diff --git a/ChangeLog b/ChangeLog
index 4af54a6f0..dba84085d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2012-02-27  Richard Frith-Macdonald <rfm@gnu.org>
+
+	* Source/NSArchiver.m:
+	* Source/NSUnarchiver.m:
+	Alter to support encoding and decoding arrays with NSUInteger counts
+	(ie more than 2^32 objects if on a 64bit system).
+
 2012-02-26  Eric Wasylishen <ewasylishen@gmail.com>
 
 	* Source/NSData.m: Various 64-bit compatibility fixes, mostly changing
diff --git a/Source/NSArchiver.m b/Source/NSArchiver.m
index c2109f79a..b74a56f55 100644
--- a/Source/NSArchiver.m
+++ b/Source/NSArchiver.m
@@ -254,9 +254,9 @@ static Class	NSMutableDataMallocClass;
 			 count: (NSUInteger)count
 			    at: (const void*)buf
 {
-  unsigned      c = count;
-  unsigned	i;
-  unsigned	offset = 0;
+  NSUInteger	c = count;
+  NSUInteger	i;
+  NSUInteger	offset = 0;
   unsigned	size = objc_sizeof_type(type);
   uchar		info;
 
@@ -287,7 +287,7 @@ static Class	NSMutableDataMallocClass;
       if (_initialPass == NO)
 	{
 	  (*_tagImp)(_dst, tagSel, _GSC_ARY_B);
-	  (*_serImp)(_dst, serSel, &c, @encode(unsigned), nil);
+	  (*_serImp)(_dst, serSel, &c, @encode(NSUInteger), nil);
 	}
       for (i = 0; i < c; i++)
 	{
@@ -298,7 +298,7 @@ static Class	NSMutableDataMallocClass;
   else if (_initialPass == NO)
     {
       (*_tagImp)(_dst, tagSel, _GSC_ARY_B);
-      (*_serImp)(_dst, serSel, &c, @encode(unsigned), nil);
+      (*_serImp)(_dst, serSel, &c, @encode(NSUInteger), nil);
 
       (*_tagImp)(_dst, tagSel, info);
       for (i = 0; i < c; i++)
@@ -320,7 +320,7 @@ static Class	NSMutableDataMallocClass;
 
       case _C_ARY_B:
 	{
-	  unsigned	count = atoi(++type);
+	  NSUInteger	count = atoll(++type);
 
 	  while (isdigit(*type))
 	    {
@@ -734,9 +734,9 @@ static Class	NSMutableDataMallocClass;
 
 - (void) encodeDataObject: (NSData*)anObject
 {
-  unsigned	l = [anObject length];
+  NSUInteger	l = [anObject length];
 
-  (*_eValImp)(self, eValSel, @encode(unsigned int), &l);
+  (*_eValImp)(self, eValSel, @encode(NSUInteger), &l);
   if (l)
     {
       const void	*b = [anObject bytes];
diff --git a/Source/NSData.m b/Source/NSData.m
index 74dafaa28..166181159 100644
--- a/Source/NSData.m
+++ b/Source/NSData.m
@@ -1870,7 +1870,7 @@ failure:
 
 - (void) encodeWithCoder: (NSCoder*)aCoder
 {
-  NSUInteger	length = [self length];
+  unsigned	length = [self length];
   void		*bytes = [self mutableBytes];
 
   if ([aCoder allowsKeyedCoding])
@@ -1881,7 +1881,7 @@ failure:
     }
   else
     {  
-      [aCoder encodeValueOfObjCType: @encode(NSUInteger)
+      [aCoder encodeValueOfObjCType: @encode(unsigned)
 			         at: &length];
       if (length)
         {
@@ -1917,9 +1917,9 @@ failure:
     }
   else
     {  
-      NSUInteger  l;
+      unsigned	l;
 
-      [aCoder decodeValueOfObjCType: @encode(NSUInteger) at: &l];
+      [aCoder decodeValueOfObjCType: @encode(unsigned) at: &l];
       if (l)
         {
           void *b;
diff --git a/Source/NSUnarchiver.m b/Source/NSUnarchiver.m
index 8d213c077..78742eeca 100644
--- a/Source/NSUnarchiver.m
+++ b/Source/NSUnarchiver.m
@@ -529,14 +529,14 @@ static Class NSDataMallocClass;
 			 count: (NSUInteger)expected
 			    at: (void*)buf
 {
-  unsigned int	i;
-  int		offset = 0;
-  unsigned int	size = (unsigned int)objc_sizeof_type(type);
+  NSUInteger	i;
+  NSUInteger	offset = 0;
+  NSUInteger	size = (unsigned int)objc_sizeof_type(type);
   unsigned char	info;
-  unsigned	count;
+  NSUInteger	count;
 
   (*tagImp)(src, tagSel, &info, 0, &cursor);
-  (*desImp)(src, desSel, &count, @encode(unsigned), &cursor, nil);
+  (*desImp)(src, desSel, &count, @encode(NSUInteger), &cursor, nil);
   if (info != _GSC_ARY_B)
     {
       [NSException raise: NSInternalInconsistencyException
@@ -545,7 +545,7 @@ static Class NSDataMallocClass;
   if (count != expected)
     {
       [NSException raise: NSInternalInconsistencyException
-		  format: @"expected array count %u and got %u",
+		  format: @"expected array count %"PRIuPTR" and got %"PRIuPTR,
 			expected, count];
     }
 
@@ -1219,9 +1219,9 @@ static Class NSDataMallocClass;
 
 - (NSData*) decodeDataObject
 {
-  unsigned	l;
+  NSUInteger	l;
 
-  (*dValImp)(self, dValSel, @encode(unsigned int), &l);
+  (*dValImp)(self, dValSel, @encode(NSUInteger), &l);
   if (l)
     {
       unsigned char	c;