diff --git a/ChangeLog b/ChangeLog
index 42382e7e..f8127807 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2009-02-05  Frank Warmerdam  <warmerdam@pobox.com>
+
+	* libtiff/tif_dirread.c: Fixed testing for failed result from
+	TIFFReadDirectoryFindFieldInfo().
+	http://bugzilla.maptools.org/show_bug.cgi?id=1992
+
 2009-01-23  Frank Warmerdam  <warmerdam@pobox.com>
 
 	* libtiff/tif_predict.c: Add support for 32bit integer horz. predictors.
diff --git a/libtiff/tif_dirread.c b/libtiff/tif_dirread.c
index 230321d0..13bf0fe2 100644
--- a/libtiff/tif_dirread.c
+++ b/libtiff/tif_dirread.c
@@ -1,4 +1,4 @@
-/* $Id: tif_dirread.c,v 1.148 2009-01-22 19:06:49 fwarmerdam Exp $ */
+/* $Id: tif_dirread.c,v 1.149 2009-02-05 16:07:59 fwarmerdam Exp $ */
 
 /*
  * Copyright (c) 1988-1997 Sam Leffler
@@ -42,6 +42,7 @@
 #include "tiffiop.h"
 
 #define IGNORE 0          /* tag placeholder used below */
+#define FAILED_FII    ((uint32) -1)
 
 #ifdef HAVE_IEEEFP
 # define TIFFCvtIEEEFloatToNative(tif, n, fp)
@@ -3483,7 +3484,7 @@ TIFFReadDirectory(TIFF* tif)
 		if (dp->tdir_tag!=IGNORE)
 		{
 			TIFFReadDirectoryFindFieldInfo(tif,dp->tdir_tag,&fii);
-			if (fii==(uint32)(-1))
+			if (fii == FAILED_FII)
 			{
 				TIFFWarningExt(tif->tif_clientdata, module,
 				    "Unknown field with tag %d (0x%x) encountered",
@@ -3503,7 +3504,7 @@ TIFFReadDirectory(TIFF* tif)
 					dp->tdir_tag=IGNORE;
 				} else {
 					TIFFReadDirectoryFindFieldInfo(tif,dp->tdir_tag,&fii);
-					assert(fii!=(uint32)(-1));
+					assert(fii != FAILED_FII);
 				}
 			}
 		}
@@ -4021,7 +4022,7 @@ TIFFReadDirectoryFindFieldInfo(TIFF* tif, uint16 tagid, uint32* fii)
 	{
 		if (ma+1==mc)
 		{
-			*fii=(uint32)(-1);
+			*fii = FAILED_FII;
 			return;
 		}
 		mb=(ma+mc)/2;
@@ -4072,7 +4073,7 @@ TIFFReadCustomDirectory(TIFF* tif, toff_t diroff,
 	for (di=0, dp=dir; di<dircount; di++, dp++)
 	{
 		TIFFReadDirectoryFindFieldInfo(tif,dp->tdir_tag,&fii);
-		if (fii==0xFFFF)
+		if (fii == FAILED_FII)
 		{
 			TIFFWarningExt(tif->tif_clientdata, module,
 			    "Unknown field with tag %d (0x%x) encountered",
@@ -4087,7 +4088,7 @@ TIFFReadCustomDirectory(TIFF* tif, toff_t diroff,
 				dp->tdir_tag=IGNORE;
 			} else {
 				TIFFReadDirectoryFindFieldInfo(tif,dp->tdir_tag,&fii);
-				assert(fii!=0xFFFF);
+				assert( fii != FAILED_FII );
 			}
 		}
 		if (dp->tdir_tag!=IGNORE)
@@ -4580,8 +4581,8 @@ TIFFFetchNormalTag(TIFF* tif, TIFFDirEntry* dp, int recover)
 	uint32 fii;
 	const TIFFField* fip;
 	TIFFReadDirectoryFindFieldInfo(tif,dp->tdir_tag,&fii);
-	assert(fii!=0xFFFFFFFF);
-        if( fii == 0xFFFFFFFF )
+	assert(fii != FAILED_FII);
+        if( fii == FAILED_FII )
         {
             TIFFErrorExt(tif->tif_clientdata, "TIFFFetchNormalTag",
                          "No definition found for tag %d",