ref: 290c921d1d01119b7d4550770da06c491508508f
dir: /sys/src/cmd/gs/jpeg/jcmaster.c/
/* * 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; }