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#include "mupdf/fitz.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, FZ_ERROR_GENERIC, "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;
}
}
static inline int read_value(const unsigned char *data, int bytes, int is_big_endian)
{
int value = 0;
if (!is_big_endian)
data += bytes;
for (; bytes > 0; bytes--)
value = (value << 8) | (is_big_endian ? *data++ : *--data);
return value;
}
static int extract_exif_resolution(jpeg_saved_marker_ptr marker, int *xres, int *yres)
{
int is_big_endian;
const unsigned char *data;
unsigned int offset, ifd_len, res_type = 0;
float x_res = 0, y_res = 0;
if (!marker || marker->marker != JPEG_APP0 + 1 || marker->data_length < 14)
return 0;
data = (const unsigned char *)marker->data;
if (read_value(data, 4, 1) != 0x45786966 /* Exif */ || read_value(data + 4, 2, 1) != 0x0000)
return 0;
if (read_value(data + 6, 4, 1) == 0x49492A00)
is_big_endian = 0;
else if (read_value(data + 6, 4, 1) == 0x4D4D002A)
is_big_endian = 1;
else
return 0;
offset = read_value(data + 10, 4, is_big_endian) + 6;
if (offset < 14 || offset + 2 > marker->data_length)
return 0;
ifd_len = read_value(data + offset, 2, is_big_endian);
for (offset += 2; ifd_len > 0 && offset + 12 < marker->data_length; ifd_len--, offset += 12)
{
int tag = read_value(data + offset, 2, is_big_endian);
int type = read_value(data + offset + 2, 2, is_big_endian);
int count = read_value(data + offset + 4, 4, is_big_endian);
unsigned int value_off = read_value(data + offset + 8, 4, is_big_endian) + 6;
switch (tag)
{
case 0x11A:
if (type == 5 && value_off > offset && value_off + 8 <= marker->data_length)
x_res = 1.0f * read_value(data + value_off, 4, is_big_endian) / read_value(data + value_off + 4, 4, is_big_endian);
break;
case 0x11B:
if (type == 5 && value_off > offset && value_off + 8 <= marker->data_length)
y_res = 1.0f * read_value(data + value_off, 4, is_big_endian) / read_value(data + value_off + 4, 4, is_big_endian);
break;
case 0x128:
if (type == 3 && count == 1)
res_type = read_value(data + offset + 8, 2, is_big_endian);
break;
}
}
if (x_res <= 0 || x_res > INT_MAX || y_res <= 0 || y_res > INT_MAX)
return 0;
if (res_type == 2)
{
*xres = (int)x_res;
*yres = (int)y_res;
}
else if (res_type == 3)
{
*xres = (int)(x_res * 254 / 100);
*yres = (int)(y_res * 254 / 100);
}
return 1;
}
static int extract_app13_resolution(jpeg_saved_marker_ptr marker, int *xres, int *yres)
{
const unsigned char *data, *data_end;
if (!marker || marker->marker != JPEG_APP0 + 13 || marker->data_length < 42 ||
strcmp((const char *)marker->data, "Photoshop 3.0") != 0)
{
return 0;
}
data = (const unsigned char *)marker->data;
data_end = data + marker->data_length;
for (data += 14; data + 12 < data_end; ) {
int data_size = -1;
int tag = read_value(data + 4, 2, 1);
int value_off = 11 + read_value(data + 6, 2, 1);
if (value_off % 2 == 1)
value_off++;
if (read_value(data, 4, 1) == 0x3842494D /* 8BIM */ && data + value_off <= data_end)
data_size = read_value(data + value_off - 4, 4, 1);
if (data_size < 0 || data + value_off + data_size > data_end)
return 0;
if (tag == 0x3ED && data_size == 16)
{
*xres = read_value(data + value_off, 2, 1);
*yres = read_value(data + value_off + 8, 2, 1);
return 1;
}
if (data_size % 2 == 1)
data_size++;
data += value_off + data_size;
}
return 0;
}
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_save_markers(&cinfo, JPEG_APP0+1, 0xffff);
jpeg_save_markers(&cinfo, JPEG_APP0+13, 0xffff);
jpeg_read_header(&cinfo, 1);
if (cinfo.num_components == 1)
*cspacep = fz_device_gray(ctx);
else if (cinfo.num_components == 3)
*cspacep = fz_device_rgb(ctx);
else if (cinfo.num_components == 4)
*cspacep = fz_device_cmyk(ctx);
else
fz_throw(ctx, FZ_ERROR_GENERIC, "bad number of components in jpeg: %d", cinfo.num_components);
*xp = cinfo.image_width;
*yp = cinfo.image_height;
if (extract_exif_resolution(cinfo.marker_list, xresp, yresp))
/* XPS prefers EXIF resolution to JFIF density */;
else if (extract_app13_resolution(cinfo.marker_list, xresp, yresp))
/* XPS prefers APP13 resolution to JFIF density */;
else 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 = 96;
if (*yresp <= 0) *yresp = 96;
}
fz_always(ctx)
{
jpeg_destroy_decompress(&cinfo);
}
fz_catch(ctx)
{
fz_rethrow(ctx);
}
}
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