int pnm_validate(jas_stream_t *in)
{
uchar buf[2];
int i;
int n;
assert(JAS_STREAM_MAXPUTBACK >= 2);
/* Read the first two characters that constitute the signature. */
if ((n = jas_stream_read(in, buf, 2)) < 0) {
return -1;
}
/* Put these characters back to the stream. */
for (i = n - 1; i >= 0; --i) {
if (jas_stream_ungetc(in, buf[i]) == EOF) {
return -1;
}
}
/* Did we read enough data? */
if (n < 2) {
return -1;
}
/* Is this the correct signature for a PNM file? */
if (buf[0] == 'P' && isdigit(buf[1])) {
return 0;
}
return -1;
}
int jp2_validate(jas_stream_t *in)
{
char buf[JP2_VALIDATELEN];
int i;
int n;
#if 0
jas_stream_t *tmpstream;
jp2_box_t *box;
#endif
assert(JAS_STREAM_MAXPUTBACK >= JP2_VALIDATELEN);
/* Read the validation data (i.e., the data used for detecting
the format). */
if ((n = jas_stream_read(in, buf, JP2_VALIDATELEN)) < 0) {
return -1;
}
/* Put the validation data back onto the stream, so that the
stream position will not be changed. */
for (i = n - 1; i >= 0; --i) {
if (jas_stream_ungetc(in, buf[i]) == EOF) {
return -1;
}
}
/* Did we read enough data? */
if (n < JP2_VALIDATELEN) {
return -1;
}
/* Is the box type correct? */
if (((buf[4] << 24) | (buf[5] << 16) | (buf[6] << 8) | buf[7]) !=
JP2_BOX_JP)
{
return -1;
}
return 0;
}