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#include <fitz.h>
#include "filt_dctc.h"
typedef struct fz_dctd_s fz_dctd;
struct mysrcmgr
{
struct jpeg_source_mgr super;
fz_buffer *buf;
int skip;
};
struct fz_dctd_s
{
fz_filter super;
struct jpeg_decompress_struct cinfo;
struct mysrcmgr src;
struct myerrmgr err;
int colortransform;
int stage;
};
static void myinitsource(j_decompress_ptr cinfo) { /* empty */ }
static boolean myfillinput(j_decompress_ptr cinfo) { return FALSE; }
static void mytermsource(j_decompress_ptr cinfo) { /* empty */ }
static void myskipinput(j_decompress_ptr cinfo, long n)
{
struct mysrcmgr *src = (struct mysrcmgr *)cinfo->src;
fz_buffer *in = src->buf;
assert(src->skip == 0);
in->rp = in->wp - src->super.bytes_in_buffer;
if (in->rp + n > in->wp) {
src->skip = (in->rp + n) - in->wp;
in->rp = in->wp;
}
else {
src->skip = 0;
in->rp += n;
}
src->super.bytes_in_buffer = in->wp - in->rp;
src->super.next_input_byte = in->rp;
}
fz_error *
fz_newdctd(fz_filter **fp, fz_obj *params)
{
fz_error *err;
fz_obj *obj;
int colortransform;
FZ_NEWFILTER(fz_dctd, d, dctd);
colortransform = 1;
if (params) {
obj = fz_dictgets(params, "ColorTransform");
if (obj) colortransform = fz_toint(obj);
}
d->colortransform = colortransform;
d->stage = 0;
/* setup error callback first thing */
myiniterr(&d->err);
d->cinfo.err = (struct jpeg_error_mgr*) &d->err;
if (setjmp(d->err.jb)) {
err = fz_throw("ioerror in dctd: %s", d->err.msg);
fz_free(d);
return err;
}
/* create decompression object. this zeroes cinfo except for err. */
jpeg_create_decompress(&d->cinfo);
/* prepare source manager */
d->cinfo.src = (struct jpeg_source_mgr *)&d->src;
d->src.super.init_source = myinitsource;
d->src.super.fill_input_buffer = myfillinput;
d->src.super.skip_input_data = myskipinput;
d->src.super.resync_to_restart = jpeg_resync_to_restart;
d->src.super.term_source = mytermsource;
d->src.super.bytes_in_buffer = 0;
d->src.super.next_input_byte = nil;
d->src.skip = 0;
/* speed up jpeg decoding a bit */
d->cinfo.dct_method = JDCT_FASTEST;
d->cinfo.do_fancy_upsampling = FALSE;
return nil;
}
void
fz_dropdctd(fz_filter *filter)
{
fz_dctd *d = (fz_dctd*)filter;
if (setjmp(d->err.jb)) {
fprintf(stderr, "ioerror in dct: jpeg_destroy_decompress: %s", d->err.msg);
return;
}
jpeg_destroy_decompress(&d->cinfo);
}
fz_error *
fz_processdctd(fz_filter *filter, fz_buffer *in, fz_buffer *out)
{
fz_dctd *d = (fz_dctd*)filter;
boolean b;
int i;
int stride;
JSAMPROW scanlines[1];
d->src.buf = in;
/* skip any bytes left over from myskipinput() */
if (d->src.skip > 0) {
if (in->rp + d->src.skip > in->wp) {
d->src.skip = (in->rp + d->src.skip) - in->wp;
in->rp = in->wp;
goto needinput;
}
else {
in->rp += d->src.skip;
d->src.skip = 0;
}
}
d->src.super.bytes_in_buffer = in->wp - in->rp;
d->src.super.next_input_byte = in->rp;
if (setjmp(d->err.jb)) {
return fz_throw("ioerror in dctd: %s", d->err.msg);
}
switch (d->stage)
{
case 0:
i = jpeg_read_header(&d->cinfo, TRUE);
if (i == JPEG_SUSPENDED)
goto needinput;
/* FIXME: default value if ColorTransform is not set */
if (!d->cinfo.saw_Adobe_marker) {
switch (d->cinfo.num_components) {
case 3:
if (d->colortransform)
d->cinfo.jpeg_color_space = JCS_YCbCr;
else
d->cinfo.jpeg_color_space = JCS_RGB;
break;
case 4:
if (d->colortransform)
d->cinfo.jpeg_color_space = JCS_YCCK;
else
d->cinfo.jpeg_color_space = JCS_CMYK;
break;
}
}
/* fall through */
d->stage = 1;
case 1:
b = jpeg_start_decompress(&d->cinfo);
if (b == FALSE)
goto needinput;
/* fall through */
d->stage = 2;
case 2:
stride = d->cinfo.output_width * d->cinfo.output_components;
while (d->cinfo.output_scanline < d->cinfo.output_height)
{
if (out->wp + stride > out->ep)
goto needoutput;
scanlines[0] = out->wp;
i = jpeg_read_scanlines(&d->cinfo, scanlines, 1);
if (i == 0)
goto needinput;
out->wp += stride;
}
/* fall through */
d->stage = 3;
case 3:
b = jpeg_finish_decompress(&d->cinfo);
if (b == FALSE)
goto needinput;
d->stage = 4;
out->eof = 1;
in->rp = in->wp - d->src.super.bytes_in_buffer;
return fz_iodone;
}
needinput:
in->rp = in->wp - d->src.super.bytes_in_buffer;
return fz_ioneedin;
needoutput:
in->rp = in->wp - d->src.super.bytes_in_buffer;
return fz_ioneedout;
}
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