@@ -789,12 +789,14 @@
 		@throw [OFNotOpenException exceptionWithObject: self];
 
 	if (_atEndOfStream)
 		return 0;
 
-	if (sizeof(length) >= sizeof(uint64_t) && length > UINT64_MAX)
+#if SIZE_MAX >= UINT64_MAX
+	if (length > UINT64_MAX)
 		@throw [OFOutOfRangeException exception];
+#endif
 
 	if ((uint64_t)length > _toRead)
 		length = (size_t)_toRead;
 
 	ret = [_decompressedStream readIntoBuffer: buffer
@@ -848,12 +850,16 @@
 - (size_t)lowlevelWriteBuffer: (const void *)buffer
 		       length: (size_t)length
 {
 	size_t bytesWritten;
 
-	if ((sizeof(length) >= sizeof(int64_t) && length > INT64_MAX) ||
-	    INT64_MAX - _bytesWritten < (int64_t)length)
+#if SIZE_MAX >= INT64_MAX
+	if (length > INT64_MAX)
+		@throw [OFOutOfRangeException exception];
+#endif
+
+	if (INT64_MAX - _bytesWritten < (int64_t)length)
 		@throw [OFOutOfRangeException exception];
 
 	bytesWritten = [_stream writeBuffer: buffer
 				     length: length];