diff --git a/src/preserves.nim b/src/preserves.nim
index fa95064..6df4210 100644
--- a/src/preserves.nim
+++ b/src/preserves.nim
@@ -678,7 +678,7 @@ proc newBufferedDecoder*(maxSize = 4096): BufferedDecoder =
   BufferedDecoder(stream: newStringStream(), maxSize: maxSize)
 
 proc feed*(dec: var BufferedDecoder; buf: pointer; len: int) =
-  if dec.maxSize < (dec.stream.getPosition + len):
+  if dec.maxSize > 0 and dec.maxSize < (dec.stream.getPosition + len):
     raise newException(IOError, "BufferedDecoder at maximum buffer size")
   dec.stream.writeData(buf, len)