#if !defined(_FX_JPEG_TURBO_) | |
/* | |
* 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 */ | |
} | |
} | |
#endif //_FX_JPEG_TURBO_ |