */
|
|
last_row = FALSE;
|
|
} else {
|
|
/* NB: can't use last_row_height here; it is input-side-dependent! */
|
|
block_rows = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
|
|
if (block_rows == 0) block_rows = compptr->v_samp_factor;
|
|
access_rows = block_rows; /* this iMCU row only */
|
|
last_row = TRUE;
|
|
}
|
|
/* Align the virtual buffer for this component. */
|
|
if (cinfo->output_iMCU_row > 0) {
|
|
access_rows += compptr->v_samp_factor; /* prior iMCU row too */
|
|
buffer = (*cinfo->mem->access_virt_barray)
|
|
((j_common_ptr) cinfo, coef->whole_image[ci],
|
|
(cinfo->output_iMCU_row - 1) * compptr->v_samp_factor,
|
|
(JDIMENSION) access_rows, FALSE);
|
|
buffer += compptr->v_samp_factor; /* point to current iMCU row */
|
|
first_row = FALSE;
|
|
} else {
|
|
buffer = (*cinfo->mem->access_virt_barray)
|
|
((j_common_ptr) cinfo, coef->whole_image[ci],
|
|
(JDIMENSION) 0, (JDIMENSION) access_rows, FALSE);
|
|
first_row = TRUE;
|
|
}
|
|
/* Fetch component-dependent info */
|
|
coef_bits = coef->coef_bits_latch + (ci * SAVED_COEFS);
|
|
quanttbl = compptr->quant_table;
|
|
Q00 = quanttbl->quantval[0];
|
|
Q01 = quanttbl->quantval[Q01_POS];
|
|
Q10 = quanttbl->quantval[Q10_POS];
|
|
Q20 = quanttbl->quantval[Q20_POS];
|
|
Q11 = quanttbl->quantval[Q11_POS];
|
|
Q02 = quanttbl->quantval[Q02_POS];
|
|
inverse_DCT = cinfo->idct->inverse_DCT[ci];
|
|
output_ptr = output_buf[ci];
|
|
/* Loop over all DCT blocks to be processed. */
|
|
for (block_row = 0; block_row < block_rows; block_row++) {
|
|
buffer_ptr = buffer[block_row];
|
|
if (first_row && block_row == 0)
|
|
prev_block_row = buffer_ptr;
|
|
else
|
|
prev_block_row = buffer[block_row-1];
|
|
if (last_row && block_row == block_rows-1)
|
|
next_block_row = buffer_ptr;
|
|
else
|
|
next_block_row = buffer[block_row+1];
|
|
/* We fetch the surrounding DC values using a sliding-register approach.
|
|
* Initialize all nine here so as to do the right thing on narrow pics.
|
|
*/
|
|
DC1 = DC2 = DC3 = (int) prev_block_row[0][0];
|
|
DC4 = DC5 = DC6 = (int) buffer_ptr[0][0];
|
|
DC7 = DC8 = DC9 = (int) next_block_row[0][0];
|
|
output_col = 0;
|
|
last_block_column = compptr->width_in_blocks - 1;
|
|
for (block_num = 0; block_num <= last_block_column; block_num++) {
|
|
/* Fetch current DCT block into workspace so we can modify it. */
|
|
jcopy_block_row(buffer_ptr, (JBLOCKROW) workspace, (JDIMENSION) 1);
|
|
/* Update DC values */
|
|
if (block_num < last_block_column) {
|
|
DC3 = (int) prev_block_row[1][0];
|
|
DC6 = (int) buffer_ptr[1][0];
|
|
DC9 = (int) next_block_row[1][0];
|
|
}
|
|
/* Compute coefficient estimates per K.8.
|
|
* An estimate is applied only if coefficient is still zero,
|
|
* and is not known to be fully accurate.
|
|
*/
|
|
/* AC01 */
|
|
if ((Al=coef_bits[1]) != 0 && workspace[1] == 0) {
|
|
num = 36 * Q00 * (DC4 - DC6);
|
|
if (num >= 0) {
|
|
pred = (int) (((Q01<<7) + num) / (Q01<<8));
|
|
if (Al > 0 && pred >= (1<<Al))
|
|
pred = (1<<Al)-1;
|
|
} else {
|
|
pred = (int) (((Q01<<7) - num) / (Q01<<8));
|
|
if (Al > 0 && pred >= (1<<Al))
|
|
pred = (1<<Al)-1;
|
|
pred = -pred;
|
|
}
|
|
workspace[1] = (JCOEF) pred;
|
|
}
|
|
/* AC10 */
|
|
if ((Al=coef_bits[2]) != 0 && workspace[8] == 0) {
|
|
num = 36 * Q00 * (DC2 - DC8);
|
|
if (num >= 0) {
|
|
pred = (int) (((Q10<<7) + num) / (Q10<<8));
|
|
if (Al > 0 && pred >= (1<<Al))
|
|
pred = (1<<Al)-1;
|
|
} else {
|
|
pred = (int) (((Q10<<7) - num) / (Q10<<8));
|
|
if (Al > 0 && pred >= (1<<Al))
|
|
pred = (1<<Al)-1;
|
|
pred = -pred;
|
|
}
|
|
workspace[8] = (JCOEF) pred;
|
|
}
|
|
/* AC20 */
|
|
if ((Al=coef_bits[3]) != 0 && workspace[16] == 0) {
|
|
num = 9 * Q00 * (DC2 + DC8 - 2*DC5);
|
|
if (num >= 0) {
|
|
pred = (int) (((Q20<<7) + num) / (Q20<<8));
|
|
if (Al > 0 && pred >= (1<<Al))
|
|
pred = (1<<Al)-1;
|
|
} else {
|
|
pred = (int) (((Q20<<7) - num) / (Q20<<8));
|
|
if (Al > 0 && pred >= (1<<Al))
|
|
pred = (1<<Al)-1;
|
|
pred = -pred;
|
|
}
|
|
workspace[16] = (JCOEF) pred;
|
|
}
|
|
/* AC11 */
|
|
if ((Al=coef_bits[4]) != 0 && workspace[9] == 0) {
|
|
num = 5 * Q00 * (DC1 - DC3 - DC7 + DC9);
|
|
if (num >= 0) {
|
|
pred = (int) (((Q11<<7) + num) / (Q11<<8));
|
|
if (Al > 0 && pred >= (1<<Al))
|
|
pred = (1<<Al)-1;
|
|
} else {
|
|
pred = (int) (((Q11<<7) - num) / (Q11<<8));
|
|
if (Al > 0 && pred >= (1<<Al))
|
|
pred = (1<<Al)-1;
|
|
pred = -pred;
|
|
}
|
|
workspace[9] = (JCOEF) pred;
|
|
}
|
|
/* AC02 */
|
|
if ((Al=coef_bits[5]) != 0 && workspace[2] == 0) {
|
|
num = 9 * Q00 * (DC4 + DC6 - 2*DC5);
|
|
if (num >= 0) {
|
|
pred = (int) (((Q02<<7) + num) / (Q02<<8));
|
|
if (Al > 0 && pred >= (1<<Al))
|
|
pred = (1<<Al)-1;
|
|
} else {
|
|
pred = (int) (((Q02<<7) - num) / (Q02<<8));
|
|
if (Al > 0 && pred >= (1<<Al))
|
|
pred = (1<<Al)-1;
|
|
pred = -pred;
|
|
}
|
|
workspace[2] = (JCOEF) pred;
|
|
}
|
|
/* OK, do the IDCT */
|
|
(*inverse_DCT) (cinfo, compptr, (JCOEFPTR) workspace,
|
|
output_ptr, output_col);
|
|
/* Advance for next column */
|
|
DC1 = DC2; DC2 = DC3;
|
|
DC4 = DC5; DC5 = DC6;
|
|
DC7 = DC8; DC8 = DC9;
|
|
buffer_ptr++, prev_block_row++, next_block_row++;
|
|
output_col += compptr->DCT_scaled_size;
|
|
}
|
|
output_ptr += compptr->DCT_scaled_size;
|
|
}
|
|
}
|
|
|
|
if (++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows)
|
|
return JPEG_ROW_COMPLETED;
|
|
return JPEG_SCAN_COMPLETED;
|
|
}
|
|
|
|
#endif /* BLOCK_SMOOTHING_SUPPORTED */
|
|
|
|
|
|
/*
|
|
* Initialize coefficient buffer controller.
|
|
*/
|
|
|
|
GLOBAL(void)
|
|
jinit_d_coef_controller (j_decompress_ptr cinfo, boolean need_full_buffer)
|
|
{
|
|
my_coef_ptr coef;
|
|
|
|
coef = (my_coef_ptr)
|
|
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
|
|
SIZEOF(my_coef_controller));
|
|
cinfo->coef = (struct jpeg_d_coef_controller *) coef;
|
|
coef->pub.start_input_pass = start_input_pass;
|
|
coef->pub.start_output_pass = start_output_pass;
|
|
#ifdef BLOCK_SMOOTHING_SUPPORTED
|
|
coef->coef_bits_latch = NULL;
|
|
#endif
|
|
|
|
/* Create the coefficient buffer. */
|
|
if (need_full_buffer) {
|
|
#ifdef D_MULTISCAN_FILES_SUPPORTED
|
|
/* Allocate a full-image virtual array for each component, */
|
|
/* padded to a multiple of samp_factor DCT blocks in each direction. */
|
|
/* Note we ask for a pre-zeroed array. */
|
|
int ci, access_rows;
|
|
jpeg_component_info *compptr;
|
|
|
|
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
|
|
ci++, compptr++) {
|
|
access_rows = compptr->v_samp_factor;
|
|
#ifdef BLOCK_SMOOTHING_SUPPORTED
|
|
/* If block smoothing could be used, need a bigger window */
|
|
if (cinfo->progressive_mode)
|
|
access_rows *= 3;
|
|
#endif
|
|
coef->whole_image[ci] = (*cinfo->mem->request_virt_barray)
|
|
((j_common_ptr) cinfo, JPOOL_IMAGE, TRUE,
|
|
(JDIMENSION) jround_up((long) compptr->width_in_blocks,
|
|
(long) compptr->h_samp_factor),
|
|
(JDIMENSION) jround_up((long) compptr->height_in_blocks,
|
|
(long) compptr->v_samp_factor),
|
|
(JDIMENSION) access_rows);
|
|
}
|
|
coef->pub.consume_data = consume_data;
|
|
coef->pub.decompress_data = decompress_data;
|
|
coef->pub.coef_arrays = coef->whole_image; /* link to virtual arrays */
|
|
#else
|
|
ERREXIT(cinfo, JERR_NOT_COMPILED);
|
|
#endif
|
|
} else {
|
|
/* We only need a single-MCU buffer. */
|
|
JBLOCKROW buffer;
|
|
int i;
|
|
|
|
buffer = (JBLOCKROW)
|
|
(*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
|
|
D_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));
|
|
for (i = 0; i < D_MAX_BLOCKS_IN_MCU; i++) {
|
|
coef->MCU_buffer[i] = buffer + i;
|
|
}
|
|
coef->pub.consume_data = dummy_consume_data;
|
|
coef->pub.decompress_data = decompress_onepass;
|
|
coef->pub.coef_arrays = NULL; /* flag for no virtual arrays */
|
|
}
|
|
}
|