1 files changed, 118 insertions, 0 deletions
diff --git a/src/decoder/OggUtil.cxx b/src/decoder/OggUtil.cxx
new file mode 100644
index 00000000..a1125a2c
--- /dev/null
+++ b/src/decoder/OggUtil.cxx
@@ -0,0 +1,118 @@
+/*
+ * Copyright (C) 2003-2012 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "OggUtil.hxx"
+#include "decoder_api.h"
+
+bool
+OggFeed(ogg_sync_state &oy, struct decoder *decoder,
+	input_stream *input_stream, size_t size)
+{
+		char *buffer = ogg_sync_buffer(&oy, size);
+		if (buffer == nullptr)
+			return false;
+
+		size_t nbytes = decoder_read(decoder, input_stream,
+					     buffer, size);
+		if (nbytes == 0)
+			return false;
+
+		ogg_sync_wrote(&oy, nbytes);
+		return true;
+}
+
+bool
+OggExpectPage(ogg_sync_state &oy, ogg_page &page,
+	      decoder *decoder, input_stream *input_stream)
+{
+	while (true) {
+		int r = ogg_sync_pageout(&oy, &page);
+		if (r != 0)
+			return r > 0;
+
+		if (!OggFeed(oy, decoder, input_stream, 1024))
+			return false;
+	}
+}
+
+bool
+OggExpectFirstPage(ogg_sync_state &oy, ogg_stream_state &os,
+		   decoder *decoder, input_stream *is)
+{
+	ogg_page page;
+	if (!OggExpectPage(oy, page, decoder, is))
+		return false;
+
+	ogg_stream_init(&os, ogg_page_serialno(&page));
+	ogg_stream_pagein(&os, &page);
+	return true;
+}
+
+bool
+OggExpectPageIn(ogg_sync_state &oy, ogg_stream_state &os,
+		decoder *decoder, input_stream *is)
+{
+	ogg_page page;
+	if (!OggExpectPage(oy, page, decoder, is))
+		return false;
+
+	ogg_stream_pagein(&os, &page);
+	return true;
+}
+
+bool
+OggExpectPageSeek(ogg_sync_state &oy, ogg_page &page,
+		  decoder *decoder, input_stream *input_stream)
+{
+	size_t remaining_skipped = 16384;
+
+	while (true) {
+		int r = ogg_sync_pageseek(&oy, &page);
+		if (r > 0)
+			return true;
+
+		if (r < 0) {
+			/* skipped -r bytes */
+			size_t nbytes = -r;
+			if (nbytes > remaining_skipped)
+				/* still no ogg page - we lost our
+				   patience, abort */
+				return false;
+
+			remaining_skipped -= nbytes;
+			continue;
+		}
+
+		if (!OggFeed(oy, decoder, input_stream, 1024))
+			return false;
+	}
+}
+
+bool
+OggExpectPageSeekIn(ogg_sync_state &oy, ogg_stream_state &os,
+		    decoder *decoder, input_stream *is)
+{
+	ogg_page page;
+	if (!OggExpectPageSeek(oy, page, decoder, is))
+		return false;
+
+	ogg_stream_pagein(&os, &page);
+	return true;
+}