unsigned scan(unsigned char *addr, size_t len, int psd_version, struct layer_info *li)
{
unsigned char *p = addr, *q;
size_t i;
int j, k;
unsigned n = 0, ps_ptr_bytes = 2 << psd_version;
struct dictentry *de;
for(i = 0; i < len;)
{
if(KEYMATCH((char*)p+i, "8BIM")){
i += 4;
// found possible layer signature
// check next 4 bytes for a known blend mode
for(de = bmdict; de->key; ++de)
if(!memcmp(de->key, (char*)p+i, 4)){
// found a possible layer blendmode signature
// try to guess number of channels
for(j = 1; j < 64; ++j){
q = p + i - 4 - j*(ps_ptr_bytes + 2) - 2;
if(peek2B(q) == j){
long t = peek4B(q-16), l = peek4B(q-12), b = peek4B(q-8), r = peek4B(q-4);
// sanity check bounding box
if(b >= t && r >= l){
// sanity check channel ids
for(k = 0; k < j; ++k){
int chid = peek2B(q + 2 + k*(ps_ptr_bytes + 2));
if(chid < -2 || chid >= j)
break; // smells bad, give up
}
if(k == j){
// channel ids were ok. could still be a valid guess...
++n;
if(li){
li->filepos = q - p - 16;
++li;
}
else
VERBOSE("scavenge @ %8td : key: %c%c%c%c could be %d channel layer: t = %ld, l = %ld, b = %ld, r = %ld\n",
q - p - 16,
de->key[0], de->key[1], de->key[2], de->key[3],
j,
t, l, b, r);
break;
}
}
}
}
break;
}
}else
++i;
}
return n;
}
static void displayinfo(int level, unsigned char data[]){
static const char *kind[] = {"ALPHACOLORSELECTED", "ALPHACOLORMASKED", "SPOTCHANNEL"};
const char *indent = tabs(level);
if(xml){
fprintf(xml, "%s<%s>\n", indent, kind[data[12]]);
colorspace(level+1, peek2B(data), data+2);
fprintf(xml, "\t%s<OPACITY>%d</OPACITY>\n", indent, peek2B(data+10));
// kind values seem to be:
// 0 = alpha channel, colour indicates selected areas
// 1 = alpha channel, colour indicates masked areas
// 2 = spot colour channel
//fprintf(xml, "\t%s<KIND>%d</KIND>\n", indent, data[12]);
fprintf(xml, "%s</%s>\n", indent, kind[data[12]]);
}
}
void scan_merged(unsigned char *addr, size_t len, struct psd_header *h)
{
size_t i, j = 0;
unsigned ps_ptr_bytes = 2 << h->version;
h->lmistart = h->lmilen = 0;
// first search for a valid image resource block (these precede layer/mask info)
for(i = 0; i < len;)
{
j = is_resource(addr, len, i);
if(j && j < len-4){
VERBOSE("scavenge: possible resource id=%d @ %lu\n", peek2B(addr+i+4), (unsigned long)i);
i = j; // found an apparently valid resource; skip over it
// is it followed by another resource?
if(memcmp("8BIM", addr+j, 4))
break; // no - stop looking
}else
++i;
}
if(!j)
alwayswarn("Did not find any plausible image resources; probably cannot locate merged image data.\n");
for(i = j; i < len; ++i)
{
psd_bytes_t lmilen = h->version == 2 ? peek8B(addr+i) : peek4B(addr+i),
layerlen = h->version == 2 ? peek8B(addr+i+ps_ptr_bytes) : peek4B(addr+i+ps_ptr_bytes);
if(lmilen > 0 && (i+lmilen) < len && layerlen == 0)
{
// sanity check compression type
int comptype = peek2Bu(addr + i + lmilen);
if(comptype == 0 || comptype == 1)
{
h->lmistart = i+ps_ptr_bytes;
h->lmilen = lmilen;
VERBOSE("scavenge: possible empty LMI @ %lld\n", h->lmistart);
UNQUIET(
"May be able to recover merged image if you can provide correct values\n\
for --mergedrows, --mergedcols, --mergedchan, --depth and --mode.\n");
break; // take first one
}
}
