chromium/third_party/libjpeg_turbo/jcapimin.c

/*
 * jcapimin.c
 *
 * This file was part of the Independent JPEG Group's software:
 * Copyright (C) 1994-1998, Thomas G. Lane.
 * Modified 2003-2010 by Guido Vollbeding.
 * libjpeg-turbo Modifications:
 * Copyright (C) 2022, D. R. Commander.
 * For conditions of distribution and use, see the accompanying README.ijg
 * 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)
{ … }


/*
 * Destruction of a JPEG compression object
 */

GLOBAL(void)
jpeg_destroy_compress(j_compress_ptr cinfo)
{ … }


/*
 * Abort processing of a JPEG compression operation,
 * but don't destroy the object itself.
 */

GLOBAL(void)
jpeg_abort_compress(j_compress_ptr cinfo)
{ … }


/*
 * 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, boolean 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)
{ … }


/*
 * 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)
{ … }

/* Same, but piecemeal. */

GLOBAL(void)
jpeg_write_m_header(j_compress_ptr cinfo, int marker, unsigned int datalen)
{ … }

GLOBAL(void)
jpeg_write_m_byte(j_compress_ptr cinfo, int val)
{ … }


/*
 * 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)
{ … }