Avoid useless stream buffer copying and workaround with chunk_size manipulation.

1 files changed, 3 insertions, 1 deletions

diff --git a/main/streams/streams.c b/main/streams/streams.c
index b82f092f0c..6f77b29af8 100644
--- a/main/streams/streams.c
+++ b/main/streams/streams.c
@@ -624,7 +624,9 @@ PHPAPI void _php_stream_fill_read_buffer(php_stream *stream, size_t size)
 
 			/* reduce buffer memory consumption if possible, to avoid a realloc */
 			if (stream->readbuf && stream->readbuflen - stream->writepos < stream->chunk_size) {
-				memmove(stream->readbuf, stream->readbuf + stream->readpos, stream->readbuflen - stream->readpos);
+				if (stream->writepos > stream->readpos) {
+					memmove(stream->readbuf, stream->readbuf + stream->readpos, stream->writepos - stream->readpos);
+				}
 				stream->writepos -= stream->readpos;
 				stream->readpos = 0;
 			}