handle invalid xing tags better.

src/inputPlugins/mp3_plugin.c

@@ -648,22 +648,9 @@ static int decodeFirstFrame(mp3DecodeData * data, DecoderControl * dc,
 	ptr = data->stream.anc_ptr;
 	bitlen = data->stream.anc_bitlen;
 
-	if (parse_xing(&xing, &ptr, &bitlen)) {
-		data->foundXing = 1;
-		data->muteFrame = MUTEFRAME_SKIP;
-
-		if (parse_lame(&lame, &ptr, &bitlen)) {
-			data->dropSamplesAtStart = lame.encoderDelay + DECODERDELAY;
-			data->dropSamplesAtEnd = lame.encoderPadding;
-		}
-
-		if (xing.flags & XING_FRAMES) {
-			mad_timer_t duration = data->frame.header.duration;
-			mad_timer_multiply(&duration, xing.frames);
-			data->totalTime = ((float)mad_timer_count(duration, MAD_UNITS_MILLISECONDS)) / 1000;
-			data->maxFrames = xing.frames;
-		}
-	} else {
+	/*
+	 * Attempt to calulcate the length of the song from filesize
+	 */
 	size_t offset = data->inStream->offset;
 	mad_timer_t duration = data->frame.header.duration;
 	float frameTime = ((float)mad_timer_count(duration, MAD_UNITS_MILLISECONDS)) / 1000;
@@ -680,8 +667,29 @@ static int decodeFirstFrame(mp3DecodeData * data, DecoderControl * dc,
 		data->maxFrames = FRAMES_CUSHION;
 		data->totalTime = 0;
 	}
+
+	/*
+	 * if an xing tag exists, use that!
+	 */
+	if (parse_xing(&xing, &ptr, &bitlen)) {
+		data->foundXing = 1;
+		data->muteFrame = MUTEFRAME_SKIP;
+
+		if (parse_lame(&lame, &ptr, &bitlen)) {
+			data->dropSamplesAtStart = lame.encoderDelay + DECODERDELAY;
+			data->dropSamplesAtEnd = lame.encoderPadding;
 		}
 
+		if ((xing.flags & XING_FRAMES) && xing.frames) {
+			mad_timer_t duration = data->frame.header.duration;
+			mad_timer_multiply(&duration, xing.frames);
+			data->totalTime = ((float)mad_timer_count(duration, MAD_UNITS_MILLISECONDS)) / 1000;
+			data->maxFrames = xing.frames;
+		}
+	} 
+
+	if (!data->maxFrames) return -1;
+
 	data->frameOffset = xmalloc(sizeof(long) * data->maxFrames);
 	data->times = xmalloc(sizeof(mad_timer_t) * data->maxFrames);