235 lines
7.1 KiB
C++
235 lines
7.1 KiB
C++
/*
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* 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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*/
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/* SCCSID = "@(#)jcapimin.cc 1.2 15:07:57 06/20/96" */
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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 compression 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_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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{
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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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/*
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* Destruction of a JPEG compression object
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*/
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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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/*
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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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*/
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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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/*
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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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*/
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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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/*
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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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*/
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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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*/
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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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/*
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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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*/
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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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/*
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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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*/
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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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#ifndef NIFTY
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/* as regards the ifndef NIFTY, it's not clear that this makes much
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difference. Most of the table data (at the high level) is allocated
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more permanently than that which a jpeg_abort() would release. */
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jpeg_abort((j_common_ptr) cinfo);
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#endif
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}
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