/*

 * 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 "libavutil/attributes.h"

#include "libavutil/channel_layout.h"

#include "libavutil/error.h"

#include "libavutil/intreadwrite.h"

#include "libavutil/log.h"

#include "libavutil/mem.h"

#include "avcodec.h"

#include "internal.h"

#include "mathops.h"

#include "opus.h"

#include "parse.h"

#include "vorbis_data.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 > OPUS_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 > OPUS_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 > OPUS_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 > OPUS_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 > OPUS_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 > OPUS_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,

                                    OpusParseContext *s)

{

    static const uint8_t default_channel_map[2] = { 0, 1 };

    int (*channel_reorder)(int, int) = channel_reorder_unknown;

    int channels = avctx->ch_layout.nb_channels;

    const uint8_t *extradata, *channel_map;

    int extradata_size;

    int version, map_type, streams, stereo_streams, i, j, ret;

    AVChannelLayout layout = { 0 };

    if (!avctx->extradata) {

        if (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);

    if (avctx->internal)

        avctx->internal->skip_samples = avctx->delay;

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

    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");

            ret = AVERROR_INVALIDDATA;

            goto fail;

        }

        layout         = (channels == 1) ? (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO :

                                           (AVChannelLayout)AV_CHANNEL_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);

            ret = AVERROR_INVALIDDATA;

            goto fail;

        }

        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);

            ret = AVERROR_INVALIDDATA;

            goto fail;

        }

        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");

                ret = AVERROR_INVALIDDATA;

                goto fail;

            }

            av_channel_layout_copy(&layout, &ff_vorbis_ch_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");

                ret = AVERROR_INVALIDDATA;

                goto fail;

            }

            if (channels > 227) {

                av_log(avctx, AV_LOG_ERROR, "Too many channels\n");

                ret = AVERROR_INVALIDDATA;

                goto fail;

            }

            layout.order = AV_CHANNEL_ORDER_AMBISONIC;

            layout.nb_channels = channels;

            if (channels != ((ambisonic_order + 1) * (ambisonic_order + 1)))

                layout.u.mask = AV_CH_LAYOUT_STEREO;

        } else {

            layout.order       = AV_CHANNEL_ORDER_UNSPEC;

            layout.nb_channels = channels;

        }

        channel_map = extradata + 21;

    } else {

        avpriv_request_sample(avctx, "Mapping type %d", map_type);

        return AVERROR_PATCHWELCOME;

    }

    s->channel_maps = av_calloc(channels, sizeof(*s->channel_maps));

    if (!s->channel_maps) {

        ret = AVERROR(ENOMEM);

        goto fail;

    }

    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);

            ret = AVERROR_INVALIDDATA;

            goto fail;

        }

        /* 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;

        }

    }

    ret = av_channel_layout_copy(&avctx->ch_layout, &layout);

    if (ret < 0)

        goto fail;

    s->nb_streams         = streams;

    s->nb_stereo_streams  = stereo_streams;

    return 0;

fail:

    av_channel_layout_uninit(&layout);

    return ret;

}