+++ /dev/null
-/*
- * jccoefct.c
- *
- * Copyright (C) 1994-1997, Thomas G. Lane.
- * This file is part of the Independent JPEG Group's software.
- * For conditions of distribution and use, see the accompanying README file.
- *
- * This file contains the coefficient buffer controller for compression.
- * This controller is the top level of the JPEG compressor proper.
- * The coefficient buffer lies between forward-DCT and entropy encoding steps.
- */
-
-#define JPEG_INTERNALS
-#include "jinclude.h"
-#include "jpeglib.h"
-
-
-/* We use a full-image coefficient buffer when doing Huffman optimization,
- * and also for writing multiple-scan JPEG files. In all cases, the DCT
- * step is run during the first pass, and subsequent passes need only read
- * the buffered coefficients.
- */
-#ifdef ENTROPY_OPT_SUPPORTED
-#define FULL_COEF_BUFFER_SUPPORTED
-#else
-#ifdef C_MULTISCAN_FILES_SUPPORTED
-#define FULL_COEF_BUFFER_SUPPORTED
-#endif
-#endif
-
-
-/* Private buffer controller object */
-
-typedef struct {
- struct jpeg_c_coef_controller pub; /* public fields */
-
- JDIMENSION iMCU_row_num; /* iMCU row # within image */
- JDIMENSION mcu_ctr; /* counts MCUs processed in current row */
- int MCU_vert_offset; /* counts MCU rows within iMCU row */
- int MCU_rows_per_iMCU_row; /* number of such rows needed */
-
- /* For single-pass compression, it's sufficient to buffer just one MCU
- * (although this may prove a bit slow in practice). We allocate a
- * workspace of C_MAX_BLOCKS_IN_MCU coefficient blocks, and reuse it for each
- * MCU constructed and sent. (On 80x86, the workspace is FAR even though
- * it's not really very big; this is to keep the module interfaces unchanged
- * when a large coefficient buffer is necessary.)
- * In multi-pass modes, this array points to the current MCU's blocks
- * within the virtual arrays.
- */
- JBLOCKROW MCU_buffer[C_MAX_BLOCKS_IN_MCU];
-
- /* In multi-pass modes, we need a virtual block array for each component. */
- jvirt_barray_ptr whole_image[MAX_COMPONENTS];
-} my_coef_controller;
-
-typedef my_coef_controller * my_coef_ptr;
-
-
-/* Forward declarations */
-METHODDEF(boolean) compress_data
- JPP((j_compress_ptr cinfo, JSAMPIMAGE input_buf));
-#ifdef FULL_COEF_BUFFER_SUPPORTED
-METHODDEF(boolean) compress_first_pass
- JPP((j_compress_ptr cinfo, JSAMPIMAGE input_buf));
-METHODDEF(boolean) compress_output
- JPP((j_compress_ptr cinfo, JSAMPIMAGE input_buf));
-#endif
-
-
-LOCAL(void)
-start_iMCU_row (j_compress_ptr cinfo)
-/* Reset within-iMCU-row counters for a new row */
-{
- my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
-
- /* In an interleaved scan, an MCU row is the same as an iMCU row.
- * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
- * But at the bottom of the image, process only what's left.
- */
- if (cinfo->comps_in_scan > 1) {
- coef->MCU_rows_per_iMCU_row = 1;
- } else {
- if (coef->iMCU_row_num < (cinfo->total_iMCU_rows-1))
- coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;
- else
- coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
- }
-
- coef->mcu_ctr = 0;
- coef->MCU_vert_offset = 0;
-}
-
-
-/*
- * Initialize for a processing pass.
- */
-
-METHODDEF(void)
-start_pass_coef (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
-{
- my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
-
- coef->iMCU_row_num = 0;
- start_iMCU_row(cinfo);
-
- switch (pass_mode) {
- case JBUF_PASS_THRU:
- if (coef->whole_image[0] != NULL)
- ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
- coef->pub.compress_data = compress_data;
- break;
-#ifdef FULL_COEF_BUFFER_SUPPORTED
- case JBUF_SAVE_AND_PASS:
- if (coef->whole_image[0] == NULL)
- ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
- coef->pub.compress_data = compress_first_pass;
- break;
- case JBUF_CRANK_DEST:
- if (coef->whole_image[0] == NULL)
- ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
- coef->pub.compress_data = compress_output;
- break;
-#endif
- default:
- ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
- break;
- }
-}
-
-
-/*
- * Process some data in the single-pass case.
- * We process the equivalent of one fully interleaved MCU row ("iMCU" row)
- * per call, ie, v_samp_factor block rows for each component in the image.
- * Returns TRUE if the iMCU row is completed, FALSE if suspended.
- *
- * NB: input_buf contains a plane for each component in image,
- * which we index according to the component's SOF position.
- */
-
-METHODDEF(boolean)
-compress_data (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
-{
- my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
- JDIMENSION MCU_col_num; /* index of current MCU within row */
- JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1;
- JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
- int blkn, bi, ci, yindex, yoffset, blockcnt;
- JDIMENSION ypos, xpos;
- jpeg_component_info *compptr;
-
- /* Loop to write as much as one whole iMCU row */
- for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
- yoffset++) {
- for (MCU_col_num = coef->mcu_ctr; MCU_col_num <= last_MCU_col;
- MCU_col_num++) {
- /* Determine where data comes from in input_buf and do the DCT thing.
- * Each call on forward_DCT processes a horizontal row of DCT blocks
- * as wide as an MCU; we rely on having allocated the MCU_buffer[] blocks
- * sequentially. Dummy blocks at the right or bottom edge are filled in
- * specially. The data in them does not matter for image reconstruction,
- * so we fill them with values that will encode to the smallest amount of
- * data, viz: all zeroes in the AC entries, DC entries equal to previous
- * block's DC value. (Thanks to Thomas Kinsman for this idea.)
- */
- blkn = 0;
- for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
- compptr = cinfo->cur_comp_info[ci];
- blockcnt = (MCU_col_num < last_MCU_col) ? compptr->MCU_width
- : compptr->last_col_width;
- xpos = MCU_col_num * compptr->MCU_sample_width;
- ypos = yoffset * DCTSIZE; /* ypos == (yoffset+yindex) * DCTSIZE */
- for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
- if (coef->iMCU_row_num < last_iMCU_row ||
- yoffset+yindex < compptr->last_row_height) {
- (*cinfo->fdct->forward_DCT) (cinfo, compptr,
- input_buf[compptr->component_index],
- coef->MCU_buffer[blkn],
- ypos, xpos, (JDIMENSION) blockcnt);
- if (blockcnt < compptr->MCU_width) {
- /* Create some dummy blocks at the right edge of the image. */
- jzero_far((void FAR *) coef->MCU_buffer[blkn + blockcnt],
- (compptr->MCU_width - blockcnt) * SIZEOF(JBLOCK));
- for (bi = blockcnt; bi < compptr->MCU_width; bi++) {
- coef->MCU_buffer[blkn+bi][0][0] = coef->MCU_buffer[blkn+bi-1][0][0];
- }
- }
- } else {
- /* Create a row of dummy blocks at the bottom of the image. */
- jzero_far((void FAR *) coef->MCU_buffer[blkn],
- compptr->MCU_width * SIZEOF(JBLOCK));
- for (bi = 0; bi < compptr->MCU_width; bi++) {
- coef->MCU_buffer[blkn+bi][0][0] = coef->MCU_buffer[blkn-1][0][0];
- }
- }
- blkn += compptr->MCU_width;
- ypos += DCTSIZE;
- }
- }
- /* Try to write the MCU. In event of a suspension failure, we will
- * re-DCT the MCU on restart (a bit inefficient, could be fixed...)
- */
- if (! (*cinfo->entropy->encode_mcu) (cinfo, coef->MCU_buffer)) {
- /* Suspension forced; update state counters and exit */
- coef->MCU_vert_offset = yoffset;
- coef->mcu_ctr = MCU_col_num;
- return FALSE;
- }
- }
- /* Completed an MCU row, but perhaps not an iMCU row */
- coef->mcu_ctr = 0;
- }
- /* Completed the iMCU row, advance counters for next one */
- coef->iMCU_row_num++;
- start_iMCU_row(cinfo);
- return TRUE;
-}
-
-
-#ifdef FULL_COEF_BUFFER_SUPPORTED
-
-/*
- * Process some data in the first pass of a multi-pass case.
- * We process the equivalent of one fully interleaved MCU row ("iMCU" row)
- * per call, ie, v_samp_factor block rows for each component in the image.
- * This amount of data is read from the source buffer, DCT'd and quantized,
- * and saved into the virtual arrays. We also generate suitable dummy blocks
- * as needed at the right and lower edges. (The dummy blocks are constructed
- * in the virtual arrays, which have been padded appropriately.) This makes
- * it possible for subsequent passes not to worry about real vs. dummy blocks.
- *
- * We must also emit the data to the entropy encoder. This is conveniently
- * done by calling compress_output() after we've loaded the current strip
- * of the virtual arrays.
- *
- * NB: input_buf contains a plane for each component in image. All
- * components are DCT'd and loaded into the virtual arrays in this pass.
- * However, it may be that only a subset of the components are emitted to
- * the entropy encoder during this first pass; be careful about looking
- * at the scan-dependent variables (MCU dimensions, etc).
- */
-
-METHODDEF(boolean)
-compress_first_pass (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
-{
- my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
- JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
- JDIMENSION blocks_across, MCUs_across, MCUindex;
- int bi, ci, h_samp_factor, block_row, block_rows, ndummy;
- JCOEF lastDC;
- jpeg_component_info *compptr;
- JBLOCKARRAY buffer;
- JBLOCKROW thisblockrow, lastblockrow;
-
- for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
- ci++, compptr++) {
- /* Align the virtual buffer for this component. */
- buffer = (*cinfo->mem->access_virt_barray)
- ((j_common_ptr) cinfo, coef->whole_image[ci],
- coef->iMCU_row_num * compptr->v_samp_factor,
- (JDIMENSION) compptr->v_samp_factor, TRUE);
- /* Count non-dummy DCT block rows in this iMCU row. */
- if (coef->iMCU_row_num < last_iMCU_row)
- block_rows = compptr->v_samp_factor;
- else {
- /* NB: can't use last_row_height here, since may not be set! */
- block_rows = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
- if (block_rows == 0) block_rows = compptr->v_samp_factor;
- }
- blocks_across = compptr->width_in_blocks;
- h_samp_factor = compptr->h_samp_factor;
- /* Count number of dummy blocks to be added at the right margin. */
- ndummy = (int) (blocks_across % h_samp_factor);
- if (ndummy > 0)
- ndummy = h_samp_factor - ndummy;
- /* Perform DCT for all non-dummy blocks in this iMCU row. Each call
- * on forward_DCT processes a complete horizontal row of DCT blocks.
- */
- for (block_row = 0; block_row < block_rows; block_row++) {
- thisblockrow = buffer[block_row];
- (*cinfo->fdct->forward_DCT) (cinfo, compptr,
- input_buf[ci], thisblockrow,
- (JDIMENSION) (block_row * DCTSIZE),
- (JDIMENSION) 0, blocks_across);
- if (ndummy > 0) {
- /* Create dummy blocks at the right edge of the image. */
- thisblockrow += blocks_across; /* => first dummy block */
- jzero_far((void FAR *) thisblockrow, ndummy * SIZEOF(JBLOCK));
- lastDC = thisblockrow[-1][0];
- for (bi = 0; bi < ndummy; bi++) {
- thisblockrow[bi][0] = lastDC;
- }
- }
- }
- /* If at end of image, create dummy block rows as needed.
- * The tricky part here is that within each MCU, we want the DC values
- * of the dummy blocks to match the last real block's DC value.
- * This squeezes a few more bytes out of the resulting file...
- */
- if (coef->iMCU_row_num == last_iMCU_row) {
- blocks_across += ndummy; /* include lower right corner */
- MCUs_across = blocks_across / h_samp_factor;
- for (block_row = block_rows; block_row < compptr->v_samp_factor;
- block_row++) {
- thisblockrow = buffer[block_row];
- lastblockrow = buffer[block_row-1];
- jzero_far((void FAR *) thisblockrow,
- (size_t) (blocks_across * SIZEOF(JBLOCK)));
- for (MCUindex = 0; MCUindex < MCUs_across; MCUindex++) {
- lastDC = lastblockrow[h_samp_factor-1][0];
- for (bi = 0; bi < h_samp_factor; bi++) {
- thisblockrow[bi][0] = lastDC;
- }
- thisblockrow += h_samp_factor; /* advance to next MCU in row */
- lastblockrow += h_samp_factor;
- }
- }
- }
- }
- /* NB: compress_output will increment iMCU_row_num if successful.
- * A suspension return will result in redoing all the work above next time.
- */
-
- /* Emit data to the entropy encoder, sharing code with subsequent passes */
- return compress_output(cinfo, input_buf);
-}
-
-
-/*
- * Process some data in subsequent passes of a multi-pass case.
- * We process the equivalent of one fully interleaved MCU row ("iMCU" row)
- * per call, ie, v_samp_factor block rows for each component in the scan.
- * The data is obtained from the virtual arrays and fed to the entropy coder.
- * Returns TRUE if the iMCU row is completed, FALSE if suspended.
- *
- * NB: input_buf is ignored; it is likely to be a NULL pointer.
- */
-
-METHODDEF(boolean)
-compress_output (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
-{
- my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
- JDIMENSION MCU_col_num; /* index of current MCU within row */
- int blkn, ci, xindex, yindex, yoffset;
- JDIMENSION start_col;
- JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN];
- JBLOCKROW buffer_ptr;
- jpeg_component_info *compptr;
-
- /* Align the virtual buffers for the components used in this scan.
- * NB: during first pass, this is safe only because the buffers will
- * already be aligned properly, so jmemmgr.c won't need to do any I/O.
- */
- for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
- compptr = cinfo->cur_comp_info[ci];
- buffer[ci] = (*cinfo->mem->access_virt_barray)
- ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index],
- coef->iMCU_row_num * compptr->v_samp_factor,
- (JDIMENSION) compptr->v_samp_factor, FALSE);
- }
-
- /* Loop to process one whole iMCU row */
- for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
- yoffset++) {
- for (MCU_col_num = coef->mcu_ctr; MCU_col_num < cinfo->MCUs_per_row;
- MCU_col_num++) {
- /* Construct list of pointers to DCT blocks belonging to this MCU */
- blkn = 0; /* index of current DCT block within MCU */
- for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
- compptr = cinfo->cur_comp_info[ci];
- start_col = MCU_col_num * compptr->MCU_width;
- for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
- buffer_ptr = buffer[ci][yindex+yoffset] + start_col;
- for (xindex = 0; xindex < compptr->MCU_width; xindex++) {
- coef->MCU_buffer[blkn++] = buffer_ptr++;
- }
- }
- }
- /* Try to write the MCU. */
- if (! (*cinfo->entropy->encode_mcu) (cinfo, coef->MCU_buffer)) {
- /* Suspension forced; update state counters and exit */
- coef->MCU_vert_offset = yoffset;
- coef->mcu_ctr = MCU_col_num;
- return FALSE;
- }
- }
- /* Completed an MCU row, but perhaps not an iMCU row */
- coef->mcu_ctr = 0;
- }
- /* Completed the iMCU row, advance counters for next one */
- coef->iMCU_row_num++;
- start_iMCU_row(cinfo);
- return TRUE;
-}
-
-#endif /* FULL_COEF_BUFFER_SUPPORTED */
-
-
-/*
- * Initialize coefficient buffer controller.
- */
-
-GLOBAL(void)
-jinit_c_coef_controller (j_compress_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_c_coef_controller *) coef;
- coef->pub.start_pass = start_pass_coef;
-
- /* Create the coefficient buffer. */
- if (need_full_buffer) {
-#ifdef FULL_COEF_BUFFER_SUPPORTED
- /* Allocate a full-image virtual array for each component, */
- /* padded to a multiple of samp_factor DCT blocks in each direction. */
- int ci;
- jpeg_component_info *compptr;
-
- for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
- ci++, compptr++) {
- coef->whole_image[ci] = (*cinfo->mem->request_virt_barray)
- ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
- (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) compptr->v_samp_factor);
- }
-#else
- ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
-#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,
- C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));
- for (i = 0; i < C_MAX_BLOCKS_IN_MCU; i++) {
- coef->MCU_buffer[i] = buffer + i;
- }
- coef->whole_image[0] = NULL; /* flag for no virtual arrays */
- }
-}
projects / opencv / blobdiff