500 строки
15 KiB
C
500 строки
15 KiB
C
/*
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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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* 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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#ifdef HAVE_MMX_INTEL_MNEMONICS
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int MMXAvailable;
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static int mmxsupport();
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#endif
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#ifdef HAVE_SSE2_INTEL_MNEMONICS
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int SSE2Available = 0;
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static int sse2support();
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#endif
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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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#ifdef HAVE_MMX_INTEL_MNEMONICS
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static int cpuidDetected = 0;
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if(!cpuidDetected)
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{
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MMXAvailable = mmxsupport();
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#ifdef HAVE_SSE2_INTEL_MNEMONICS
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/* only do the sse2 support check if mmx is supported (so
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we know the processor supports cpuid) */
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if (MMXAvailable)
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SSE2Available = sse2support();
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#endif
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cpuidDetected = 1;
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}
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#endif
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/* For debugging purposes, zero the whole master structure.
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* But error manager pointer is already there, so save and restore it.
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*/
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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 = 1; /* 1:1 scaling */
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cinfo->scale_denom = 1;
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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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#ifdef HAVE_MMX_INTEL_MNEMONICS
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static int mmxsupport()
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{
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int mmx_supported = 0;
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_asm {
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pushfd //Save Eflag to stack
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pop eax //Get Eflag from stack into eax
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mov ecx, eax //Make another copy of Eflag in ecx
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xor eax, 0x200000 //Toggle ID bit in Eflag [i.e. bit(21)]
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push eax //Save modified Eflag back to stack
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popfd //Restored modified value back to Eflag reg
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pushfd //Save Eflag to stack
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pop eax //Get Eflag from stack
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xor eax, ecx //Compare the new Eflag with the original Eflag
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jz NOT_SUPPORTED //If the same, CPUID instruction is not supported,
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//skip following instructions and jump to
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//NOT_SUPPORTED label
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xor eax, eax //Set eax to zero
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cpuid
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cmp eax, 1 //make sure eax return non-zero value
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jl NOT_SUPPORTED //If eax is zero, mmx not supported
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xor eax, eax //set eax to zero
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inc eax //Now increment eax to 1. This instruction is
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//faster than the instruction "mov eax, 1"
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cpuid
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and edx, 0x00800000 //mask out all bits but mmx bit(24)
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cmp edx, 0 // 0 = mmx not supported
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jz NOT_SUPPORTED // non-zero = Yes, mmx IS supported
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mov mmx_supported, 1 //set return value to 1
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NOT_SUPPORTED:
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mov eax, mmx_supported //move return value to eax
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}
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return mmx_supported;
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}
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#endif
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#ifdef HAVE_SSE2_INTEL_MNEMONICS
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static int sse2support()
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{
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int sse2available = 0;
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int my_edx;
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_asm
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{
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mov eax, 01
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cpuid
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mov my_edx, edx
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}
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if (my_edx & (0x1 << 26))
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sse2available = 1;
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else sse2available = 2;
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return sse2available;
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}
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#endif
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