+/* 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;
+}
projects / paraslash.git / commitdiff