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396 lines
12 KiB
396 lines
12 KiB
/* |
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* jdapimin.c |
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* |
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* Copyright (C) 1994-1998, Thomas G. Lane. |
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* Modified 2009 by Guido Vollbeding. |
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* This file is part of the Independent JPEG Group's software. |
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* For conditions of distribution and use, see the accompanying README file. |
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* |
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* This file contains application interface code for the decompression half |
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* of the JPEG library. These are the "minimum" API routines that may be |
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* needed in either the normal full-decompression case or the |
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* transcoding-only case. |
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* |
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* Most of the routines intended to be called directly by an application |
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* are in this file or in jdapistd.c. But also see jcomapi.c for routines |
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* shared by compression and decompression, and jdtrans.c for the transcoding |
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* case. |
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*/ |
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#define JPEG_INTERNALS |
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#include "jinclude.h" |
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#include "jpeglib.h" |
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/* |
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* Initialization of a JPEG decompression object. |
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* The error manager must already be set up (in case memory manager fails). |
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*/ |
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GLOBAL(void) |
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jpeg_CreateDecompress (j_decompress_ptr cinfo, int version, size_t structsize) |
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{ |
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int i; |
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/* Guard against version mismatches between library and caller. */ |
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cinfo->mem = NULL; /* so jpeg_destroy knows mem mgr not called */ |
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if (version != JPEG_LIB_VERSION) |
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ERREXIT2(cinfo, JERR_BAD_LIB_VERSION, JPEG_LIB_VERSION, version); |
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if (structsize != SIZEOF(struct jpeg_decompress_struct)) |
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ERREXIT2(cinfo, JERR_BAD_STRUCT_SIZE, |
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(int) SIZEOF(struct jpeg_decompress_struct), (int) structsize); |
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/* For debugging purposes, we zero the whole master structure. |
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* But the application has already set the err pointer, and may have set |
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* client_data, so we have to save and restore those fields. |
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* Note: if application hasn't set client_data, tools like Purify may |
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* complain here. |
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*/ |
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{ |
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struct jpeg_error_mgr * err = cinfo->err; |
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void * client_data = cinfo->client_data; /* ignore Purify complaint here */ |
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MEMZERO(cinfo, SIZEOF(struct jpeg_decompress_struct)); |
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cinfo->err = err; |
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cinfo->client_data = client_data; |
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} |
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cinfo->is_decompressor = TRUE; |
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/* Initialize a memory manager instance for this object */ |
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jinit_memory_mgr((j_common_ptr) cinfo); |
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/* Zero out pointers to permanent structures. */ |
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cinfo->progress = NULL; |
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cinfo->src = NULL; |
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for (i = 0; i < NUM_QUANT_TBLS; i++) |
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cinfo->quant_tbl_ptrs[i] = NULL; |
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for (i = 0; i < NUM_HUFF_TBLS; i++) { |
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cinfo->dc_huff_tbl_ptrs[i] = NULL; |
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cinfo->ac_huff_tbl_ptrs[i] = NULL; |
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} |
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/* Initialize marker processor so application can override methods |
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* for COM, APPn markers before calling jpeg_read_header. |
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*/ |
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cinfo->marker_list = NULL; |
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jinit_marker_reader(cinfo); |
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/* And initialize the overall input controller. */ |
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jinit_input_controller(cinfo); |
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/* OK, I'm ready */ |
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cinfo->global_state = DSTATE_START; |
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} |
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/* |
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* Destruction of a JPEG decompression object |
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*/ |
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GLOBAL(void) |
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jpeg_destroy_decompress (j_decompress_ptr cinfo) |
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{ |
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jpeg_destroy((j_common_ptr) cinfo); /* use common routine */ |
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} |
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/* |
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* Abort processing of a JPEG decompression operation, |
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* but don't destroy the object itself. |
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*/ |
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GLOBAL(void) |
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jpeg_abort_decompress (j_decompress_ptr cinfo) |
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{ |
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jpeg_abort((j_common_ptr) cinfo); /* use common routine */ |
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} |
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/* |
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* Set default decompression parameters. |
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*/ |
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LOCAL(void) |
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default_decompress_parms (j_decompress_ptr cinfo) |
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{ |
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/* Guess the input colorspace, and set output colorspace accordingly. */ |
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/* (Wish JPEG committee had provided a real way to specify this...) */ |
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/* Note application may override our guesses. */ |
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switch (cinfo->num_components) { |
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case 1: |
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cinfo->jpeg_color_space = JCS_GRAYSCALE; |
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cinfo->out_color_space = JCS_GRAYSCALE; |
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break; |
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case 3: |
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if (cinfo->saw_JFIF_marker) { |
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cinfo->jpeg_color_space = JCS_YCbCr; /* JFIF implies YCbCr */ |
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} else if (cinfo->saw_Adobe_marker) { |
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switch (cinfo->Adobe_transform) { |
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case 0: |
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cinfo->jpeg_color_space = JCS_RGB; |
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break; |
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case 1: |
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cinfo->jpeg_color_space = JCS_YCbCr; |
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break; |
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default: |
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WARNMS1(cinfo, JWRN_ADOBE_XFORM, cinfo->Adobe_transform); |
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cinfo->jpeg_color_space = JCS_YCbCr; /* assume it's YCbCr */ |
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break; |
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} |
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} else { |
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/* Saw no special markers, try to guess from the component IDs */ |
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int cid0 = cinfo->comp_info[0].component_id; |
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int cid1 = cinfo->comp_info[1].component_id; |
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int cid2 = cinfo->comp_info[2].component_id; |
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if (cid0 == 1 && cid1 == 2 && cid2 == 3) |
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cinfo->jpeg_color_space = JCS_YCbCr; /* assume JFIF w/out marker */ |
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else if (cid0 == 82 && cid1 == 71 && cid2 == 66) |
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cinfo->jpeg_color_space = JCS_RGB; /* ASCII 'R', 'G', 'B' */ |
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else { |
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TRACEMS3(cinfo, 1, JTRC_UNKNOWN_IDS, cid0, cid1, cid2); |
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cinfo->jpeg_color_space = JCS_YCbCr; /* assume it's YCbCr */ |
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} |
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} |
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/* Always guess RGB is proper output colorspace. */ |
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cinfo->out_color_space = JCS_RGB; |
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break; |
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case 4: |
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if (cinfo->saw_Adobe_marker) { |
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switch (cinfo->Adobe_transform) { |
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case 0: |
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cinfo->jpeg_color_space = JCS_CMYK; |
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break; |
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case 2: |
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cinfo->jpeg_color_space = JCS_YCCK; |
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break; |
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default: |
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WARNMS1(cinfo, JWRN_ADOBE_XFORM, cinfo->Adobe_transform); |
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cinfo->jpeg_color_space = JCS_YCCK; /* assume it's YCCK */ |
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break; |
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} |
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} else { |
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/* No special markers, assume straight CMYK. */ |
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cinfo->jpeg_color_space = JCS_CMYK; |
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} |
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cinfo->out_color_space = JCS_CMYK; |
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break; |
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default: |
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cinfo->jpeg_color_space = JCS_UNKNOWN; |
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cinfo->out_color_space = JCS_UNKNOWN; |
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break; |
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} |
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/* Set defaults for other decompression parameters. */ |
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cinfo->scale_num = cinfo->block_size; /* 1:1 scaling */ |
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cinfo->scale_denom = cinfo->block_size; |
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cinfo->output_gamma = 1.0; |
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cinfo->buffered_image = FALSE; |
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cinfo->raw_data_out = FALSE; |
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cinfo->dct_method = JDCT_DEFAULT; |
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cinfo->do_fancy_upsampling = TRUE; |
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cinfo->do_block_smoothing = TRUE; |
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cinfo->quantize_colors = FALSE; |
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/* We set these in case application only sets quantize_colors. */ |
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cinfo->dither_mode = JDITHER_FS; |
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#ifdef QUANT_2PASS_SUPPORTED |
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cinfo->two_pass_quantize = TRUE; |
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#else |
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cinfo->two_pass_quantize = FALSE; |
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#endif |
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cinfo->desired_number_of_colors = 256; |
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cinfo->colormap = NULL; |
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/* Initialize for no mode change in buffered-image mode. */ |
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cinfo->enable_1pass_quant = FALSE; |
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cinfo->enable_external_quant = FALSE; |
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cinfo->enable_2pass_quant = FALSE; |
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} |
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/* |
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* Decompression startup: read start of JPEG datastream to see what's there. |
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* Need only initialize JPEG object and supply a data source before calling. |
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* |
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* This routine will read as far as the first SOS marker (ie, actual start of |
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* compressed data), and will save all tables and parameters in the JPEG |
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* object. It will also initialize the decompression parameters to default |
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* values, and finally return JPEG_HEADER_OK. On return, the application may |
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* adjust the decompression parameters and then call jpeg_start_decompress. |
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* (Or, if the application only wanted to determine the image parameters, |
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* the data need not be decompressed. In that case, call jpeg_abort or |
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* jpeg_destroy to release any temporary space.) |
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* If an abbreviated (tables only) datastream is presented, the routine will |
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* return JPEG_HEADER_TABLES_ONLY upon reaching EOI. The application may then |
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* re-use the JPEG object to read the abbreviated image datastream(s). |
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* It is unnecessary (but OK) to call jpeg_abort in this case. |
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* The JPEG_SUSPENDED return code only occurs if the data source module |
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* requests suspension of the decompressor. In this case the application |
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* should load more source data and then re-call jpeg_read_header to resume |
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* processing. |
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* If a non-suspending data source is used and require_image is TRUE, then the |
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* return code need not be inspected since only JPEG_HEADER_OK is possible. |
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* |
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* This routine is now just a front end to jpeg_consume_input, with some |
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* extra error checking. |
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*/ |
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GLOBAL(int) |
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jpeg_read_header (j_decompress_ptr cinfo, boolean require_image) |
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{ |
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int retcode; |
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if (cinfo->global_state != DSTATE_START && |
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cinfo->global_state != DSTATE_INHEADER) |
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ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
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retcode = jpeg_consume_input(cinfo); |
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switch (retcode) { |
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case JPEG_REACHED_SOS: |
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retcode = JPEG_HEADER_OK; |
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break; |
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case JPEG_REACHED_EOI: |
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if (require_image) /* Complain if application wanted an image */ |
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ERREXIT(cinfo, JERR_NO_IMAGE); |
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/* Reset to start state; it would be safer to require the application to |
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* call jpeg_abort, but we can't change it now for compatibility reasons. |
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* A side effect is to free any temporary memory (there shouldn't be any). |
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*/ |
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jpeg_abort((j_common_ptr) cinfo); /* sets state = DSTATE_START */ |
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retcode = JPEG_HEADER_TABLES_ONLY; |
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break; |
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case JPEG_SUSPENDED: |
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/* no work */ |
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break; |
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} |
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return retcode; |
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} |
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/* |
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* Consume data in advance of what the decompressor requires. |
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* This can be called at any time once the decompressor object has |
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* been created and a data source has been set up. |
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* |
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* This routine is essentially a state machine that handles a couple |
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* of critical state-transition actions, namely initial setup and |
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* transition from header scanning to ready-for-start_decompress. |
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* All the actual input is done via the input controller's consume_input |
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* method. |
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*/ |
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GLOBAL(int) |
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jpeg_consume_input (j_decompress_ptr cinfo) |
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{ |
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int retcode = JPEG_SUSPENDED; |
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/* NB: every possible DSTATE value should be listed in this switch */ |
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switch (cinfo->global_state) { |
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case DSTATE_START: |
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/* Start-of-datastream actions: reset appropriate modules */ |
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(*cinfo->inputctl->reset_input_controller) (cinfo); |
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/* Initialize application's data source module */ |
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(*cinfo->src->init_source) (cinfo); |
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cinfo->global_state = DSTATE_INHEADER; |
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/*FALLTHROUGH*/ |
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case DSTATE_INHEADER: |
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retcode = (*cinfo->inputctl->consume_input) (cinfo); |
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if (retcode == JPEG_REACHED_SOS) { /* Found SOS, prepare to decompress */ |
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/* Set up default parameters based on header data */ |
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default_decompress_parms(cinfo); |
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/* Set global state: ready for start_decompress */ |
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cinfo->global_state = DSTATE_READY; |
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} |
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break; |
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case DSTATE_READY: |
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/* Can't advance past first SOS until start_decompress is called */ |
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retcode = JPEG_REACHED_SOS; |
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break; |
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case DSTATE_PRELOAD: |
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case DSTATE_PRESCAN: |
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case DSTATE_SCANNING: |
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case DSTATE_RAW_OK: |
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case DSTATE_BUFIMAGE: |
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case DSTATE_BUFPOST: |
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case DSTATE_STOPPING: |
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retcode = (*cinfo->inputctl->consume_input) (cinfo); |
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break; |
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default: |
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ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
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} |
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return retcode; |
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} |
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/* |
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* Have we finished reading the input file? |
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*/ |
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GLOBAL(boolean) |
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jpeg_input_complete (j_decompress_ptr cinfo) |
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{ |
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/* Check for valid jpeg object */ |
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if (cinfo->global_state < DSTATE_START || |
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cinfo->global_state > DSTATE_STOPPING) |
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ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
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return cinfo->inputctl->eoi_reached; |
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} |
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/* |
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* Is there more than one scan? |
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*/ |
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GLOBAL(boolean) |
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jpeg_has_multiple_scans (j_decompress_ptr cinfo) |
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{ |
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/* Only valid after jpeg_read_header completes */ |
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if (cinfo->global_state < DSTATE_READY || |
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cinfo->global_state > DSTATE_STOPPING) |
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ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
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return cinfo->inputctl->has_multiple_scans; |
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} |
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/* |
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* Finish JPEG decompression. |
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* |
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* This will normally just verify the file trailer and release temp storage. |
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* |
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* Returns FALSE if suspended. The return value need be inspected only if |
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* a suspending data source is used. |
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*/ |
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GLOBAL(boolean) |
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jpeg_finish_decompress (j_decompress_ptr cinfo) |
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{ |
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if ((cinfo->global_state == DSTATE_SCANNING || |
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cinfo->global_state == DSTATE_RAW_OK) && ! cinfo->buffered_image) { |
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/* Terminate final pass of non-buffered mode */ |
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if (cinfo->output_scanline < cinfo->output_height) |
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ERREXIT(cinfo, JERR_TOO_LITTLE_DATA); |
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(*cinfo->master->finish_output_pass) (cinfo); |
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cinfo->global_state = DSTATE_STOPPING; |
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} else if (cinfo->global_state == DSTATE_BUFIMAGE) { |
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/* Finishing after a buffered-image operation */ |
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cinfo->global_state = DSTATE_STOPPING; |
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} else if (cinfo->global_state != DSTATE_STOPPING) { |
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/* STOPPING = repeat call after a suspension, anything else is error */ |
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ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
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} |
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/* Read until EOI */ |
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while (! cinfo->inputctl->eoi_reached) { |
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if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED) |
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return FALSE; /* Suspend, come back later */ |
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} |
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/* Do final cleanup */ |
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(*cinfo->src->term_source) (cinfo); |
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/* We can use jpeg_abort to release memory and reset global_state */ |
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jpeg_abort((j_common_ptr) cinfo); |
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return TRUE; |
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}
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