static int
scan_file (ximage_info *info, FILE *fp)
{
int error = 0, have_jp2h = 0;
long size;
unsigned long len, lbox, tbox;
size = file_size(fp);
/* Should have already been checked before. */
/* JPEG 2000 Singature box */
if (!check_jp___box(fp))
return -1;
size -= 12;
/* File Type box shall immediately follow */
len = read_box_hdr(fp, &lbox, &tbox);
if (tbox != JP2_BOX_FTYP)
return -1;
if (!check_ftyp_data(fp, lbox - len))
return -1;
size -= lbox;
/* Search for JP2 Header box */
while (size > 0 && !error) {
len = read_box_hdr(fp, &lbox, &tbox);
if (lbox == 0)
lbox = size;
switch (tbox) {
case JP2_BOX_JP2H:
error = scan_jp2h(info, fp, lbox - len);
have_jp2h = 1;
break;
case JP2_BOX_JP2C:
/* JP2 requires JP2H appears before JP2C. */
if (!have_jp2h)
WARN("JPEG 2000 Codestream box found before JP2 Header box.");
seek_relative(fp, lbox - len);
break;
default:
seek_relative(fp, lbox - len);
}
size -= lbox;
}
/* From ISO/IEC 15444-2 M.9.2.7
The JP2 Header box shall be found in the file before the first
Contiguous Codestream box, Fragment Table box, Media Data box,
Codestream Header box, and Compositing Layer Header box. ...
*/
if (!have_jp2h && !error) {
WARN("No JP2 Header box found. Not a JP2/JPX baseline file?");
error = -1;
}
return error;
}
static int
scan_res_ (ximage_info *info, FILE *fp, unsigned long size)
{
unsigned long len, lbox, tbox;
int have_resd = 0;
while (size > 0) {
len = read_box_hdr(fp, &lbox, &tbox);
if (lbox == 0) {
WARN("Unexpected lbox value 0 in JP2 Resolution box.");
break;
}
switch (tbox) {
case JP2_BOX_RESC:
if (!have_resd) {
read_res__data(info, fp, lbox - len);
} else {
seek_relative(fp, lbox - len);
}
break;
case JP2_BOX_RESD:
read_res__data(info, fp, lbox - len);
have_resd = 1;
break;
default:
WARN("Unknown JPEG 2000 box type in Resolution box.");
seek_relative(fp, lbox - len);
}
size -= lbox;
}
return size == 0 ? 0 : -1;
}
static int
scan_jp2h (ximage_info *info, int *smask, FILE *fp, unsigned int size)
{
int error = 0, have_ihdr = 0;
unsigned int len, lbox, tbox;
while (size > 0 && !error) {
len = read_box_hdr(fp, &lbox, &tbox);
if (lbox == 0) {
WARN("JPEG2000: Unexpected lbox value 0 in JP2 Header box...");
error = -1;
break;
}
switch (tbox) {
case JP2_BOX_IHDR:
info->height = get_unsigned_quad(fp);
info->width = get_unsigned_quad(fp);
info->num_components = get_unsigned_pair(fp);
/* c = */ get_unsigned_byte(fp); /* BPC - 1 */
/* c = */ get_unsigned_byte(fp); /* C: Compression type */
/* c = */ get_unsigned_byte(fp); /* UnkC */
/* c = */ get_unsigned_byte(fp); /* IPR */
have_ihdr = 1;
break;
case JP2_BOX_RES_:
error = scan_res_(info, fp, lbox - len);
break;
case JP2_BOX_CDEF:
error = scan_cdef(info, smask, fp, lbox - len);
break;
case JP2_BOX_BPCC: case JP2_BOX_COLR: case JP2_BOX_PCLR:
case JP2_BOX_CMAP:
case JPX_BOX_LBL_:
seek_relative(fp, lbox - len);
break;
default:
WARN("JPEG2000: Unknown JPEG 2000 box in JP2 Header box.");
seek_relative(fp, lbox - len);
error = -1;
}
size -= lbox;
}
if (!have_ihdr)
WARN("JPEG2000: Expecting JPEG 2000 Image Header box but could not find.");
return (!error && have_ihdr && size == 0) ? 0 : -1;
}
int
check_for_jp2 (FILE *fp)
{
unsigned long len, lbox, tbox;
if (!fp)
return 0;
rewind(fp);
/* JPEG 2000 Singature box */
if (!check_jp___box(fp))
return 0;
/* File Type box shall immediately follow */
len = read_box_hdr(fp, &lbox, &tbox);
if (tbox != JP2_BOX_FTYP)
return 0;
if (!check_ftyp_data(fp, lbox - len))
return 0;
return 1;
}
