zlib compression/decompression skipped on empty blocks
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 139aea9..62d8d55 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -1296,6 +1296,9 @@
 
     SSL_DEBUG_MSG( 2, ( "=> compress buf" ) );
 
+    if( len_pre == 0 )
+        return( 0 );
+
     msg_pre = (unsigned char*) malloc( len_pre );
     if( msg_pre == NULL )
     {
@@ -1347,6 +1350,9 @@
 
     SSL_DEBUG_MSG( 2, ( "=> decompress buf" ) );
 
+    if( len_pre == 0 )
+        return( 0 );
+
     msg_pre = (unsigned char*) malloc( len_pre );
     if( msg_pre == NULL )
     {