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#include "fitz.h"
#include <jpeglib.h>
#include <setjmp.h>
typedef struct fz_dctd_s fz_dctd;
struct fz_dctd_s
{
fz_stream *chain;
int color_transform;
int init;
int stride;
unsigned char *scanline;
unsigned char *rp, *wp;
struct jpeg_decompress_struct cinfo;
struct jpeg_source_mgr srcmgr;
struct jpeg_error_mgr errmgr;
jmp_buf jb;
char msg[JMSG_LENGTH_MAX];
};
static void error_exit(j_common_ptr cinfo)
{
fz_dctd *state = cinfo->client_data;
cinfo->err->format_message(cinfo, state->msg);
longjmp(state->jb, 1);
}
static void init_source(j_decompress_ptr cinfo)
{
/* nothing to do */
}
static void term_source(j_decompress_ptr cinfo)
{
/* nothing to do */
}
static boolean fill_input_buffer(j_decompress_ptr cinfo)
{
struct jpeg_source_mgr *src = cinfo->src;
fz_dctd *state = cinfo->client_data;
fz_stream *chain = state->chain;
chain->rp = chain->wp;
fz_fill_buffer(chain);
src->next_input_byte = chain->rp;
src->bytes_in_buffer = chain->wp - chain->rp;
if (src->bytes_in_buffer == 0)
{
static unsigned char eoi[2] = { 0xFF, JPEG_EOI };
fz_warn("premature end of file in jpeg");
src->next_input_byte = eoi;
src->bytes_in_buffer = 2;
}
return 1;
}
static void skip_input_data(j_decompress_ptr cinfo, long num_bytes)
{
struct jpeg_source_mgr *src = cinfo->src;
if (num_bytes > 0)
{
while ((size_t)num_bytes > src->bytes_in_buffer)
{
num_bytes -= src->bytes_in_buffer;
(void) src->fill_input_buffer(cinfo);
}
src->next_input_byte += num_bytes;
src->bytes_in_buffer -= num_bytes;
}
}
static int
read_dctd(fz_stream *stm, unsigned char *buf, int len)
{
fz_dctd *state = stm->state;
j_decompress_ptr cinfo = &state->cinfo;
unsigned char *p = buf;
unsigned char *ep = buf + len;
if (setjmp(state->jb))
{
if (cinfo->src)
state->chain->rp = state->chain->wp - cinfo->src->bytes_in_buffer;
return fz_error_make("jpeg error: %s", state->msg);
}
if (!state->init)
{
cinfo->client_data = state;
cinfo->err = &state->errmgr;
jpeg_std_error(cinfo->err);
cinfo->err->error_exit = error_exit;
jpeg_create_decompress(cinfo);
cinfo->src = &state->srcmgr;
cinfo->src->init_source = init_source;
cinfo->src->fill_input_buffer = fill_input_buffer;
cinfo->src->skip_input_data = skip_input_data;
cinfo->src->resync_to_restart = jpeg_resync_to_restart;
cinfo->src->term_source = term_source;
cinfo->src->next_input_byte = state->chain->rp;
cinfo->src->bytes_in_buffer = state->chain->wp - state->chain->rp;
jpeg_read_header(cinfo, 1);
/* speed up jpeg decoding a bit */
cinfo->dct_method = JDCT_FASTEST;
cinfo->do_fancy_upsampling = FALSE;
/* default value if ColorTransform is not set */
if (state->color_transform == -1)
{
if (state->cinfo.num_components == 3)
state->color_transform = 1;
else
state->color_transform = 0;
}
if (cinfo->saw_Adobe_marker)
state->color_transform = cinfo->Adobe_transform;
/* Guess the input colorspace, and set output colorspace accordingly */
switch (cinfo->num_components)
{
case 3:
if (state->color_transform)
cinfo->jpeg_color_space = JCS_YCbCr;
else
cinfo->jpeg_color_space = JCS_RGB;
break;
case 4:
if (state->color_transform)
cinfo->jpeg_color_space = JCS_YCCK;
else
cinfo->jpeg_color_space = JCS_CMYK;
break;
}
jpeg_start_decompress(cinfo);
state->stride = cinfo->output_width * cinfo->output_components;
state->scanline = fz_malloc(state->stride);
state->rp = state->scanline;
state->wp = state->scanline;
state->init = 1;
}
while (state->rp < state->wp && p < ep)
*p++ = *state->rp++;
while (p < ep)
{
if (cinfo->output_scanline == cinfo->output_height)
break;
if (p + state->stride <= ep)
{
jpeg_read_scanlines(cinfo, &p, 1);
p += state->stride;
}
else
{
jpeg_read_scanlines(cinfo, &state->scanline, 1);
state->rp = state->scanline;
state->wp = state->scanline + state->stride;
}
while (state->rp < state->wp && p < ep)
*p++ = *state->rp++;
}
return p - buf;
}
static void
close_dctd(fz_stream *stm)
{
fz_dctd *state = stm->state;
if (setjmp(state->jb))
{
state->chain->rp = state->chain->wp - state->cinfo.src->bytes_in_buffer;
fz_warn("jpeg error: %s", state->msg);
goto skip;
}
if (state->init)
jpeg_finish_decompress(&state->cinfo);
skip:
state->chain->rp = state->chain->wp - state->cinfo.src->bytes_in_buffer;
jpeg_destroy_decompress(&state->cinfo);
fz_free(state->scanline);
fz_close(state->chain);
fz_free(state);
}
fz_stream *
fz_open_dctd(fz_stream *chain, fz_obj *params)
{
fz_dctd *state;
fz_obj *obj;
state = fz_malloc(sizeof(fz_dctd));
memset(state, 0, sizeof(fz_dctd));
state->chain = chain;
state->color_transform = -1; /* unset */
state->init = 0;
obj = fz_dict_gets(params, "ColorTransform");
if (obj)
state->color_transform = fz_to_int(obj);
return fz_new_stream(state, read_dctd, close_dctd);
}
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