2006.10.26 15:21 "[Tiff] TIFFReadPrivateDirectory function is not working for SUBIFD", by Anurag Singh

2006.10.27 06:34 "Re: [Tiff] TIFFReadPrivateDirectory function is not working for SUBIFD", by Anurag Singh

On 10/27/06, Sebastian Boehmer <sebastian.boehmer@web.de> wrote:

> Hello,

Yes that's right.

The __TIFFReadCustomDirectoryPart function reads only the tags with are "registered" in parameter TIFFFieldInfo** info[]. The parameter size_t* nfields is the size of this array.

You have to register the filed with TIFFMergeFieldInfo... Anyway is it although a question if we should read the tags which are not registered like in TIFFReadDirectory.

I think we should. I will correct this next week. So long use the TIFFMergeField function, please.

one another important issue comes, i have made one change in __TIFFReadCustomDirectoryPart for our own purpose to read subifd, it's very true that at the time of reading any SubIFD, there's no one tag is registered, because we are passing these parameters tif->tif_nPrivateFields, tif->tif_privateFieldInfo, which are initially NULL.

So each n very time tag goes to merge by using TIFFMergePrivateFieldInfo() and in turn this function make call __TIFFMergeFieldInfo(&tif->tif_nPrivateFields,&tif->tif_privateFieldInfo,n,info,1), after merging 2-3 times, i got HEAP error in this funtion, and reason of it, mergedIndices is currupted.

i want explain it, we are merging one tag each n every time, so here n=1 and info have one tag only.

I think problem is here. this is the code of function __TIFFMergeFieldInfo

if ( support ) {

mergedIndices = _TIFFmalloc(n*sizeof(int));


if (*nfields > 0) {
if ( support ) {


* Merge only not already existing tags. Asume unsorted TIFFFieldInfo array.


for (fi=0; fi < *nfields; ++fi) {

     for (i =0; i < n; ++i)

        if (info_new[i].field_tag == (*info)[fi]->field_tag)


    if ( i >= n ) { // entry not found

    mergedIndices[nn] = i; // remember index




if ( nn == 0 ) goto end; // no new entries;

n = nn;


we are allocationg memory to mergedIndices of size n, mean in the SubIFD's case 1 and adding more than value, here is some logical error for tha case when only one tag is merged in a group.

Please have a look on this problem.