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February 2009
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2009.02.06 14:56 "Re: assertions, and building with DEBUG/NDEBUG", by Frank Warmerdam
Joris Van Damme (AWare Systems) wrote: > Frank, folks, > > This is about http://bugzilla.maptools.org/show_bug.cgi?id=1994. I've > currently no bugzilla log-in, and/or I forgot about it, so I'll go ahead > and abuse the mailing list. Joris, I would appreciate it if you could get a bugzilla account, and be prepared to interact with bugs there. In the meantime I've appended your email to the ticket. > The thing is, since the compression tag is read in the first stage, and > flagged IGNORE, the hacky second and third stages aren't supposed to > have to deal with it. Thus, a routine like TIFFFetchNormalTag for > example, is never called for the compression tag. In TIFFFetchNormalTag() we have lots of logic like: case TIFF_SETGET_UINT16: { uint16 data; assert(fip->field_readcount==1); assert(fip->field_passcount==0); err=TIFFReadDirEntryShort(tif,dp,&data); if (err==TIFFReadDirEntryErrOk) { if (!TIFFSetField(tif,dp->tdir_tag,data)) return(0); } } break; Would it be better to change these assertions to a runtime error indicating that this tag is not suitable for processing in TIFFFetchNormalTag(), possibly indicating a corrupt file or a logic error in libtiff? This is quite a dirty file so I'm pleased to settle with reasonable error reports and recovery. I presume the "fip" description of the tag cannot be made compatible with TIFFFetchNormalTag for some reason? It does not *seem* like a particularly complicated tag to handle generically. It is currently: { TIFFTAG_COMPRESSION, -1, 1, TIFF_SHORT, 0, TIFF_SETGET_UINT16, TIFF_SETGET_UNDEFINED, FIELD_COMPRESSION, 0, 0, "Compression", NULL }, I a bit lost in aspects of this - particularly the stuff about set_field_type and get_field_type in the TIFFField structure. Actually, can't we just set the field_readcount to 1 and then this definition would work? Best regards, -- ---------------------------------------+-------------------------------------- I set the clouds in motion - turn up | Frank Warmerdam, warmerdam@pobox.com light and sound - activate the windows | http://pobox.com/~warmerdam and watch the world go round - Rush | Geospatial Programmer for Rent