/* * jdapimin.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. These are the "minimum" API routines that may be * needed in either the normal full-decompression case or the * transcoding-only case. * * Most of the routines intended to be called directly by an application * are in this file or in jdapistd.c. But also see jcomapi.c for routines * shared by compression and decompression, and jdtrans.c for the transcoding * case. */ #define JPEG_INTERNALS #include "jinclude.h" #include "radiant_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; i = sizeof(struct jpeg_decompress_struct); i = SIZEOF(struct jpeg_decompress_struct); 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; } /* Initialize marker processor so application can override methods * for COM, APPn markers before calling jpeg_read_header. */ jinit_marker_reader(cinfo); /* And initialize the overall input controller. */ jinit_input_controller(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 */ } /* * 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 */ } /* * 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->buffered_image = FALSE; cinfo->raw_data_out = FALSE; cinfo->dct_method = JDCT_DEFAULT; cinfo->do_fancy_upsampling = TRUE; cinfo->do_block_smoothing = TRUE; cinfo->quantize_colors = FALSE; /* We set these in case application only sets quantize_colors. */ cinfo->dither_mode = JDITHER_FS; #ifdef QUANT_2PASS_SUPPORTED cinfo->two_pass_quantize = TRUE; #else cinfo->two_pass_quantize = FALSE; #endif cinfo->desired_number_of_colors = 256; cinfo->colormap = NULL; /* Initialize for no mode change in buffered-image mode. */ cinfo->enable_1pass_quant = FALSE; cinfo->enable_external_quant = FALSE; cinfo->enable_2pass_quant = FALSE; } /* * 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. * * This routine is now just a front end to jpeg_consume_input, with some * extra error checking. */ GLOBAL int jpeg_read_header (j_decompress_ptr cinfo, boolean require_image) { int retcode; if (cinfo->global_state != DSTATE_START && cinfo->global_state != DSTATE_INHEADER) ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); retcode = jpeg_consume_input(cinfo); switch (retcode) { case JPEG_REACHED_SOS: retcode = JPEG_HEADER_OK; break; case JPEG_REACHED_EOI: if (require_image) /* Complain if application wanted an image */ ERREXIT(cinfo, JERR_NO_IMAGE); /* Reset to start state; it would be safer to require the application to * call jpeg_abort, but we can't change it now for compatibility reasons. * A side effect is to free any temporary memory (there shouldn't be any). */ jpeg_abort((j_common_ptr) cinfo); /* sets state = DSTATE_START */ retcode = JPEG_HEADER_TABLES_ONLY; break; case JPEG_SUSPENDED: /* no work */ break; } return retcode; } /* * Consume data in advance of what the decompressor requires. * This can be called at any time once the decompressor object has * been created and a data source has been set up. * * This routine is essentially a state machine that handles a couple * of critical state-transition actions, namely initial setup and * transition from header scanning to ready-for-start_decompress. * All the actual input is done via the input controller's consume_input * method. */ GLOBAL int jpeg_consume_input (j_decompress_ptr cinfo) { int retcode = JPEG_SUSPENDED; /* NB: every possible DSTATE value should be listed in this switch */ switch (cinfo->global_state) { case DSTATE_START: /* Start-of-datastream actions: reset appropriate modules */ (*cinfo->inputctl->reset_input_controller) (cinfo); /* Initialize application's data source module */ (*cinfo->src->init_source) (cinfo); cinfo->global_state = DSTATE_INHEADER; /*FALLTHROUGH*/ case DSTATE_INHEADER: retcode = (*cinfo->inputctl->consume_input) (cinfo); if (retcode == JPEG_REACHED_SOS) { /* 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 DSTATE_READY: /* Can't advance past first SOS until start_decompress is called */ retcode = JPEG_REACHED_SOS; break; case DSTATE_PRELOAD: case DSTATE_PRESCAN: case DSTATE_SCANNING: case DSTATE_RAW_OK: case DSTATE_BUFIMAGE: case DSTATE_BUFPOST: case DSTATE_STOPPING: retcode = (*cinfo->inputctl->consume_input) (cinfo); break; default: ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); } return retcode; } /* * Have we finished reading the input file? */ GLOBAL boolean jpeg_input_complete (j_decompress_ptr cinfo) { /* Check for valid jpeg object */ if (cinfo->global_state < DSTATE_START || cinfo->global_state > DSTATE_STOPPING) ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); return cinfo->inputctl->eoi_reached; } /* * Is there more than one scan? */ GLOBAL boolean jpeg_has_multiple_scans (j_decompress_ptr cinfo) { /* Only valid after jpeg_read_header completes */ if (cinfo->global_state < DSTATE_READY || cinfo->global_state > DSTATE_STOPPING) ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); return cinfo->inputctl->has_multiple_scans; } /* * 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) && ! cinfo->buffered_image) { /* Terminate final pass of non-buffered mode */ if (cinfo->output_scanline < cinfo->output_height) ERREXIT(cinfo, JERR_TOO_LITTLE_DATA); (*cinfo->master->finish_output_pass) (cinfo); cinfo->global_state = DSTATE_STOPPING; } else if (cinfo->global_state == DSTATE_BUFIMAGE) { /* Finishing after a buffered-image operation */ cinfo->global_state = DSTATE_STOPPING; } else if (cinfo->global_state != DSTATE_STOPPING) { /* STOPPING = repeat call after a suspension, anything else is error */ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); } /* Read until EOI */ while (! cinfo->inputctl->eoi_reached) { if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED) return FALSE; /* Suspend, come back later */ } /* 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; }