jcmaster.c
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上传用户:tongfa
上传日期:2007-01-06
资源大小:1071k
文件大小:20k
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WINDOWS
- /*
- * jcmaster.c
- *
- * Copyright (C) 1991-1997, 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 master control logic for the JPEG compressor.
- * These routines are concerned with parameter validation, initial setup,
- * and inter-pass control (determining the number of passes and the work
- * to be done in each pass).
- */
- #define JPEG_INTERNALS
- #include "jinclude.h"
- #include "jpeglib.h"
- /* Private state */
- typedef enum {
- main_pass, /* input data, also do first output step */
- huff_opt_pass, /* Huffman code optimization pass */
- output_pass /* data output pass */
- } c_pass_type;
- typedef struct {
- struct jpeg_comp_master pub; /* public fields */
- c_pass_type pass_type; /* the type of the current pass */
- int pass_number; /* # of passes completed */
- int total_passes; /* total # of passes needed */
- int scan_number; /* current index in scan_info[] */
- } my_comp_master;
- typedef my_comp_master * my_master_ptr;
- /*
- * Support routines that do various essential calculations.
- */
- LOCAL(void)
- initial_setup (j_compress_ptr cinfo)
- /* Do computations that are needed before master selection phase */
- {
- int ci;
- jpeg_component_info *compptr;
- long samplesperrow;
- JDIMENSION jd_samplesperrow;
- /* Sanity check on image dimensions */
- if (cinfo->image_height <= 0 || cinfo->image_width <= 0
- || cinfo->num_components <= 0 || cinfo->input_components <= 0)
- ERREXIT(cinfo, JERR_EMPTY_IMAGE);
- /* 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);
- /* Width of an input scanline must be representable as JDIMENSION. */
- samplesperrow = (long) cinfo->image_width * (long) cinfo->input_components;
- jd_samplesperrow = (JDIMENSION) samplesperrow;
- if ((long) jd_samplesperrow != samplesperrow)
- ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
- /* 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);
- }
- /* Compute dimensions of components */
- for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
- ci++, compptr++) {
- /* Fill in the correct component_index value; don't rely on application */
- compptr->component_index = ci;
- /* For compression, we never do DCT scaling. */
- compptr->DCT_scaled_size = DCTSIZE;
- /* 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));
- /* 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 (this flag isn't actually used for compression) */
- compptr->component_needed = TRUE;
- }
- /* Compute number of fully interleaved MCU rows (number of times that
- * main controller will call coefficient controller).
- */
- cinfo->total_iMCU_rows = (JDIMENSION)
- jdiv_round_up((long) cinfo->image_height,
- (long) (cinfo->max_v_samp_factor*DCTSIZE));
- }
- #ifdef C_MULTISCAN_FILES_SUPPORTED
- LOCAL(void)
- validate_script (j_compress_ptr cinfo)
- /* Verify that the scan script in cinfo->scan_info[] is valid; also
- * determine whether it uses progressive JPEG, and set cinfo->progressive_mode.
- */
- {
- const jpeg_scan_info * scanptr;
- int scanno, ncomps, ci, coefi, thisi;
- int Ss, Se, Ah, Al;
- boolean component_sent[MAX_COMPONENTS];
- #ifdef C_PROGRESSIVE_SUPPORTED
- int * last_bitpos_ptr;
- int last_bitpos[MAX_COMPONENTS][DCTSIZE2];
- /* -1 until that coefficient has been seen; then last Al for it */
- #endif
- if (cinfo->num_scans <= 0)
- ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, 0);
- /* For sequential JPEG, all scans must have Ss=0, Se=DCTSIZE2-1;
- * for progressive JPEG, no scan can have this.
- */
- scanptr = cinfo->scan_info;
- if (scanptr->Ss != 0 || scanptr->Se != DCTSIZE2-1) {
- #ifdef C_PROGRESSIVE_SUPPORTED
- cinfo->progressive_mode = TRUE;
- last_bitpos_ptr = & last_bitpos[0][0];
- for (ci = 0; ci < cinfo->num_components; ci++)
- for (coefi = 0; coefi < DCTSIZE2; coefi++)
- *last_bitpos_ptr++ = -1;
- #else
- ERREXIT(cinfo, JERR_NOT_COMPILED);
- #endif
- } else {
- cinfo->progressive_mode = FALSE;
- for (ci = 0; ci < cinfo->num_components; ci++)
- component_sent[ci] = FALSE;
- }
- for (scanno = 1; scanno <= cinfo->num_scans; scanptr++, scanno++) {
- /* Validate component indexes */
- ncomps = scanptr->comps_in_scan;
- if (ncomps <= 0 || ncomps > MAX_COMPS_IN_SCAN)
- ERREXIT2(cinfo, JERR_COMPONENT_COUNT, ncomps, MAX_COMPS_IN_SCAN);
- for (ci = 0; ci < ncomps; ci++) {
- thisi = scanptr->component_index[ci];
- if (thisi < 0 || thisi >= cinfo->num_components)
- ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
- /* Components must appear in SOF order within each scan */
- if (ci > 0 && thisi <= scanptr->component_index[ci-1])
- ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
- }
- /* Validate progression parameters */
- Ss = scanptr->Ss;
- Se = scanptr->Se;
- Ah = scanptr->Ah;
- Al = scanptr->Al;
- if (cinfo->progressive_mode) {
- #ifdef C_PROGRESSIVE_SUPPORTED
- /* The JPEG spec simply gives the ranges 0..13 for Ah and Al, but that
- * seems wrong: the upper bound ought to depend on data precision.
- * Perhaps they really meant 0..N+1 for N-bit precision.
- * Here we allow 0..10 for 8-bit data; Al larger than 10 results in
- * out-of-range reconstructed DC values during the first DC scan,
- * which might cause problems for some decoders.
- */
- #if BITS_IN_JSAMPLE == 8
- #define MAX_AH_AL 10
- #else
- #define MAX_AH_AL 13
- #endif
- if (Ss < 0 || Ss >= DCTSIZE2 || Se < Ss || Se >= DCTSIZE2 ||
- Ah < 0 || Ah > MAX_AH_AL || Al < 0 || Al > MAX_AH_AL)
- ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
- if (Ss == 0) {
- if (Se != 0) /* DC and AC together not OK */
- ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
- } else {
- if (ncomps != 1) /* AC scans must be for only one component */
- ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
- }
- for (ci = 0; ci < ncomps; ci++) {
- last_bitpos_ptr = & last_bitpos[scanptr->component_index[ci]][0];
- if (Ss != 0 && last_bitpos_ptr[0] < 0) /* AC without prior DC scan */
- ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
- for (coefi = Ss; coefi <= Se; coefi++) {
- if (last_bitpos_ptr[coefi] < 0) {
- /* first scan of this coefficient */
- if (Ah != 0)
- ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
- } else {
- /* not first scan */
- if (Ah != last_bitpos_ptr[coefi] || Al != Ah-1)
- ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
- }
- last_bitpos_ptr[coefi] = Al;
- }
- }
- #endif
- } else {
- /* For sequential JPEG, all progression parameters must be these: */
- if (Ss != 0 || Se != DCTSIZE2-1 || Ah != 0 || Al != 0)
- ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
- /* Make sure components are not sent twice */
- for (ci = 0; ci < ncomps; ci++) {
- thisi = scanptr->component_index[ci];
- if (component_sent[thisi])
- ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
- component_sent[thisi] = TRUE;
- }
- }
- }
- /* Now verify that everything got sent. */
- if (cinfo->progressive_mode) {
- #ifdef C_PROGRESSIVE_SUPPORTED
- /* For progressive mode, we only check that at least some DC data
- * got sent for each component; the spec does not require that all bits
- * of all coefficients be transmitted. Would it be wiser to enforce
- * transmission of all coefficient bits??
- */
- for (ci = 0; ci < cinfo->num_components; ci++) {
- if (last_bitpos[ci][0] < 0)
- ERREXIT(cinfo, JERR_MISSING_DATA);
- }
- #endif
- } else {
- for (ci = 0; ci < cinfo->num_components; ci++) {
- if (! component_sent[ci])
- ERREXIT(cinfo, JERR_MISSING_DATA);
- }
- }
- }
- #endif /* C_MULTISCAN_FILES_SUPPORTED */
- LOCAL(void)
- select_scan_parameters (j_compress_ptr cinfo)
- /* Set up the scan parameters for the current scan */
- {
- int ci;
- #ifdef C_MULTISCAN_FILES_SUPPORTED
- if (cinfo->scan_info != NULL) {
- /* Prepare for current scan --- the script is already validated */
- my_master_ptr master = (my_master_ptr) cinfo->master;
- const jpeg_scan_info * scanptr = cinfo->scan_info + master->scan_number;
- cinfo->comps_in_scan = scanptr->comps_in_scan;
- for (ci = 0; ci < scanptr->comps_in_scan; ci++) {
- cinfo->cur_comp_info[ci] =
- &cinfo->comp_info[scanptr->component_index[ci]];
- }
- cinfo->Ss = scanptr->Ss;
- cinfo->Se = scanptr->Se;
- cinfo->Ah = scanptr->Ah;
- cinfo->Al = scanptr->Al;
- }
- else
- #endif
- {
- /* Prepare for single sequential-JPEG scan containing all components */
- if (cinfo->num_components > MAX_COMPS_IN_SCAN)
- ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
- MAX_COMPS_IN_SCAN);
- cinfo->comps_in_scan = cinfo->num_components;
- for (ci = 0; ci < cinfo->num_components; ci++) {
- cinfo->cur_comp_info[ci] = &cinfo->comp_info[ci];
- }
- cinfo->Ss = 0;
- cinfo->Se = DCTSIZE2-1;
- cinfo->Ah = 0;
- cinfo->Al = 0;
- }
- }
- LOCAL(void)
- per_scan_setup (j_compress_ptr cinfo)
- /* Do computations that are needed before processing a JPEG scan */
- /* cinfo->comps_in_scan and cinfo->cur_comp_info[] are already set */
- {
- 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 = DCTSIZE;
- 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 * DCTSIZE;
- /* 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 > C_MAX_BLOCKS_IN_MCU)
- ERREXIT(cinfo, JERR_BAD_MCU_SIZE);
- while (mcublks-- > 0) {
- cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci;
- }
- }
- }
- /* Convert restart specified in rows to actual MCU count. */
- /* Note that count must fit in 16 bits, so we provide limiting. */
- if (cinfo->restart_in_rows > 0) {
- long nominal = (long) cinfo->restart_in_rows * (long) cinfo->MCUs_per_row;
- cinfo->restart_interval = (unsigned int) MIN(nominal, 65535L);
- }
- }
- /*
- * Per-pass setup.
- * This is called at the beginning of each pass. We determine which modules
- * will be active during this pass and give them appropriate start_pass calls.
- * We also set is_last_pass to indicate whether any more passes will be
- * required.
- */
- METHODDEF(void)
- prepare_for_pass (j_compress_ptr cinfo)
- {
- my_master_ptr master = (my_master_ptr) cinfo->master;
- switch (master->pass_type) {
- case main_pass:
- /* Initial pass: will collect input data, and do either Huffman
- * optimization or data output for the first scan.
- */
- select_scan_parameters(cinfo);
- per_scan_setup(cinfo);
- if (! cinfo->raw_data_in) {
- (*cinfo->cconvert->start_pass) (cinfo);
- (*cinfo->downsample->start_pass) (cinfo);
- (*cinfo->prep->start_pass) (cinfo, JBUF_PASS_THRU);
- }
- (*cinfo->fdct->start_pass) (cinfo);
- (*cinfo->entropy->start_pass) (cinfo, cinfo->optimize_coding);
- (*cinfo->coef->start_pass) (cinfo,
- (master->total_passes > 1 ?
- JBUF_SAVE_AND_PASS : JBUF_PASS_THRU));
- (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU);
- if (cinfo->optimize_coding) {
- /* No immediate data output; postpone writing frame/scan headers */
- master->pub.call_pass_startup = FALSE;
- } else {
- /* Will write frame/scan headers at first jpeg_write_scanlines call */
- master->pub.call_pass_startup = TRUE;
- }
- break;
- #ifdef ENTROPY_OPT_SUPPORTED
- case huff_opt_pass:
- /* Do Huffman optimization for a scan after the first one. */
- select_scan_parameters(cinfo);
- per_scan_setup(cinfo);
- if (cinfo->Ss != 0 || cinfo->Ah == 0 || cinfo->arith_code) {
- (*cinfo->entropy->start_pass) (cinfo, TRUE);
- (*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST);
- master->pub.call_pass_startup = FALSE;
- break;
- }
- /* Special case: Huffman DC refinement scans need no Huffman table
- * and therefore we can skip the optimization pass for them.
- */
- master->pass_type = output_pass;
- master->pass_number++;
- /*FALLTHROUGH*/
- #endif
- case output_pass:
- /* Do a data-output pass. */
- /* We need not repeat per-scan setup if prior optimization pass did it. */
- if (! cinfo->optimize_coding) {
- select_scan_parameters(cinfo);
- per_scan_setup(cinfo);
- }
- (*cinfo->entropy->start_pass) (cinfo, FALSE);
- (*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST);
- /* We emit frame/scan headers now */
- if (master->scan_number == 0)
- (*cinfo->marker->write_frame_header) (cinfo);
- (*cinfo->marker->write_scan_header) (cinfo);
- master->pub.call_pass_startup = FALSE;
- break;
- default:
- ERREXIT(cinfo, JERR_NOT_COMPILED);
- }
- master->pub.is_last_pass = (master->pass_number == master->total_passes-1);
- /* Set up progress monitor's pass info if present */
- if (cinfo->progress != NULL) {
- cinfo->progress->completed_passes = master->pass_number;
- cinfo->progress->total_passes = master->total_passes;
- }
- }
- /*
- * Special start-of-pass hook.
- * This is called by jpeg_write_scanlines if call_pass_startup is TRUE.
- * In single-pass processing, we need this hook because we don't want to
- * write frame/scan headers during jpeg_start_compress; we want to let the
- * application write COM markers etc. between jpeg_start_compress and the
- * jpeg_write_scanlines loop.
- * In multi-pass processing, this routine is not used.
- */
- METHODDEF(void)
- pass_startup (j_compress_ptr cinfo)
- {
- cinfo->master->call_pass_startup = FALSE; /* reset flag so call only once */
- (*cinfo->marker->write_frame_header) (cinfo);
- (*cinfo->marker->write_scan_header) (cinfo);
- }
- /*
- * Finish up at end of pass.
- */
- METHODDEF(void)
- finish_pass_master (j_compress_ptr cinfo)
- {
- my_master_ptr master = (my_master_ptr) cinfo->master;
- /* The entropy coder always needs an end-of-pass call,
- * either to analyze statistics or to flush its output buffer.
- */
- (*cinfo->entropy->finish_pass) (cinfo);
- /* Update state for next pass */
- switch (master->pass_type) {
- case main_pass:
- /* next pass is either output of scan 0 (after optimization)
- * or output of scan 1 (if no optimization).
- */
- master->pass_type = output_pass;
- if (! cinfo->optimize_coding)
- master->scan_number++;
- break;
- case huff_opt_pass:
- /* next pass is always output of current scan */
- master->pass_type = output_pass;
- break;
- case output_pass:
- /* next pass is either optimization or output of next scan */
- if (cinfo->optimize_coding)
- master->pass_type = huff_opt_pass;
- master->scan_number++;
- break;
- }
- master->pass_number++;
- }
- /*
- * Initialize master compression control.
- */
- GLOBAL(void)
- jinit_c_master_control (j_compress_ptr cinfo, boolean transcode_only)
- {
- my_master_ptr master;
- master = (my_master_ptr)
- (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
- SIZEOF(my_comp_master));
- cinfo->master = (struct jpeg_comp_master *) master;
- master->pub.prepare_for_pass = prepare_for_pass;
- master->pub.pass_startup = pass_startup;
- master->pub.finish_pass = finish_pass_master;
- master->pub.is_last_pass = FALSE;
- /* Validate parameters, determine derived values */
- initial_setup(cinfo);
- if (cinfo->scan_info != NULL) {
- #ifdef C_MULTISCAN_FILES_SUPPORTED
- validate_script(cinfo);
- #else
- ERREXIT(cinfo, JERR_NOT_COMPILED);
- #endif
- } else {
- cinfo->progressive_mode = FALSE;
- cinfo->num_scans = 1;
- }
- if (cinfo->progressive_mode) /* TEMPORARY HACK ??? */
- cinfo->optimize_coding = TRUE; /* assume default tables no good for progressive mode */
- /* Initialize my private state */
- if (transcode_only) {
- /* no main pass in transcoding */
- if (cinfo->optimize_coding)
- master->pass_type = huff_opt_pass;
- else
- master->pass_type = output_pass;
- } else {
- /* for normal compression, first pass is always this type: */
- master->pass_type = main_pass;
- }
- master->scan_number = 0;
- master->pass_number = 0;
- if (cinfo->optimize_coding)
- master->total_passes = cinfo->num_scans * 2;
- else
- master->total_passes = cinfo->num_scans;
- }