X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=opus_common.c;h=927df1f3c2f881fb036b13df50fbd49b43ec568d;hp=e69de29bb2d1d6434b8b29ae775ad8c2e48c5391;hb=465f84546f810776ea6c4bd06fec34ff8452e933;hpb=8bcf75a3921d15e03c4351b3efa609eac67c3817

diff --git a/opus_common.c b/opus_common.c
index e69de29b..927df1f3 100644
--- a/opus_common.c
+++ b/opus_common.c
@@ -0,0 +1,169 @@
+/* Copyright (C)2012 Xiph.Org Foundation
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/**
+ * \file opus_common.c Common functions of the opus decoder and audio format
+ * handler.
+ */
+
+#include <ogg/ogg.h>
+
+#include "para.h"
+#include "error.h"
+#include "opus_common.h"
+#include "portable_io.h"
+
+struct packet {
+	const char *data;
+	int maxlen;
+	int pos;
+};
+
+static int read_chars(struct packet *p, unsigned char *str, int nb_chars)
+{
+	int i;
+
+	if (p->pos > p->maxlen - nb_chars)
+		return 0;
+	for (i = 0; i < nb_chars; i++)
+		str[i] = p->data[p->pos++];
+	return 1;
+}
+
+static int read_uint32(struct packet *p, ogg_uint32_t *val)
+{
+	if (p->pos > p->maxlen - 4)
+		return 0;
+	*val = read_u32(p->data + p->pos);
+	p->pos += 4;
+	return 1;
+}
+
+static int read_uint16(struct packet *p, ogg_uint16_t *val)
+{
+	if (p->pos > p->maxlen - 2)
+		return 0;
+	*val = read_u16(p->data + p->pos);
+	p->pos += 2;
+	return 1;
+}
+
+/**
+ * Get metadata of an opus stream.
+ *
+ * This is called from both the audio format handler (which passes ogg packet
+ * 0) and from the decoder.
+ *
+ * \param packet Start of the packet.
+ * \param len Number of bytes.
+ * \param h Result.
+ *
+ * \return Standard.
+ */
+int opus_parse_header(const char *packet, int len, struct opus_header *h)
+{
+	int i;
+	char str[9];
+	struct packet p;
+	unsigned char ch, channel_mapping;
+	ogg_uint16_t shortval;
+
+	p.data = packet;
+	p.maxlen = len;
+	p.pos = 0;
+	str[8] = 0;
+	if (len < 19)
+		return -E_OPUS_HEADER;
+	read_chars(&p, (unsigned char*)str, 8);
+	if (memcmp(str, "OpusHead", 8) != 0)
+		return -E_OPUS_HEADER;
+
+	if (!read_chars(&p, &ch, 1))
+		return -E_OPUS_HEADER;
+	h->version = ch;
+	if((h->version & 240) != 0) /* Only major version 0 supported. */
+		return -E_OPUS_HEADER;
+
+	if (!read_chars(&p, &ch, 1))
+		return -E_OPUS_HEADER;
+	h->channels = ch;
+	if (h->channels == 0)
+		return -E_OPUS_HEADER;
+
+	if (!read_uint16(&p, &shortval))
+		return -E_OPUS_HEADER;
+	h->preskip = shortval;
+
+	if (!read_uint32(&p, &h->input_sample_rate))
+		return -E_OPUS_HEADER;
+
+	if (!read_uint16(&p, &shortval))
+		return -E_OPUS_HEADER;
+	h->gain = (short)shortval;
+
+	if (!read_chars(&p, &ch, 1))
+		return -E_OPUS_HEADER;
+	channel_mapping = ch;
+
+	if (channel_mapping != 0) {
+		if (!read_chars(&p, &ch, 1))
+			return -E_OPUS_HEADER;
+
+		if (ch < 1)
+			return -E_OPUS_HEADER;
+		h->nb_streams = ch;
+
+		if (!read_chars(&p, &ch, 1))
+			return -E_OPUS_HEADER;
+
+		if (ch > h->nb_streams || (ch + h->nb_streams) > 255)
+			return -E_OPUS_HEADER;
+		h->nb_coupled = ch;
+
+		/* Multi-stream support */
+		for (i = 0; i < h->channels; i++) {
+			if (!read_chars(&p, &h->stream_map[i], 1))
+				return -E_OPUS_HEADER;
+			if (h->stream_map[i] > (h->nb_streams + h->nb_coupled)
+					&& h->stream_map[i] != 255)
+				return -E_OPUS_HEADER;
+		}
+	} else {
+		if (h->channels > 2)
+			return -E_OPUS_HEADER;
+		h->nb_streams = 1;
+		h->nb_coupled = h->channels > 1;
+		h->stream_map[0] = 0;
+		h->stream_map[1] = 1;
+	}
+	/*
+	 * For version 0/1 we know there won't be any more data so reject any
+	 * that have data past the end.
+	 */
+	if ((h->version == 0 || h->version == 1) && p.pos != len)
+		return -E_OPUS_HEADER;
+	return 1;
+}