212 lines
6.8 KiB
C++
212 lines
6.8 KiB
C++
// * jcapimin.c
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// *
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// * Copyright (C) 1994-1995, 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 compression 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-compression case or the transcoding-only
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// * 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 jcapistd.c. But also see jcparam.c for
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// * parameter-setup helper routines, jcomapi.c for routines shared by
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// * compression and decompression, and jctrans.c for the transcoding case.
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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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// * Initialization of a JPEG compression object.
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// * The error manager must already be set up (in case memory manager fails).
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GLOBAL void
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jpeg_create_compress (j_compress_ptr cinfo)
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{
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int i;
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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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struct jpeg_error_mgr * err = cinfo->err;
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MEMZERO(cinfo, SIZEOF(struct jpeg_compress_struct));
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cinfo->err = err;
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}
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cinfo->is_decompressor = FALSE;
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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->dest = NULL;
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cinfo->comp_info = 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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cinfo->input_gamma = 1.0; // in case application forgets
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// OK, I'm ready
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cinfo->global_state = CSTATE_START;
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}
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// * Destruction of a JPEG compression object
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GLOBAL void
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jpeg_destroy_compress (j_compress_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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// * Abort processing of a JPEG compression operation,
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// * but don't destroy the object itself.
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GLOBAL void
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jpeg_abort_compress (j_compress_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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// * Forcibly suppress or un-suppress all quantization and Huffman tables.
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// * Marks all currently defined tables as already written (if suppress)
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// * or not written (if !suppress). This will control whether they get emitted
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// * by a subsequent jpeg_start_compress call.
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// *
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// * This routine is exported for use by applications that want to produce
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// * abbreviated JPEG datastreams. It logically belongs in jcparam.c, but
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// * since it is called by jpeg_start_compress, we put it here --- otherwise
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// * jcparam.o would be linked whether the application used it or not.
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GLOBAL void
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jpeg_suppress_tables (j_compress_ptr cinfo, boolean suppress)
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{
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int i;
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JQUANT_TBL * qtbl;
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JHUFF_TBL * htbl;
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for (i = 0; i < NUM_QUANT_TBLS; i++) {
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if ((qtbl = cinfo->quant_tbl_ptrs[i]) != NULL)
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qtbl->sent_table = suppress;
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}
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for (i = 0; i < NUM_HUFF_TBLS; i++) {
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if ((htbl = cinfo->dc_huff_tbl_ptrs[i]) != NULL)
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htbl->sent_table = suppress;
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if ((htbl = cinfo->ac_huff_tbl_ptrs[i]) != NULL)
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htbl->sent_table = suppress;
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}
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}
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// * Finish JPEG compression.
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// *
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// * If a multipass operating mode was selected, this may do a great deal of
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// * work including most of the actual output.
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GLOBAL void
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jpeg_finish_compress (j_compress_ptr cinfo)
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{
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JDIMENSION iMCU_row;
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if (cinfo->global_state == CSTATE_SCANNING ||
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cinfo->global_state == CSTATE_RAW_OK) {
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// Terminate first pass
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if (cinfo->next_scanline < cinfo->image_height)
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ERREXIT(cinfo, JERR_TOO_LITTLE_DATA);
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(*cinfo->master->finish_pass) (cinfo);
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} else if (cinfo->global_state != CSTATE_WRCOEFS)
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ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
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// Perform any remaining passes
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while (! cinfo->master->is_last_pass) {
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(*cinfo->master->prepare_for_pass) (cinfo);
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for (iMCU_row = 0; iMCU_row < cinfo->total_iMCU_rows; iMCU_row++) {
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if (cinfo->progress != NULL) {
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cinfo->progress->pass_counter = (LONG) iMCU_row;
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cinfo->progress->pass_limit = (LONG) cinfo->total_iMCU_rows;
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(*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
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}
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// We bypass the main controller and invoke coef controller directly;
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// * all work is being done from the coefficient buffer.
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if (! (*cinfo->coef->compress_data) (cinfo, (JSAMPIMAGE) NULL))
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ERREXIT(cinfo, JERR_CANT_SUSPEND);
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}
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(*cinfo->master->finish_pass) (cinfo);
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}
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// Write EOI, do final cleanup
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(*cinfo->marker->write_file_trailer) (cinfo);
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(*cinfo->dest->term_destination) (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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}
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// * Write a special marker.
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// * This is only recommended for writing COM or APPn markers.
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// * Must be called after jpeg_start_compress() and before
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// * first call to jpeg_write_scanlines() or jpeg_write_raw_data().
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GLOBAL void
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jpeg_write_marker (j_compress_ptr cinfo, int marker,
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const JOCTET *dataptr, unsigned int datalen)
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{
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if (cinfo->next_scanline != 0 ||
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(cinfo->global_state != CSTATE_SCANNING &&
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cinfo->global_state != CSTATE_RAW_OK &&
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cinfo->global_state != CSTATE_WRCOEFS))
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ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
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(*cinfo->marker->write_any_marker) (cinfo, marker, dataptr, datalen);
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}
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// * Alternate compression function: just write an abbreviated table file.
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// * Before calling this, all parameters and a data destination must be set up.
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// *
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// * To produce a pair of files containing abbreviated tables and abbreviated
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// * image data, one would proceed as follows:
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// *
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// * initialize JPEG object
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// * set JPEG parameters
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// * set destination to table file
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// * jpeg_write_tables(cinfo);
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// * set destination to image file
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// * jpeg_start_compress(cinfo, FALSE);
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// * write data...
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// * jpeg_finish_compress(cinfo);
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// *
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// * jpeg_write_tables has the side effect of marking all tables written
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// * (same as jpeg_suppress_tables(..., TRUE)). Thus a subsequent start_compress
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// * will not re-emit the tables unless it is passed write_all_tables=TRUE.
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GLOBAL void
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jpeg_write_tables (j_compress_ptr cinfo)
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{
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if (cinfo->global_state != CSTATE_START)
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ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
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// (Re)initialize error mgr and destination modules
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(*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
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(*cinfo->dest->init_destination) (cinfo);
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// Initialize the marker writer ... bit of a crock to do it here.
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jinit_marker_writer(cinfo);
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// Write them tables!
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(*cinfo->marker->write_tables_only) (cinfo);
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// And clean up.
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(*cinfo->dest->term_destination) (cinfo);
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// We can use jpeg_abort to release memory.
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jpeg_abort((j_common_ptr) cinfo);
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}
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