| /* |
| * jdapi.c |
| * |
| * Copyright (C) 1994-1995, 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 application interface code for the decompression half of |
| * the JPEG library. Most of the routines intended to be called directly by |
| * an application are in this file. But also see jcomapi.c for routines |
| * shared by compression and decompression. |
| */ |
| |
| #define JPEG_INTERNALS |
| #include "jinclude.h" |
| #include "jpeglib.h" |
| |
| |
| /* |
| * Initialization of a JPEG decompression object. |
| * The error manager must already be set up (in case memory manager fails). |
| */ |
| |
| GLOBAL void |
| jpeg_create_decompress (j_decompress_ptr cinfo) |
| { |
| int i; |
| |
| /* For debugging purposes, zero the whole master structure. |
| * But error manager pointer is already there, so save and restore it. |
| */ |
| { |
| struct jpeg_error_mgr * err = cinfo->err; |
| MEMZERO(cinfo, SIZEOF(struct jpeg_decompress_struct)); |
| cinfo->err = err; |
| } |
| cinfo->is_decompressor = TRUE; |
| |
| /* Initialize a memory manager instance for this object */ |
| jinit_memory_mgr((j_common_ptr) cinfo); |
| |
| /* Zero out pointers to permanent structures. */ |
| cinfo->progress = NULL; |
| cinfo->src = NULL; |
| |
| for (i = 0; i < NUM_QUANT_TBLS; i++) |
| cinfo->quant_tbl_ptrs[i] = NULL; |
| |
| for (i = 0; i < NUM_HUFF_TBLS; i++) { |
| cinfo->dc_huff_tbl_ptrs[i] = NULL; |
| cinfo->ac_huff_tbl_ptrs[i] = NULL; |
| } |
| |
| cinfo->sample_range_limit = NULL; |
| |
| /* Initialize marker processor so application can override methods |
| * for COM, APPn markers before calling jpeg_read_header. |
| */ |
| cinfo->marker = NULL; |
| jinit_marker_reader(cinfo); |
| |
| /* OK, I'm ready */ |
| cinfo->global_state = DSTATE_START; |
| } |
| |
| |
| /* |
| * Destruction of a JPEG decompression object |
| */ |
| |
| GLOBAL void |
| jpeg_destroy_decompress (j_decompress_ptr cinfo) |
| { |
| jpeg_destroy((j_common_ptr) cinfo); /* use common routine */ |
| } |
| |
| |
| /* |
| * Install a special processing method for COM or APPn markers. |
| */ |
| |
| GLOBAL void |
| jpeg_set_marker_processor (j_decompress_ptr cinfo, int marker_code, |
| jpeg_marker_parser_method routine) |
| { |
| if (marker_code == JPEG_COM) |
| cinfo->marker->process_COM = routine; |
| else if (marker_code >= JPEG_APP0 && marker_code <= JPEG_APP0+15) |
| cinfo->marker->process_APPn[marker_code-JPEG_APP0] = routine; |
| else |
| ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code); |
| } |
| |
| |
| /* |
| * Set default decompression parameters. |
| */ |
| |
| LOCAL void |
| default_decompress_parms (j_decompress_ptr cinfo) |
| { |
| /* Guess the input colorspace, and set output colorspace accordingly. */ |
| /* (Wish JPEG committee had provided a real way to specify this...) */ |
| /* Note application may override our guesses. */ |
| switch (cinfo->num_components) { |
| case 1: |
| cinfo->jpeg_color_space = JCS_GRAYSCALE; |
| cinfo->out_color_space = JCS_GRAYSCALE; |
| break; |
| |
| case 3: |
| if (cinfo->saw_JFIF_marker) { |
| cinfo->jpeg_color_space = JCS_YCbCr; /* JFIF implies YCbCr */ |
| } else if (cinfo->saw_Adobe_marker) { |
| switch (cinfo->Adobe_transform) { |
| case 0: |
| cinfo->jpeg_color_space = JCS_RGB; |
| break; |
| case 1: |
| cinfo->jpeg_color_space = JCS_YCbCr; |
| break; |
| default: |
| WARNMS1(cinfo, JWRN_ADOBE_XFORM, cinfo->Adobe_transform); |
| cinfo->jpeg_color_space = JCS_YCbCr; /* assume it's YCbCr */ |
| break; |
| } |
| } else { |
| /* Saw no special markers, try to guess from the component IDs */ |
| int cid0 = cinfo->comp_info[0].component_id; |
| int cid1 = cinfo->comp_info[1].component_id; |
| int cid2 = cinfo->comp_info[2].component_id; |
| |
| if (cid0 == 1 && cid1 == 2 && cid2 == 3) |
| cinfo->jpeg_color_space = JCS_YCbCr; /* assume JFIF w/out marker */ |
| else if (cid0 == 82 && cid1 == 71 && cid2 == 66) |
| cinfo->jpeg_color_space = JCS_RGB; /* ASCII 'R', 'G', 'B' */ |
| else { |
| TRACEMS3(cinfo, 1, JTRC_UNKNOWN_IDS, cid0, cid1, cid2); |
| cinfo->jpeg_color_space = JCS_YCbCr; /* assume it's YCbCr */ |
| } |
| } |
| /* Always guess RGB is proper output colorspace. */ |
| cinfo->out_color_space = JCS_RGB; |
| break; |
| |
| case 4: |
| if (cinfo->saw_Adobe_marker) { |
| switch (cinfo->Adobe_transform) { |
| case 0: |
| cinfo->jpeg_color_space = JCS_CMYK; |
| break; |
| case 2: |
| cinfo->jpeg_color_space = JCS_YCCK; |
| break; |
| default: |
| WARNMS1(cinfo, JWRN_ADOBE_XFORM, cinfo->Adobe_transform); |
| cinfo->jpeg_color_space = JCS_YCCK; /* assume it's YCCK */ |
| break; |
| } |
| } else { |
| /* No special markers, assume straight CMYK. */ |
| cinfo->jpeg_color_space = JCS_CMYK; |
| } |
| cinfo->out_color_space = JCS_CMYK; |
| break; |
| |
| default: |
| cinfo->jpeg_color_space = JCS_UNKNOWN; |
| cinfo->out_color_space = JCS_UNKNOWN; |
| break; |
| } |
| |
| /* Set defaults for other decompression parameters. */ |
| cinfo->scale_num = 1; /* 1:1 scaling */ |
| cinfo->scale_denom = 1; |
| cinfo->output_gamma = 1.0; |
| cinfo->raw_data_out = FALSE; |
| cinfo->quantize_colors = FALSE; |
| /* We set these in case application only sets quantize_colors. */ |
| cinfo->two_pass_quantize = TRUE; |
| cinfo->dither_mode = JDITHER_FS; |
| cinfo->desired_number_of_colors = 256; |
| cinfo->colormap = NULL; |
| /* DCT algorithm preference */ |
| cinfo->dct_method = JDCT_DEFAULT; |
| cinfo->do_fancy_upsampling = TRUE; |
| } |
| |
| |
| /* |
| * Decompression startup: read start of JPEG datastream to see what's there. |
| * Need only initialize JPEG object and supply a data source before calling. |
| * |
| * This routine will read as far as the first SOS marker (ie, actual start of |
| * compressed data), and will save all tables and parameters in the JPEG |
| * object. It will also initialize the decompression parameters to default |
| * values, and finally return JPEG_HEADER_OK. On return, the application may |
| * adjust the decompression parameters and then call jpeg_start_decompress. |
| * (Or, if the application only wanted to determine the image parameters, |
| * the data need not be decompressed. In that case, call jpeg_abort or |
| * jpeg_destroy to release any temporary space.) |
| * If an abbreviated (tables only) datastream is presented, the routine will |
| * return JPEG_HEADER_TABLES_ONLY upon reaching EOI. The application may then |
| * re-use the JPEG object to read the abbreviated image datastream(s). |
| * It is unnecessary (but OK) to call jpeg_abort in this case. |
| * The JPEG_SUSPENDED return code only occurs if the data source module |
| * requests suspension of the decompressor. In this case the application |
| * should load more source data and then re-call jpeg_read_header to resume |
| * processing. |
| * If a non-suspending data source is used and require_image is TRUE, then the |
| * return code need not be inspected since only JPEG_HEADER_OK is possible. |
| */ |
| |
| GLOBAL int |
| jpeg_read_header (j_decompress_ptr cinfo, boolean require_image) |
| { |
| int retcode; |
| |
| if (cinfo->global_state == DSTATE_START) { |
| /* First-time actions: reset appropriate modules */ |
| (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo); |
| (*cinfo->marker->reset_marker_reader) (cinfo); |
| (*cinfo->src->init_source) (cinfo); |
| cinfo->global_state = DSTATE_INHEADER; |
| } else if (cinfo->global_state != DSTATE_INHEADER) { |
| ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
| } |
| |
| retcode = (*cinfo->marker->read_markers) (cinfo); |
| |
| switch (retcode) { |
| case JPEG_HEADER_OK: /* Found SOS, prepare to decompress */ |
| /* Set up default parameters based on header data */ |
| default_decompress_parms(cinfo); |
| /* Set global state: ready for start_decompress */ |
| cinfo->global_state = DSTATE_READY; |
| break; |
| |
| case JPEG_HEADER_TABLES_ONLY: /* Found EOI before any SOS */ |
| if (cinfo->marker->saw_SOF) |
| ERREXIT(cinfo, JERR_SOF_NO_SOS); |
| if (require_image) /* Complain if application wants an image */ |
| ERREXIT(cinfo, JERR_NO_IMAGE); |
| /* We need not do any cleanup since only permanent storage (for DQT, DHT) |
| * has been allocated. |
| */ |
| /* Set global state: ready for a new datastream */ |
| cinfo->global_state = DSTATE_START; |
| break; |
| |
| case JPEG_SUSPENDED: /* Had to suspend before end of headers */ |
| /* no work */ |
| break; |
| } |
| |
| return retcode; |
| } |
| |
| |
| /* |
| * Decompression initialization. |
| * jpeg_read_header must be completed before calling this. |
| * |
| * If a multipass operating mode was selected, this will do all but the |
| * last pass, and thus may take a great deal of time. |
| */ |
| |
| GLOBAL void |
| jpeg_start_decompress (j_decompress_ptr cinfo) |
| { |
| JDIMENSION chunk_ctr, last_chunk_ctr; |
| |
| if (cinfo->global_state != DSTATE_READY) |
| ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
| /* Perform master selection of active modules */ |
| jinit_master_decompress(cinfo); |
| /* Do all but the final (output) pass, and set up for that one. */ |
| for (;;) { |
| (*cinfo->master->prepare_for_pass) (cinfo); |
| if (cinfo->master->is_last_pass) |
| break; |
| chunk_ctr = 0; |
| while (chunk_ctr < cinfo->main->num_chunks) { |
| /* Call progress monitor hook if present */ |
| if (cinfo->progress != NULL) { |
| cinfo->progress->pass_counter = (long) chunk_ctr; |
| cinfo->progress->pass_limit = (long) cinfo->main->num_chunks; |
| (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo); |
| } |
| /* Process some data */ |
| last_chunk_ctr = chunk_ctr; |
| (*cinfo->main->process_data) (cinfo, (JSAMPARRAY) NULL, |
| &chunk_ctr, (JDIMENSION) 0); |
| if (chunk_ctr == last_chunk_ctr) /* check for failure to make progress */ |
| ERREXIT(cinfo, JERR_CANT_SUSPEND); |
| } |
| (*cinfo->master->finish_pass) (cinfo); |
| } |
| /* Ready for application to drive last pass through jpeg_read_scanlines |
| * or jpeg_read_raw_data. |
| */ |
| cinfo->output_scanline = 0; |
| cinfo->global_state = (cinfo->raw_data_out ? DSTATE_RAW_OK : DSTATE_SCANNING); |
| } |
| |
| |
| /* |
| * Read some scanlines of data from the JPEG decompressor. |
| * |
| * The return value will be the number of lines actually read. |
| * This may be less than the number requested in several cases, |
| * including bottom of image, data source suspension, and operating |
| * modes that emit multiple scanlines at a time. |
| * |
| * Note: we warn about excess calls to jpeg_read_scanlines() since |
| * this likely signals an application programmer error. However, |
| * an oversize buffer (max_lines > scanlines remaining) is not an error. |
| */ |
| |
| GLOBAL JDIMENSION |
| jpeg_read_scanlines (j_decompress_ptr cinfo, JSAMPARRAY scanlines, |
| JDIMENSION max_lines) |
| { |
| JDIMENSION row_ctr; |
| |
| if (cinfo->global_state != DSTATE_SCANNING) |
| ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
| if (cinfo->output_scanline >= cinfo->output_height) |
| WARNMS(cinfo, JWRN_TOO_MUCH_DATA); |
| |
| /* Call progress monitor hook if present */ |
| if (cinfo->progress != NULL) { |
| cinfo->progress->pass_counter = (long) cinfo->output_scanline; |
| cinfo->progress->pass_limit = (long) cinfo->output_height; |
| (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo); |
| } |
| |
| /* Process some data */ |
| row_ctr = 0; |
| (*cinfo->main->process_data) (cinfo, scanlines, &row_ctr, max_lines); |
| cinfo->output_scanline += row_ctr; |
| return row_ctr; |
| } |
| |
| |
| /* |
| * Alternate entry point to read raw data. |
| * Processes exactly one iMCU row per call, unless suspended. |
| */ |
| |
| GLOBAL JDIMENSION |
| jpeg_read_raw_data (j_decompress_ptr cinfo, JSAMPIMAGE data, |
| JDIMENSION max_lines) |
| { |
| JDIMENSION lines_per_iMCU_row; |
| |
| if (cinfo->global_state != DSTATE_RAW_OK) |
| ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
| if (cinfo->output_scanline >= cinfo->output_height) { |
| WARNMS(cinfo, JWRN_TOO_MUCH_DATA); |
| return 0; |
| } |
| |
| /* Call progress monitor hook if present */ |
| if (cinfo->progress != NULL) { |
| cinfo->progress->pass_counter = (long) cinfo->output_scanline; |
| cinfo->progress->pass_limit = (long) cinfo->output_height; |
| (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo); |
| } |
| |
| /* Verify that at least one iMCU row can be returned. */ |
| lines_per_iMCU_row = cinfo->max_v_samp_factor * cinfo->min_DCT_scaled_size; |
| if (max_lines < lines_per_iMCU_row) |
| ERREXIT(cinfo, JERR_BUFFER_SIZE); |
| |
| /* Decompress directly into user's buffer. */ |
| if (! (*cinfo->coef->decompress_data) (cinfo, data)) |
| return 0; /* suspension forced, can do nothing more */ |
| |
| /* OK, we processed one iMCU row. */ |
| cinfo->output_scanline += lines_per_iMCU_row; |
| return lines_per_iMCU_row; |
| } |
| |
| |
| /* |
| * Finish JPEG decompression. |
| * |
| * This will normally just verify the file trailer and release temp storage. |
| * |
| * Returns FALSE if suspended. The return value need be inspected only if |
| * a suspending data source is used. |
| */ |
| |
| GLOBAL boolean |
| jpeg_finish_decompress (j_decompress_ptr cinfo) |
| { |
| if (cinfo->global_state == DSTATE_SCANNING || |
| cinfo->global_state == DSTATE_RAW_OK) { |
| /* Terminate final pass */ |
| if (cinfo->output_scanline < cinfo->output_height) |
| ERREXIT(cinfo, JERR_TOO_LITTLE_DATA); |
| (*cinfo->master->finish_pass) (cinfo); |
| cinfo->global_state = DSTATE_STOPPING; |
| } else if (cinfo->global_state != DSTATE_STOPPING) { |
| /* Repeat call after a suspension? */ |
| ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
| } |
| /* Check for EOI in source file, unless master control already read it */ |
| if (! cinfo->master->eoi_processed) { |
| switch ((*cinfo->marker->read_markers) (cinfo)) { |
| case JPEG_HEADER_OK: /* Found SOS!? */ |
| ERREXIT(cinfo, JERR_EOI_EXPECTED); |
| break; |
| case JPEG_HEADER_TABLES_ONLY: /* Found EOI, A-OK */ |
| break; |
| case JPEG_SUSPENDED: /* Suspend, come back later */ |
| return FALSE; |
| } |
| } |
| /* Do final cleanup */ |
| (*cinfo->src->term_source) (cinfo); |
| /* We can use jpeg_abort to release memory and reset global_state */ |
| jpeg_abort((j_common_ptr) cinfo); |
| return TRUE; |
| } |
| |
| |
| /* |
| * Abort processing of a JPEG decompression operation, |
| * but don't destroy the object itself. |
| */ |
| |
| GLOBAL void |
| jpeg_abort_decompress (j_decompress_ptr cinfo) |
| { |
| jpeg_abort((j_common_ptr) cinfo); /* use common routine */ |
| } |