From 2dcdfe76d02fed91b71e5b49b6028c6c82e10d4c Mon Sep 17 00:00:00 2001
From: Gabriel Garcia <garciat@live.com>
Date: Mon, 6 Apr 2015 13:59:43 -0400
Subject: [PATCH] [System] Fix DeflateStream throw on empty flush, double
 flush. Fixes #28777

diff --git a/support/zlib-helper.c b/support/zlib-helper.c
index 8345541..3869626 100644
--- a/support/zlib-helper.c
+++ b/support/zlib-helper.c
@@ -90,6 +90,8 @@ CreateZStream (gint compress, guchar gzip, read_write_func func, void *gchandle)
 	result->gchandle = gchandle;
 	result->compress = compress;
 	result->buffer = g_new (guchar, BUFFER_SIZE);
+	result->stream->next_out = result->buffer;
+	result->stream->avail_out = BUFFER_SIZE;
 	return result;
 }
 
@@ -148,7 +150,7 @@ flush_internal (ZStream *stream, gboolean is_final)
 	if (!stream->compress)
 		return 0;
 
-	if (!is_final) {
+	if (!is_final && stream->stream->avail_in != 0) {
 		status = deflate (stream->stream, Z_PARTIAL_FLUSH);
 		if (status != Z_OK && status != Z_STREAM_END)
 			return status;