/*
  * Copyright (c) 2012 Andrew D'Addesio
  * Copyright (c) 2013-2014 Mozilla Corporation
  *

  * This file is part of FFmpeg.

  *

  * FFmpeg is free software; you can redistribute it and/or

  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *

  * FFmpeg 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
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public

  * License along with FFmpeg; if not, write to the Free Software

  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 /**
  * @file
  * Opus decoder/parser shared code
  */
 
 #include <stdint.h>
 
 #include "libavutil/error.h"

 #include "libavutil/ffmath.h"

 
 #include "opus.h"
 #include "vorbis.h"
 
 static const uint16_t opus_frame_duration[32] = {
     480, 960, 1920, 2880,
     480, 960, 1920, 2880,
     480, 960, 1920, 2880,
     480, 960,
     480, 960,
     120, 240,  480,  960,
     120, 240,  480,  960,
     120, 240,  480,  960,
     120, 240,  480,  960,
 };
 
 /**
  * Read a 1- or 2-byte frame length
  */
 static inline int xiph_lacing_16bit(const uint8_t **ptr, const uint8_t *end)
 {
     int val;
 
     if (*ptr >= end)
         return AVERROR_INVALIDDATA;
     val = *(*ptr)++;
     if (val >= 252) {
         if (*ptr >= end)
             return AVERROR_INVALIDDATA;
         val += 4 * *(*ptr)++;
     }
     return val;
 }
 
 /**
  * Read a multi-byte length (used for code 3 packet padding size)
  */
 static inline int xiph_lacing_full(const uint8_t **ptr, const uint8_t *end)
 {
     int val = 0;
     int next;
 
     while (1) {
         if (*ptr >= end || val > INT_MAX - 254)
             return AVERROR_INVALIDDATA;
         next = *(*ptr)++;
         val += next;
         if (next < 255)
             break;
         else
             val--;
     }
     return val;
 }
 
 /**
  * Parse Opus packet info from raw packet data
  */
 int ff_opus_parse_packet(OpusPacket *pkt, const uint8_t *buf, int buf_size,
                          int self_delimiting)
 {
     const uint8_t *ptr = buf;
     const uint8_t *end = buf + buf_size;
     int padding = 0;
     int frame_bytes, i;
 
     if (buf_size < 1)
         goto fail;
 
     /* TOC byte */
     i = *ptr++;
     pkt->code   = (i     ) & 0x3;
     pkt->stereo = (i >> 2) & 0x1;
     pkt->config = (i >> 3) & 0x1F;
 
     /* code 2 and code 3 packets have at least 1 byte after the TOC */
     if (pkt->code >= 2 && buf_size < 2)
         goto fail;
 
     switch (pkt->code) {
     case 0:
         /* 1 frame */
         pkt->frame_count = 1;
         pkt->vbr         = 0;
 
         if (self_delimiting) {
             int len = xiph_lacing_16bit(&ptr, end);
             if (len < 0 || len > end - ptr)
                 goto fail;
             end      = ptr + len;
             buf_size = end - buf;
         }
 
         frame_bytes = end - ptr;
         if (frame_bytes > MAX_FRAME_SIZE)
             goto fail;
         pkt->frame_offset[0] = ptr - buf;
         pkt->frame_size[0]   = frame_bytes;
         break;
     case 1:
         /* 2 frames, equal size */
         pkt->frame_count = 2;
         pkt->vbr         = 0;
 
         if (self_delimiting) {
             int len = xiph_lacing_16bit(&ptr, end);
             if (len < 0 || 2 * len > end - ptr)
                 goto fail;
             end      = ptr + 2 * len;
             buf_size = end - buf;
         }
 
         frame_bytes = end - ptr;
         if (frame_bytes & 1 || frame_bytes >> 1 > MAX_FRAME_SIZE)
             goto fail;
         pkt->frame_offset[0] = ptr - buf;
         pkt->frame_size[0]   = frame_bytes >> 1;
         pkt->frame_offset[1] = pkt->frame_offset[0] + pkt->frame_size[0];
         pkt->frame_size[1]   = frame_bytes >> 1;
         break;
     case 2:
         /* 2 frames, different sizes */
         pkt->frame_count = 2;
         pkt->vbr         = 1;
 
         /* read 1st frame size */
         frame_bytes = xiph_lacing_16bit(&ptr, end);
         if (frame_bytes < 0)
             goto fail;
 
         if (self_delimiting) {
             int len = xiph_lacing_16bit(&ptr, end);
             if (len < 0 || len + frame_bytes > end - ptr)
                 goto fail;
             end      = ptr + frame_bytes + len;
             buf_size = end - buf;
         }
 
         pkt->frame_offset[0] = ptr - buf;
         pkt->frame_size[0]   = frame_bytes;
 
         /* calculate 2nd frame size */
         frame_bytes = end - ptr - pkt->frame_size[0];
         if (frame_bytes < 0 || frame_bytes > MAX_FRAME_SIZE)
             goto fail;
         pkt->frame_offset[1] = pkt->frame_offset[0] + pkt->frame_size[0];
         pkt->frame_size[1]   = frame_bytes;
         break;
     case 3:
         /* 1 to 48 frames, can be different sizes */
         i = *ptr++;
         pkt->frame_count = (i     ) & 0x3F;
         padding          = (i >> 6) & 0x01;
         pkt->vbr         = (i >> 7) & 0x01;
 
         if (pkt->frame_count == 0 || pkt->frame_count > MAX_FRAMES)
             goto fail;
 
         /* read padding size */
         if (padding) {
             padding = xiph_lacing_full(&ptr, end);
             if (padding < 0)
                 goto fail;
         }
 
         /* read frame sizes */
         if (pkt->vbr) {
             /* for VBR, all frames except the final one have their size coded
                in the bitstream. the last frame size is implicit. */
             int total_bytes = 0;
             for (i = 0; i < pkt->frame_count - 1; i++) {
                 frame_bytes = xiph_lacing_16bit(&ptr, end);
                 if (frame_bytes < 0)
                     goto fail;
                 pkt->frame_size[i] = frame_bytes;
                 total_bytes += frame_bytes;
             }
 
             if (self_delimiting) {
                 int len = xiph_lacing_16bit(&ptr, end);
                 if (len < 0 || len + total_bytes + padding > end - ptr)
                     goto fail;
                 end      = ptr + total_bytes + len + padding;
                 buf_size = end - buf;
             }
 
             frame_bytes = end - ptr - padding;
             if (total_bytes > frame_bytes)
                 goto fail;
             pkt->frame_offset[0] = ptr - buf;
             for (i = 1; i < pkt->frame_count; i++)
                 pkt->frame_offset[i] = pkt->frame_offset[i-1] + pkt->frame_size[i-1];
             pkt->frame_size[pkt->frame_count-1] = frame_bytes - total_bytes;
         } else {
             /* for CBR, the remaining packet bytes are divided evenly between
                the frames */
             if (self_delimiting) {
                 frame_bytes = xiph_lacing_16bit(&ptr, end);
                 if (frame_bytes < 0 || pkt->frame_count * frame_bytes + padding > end - ptr)
                     goto fail;
                 end      = ptr + pkt->frame_count * frame_bytes + padding;
                 buf_size = end - buf;
             } else {
                 frame_bytes = end - ptr - padding;
                 if (frame_bytes % pkt->frame_count ||
                     frame_bytes / pkt->frame_count > MAX_FRAME_SIZE)
                     goto fail;
                 frame_bytes /= pkt->frame_count;
             }
 
             pkt->frame_offset[0] = ptr - buf;
             pkt->frame_size[0]   = frame_bytes;
             for (i = 1; i < pkt->frame_count; i++) {
                 pkt->frame_offset[i] = pkt->frame_offset[i-1] + pkt->frame_size[i-1];
                 pkt->frame_size[i]   = frame_bytes;
             }
         }
     }
 
     pkt->packet_size = buf_size;
     pkt->data_size   = pkt->packet_size - padding;
 
     /* total packet duration cannot be larger than 120ms */
     pkt->frame_duration = opus_frame_duration[pkt->config];
     if (pkt->frame_duration * pkt->frame_count > MAX_PACKET_DUR)
         goto fail;
 
     /* set mode and bandwidth */
     if (pkt->config < 12) {
         pkt->mode = OPUS_MODE_SILK;
         pkt->bandwidth = pkt->config >> 2;
     } else if (pkt->config < 16) {
         pkt->mode = OPUS_MODE_HYBRID;
         pkt->bandwidth = OPUS_BANDWIDTH_SUPERWIDEBAND + (pkt->config >= 14);
     } else {
         pkt->mode = OPUS_MODE_CELT;
         pkt->bandwidth = (pkt->config - 16) >> 2;

         /* skip medium band */

         if (pkt->bandwidth)
             pkt->bandwidth++;
     }
 
     return 0;
 
 fail:
     memset(pkt, 0, sizeof(*pkt));
     return AVERROR_INVALIDDATA;
 }
 
 static int channel_reorder_vorbis(int nb_channels, int channel_idx)
 {
     return ff_vorbis_channel_layout_offsets[nb_channels - 1][channel_idx];
 }
 
 static int channel_reorder_unknown(int nb_channels, int channel_idx)
 {
     return channel_idx;
 }
 
 av_cold int ff_opus_parse_extradata(AVCodecContext *avctx,
                                     OpusContext *s)
 {
     static const uint8_t default_channel_map[2] = { 0, 1 };
 
     int (*channel_reorder)(int, int) = channel_reorder_unknown;
 
     const uint8_t *extradata, *channel_map;
     int extradata_size;
     int version, channels, map_type, streams, stereo_streams, i, j;
     uint64_t layout;
 
     if (!avctx->extradata) {
         if (avctx->channels > 2) {
             av_log(avctx, AV_LOG_ERROR,
                    "Multichannel configuration without extradata.\n");
             return AVERROR(EINVAL);
         }

         extradata      = opus_default_extradata;
         extradata_size = sizeof(opus_default_extradata);

     } else {
         extradata = avctx->extradata;
         extradata_size = avctx->extradata_size;
     }
 
     if (extradata_size < 19) {
         av_log(avctx, AV_LOG_ERROR, "Invalid extradata size: %d\n",
                extradata_size);
         return AVERROR_INVALIDDATA;
     }
 
     version = extradata[8];
     if (version > 15) {
         avpriv_request_sample(avctx, "Extradata version %d", version);
         return AVERROR_PATCHWELCOME;
     }
 
     avctx->delay = AV_RL16(extradata + 10);
 

     channels = avctx->extradata ? extradata[9] : (avctx->channels == 1) ? 1 : 2;

     if (!channels) {

         av_log(avctx, AV_LOG_ERROR, "Zero channel count specified in the extradata\n");

         return AVERROR_INVALIDDATA;
     }
 
     s->gain_i = AV_RL16(extradata + 16);
     if (s->gain_i)

         s->gain = ff_exp10(s->gain_i / (20.0 * 256));

 
     map_type = extradata[18];
     if (!map_type) {
         if (channels > 2) {
             av_log(avctx, AV_LOG_ERROR,
                    "Channel mapping 0 is only specified for up to 2 channels\n");
             return AVERROR_INVALIDDATA;
         }
         layout         = (channels == 1) ? AV_CH_LAYOUT_MONO : AV_CH_LAYOUT_STEREO;
         streams        = 1;
         stereo_streams = channels - 1;
         channel_map    = default_channel_map;

     } else if (map_type == 1 || map_type == 2 || map_type == 255) {

         if (extradata_size < 21 + channels) {
             av_log(avctx, AV_LOG_ERROR, "Invalid extradata size: %d\n",
                    extradata_size);
             return AVERROR_INVALIDDATA;
         }
 
         streams        = extradata[19];
         stereo_streams = extradata[20];
         if (!streams || stereo_streams > streams ||
             streams + stereo_streams > 255) {
             av_log(avctx, AV_LOG_ERROR,
                    "Invalid stream/stereo stream count: %d/%d\n", streams, stereo_streams);
             return AVERROR_INVALIDDATA;
         }
 
         if (map_type == 1) {
             if (channels > 8) {
                 av_log(avctx, AV_LOG_ERROR,
                        "Channel mapping 1 is only specified for up to 8 channels\n");
                 return AVERROR_INVALIDDATA;
             }
             layout = ff_vorbis_channel_layouts[channels - 1];
             channel_reorder = channel_reorder_vorbis;

         } else if (map_type == 2) {
             int ambisonic_order = ff_sqrt(channels) - 1;

             if (channels != ((ambisonic_order + 1) * (ambisonic_order + 1)) &&
                 channels != ((ambisonic_order + 1) * (ambisonic_order + 1) + 2)) {

                 av_log(avctx, AV_LOG_ERROR,
                        "Channel mapping 2 is only specified for channel counts"

                        " which can be written as (n + 1)^2 or (n + 1)^2 + 2"
                        " for nonnegative integer n\n");

                 return AVERROR_INVALIDDATA;
             }

             if (channels > 227) {
                 av_log(avctx, AV_LOG_ERROR, "Too many channels\n");
                 return AVERROR_INVALIDDATA;
             }

             layout = 0;

         } else
             layout = 0;
 
         channel_map = extradata + 21;
     } else {
         avpriv_request_sample(avctx, "Mapping type %d", map_type);
         return AVERROR_PATCHWELCOME;
     }
 
     s->channel_maps = av_mallocz_array(channels, sizeof(*s->channel_maps));
     if (!s->channel_maps)
         return AVERROR(ENOMEM);
 
     for (i = 0; i < channels; i++) {
         ChannelMap *map = &s->channel_maps[i];
         uint8_t     idx = channel_map[channel_reorder(channels, i)];
 
         if (idx == 255) {
             map->silence = 1;
             continue;
         } else if (idx >= streams + stereo_streams) {
             av_log(avctx, AV_LOG_ERROR,
                    "Invalid channel map for output channel %d: %d\n", i, idx);

             av_freep(&s->channel_maps);

             return AVERROR_INVALIDDATA;
         }
 

         /* check that we did not see this index yet */

         map->copy = 0;
         for (j = 0; j < i; j++)
             if (channel_map[channel_reorder(channels, j)] == idx) {
                 map->copy     = 1;
                 map->copy_idx = j;
                 break;
             }
 
         if (idx < 2 * stereo_streams) {
             map->stream_idx  = idx / 2;
             map->channel_idx = idx & 1;
         } else {
             map->stream_idx  = idx - stereo_streams;
             map->channel_idx = 0;
         }
     }
 
     avctx->channels       = channels;
     avctx->channel_layout = layout;
     s->nb_streams         = streams;
     s->nb_stereo_streams  = stereo_streams;
 
     return 0;
 }