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/*
Code for JPEG decompression by the Independent JPEG Group. Please see
README.jpeg in the top level directory.
*/
#include "../include/sane/config.h"
#ifdef HAVE_LIBJPEG
#include "../include/sane/sanei_jpeg.h"
typedef struct
{
struct djpeg_dest_struct pub; /* public fields */
/* Usually these two pointers point to the same place: */
char *iobuffer; /* fwrite's I/O buffer */
JSAMPROW pixrow; /* decompressor output buffer */
size_t buffer_width; /* width of I/O buffer */
JDIMENSION samples_per_row; /* JSAMPLEs per output row */
}
ppm_dest_struct;
typedef ppm_dest_struct *ppm_dest_ptr;
/*
* For 12-bit JPEG data, we either downscale the values to 8 bits
* (to write standard byte-per-sample PPM/PGM files), or output
* nonstandard word-per-sample PPM/PGM files. Downscaling is done
* if PPM_NORAWWORD is defined (this can be done in the Makefile
* or in jconfig.h).
* (When the core library supports data precision reduction, a cleaner
* implementation will be to ask for that instead.)
*/
#if BITS_IN_JSAMPLE==8
#define PUTPPMSAMPLE(ptr,v) *ptr++=(char) (v)
#define BYTESPERSAMPLE 1
#define PPM_MAXVAL 255
#else
#ifdef PPM_NORAWWORD
#define PUTPPMSAMPLE(ptr,v) *ptr++=(char) ((v) >> (BITS_IN_JSAMPLE-8))
#define BYTESPERSAMPLE 1
#define PPM_MAXVAL 255
#else
/* The word-per-sample format always puts the LSB first. */
#define PUTPPMSAMPLE(ptr,v) \
{ register int val_=v; \
*ptr++=(char) (val_ & 0xFF); \
*ptr++=(char) ((val_ >> 8) & 0xFF); \
}
#define BYTESPERSAMPLE 2
#define PPM_MAXVAL ((1<<BITS_IN_JSAMPLE)-1)
#endif
#endif
METHODDEF (void)
sanei_jpeg_start_output_ppm (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)
{
cinfo = cinfo;
dinfo = dinfo;
/* header image is supplied for us */
}
METHODDEF (void)
sanei_jpeg_finish_output_ppm (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)
{
cinfo = cinfo;
dinfo = dinfo;
/* nothing to do */
}
/*
* Write some pixel data.
* In this module rows_supplied will always be 1.
*
* put_pixel_rows handles the "normal" 8-bit case where the decompressor
* output buffer is physically the same as the fwrite buffer.
*/
METHODDEF (void)
sanei_jpeg_put_pixel_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
JDIMENSION rows_supplied, char *data)
{
ppm_dest_ptr dest = (ppm_dest_ptr) dinfo;
cinfo = cinfo;
dinfo = dinfo;
rows_supplied = rows_supplied;
memcpy (data, dest->iobuffer, dest->buffer_width);
}
/*
* This code is used when we have to copy the data and apply a pixel
* format translation. Typically this only happens in 12-bit mode.
*/
METHODDEF (void)
sanei_jpeg_copy_pixel_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
JDIMENSION rows_supplied, char *data)
{
ppm_dest_ptr dest = (ppm_dest_ptr) dinfo;
register char *bufferptr;
register JSAMPROW ptr;
register JDIMENSION col;
cinfo = cinfo;
dinfo = dinfo;
rows_supplied = rows_supplied;
ptr = dest->pub.buffer[0];
bufferptr = dest->iobuffer;
for (col = dest->samples_per_row; col > 0; col--)
{
PUTPPMSAMPLE (bufferptr, GETJSAMPLE (*ptr++));
}
memcpy (data, dest->iobuffer, dest->buffer_width);
}
/*
* Write some pixel data when color quantization is in effect.
* We have to demap the color index values to straight data.
*/
METHODDEF (void)
sanei_jpeg_put_demapped_rgb (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
JDIMENSION rows_supplied, char *data)
{
ppm_dest_ptr dest = (ppm_dest_ptr) dinfo;
register char *bufferptr;
register int pixval;
register JSAMPROW ptr;
register JSAMPROW color_map0 = cinfo->colormap[0];
register JSAMPROW color_map1 = cinfo->colormap[1];
register JSAMPROW color_map2 = cinfo->colormap[2];
register JDIMENSION col;
rows_supplied = rows_supplied;
ptr = dest->pub.buffer[0];
bufferptr = dest->iobuffer;
for (col = cinfo->output_width; col > 0; col--)
{
pixval = GETJSAMPLE (*ptr++);
PUTPPMSAMPLE (bufferptr, GETJSAMPLE (color_map0[pixval]));
PUTPPMSAMPLE (bufferptr, GETJSAMPLE (color_map1[pixval]));
PUTPPMSAMPLE (bufferptr, GETJSAMPLE (color_map2[pixval]));
}
memcpy (data, dest->iobuffer, dest->buffer_width);
}
METHODDEF (void)
sanei_jpeg_put_demapped_gray (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
JDIMENSION rows_supplied, char *data)
{
ppm_dest_ptr dest = (ppm_dest_ptr) dinfo;
register char *bufferptr;
register JSAMPROW ptr;
register JSAMPROW color_map = cinfo->colormap[0];
register JDIMENSION col;
rows_supplied = rows_supplied;
ptr = dest->pub.buffer[0];
bufferptr = dest->iobuffer;
for (col = cinfo->output_width; col > 0; col--)
{
PUTPPMSAMPLE (bufferptr,
GETJSAMPLE (color_map[GETJSAMPLE (*ptr++)]));
}
memcpy (data, dest->iobuffer, dest->buffer_width);
}
GLOBAL (djpeg_dest_ptr)
sanei_jpeg_jinit_write_ppm (j_decompress_ptr cinfo)
{
ppm_dest_ptr dest;
/* Create module interface object, fill in method pointers */
dest = (ppm_dest_ptr)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
SIZEOF (ppm_dest_struct));
dest->pub.start_output = sanei_jpeg_start_output_ppm;
dest->pub.finish_output = sanei_jpeg_finish_output_ppm;
/* Calculate output image dimensions so we can allocate space */
jpeg_calc_output_dimensions (cinfo);
/* Create physical I/O buffer. Note we make this near on a PC. */
dest->samples_per_row = cinfo->output_width * cinfo->out_color_components;
dest->buffer_width = dest->samples_per_row * (BYTESPERSAMPLE * SIZEOF (char));
dest->iobuffer = (char *) (*cinfo->mem->alloc_small)
((j_common_ptr) cinfo, JPOOL_IMAGE, dest->buffer_width);
if (cinfo->quantize_colors || BITS_IN_JSAMPLE != 8 ||
SIZEOF (JSAMPLE) != SIZEOF (char))
{
/* When quantizing, we need an output buffer for clrmap indexes
* that's separate from the physical I/O buffer. We also need a
* separate buffer if pixel format translation must take place.
*/
dest->pub.buffer = (*cinfo->mem->alloc_sarray)
((j_common_ptr) cinfo, JPOOL_IMAGE,
cinfo->output_width * cinfo->output_components,
(JDIMENSION) 1);
dest->pub.buffer_height = 1;
if (!cinfo->quantize_colors)
dest->pub.put_pixel_rows = sanei_jpeg_copy_pixel_rows;
else if (cinfo->out_color_space == JCS_GRAYSCALE)
dest->pub.put_pixel_rows = sanei_jpeg_put_demapped_gray;
else
dest->pub.put_pixel_rows = sanei_jpeg_put_demapped_rgb;
}
else
{
/* We will fwrite() directly from decompressor output buffer. */
/* Synthesize a JSAMPARRAY pointer structure */
/* Cast here implies near->far pointer conversion on PCs */
dest->pixrow = (JSAMPROW) dest->iobuffer;
dest->pub.buffer = &dest->pixrow;
dest->pub.buffer_height = 1;
dest->pub.put_pixel_rows = sanei_jpeg_put_pixel_rows;
}
return (djpeg_dest_ptr) dest;
}
#endif
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