/* Copyright (C) 1994, 1998, 1999 Aladdin Enterprises.  All rights reserved.
  
  This file is part of AFPL Ghostscript.
  
  AFPL Ghostscript is distributed with NO WARRANTY OF ANY KIND.  No author or
  distributor accepts any responsibility for the consequences of using it, or
  for whether it serves any particular purpose or works at all, unless he or
  she says so in writing.  Refer to the Aladdin Free Public License (the
  "License") for full details.
  
  Every copy of AFPL Ghostscript must include a copy of the License, normally
  in a plain ASCII text file named PUBLIC.  The License grants you the right
  to copy, modify and redistribute AFPL Ghostscript, but only under certain
  conditions described in the License.  Among other things, the License
  requires that the copyright notice and this notice be preserved on all
  copies.
*/

/*$Id$ */
/* Interface routines for IJG decoding code. */
#include "stdio_.h"
#include "string_.h"
#include "jpeglib_.h"
#include "jerror_.h"
#include "gx.h"
#include "gserrors.h"
#include "strimpl.h"
#include "sdct.h"
#include "sjpeg.h"

/*
 * Interface routines.  This layer of routines exists solely to limit
 * side-effects from using setjmp.
 */

int
gs_jpeg_create_decompress(stream_DCT_state * st)
{				/* Initialize error handling */
    gs_jpeg_error_setup(st);
    /* Establish the setjmp return context for gs_jpeg_error_exit to use. */
    if (setjmp(st->data.common->exit_jmpbuf))
	return_error(gs_jpeg_log_error(st));

    jpeg_create_decompress(&st->data.decompress->dinfo);
    jpeg_stream_data_common_init(st->data.decompress);
    return 0;
}

int
gs_jpeg_read_header(stream_DCT_state * st,
		    boolean require_image)
{
    if (setjmp(st->data.common->exit_jmpbuf))
	return_error(gs_jpeg_log_error(st));
    return jpeg_read_header(&st->data.decompress->dinfo, require_image);
}

int
gs_jpeg_start_decompress(stream_DCT_state * st)
{
    if (setjmp(st->data.common->exit_jmpbuf))
	return_error(gs_jpeg_log_error(st));
#if JPEG_LIB_VERSION > 55
    return (int)jpeg_start_decompress(&st->data.decompress->dinfo);
#else
    /* in IJG version 5, jpeg_start_decompress had no return value */
    jpeg_start_decompress(&st->data.decompress->dinfo);
    return 1;
#endif
}

int
gs_jpeg_read_scanlines(stream_DCT_state * st,
		       JSAMPARRAY scanlines,
		       int max_lines)
{
    if (setjmp(st->data.common->exit_jmpbuf))
	return_error(gs_jpeg_log_error(st));
    return (int)jpeg_read_scanlines(&st->data.decompress->dinfo,
				    scanlines, (JDIMENSION) max_lines);
}

int
gs_jpeg_finish_decompress(stream_DCT_state * st)
{
    if (setjmp(st->data.common->exit_jmpbuf))
	return_error(gs_jpeg_log_error(st));
    return (int)jpeg_finish_decompress(&st->data.decompress->dinfo);
}