/*
* Helper routine to bridge to packJPG C++ lib, without changing packJPG itself.
*/
size_t
packjpg_filter_process(uchar_t *in_buf, size_t len, uchar_t **out_buf)
{
unsigned int len1;
uchar_t *pos;
/*
* Workaround for packJPG limitation, not a bug per se. Images created with
* Polaroid cameras appear to have some weird huffman data in the middle which
* appears not to be interpreted by any image viewer/editor. This data gets
* stripped by packJPG.
* So the restored images will be visually correct, but, will be smaller than the
* original. So we need to look at the Exif Manufacturer tag for 'Polaroid' and
* skip those images. This should be within the first 512 bytes of the
* file (really...?) so we do a simple buffer scan without trying to parse Exif
* data.
*/
pos = (uchar_t *)memchr(in_buf, 'P', 512);
while (pos) {
if (LE64(U64_P(pos)) == POLAROID_LE)
return (0);
pos++;
pos = (uchar_t *)memchr(pos, 'P', 512);
}
pjglib_init_streams(in_buf, 1, len, *out_buf, 1);
len1 = len;
if (!pjglib_convert_stream2mem(out_buf, &len1, NULL))
return (0);
if (len1 == len)
return (0);
return (len1);
}
int
zero_rle_encode(const void *ibuf, const unsigned int ilen,
void *obuf, unsigned int *olen)
{
unsigned int pos1, pos2, sz;
unsigned short count;
const uchar_t *ib = (const uchar_t *)ibuf;
uchar_t *ob = (uchar_t *)obuf;
uint64_t val;
sz = sizeof (val) - 1;
pos2 = 0;
for (pos1=0; pos1<ilen && pos2<*olen;) {
count = 0;
if (ib[pos1] == 0) {
/*
* We have a run of zeroes. Count them and store only the count.
*/
while (pos1 < (ilen - sz) && count < (COUNT_MAX - sz)) {
val = U64_P(ib+pos1);
if (val) break;
pos1 += sizeof (val); count += sizeof (val);
}
for (;pos1<ilen && ib[pos1]==0 && count<COUNT_MAX; pos1++) ++count;
count |= ZERO_MASK;
U16_P(ob + pos2) = htons(count);
pos2 += 2;
if (pos2 > *olen) break;
} else {
unsigned int pos3, pos4, state;
pos3 = pos2;
pos2 += 2;
if (pos2 > *olen) break;
state = 0;
for (;pos1<ilen && pos2<*olen && count<COUNT_MAX;) {
if (ib[pos1] != 0) state = 0;
if (ib[pos1] == 0 && !state) {
state = 1;
// Lookahead if there are at least 4 consecutive zeroes
if (ilen > 3) {
pos4 = *((unsigned int *)(ib+pos1));
if (!pos4) break;
}
}
ob[pos2++] = ib[pos1++];
++count;
}
U16_P(ob + pos3) = htons(count);
}
}
*olen = pos2;
if (pos1 < ilen) {
return (-1);
} else {
return (0);
}
}
