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#include "fitz.h"
#include <jpeglib.h>
#include <setjmp.h>
struct jpeg_error_mgr_jmp
{
struct jpeg_error_mgr super;
jmp_buf env;
char msg[JMSG_LENGTH_MAX];
};
static void error_exit(j_common_ptr cinfo)
{
struct jpeg_error_mgr_jmp *err = (struct jpeg_error_mgr_jmp *)cinfo->err;
cinfo->err->format_message(cinfo, err->msg);
longjmp(err->env, 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)
{
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)
{
src->next_input_byte += num_bytes;
src->bytes_in_buffer -= num_bytes;
}
}
fz_pixmap *
fz_load_jpeg(fz_context *ctx, unsigned char *rbuf, int rlen)
{
struct jpeg_decompress_struct cinfo;
struct jpeg_error_mgr_jmp err;
struct jpeg_source_mgr src;
unsigned char *row[1], *sp, *dp;
fz_colorspace *colorspace;
unsigned int x;
int k;
fz_pixmap *image = NULL;
if (setjmp(err.env))
{
if (image)
fz_drop_pixmap(ctx, image);
fz_throw(ctx, "jpeg error: %s", err.msg);
}
cinfo.err = jpeg_std_error(&err.super);
err.super.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);
jpeg_start_decompress(&cinfo);
if (cinfo.output_components == 1)
colorspace = fz_device_gray;
else if (cinfo.output_components == 3)
colorspace = fz_device_rgb;
else if (cinfo.output_components == 4)
colorspace = fz_device_cmyk;
else
fz_throw(ctx, "bad number of components in jpeg: %d", cinfo.output_components);
fz_try(ctx)
{
image = fz_new_pixmap(ctx, colorspace, cinfo.output_width, cinfo.output_height);
}
fz_catch(ctx)
{
jpeg_finish_decompress(&cinfo);
jpeg_destroy_decompress(&cinfo);
fz_throw(ctx, "out of memory");
}
if (cinfo.density_unit == 1)
{
image->xres = cinfo.X_density;
image->yres = cinfo.Y_density;
}
else if (cinfo.density_unit == 2)
{
image->xres = cinfo.X_density * 254 / 100;
image->yres = cinfo.Y_density * 254 / 100;
}
fz_clear_pixmap(ctx, image);
row[0] = fz_malloc(ctx, cinfo.output_components * cinfo.output_width);
dp = image->samples;
while (cinfo.output_scanline < cinfo.output_height)
{
jpeg_read_scanlines(&cinfo, row, 1);
sp = row[0];
for (x = 0; x < cinfo.output_width; x++)
{
for (k = 0; k < cinfo.output_components; k++)
*dp++ = *sp++;
*dp++ = 255;
}
}
fz_free(ctx, row[0]);
jpeg_finish_decompress(&cinfo);
jpeg_destroy_decompress(&cinfo);
return image;
}
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