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src/Source/LibTIFF4/tif_dir.c  view on Meta::CPAN

        {
		const TIFFField* fip=TIFFFieldWithTag(tif,tag);
		TIFFErrorExt(tif->tif_clientdata, module,
		     "%s: Bad value %u for \"%s\" tag",
		     tif->tif_name, v32,
		     fip ? fip->field_name : "Unknown");
		va_end(ap);
        }
	return (0);
badvaluedouble:
        {
        const TIFFField* fip=TIFFFieldWithTag(tif,tag);
        TIFFErrorExt(tif->tif_clientdata, module,
             "%s: Bad value %f for \"%s\" tag",
             tif->tif_name, dblval,
             fip ? fip->field_name : "Unknown");
        va_end(ap);
        }
    return (0);
}

/*
 * Return 1/0 according to whether or not
 * it is permissible to set the tag's value.
 * Note that we allow ImageLength to be changed
 * so that we can append and extend to images.
 * Any other tag may not be altered once writing
 * has commenced, unless its value has no effect
 * on the format of the data that is written.
 */
static int
OkToChangeTag(TIFF* tif, uint32 tag)
{
	const TIFFField* fip = TIFFFindField(tif, tag, TIFF_ANY);
	if (!fip) {			/* unknown tag */
		TIFFErrorExt(tif->tif_clientdata, "TIFFSetField", "%s: Unknown %stag %u",
		    tif->tif_name, isPseudoTag(tag) ? "pseudo-" : "", tag);
		return (0);
	}
	if (tag != TIFFTAG_IMAGELENGTH && (tif->tif_flags & TIFF_BEENWRITING) &&
	    !fip->field_oktochange) {
		/*
		 * Consult info table to see if tag can be changed
		 * after we've started writing.  We only allow changes
		 * to those tags that don't/shouldn't affect the
		 * compression and/or format of the data.
		 */
		TIFFErrorExt(tif->tif_clientdata, "TIFFSetField",
		    "%s: Cannot modify tag \"%s\" while writing",
		    tif->tif_name, fip->field_name);
		return (0);
	}
	return (1);
}

/*
 * Record the value of a field in the
 * internal directory structure.  The
 * field will be written to the file
 * when/if the directory structure is
 * updated.
 */
int
TIFFSetField(TIFF* tif, uint32 tag, ...)
{
	va_list ap;
	int status;

	va_start(ap, tag);
	status = TIFFVSetField(tif, tag, ap);
	va_end(ap);
	return (status);
}

/*
 * Clear the contents of the field in the internal structure.
 */
int
TIFFUnsetField(TIFF* tif, uint32 tag)
{
    const TIFFField *fip =  TIFFFieldWithTag(tif, tag);
    TIFFDirectory* td = &tif->tif_dir;

    if( !fip )
        return 0;

    if( fip->field_bit != FIELD_CUSTOM )
        TIFFClrFieldBit(tif, fip->field_bit);
    else
    {
        TIFFTagValue *tv = NULL;
        int i;

        for (i = 0; i < td->td_customValueCount; i++) {
                
            tv = td->td_customValues + i;
            if( tv->info->field_tag == tag )
                break;
        }

        if( i < td->td_customValueCount )
        {
            _TIFFfree(tv->value);
            for( ; i < td->td_customValueCount-1; i++) {
                td->td_customValues[i] = td->td_customValues[i+1];
            }
            td->td_customValueCount--;
        }
    }
        
    tif->tif_flags |= TIFF_DIRTYDIRECT;

    return (1);
}

/*
 * Like TIFFSetField, but taking a varargs
 * parameter list.  This routine is useful
 * for building higher-level interfaces on
 * top of the library.
 */