JCAPIMIN.c
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上传日期:2022-05-11
资源大小:5032k
文件大小:8k
源码类别:
网络截获/分析
开发平台:
Visual C++
- ////////////////////////////////////////////////////////////////////////
- //
- // Note : this file is included as part of the Smaller Animals Software
- // JpegFile package. Though this file has not been modified from it's
- // original IJG 6a form, it is not the responsibility on the Independent
- // JPEG Group to answer questions regarding this code.
- //
- // Any questions you have about this code should be addressed to :
- //
- // CHRISDL@PAGESZ.NET - the distributor of this package.
- //
- // Remember, by including this code in the JpegFile package, Smaller
- // Animals Software assumes all responsibilities for answering questions
- // about it. If we (SA Software) can't answer your questions ourselves, we
- // will direct you to people who can.
- //
- // Thanks, CDL.
- //
- ////////////////////////////////////////////////////////////////////////
- /*
- * jcapimin.c
- *
- * Copyright (C) 1994-1996, Thomas G. Lane.
- * This file is part of the Independent JPEG Group's software.
- * For conditions of distribution and use, see the accompanying README file.
- *
- * This file contains application interface code for the compression half
- * of the JPEG library. These are the "minimum" API routines that may be
- * needed in either the normal full-compression case or the transcoding-only
- * case.
- *
- * Most of the routines intended to be called directly by an application
- * are in this file or in jcapistd.c. But also see jcparam.c for
- * parameter-setup helper routines, jcomapi.c for routines shared by
- * compression and decompression, and jctrans.c for the transcoding case.
- */
- #define JPEG_INTERNALS
- #include "jinclude.h"
- #include "jpeglib.h"
- /*
- * Initialization of a JPEG compression object.
- * The error manager must already be set up (in case memory manager fails).
- */
- GLOBAL(void)
- jpeg_CreateCompress (j_compress_ptr cinfo, int version, size_t structsize)
- {
- int i;
- cinfo->i_stream = 0;
- cinfo->l_size = 0;
- cinfo->l_point = 0;
- cinfo->buffer = NULL;
- /* Guard against version mismatches between library and caller. */
- cinfo->mem = NULL; /* so jpeg_destroy knows mem mgr not called */
- if (version != JPEG_LIB_VERSION)
- ERREXIT2(cinfo, JERR_BAD_LIB_VERSION, JPEG_LIB_VERSION, version);
- if (structsize != SIZEOF(struct jpeg_compress_struct))
- ERREXIT2(cinfo, JERR_BAD_STRUCT_SIZE,
- (int) SIZEOF(struct jpeg_compress_struct), (int) structsize);
- /* For debugging purposes, zero the whole master structure.
- * But error manager pointer is already there, so save and restore it.
- */
- {
- struct jpeg_error_mgr * err = cinfo->err;
- MEMZERO(cinfo, SIZEOF(struct jpeg_compress_struct));
- cinfo->err = err;
- }
- cinfo->is_decompressor = FALSE;
- /* Initialize a memory manager instance for this object */
- jinit_memory_mgr((j_common_ptr) cinfo);
- /* Zero out pointers to permanent structures. */
- cinfo->progress = NULL;
- cinfo->dest = NULL;
- cinfo->comp_info = NULL;
- for (i = 0; i < NUM_QUANT_TBLS; i++)
- cinfo->quant_tbl_ptrs[i] = NULL;
- for (i = 0; i < NUM_HUFF_TBLS; i++) {
- cinfo->dc_huff_tbl_ptrs[i] = NULL;
- cinfo->ac_huff_tbl_ptrs[i] = NULL;
- }
- cinfo->input_gamma = 1.0; /* in case application forgets */
- /* OK, I'm ready */
- cinfo->global_state = CSTATE_START;
- }
- /*
- * Destruction of a JPEG compression object
- */
- GLOBAL(void)
- jpeg_destroy_compress (j_compress_ptr cinfo)
- {
- jpeg_destroy((j_common_ptr) cinfo); /* use common routine */
- }
- /*
- * Abort processing of a JPEG compression operation,
- * but don't destroy the object itself.
- */
- GLOBAL(void)
- jpeg_abort_compress (j_compress_ptr cinfo)
- {
- jpeg_abort((j_common_ptr) cinfo); /* use common routine */
- }
- /*
- * Forcibly suppress or un-suppress all quantization and Huffman tables.
- * Marks all currently defined tables as already written (if suppress)
- * or not written (if !suppress). This will control whether they get emitted
- * by a subsequent jpeg_start_compress call.
- *
- * This routine is exported for use by applications that want to produce
- * abbreviated JPEG datastreams. It logically belongs in jcparam.c, but
- * since it is called by jpeg_start_compress, we put it here --- otherwise
- * jcparam.o would be linked whether the application used it or not.
- */
- GLOBAL(void)
- jpeg_suppress_tables (j_compress_ptr cinfo, unsigned int suppress)
- {
- int i;
- JQUANT_TBL * qtbl;
- JHUFF_TBL * htbl;
- for (i = 0; i < NUM_QUANT_TBLS; i++) {
- if ((qtbl = cinfo->quant_tbl_ptrs[i]) != NULL)
- qtbl->sent_table = suppress;
- }
- for (i = 0; i < NUM_HUFF_TBLS; i++) {
- if ((htbl = cinfo->dc_huff_tbl_ptrs[i]) != NULL)
- htbl->sent_table = suppress;
- if ((htbl = cinfo->ac_huff_tbl_ptrs[i]) != NULL)
- htbl->sent_table = suppress;
- }
- }
- /*
- * Finish JPEG compression.
- *
- * If a multipass operating mode was selected, this may do a great deal of
- * work including most of the actual output.
- */
- GLOBAL(void)
- jpeg_finish_compress (j_compress_ptr cinfo)
- {
- JDIMENSION iMCU_row;
- if (cinfo->global_state == CSTATE_SCANNING ||
- cinfo->global_state == CSTATE_RAW_OK) {
- /* Terminate first pass */
- if (cinfo->next_scanline < cinfo->image_height)
- ERREXIT(cinfo, JERR_TOO_LITTLE_DATA);
- (*cinfo->master->finish_pass) (cinfo);
- } else if (cinfo->global_state != CSTATE_WRCOEFS)
- ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
- /* Perform any remaining passes */
- while (! cinfo->master->is_last_pass) {
- (*cinfo->master->prepare_for_pass) (cinfo);
- for (iMCU_row = 0; iMCU_row < cinfo->total_iMCU_rows; iMCU_row++) {
- if (cinfo->progress != NULL) {
- cinfo->progress->pass_counter = (long) iMCU_row;
- cinfo->progress->pass_limit = (long) cinfo->total_iMCU_rows;
- (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
- }
- /* We bypass the main controller and invoke coef controller directly;
- * all work is being done from the coefficient buffer.
- */
- if (! (*cinfo->coef->compress_data) (cinfo, (JSAMPIMAGE) NULL))
- ERREXIT(cinfo, JERR_CANT_SUSPEND);
- }
- (*cinfo->master->finish_pass) (cinfo);
- }
- /* Write EOI, do final cleanup */
- (*cinfo->marker->write_file_trailer) (cinfo);
- (*cinfo->dest->term_destination) (cinfo);
- /* We can use jpeg_abort to release memory and reset global_state */
- jpeg_abort((j_common_ptr) cinfo);
- }
- /*
- * Write a special marker.
- * This is only recommended for writing COM or APPn markers.
- * Must be called after jpeg_start_compress() and before
- * first call to jpeg_write_scanlines() or jpeg_write_raw_data().
- */
- GLOBAL(void)
- jpeg_write_marker (j_compress_ptr cinfo, int marker,
- const JOCTET *dataptr, unsigned int datalen)
- {
- if (cinfo->next_scanline != 0 ||
- (cinfo->global_state != CSTATE_SCANNING &&
- cinfo->global_state != CSTATE_RAW_OK &&
- cinfo->global_state != CSTATE_WRCOEFS))
- ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
- (*cinfo->marker->write_any_marker) (cinfo, marker, dataptr, datalen);
- }
- /*
- * Alternate compression function: just write an abbreviated table file.
- * Before calling this, all parameters and a data destination must be set up.
- *
- * To produce a pair of files containing abbreviated tables and abbreviated
- * image data, one would proceed as follows:
- *
- * initialize JPEG object
- * set JPEG parameters
- * set destination to table file
- * jpeg_write_tables(cinfo);
- * set destination to image file
- * jpeg_start_compress(cinfo, FALSE);
- * write data...
- * jpeg_finish_compress(cinfo);
- *
- * jpeg_write_tables has the side effect of marking all tables written
- * (same as jpeg_suppress_tables(..., TRUE)). Thus a subsequent start_compress
- * will not re-emit the tables unless it is passed write_all_tables=TRUE.
- */
- GLOBAL(void)
- jpeg_write_tables (j_compress_ptr cinfo)
- {
- if (cinfo->global_state != CSTATE_START)
- ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
- /* (Re)initialize error mgr and destination modules */
- (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
- (*cinfo->dest->init_destination) (cinfo);
- /* Initialize the marker writer ... bit of a crock to do it here. */
- jinit_marker_writer(cinfo);
- /* Write them tables! */
- (*cinfo->marker->write_tables_only) (cinfo);
- /* And clean up. */
- (*cinfo->dest->term_destination) (cinfo);
- /* We can use jpeg_abort to release memory. */
- jpeg_abort((j_common_ptr) cinfo);
- }