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/* Copyright (C) 1994 Aladdin Enterprises. All rights reserved.
This file is part of GNU Ghostscript.
GNU Ghostscript is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY. No author or distributor accepts responsibility to
anyone for the consequences of using it or for whether it serves any
particular purpose or works at all, unless he says so in writing. Refer
to the GNU Ghostscript General Public License for full details.
*/
/* sdctd.c */
/* DCT decoding filter stream */
#include "memory_.h"
#include "stdio_.h"
#include "jpeglib.h"
#include "jerror.h"
#include "gdebug.h"
#include "strimpl.h"
#include "sdct.h"
#include "sjpeg.h"
#define ss ((stream_DCT_state *)st)
/* ------ DCTDecode ------ */
/* JPEG source manager procedures */
private void
dctd_init_source(j_decompress_ptr dinfo)
{
}
static const JOCTET fake_eoi[2] = { 0xFF , JPEG_EOI };
private boolean
dctd_fill_input_buffer(j_decompress_ptr dinfo)
{ jpeg_decompress_data *jddp =
(jpeg_decompress_data *)((char *)dinfo -
offset_of(jpeg_decompress_data, dinfo));
if (! jddp->input_eod)
return FALSE; /* normal case: suspend processing */
/* Reached end of source data without finding EOI */
WARNMS(dinfo, JWRN_JPEG_EOF);
/* Insert a fake EOI marker */
dinfo->src->next_input_byte = fake_eoi;
dinfo->src->bytes_in_buffer = 2;
jddp->faked_eoi = true; /* so process routine doesn't use next_input_byte */
return TRUE;
}
private void
dctd_skip_input_data(j_decompress_ptr dinfo, long num_bytes)
{ struct jpeg_source_mgr *src = dinfo->src;
jpeg_decompress_data *jddp =
(jpeg_decompress_data *)((char *)dinfo -
offset_of(jpeg_decompress_data, dinfo));
if ( num_bytes > 0 )
{ if ( num_bytes > src->bytes_in_buffer )
{ jddp->skip += num_bytes - src->bytes_in_buffer;
src->next_input_byte += src->bytes_in_buffer;
src->bytes_in_buffer = 0;
return;
}
src->next_input_byte += num_bytes;
src->bytes_in_buffer -= num_bytes;
}
}
private void
dctd_term_source(j_decompress_ptr dinfo)
{
}
/* Initialize DCTDecode filter */
private int
s_DCTD_init(stream_state *st)
{ struct jpeg_source_mgr *src = &ss->data.decompress->source;
src->init_source = dctd_init_source;
src->fill_input_buffer = dctd_fill_input_buffer;
src->skip_input_data = dctd_skip_input_data;
src->term_source = dctd_term_source;
src->resync_to_restart = jpeg_resync_to_restart; /* use default method */
ss->data.decompress->dinfo.src = src;
ss->data.decompress->skip = 0;
ss->data.decompress->input_eod = false;
ss->data.decompress->faked_eoi = false;
ss->phase = 0;
return 0;
}
/* Process a buffer */
private int
s_DCTD_process(stream_state *st, stream_cursor_read *pr,
stream_cursor_write *pw, bool last)
{ jpeg_decompress_data *jddp = ss->data.decompress;
struct jpeg_source_mgr *src = jddp->dinfo.src;
int code;
if ( jddp->skip != 0 )
{ long avail = pr->limit - pr->ptr;
if ( avail < jddp->skip )
{ jddp->skip -= avail;
pr->ptr = pr->limit;
if (! last)
return 0; /* need more data */
jddp->skip = 0; /* don't skip past input EOD */
}
pr->ptr += jddp->skip;
jddp->skip = 0;
}
src->next_input_byte = pr->ptr + 1;
src->bytes_in_buffer = pr->limit - pr->ptr;
jddp->input_eod = last;
switch ( ss->phase )
{
case 0: /* not initialized yet */
/*
* Adobe implementations seem to ignore leading garbage bytes,
* even though neither the standard nor Adobe's own
* documentation mention this.
*/
while ( pr->ptr < pr->limit && pr->ptr[1] != 0xff )
pr->ptr++;
if ( pr->ptr == pr->limit )
return 0;
src->next_input_byte = pr->ptr + 1;
src->bytes_in_buffer = pr->limit - pr->ptr;
if ( (code = gs_jpeg_read_header(ss, TRUE)) < 0 )
return ERRC;
pr->ptr = jddp->faked_eoi ? pr->limit : src->next_input_byte-1;
switch ( code )
{
case JPEG_SUSPENDED:
return 0;
/*case JPEG_HEADER_OK: */
}
/* If we have a ColorTransform parameter, and it's not
* overridden by an Adobe marker in the data, set colorspace.
*/
if ( ss->ColorTransform >= 0 &&
! jddp->dinfo.saw_Adobe_marker )
{ switch ( jddp->dinfo.num_components )
{
case 3:
jddp->dinfo.jpeg_color_space =
ss->ColorTransform ? JCS_YCbCr : JCS_RGB;
/* out_color_space will default to JCS_RGB */
break;
case 4:
jddp->dinfo.jpeg_color_space =
ss->ColorTransform ? JCS_YCCK : JCS_CMYK;
/* out_color_space will default to JCS_CMYK */
break;
}
}
if ( gs_jpeg_start_decompress(ss) < 0 )
return ERRC;
ss->scan_line_size =
jddp->dinfo.output_width * jddp->dinfo.output_components;
if ( ss->scan_line_size > (uint) jddp->template.min_out_size )
{
/* Create a spare buffer for oversize scanline */
jddp->scanline_buffer = (byte *)
gs_malloc(ss->scan_line_size, sizeof(byte),
"s_DCTD_process(scanline_buffer)");
if ( jddp->scanline_buffer == NULL )
return ERRC;
}
jddp->bytes_in_scanline = 0;
ss->phase = 1;
/* falls through */
case 1: /* reading data */
dumpbuffer:
if ( jddp->bytes_in_scanline != 0 )
{ uint avail = pw->limit - pw->ptr;
uint tomove = min(jddp->bytes_in_scanline,
avail);
memcpy(pw->ptr + 1, jddp->scanline_buffer +
(ss->scan_line_size - jddp->bytes_in_scanline),
tomove);
pw->ptr += tomove;
jddp->bytes_in_scanline -= tomove;
if ( jddp->bytes_in_scanline != 0 )
return 1; /* need more room */
}
while ( jddp->dinfo.output_height > jddp->dinfo.output_scanline )
{ int read;
byte *samples;
if ( jddp->scanline_buffer != NULL )
samples = jddp->scanline_buffer;
else
{ if ( (uint)(pw->limit - pw->ptr) < ss->scan_line_size )
return 1; /* need more room */
samples = (byte *)(pw->ptr + 1);
}
read = gs_jpeg_read_scanlines(ss, &samples, 1);
if ( read < 0 )
return ERRC;
pr->ptr = jddp->faked_eoi ? pr->limit : src->next_input_byte-1;
if ( !read )
return 0; /* need more data */
if ( jddp->scanline_buffer != NULL )
{ jddp->bytes_in_scanline = ss->scan_line_size;
goto dumpbuffer;
}
pw->ptr += ss->scan_line_size;
}
ss->phase = 2;
/* falls through */
case 2: /* end of image; scan for EOI */
if ( (code = gs_jpeg_finish_decompress(ss)) < 0 )
return ERRC;
pr->ptr = jddp->faked_eoi ? pr->limit : src->next_input_byte-1;
if ( code == 0 )
return 0;
ss->phase = 3;
/* falls through */
case 3: /* we are DONE */
return EOFC;
}
/* Default case can't happen.... */
return ERRC;
}
/* Release the stream */
private void
s_DCTD_release(stream_state *st)
{ gs_jpeg_destroy(ss);
if ( ss->data.decompress->scanline_buffer != NULL )
{
gs_free(ss->data.decompress->scanline_buffer,
ss->scan_line_size, sizeof(byte),
"s_DCTD_release(scanline_buffer)");
}
gs_free(ss->data.decompress, 1, sizeof(jpeg_decompress_data),
"s_DCTD_release");
/* Switch the template pointer back in case we still need it. */
st->template = &s_DCTD_template;
}
/* Stream template */
const stream_template s_DCTD_template =
{ &st_DCT_state, s_DCTD_init, s_DCTD_process, 2000, 4000, s_DCTD_release
};
#undef ss
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