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#include "fitz-internal.h"
#include <jpeglib.h>
static void error_exit(j_common_ptr cinfo)
{
char msg[JMSG_LENGTH_MAX];
fz_context *ctx = (fz_context *)cinfo->client_data;
cinfo->err->format_message(cinfo, msg);
fz_throw(ctx, "jpeg error: %s", msg);
}
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)
{
static unsigned char eoi[2] = { 0xFF, JPEG_EOI };
struct jpeg_source_mgr *src = cinfo->src;
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)
{
size_t skip = (size_t)num_bytes; /* size_t may be 64bit */
if (skip > src->bytes_in_buffer)
skip = (size_t)src->bytes_in_buffer;
src->next_input_byte += skip;
src->bytes_in_buffer -= skip;
}
}
void
fz_load_jpeg_info(fz_context *ctx, unsigned char *rbuf, int rlen, int *xp, int *yp, int *xresp, int *yresp, fz_colorspace **cspacep)
{
struct jpeg_decompress_struct cinfo;
struct jpeg_error_mgr err;
struct jpeg_source_mgr src;
fz_try(ctx)
{
cinfo.client_data = ctx;
cinfo.err = jpeg_std_error(&err);
err.error_exit = error_exit;
jpeg_create_decompress(&cinfo);
cinfo.src = &src;
src.init_source = init_source;
src.fill_input_buffer = fill_input_buffer;
src.skip_input_data = skip_input_data;
src.resync_to_restart = jpeg_resync_to_restart;
src.term_source = term_source;
src.next_input_byte = rbuf;
src.bytes_in_buffer = rlen;
jpeg_read_header(&cinfo, 1);
if (cinfo.num_components == 1)
*cspacep = fz_device_gray;
else if (cinfo.num_components == 3)
*cspacep = fz_device_rgb;
else if (cinfo.num_components == 4)
*cspacep = fz_device_cmyk;
else
fz_throw(ctx, "bad number of components in jpeg: %d", cinfo.num_components);
*xp = cinfo.image_width;
*yp = cinfo.image_height;
if (cinfo.density_unit == 1)
{
*xresp = cinfo.X_density;
*yresp = cinfo.Y_density;
}
else if (cinfo.density_unit == 2)
{
*xresp = cinfo.X_density * 254 / 100;
*yresp = cinfo.Y_density * 254 / 100;
}
else
{
*xresp = 0;
*yresp = 0;
}
if (*xresp <= 0) *xresp = 72;
if (*yresp <= 0) *yresp = 72;
}
fz_always(ctx)
{
jpeg_destroy_decompress(&cinfo);
}
fz_catch(ctx)
{
fz_rethrow(ctx);
}
}
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