optimize code

Author: NathanFreeman

ext/mbstring/libmbfl/mbfl/mbfilter.c

@@ -1096,9 +1096,8 @@ mbfl_strcut(
 	} else {
 		mbfl_convert_filter *encoder     = NULL;
 		mbfl_convert_filter *decoder     = NULL;
+		int mode_backup;
 		const unsigned char *p, *q, *r;
-		size_t position = 0;
-		unsigned char illegal_substchar;
 		struct {
 			mbfl_convert_filter encoder;
 			mbfl_convert_filter decoder;
@@ -1114,6 +1113,8 @@ mbfl_strcut(
 			return NULL;
 		}
 
+		mode_backup = decoder->illegal_mode;
+
 		/* wchar filter */
 		if (!(encoder = mbfl_convert_filter_new(
 				string->encoding,
@@ -1278,19 +1279,9 @@ mbfl_strcut(
 			bk = _bk;
 		}
 
-		position = device.pos;
+		decoder->illegal_mode = MBFL_OUTPUTFILTER_ILLEGAL_MODE_NONE;
 		(*encoder->filter_flush)(encoder);
-
-		if ((encoder->status && ((encoder->status & 0xF) || (encoder->status == 0x11))) || encoder->cache) {
-			illegal_substchar = (unsigned char) encoder->illegal_substchar;
-			while(device.pos > position) {
-				/* check illegal output */
-				if (device.buffer[position++] == illegal_substchar) {
-					device.pos = position - 1;
-					break;
-				}
-			}
-		}
+		decoder->illegal_mode = mode_backup;
 
 		if (bk.decoder.filter_dtor)
 			bk.decoder.filter_dtor(&bk.decoder);