/*

 * TTA (The Lossless True Audio) decoder

 * Copyright (c) 2006 Alex Beregszaszi

 *

 * 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

 * TTA (The Lossless True Audio) decoder

 * @see http://www.true-audio.com/

 * @see http://tta.corecodec.org/

 * @author Alex Beregszaszi

 */

#include <limits.h>

#include "libavutil/channel_layout.h"

#include "libavutil/crc.h"

#include "libavutil/intreadwrite.h"

#include "libavutil/mem.h"

#include "libavutil/opt.h"

#define BITSTREAM_READER_LE

#include "ttadata.h"

#include "ttadsp.h"

#include "avcodec.h"

#include "codec_internal.h"

#include "get_bits.h"

#include "thread.h"

#include "unary.h"

#define FORMAT_SIMPLE    1

#define FORMAT_ENCRYPTED 2

typedef struct TTAContext {

    AVClass *class;

    AVCodecContext *avctx;

    const AVCRC *crc_table;

    int format, channels, bps;

    unsigned data_length;

    int frame_length, last_frame_length;

    int32_t *decode_buffer;

    uint8_t crc_pass[8];

    uint8_t *pass;

    TTAChannel *ch_ctx;

    TTADSPContext dsp;

} TTAContext;

static const int64_t tta_channel_layouts[7] = {

    AV_CH_LAYOUT_STEREO,

    AV_CH_LAYOUT_STEREO|AV_CH_LOW_FREQUENCY,

    AV_CH_LAYOUT_QUAD,

    0,

    AV_CH_LAYOUT_5POINT1_BACK,

    AV_CH_LAYOUT_5POINT1_BACK|AV_CH_BACK_CENTER,

    AV_CH_LAYOUT_7POINT1_WIDE

};

static int tta_check_crc(TTAContext *s, const uint8_t *buf, int buf_size)

{

    uint32_t crc, CRC;

    CRC = AV_RL32(buf + buf_size);

    crc = av_crc(s->crc_table, 0xFFFFFFFFU, buf, buf_size);

    if (CRC != (crc ^ 0xFFFFFFFFU)) {

        av_log(s->avctx, AV_LOG_ERROR, "CRC error\n");

        return AVERROR_INVALIDDATA;

    }

    return 0;

}

static uint64_t tta_check_crc64(uint8_t *pass)

{

    uint64_t crc = UINT64_MAX, poly = 0x42F0E1EBA9EA3693U;

    uint8_t *end = pass + strlen(pass);

    int i;

    while (pass < end) {

        crc ^= (uint64_t)*pass++ << 56;

        for (i = 0; i < 8; i++)

            crc = (crc << 1) ^ (poly & (((int64_t) crc) >> 63));

    }

    return crc ^ UINT64_MAX;

}

static int allocate_buffers(AVCodecContext *avctx)

{

    TTAContext *s = avctx->priv_data;

    if (s->bps < 3) {

        s->decode_buffer = av_calloc(s->frame_length,

                                     sizeof(*s->decode_buffer) * s->channels);

        if (!s->decode_buffer)

            return AVERROR(ENOMEM);

    } else

        s->decode_buffer = NULL;

    s->ch_ctx = av_malloc_array(avctx->ch_layout.nb_channels, sizeof(*s->ch_ctx));

    if (!s->ch_ctx)

        return AVERROR(ENOMEM);

    return 0;

}

static av_cold int tta_decode_init(AVCodecContext * avctx)

{

    TTAContext *s = avctx->priv_data;

    GetBitContext gb;

    int total_frames;

    int ret;

    s->avctx = avctx;

    // 22 bytes for a TTA1 header

    if (avctx->extradata_size < 22)

        return AVERROR_INVALIDDATA;

    s->crc_table = av_crc_get_table(AV_CRC_32_IEEE_LE);

    ret = init_get_bits8(&gb, avctx->extradata, avctx->extradata_size);

    if (ret < 0)

        return ret;

    if (show_bits_long(&gb, 32) == AV_RL32("TTA1")) {

        /* signature */

        skip_bits_long(&gb, 32);

        s->format = get_bits(&gb, 16);

        if (s->format > 2) {

            av_log(avctx, AV_LOG_ERROR, "Invalid format\n");

            return AVERROR_INVALIDDATA;

        }

        if (s->format == FORMAT_ENCRYPTED) {

            if (!s->pass) {

                av_log(avctx, AV_LOG_ERROR, "Missing password for encrypted stream. Please use the -password option\n");

                return AVERROR(EINVAL);

            }

            AV_WL64(s->crc_pass, tta_check_crc64(s->pass));

        }

        s->channels = get_bits(&gb, 16);

        av_channel_layout_uninit(&avctx->ch_layout);

        if (s->channels > 1 && s->channels < 9) {

            av_channel_layout_from_mask(&avctx->ch_layout, tta_channel_layouts[s->channels-2]);

        }

        if (avctx->ch_layout.nb_channels == 0) {

            avctx->ch_layout.order       = AV_CHANNEL_ORDER_UNSPEC;

            avctx->ch_layout.nb_channels = s->channels;

        }

        avctx->bits_per_raw_sample = get_bits(&gb, 16);

        s->bps = (avctx->bits_per_raw_sample + 7) / 8;

        avctx->sample_rate = get_bits_long(&gb, 32);

        s->data_length = get_bits_long(&gb, 32);

        skip_bits_long(&gb, 32); // CRC32 of header

        if (s->channels == 0 || s->channels > 16) {

            av_log(avctx, AV_LOG_ERROR, "Invalid number of channels\n");

            return AVERROR_INVALIDDATA;

        } else if (avctx->sample_rate == 0) {

            av_log(avctx, AV_LOG_ERROR, "Invalid samplerate\n");

            return AVERROR_INVALIDDATA;

        }

        switch(s->bps) {

        case 1: avctx->sample_fmt = AV_SAMPLE_FMT_U8; break;

        case 2:

            avctx->sample_fmt = AV_SAMPLE_FMT_S16;

            break;

        case 3:

            avctx->sample_fmt = AV_SAMPLE_FMT_S32;

            break;

        //case 4: avctx->sample_fmt = AV_SAMPLE_FMT_S32; break;

        default:

            av_log(avctx, AV_LOG_ERROR, "Invalid/unsupported sample format.\n");

            return AVERROR_INVALIDDATA;

        }

        // prevent overflow

        if (avctx->sample_rate > 0x7FFFFFu) {

            av_log(avctx, AV_LOG_ERROR, "sample_rate too large\n");

            return AVERROR(EINVAL);

        }

        s->frame_length = 256 * avctx->sample_rate / 245;

        s->last_frame_length = s->data_length % s->frame_length;

        total_frames = s->data_length / s->frame_length +

                       (s->last_frame_length ? 1 : 0);

        av_log(avctx, AV_LOG_DEBUG, "format: %d chans: %d bps: %d rate: %d block: %d\n",

            s->format, avctx->ch_layout.nb_channels, avctx->bits_per_coded_sample, avctx->sample_rate,

            avctx->block_align);

        av_log(avctx, AV_LOG_DEBUG, "data_length: %d frame_length: %d last: %d total: %d\n",

            s->data_length, s->frame_length, s->last_frame_length, total_frames);

        if (s->frame_length >= UINT_MAX / (s->channels * sizeof(int32_t))) {

            av_log(avctx, AV_LOG_ERROR, "frame_length too large\n");

            return AVERROR_INVALIDDATA;

        }

    } else {

        av_log(avctx, AV_LOG_ERROR, "Wrong extradata present\n");

        return AVERROR_INVALIDDATA;

    }

    ff_ttadsp_init(&s->dsp);

    return allocate_buffers(avctx);

}

static int tta_decode_frame(AVCodecContext *avctx, AVFrame *frame,

                            int *got_frame_ptr, AVPacket *avpkt)

{

    const uint8_t *buf = avpkt->data;

    int buf_size = avpkt->size;

    TTAContext *s = avctx->priv_data;

    GetBitContext gb;

    int i, ret;

    int cur_chan = 0, framelen = s->frame_length;

    uint32_t *p;

    if (avctx->err_recognition & AV_EF_CRCCHECK) {

        if (buf_size < 4 ||

            (tta_check_crc(s, buf, buf_size - 4) && avctx->err_recognition & AV_EF_EXPLODE))

            return AVERROR_INVALIDDATA;

    }

    if ((ret = init_get_bits8(&gb, avpkt->data, avpkt->size)) < 0)

        return ret;

    /* get output buffer */

    frame->nb_samples = framelen;

    if ((ret = ff_thread_get_buffer(avctx, frame, 0)) < 0)

        return ret;

    // decode directly to output buffer for 24-bit sample format

    if (s->bps == 3)

        s->decode_buffer = (int32_t *)frame->data[0];

    // init per channel states

    for (i = 0; i < s->channels; i++) {

        TTAFilter *filter = &s->ch_ctx[i].filter;

        s->ch_ctx[i].predictor = 0;

        ff_tta_filter_init(filter, ff_tta_filter_configs[s->bps-1]);

        if (s->format == FORMAT_ENCRYPTED) {

            int i;

            for (i = 0; i < 8; i++)

                filter->qm[i] = sign_extend(s->crc_pass[i], 8);

        }

        ff_tta_rice_init(&s->ch_ctx[i].rice, 10, 10);

    }

    i = 0;

    for (p = s->decode_buffer; (int32_t*)p < s->decode_buffer + (framelen * s->channels); p++) {

        int32_t *predictor = &s->ch_ctx[cur_chan].predictor;

        TTAFilter *filter = &s->ch_ctx[cur_chan].filter;

        TTARice *rice = &s->ch_ctx[cur_chan].rice;

        uint32_t unary, depth, k;

        int32_t value;

        unary = get_unary(&gb, 0, get_bits_left(&gb));

        if (unary == 0) {

            depth = 0;

            k = rice->k0;

        } else {

            depth = 1;

            k = rice->k1;

            unary--;

        }

        if (get_bits_left(&gb) < k) {

            ret = AVERROR_INVALIDDATA;

            goto error;

        }

        if (k) {

            if (k > MIN_CACHE_BITS || unary > INT32_MAX >> k) {

                ret = AVERROR_INVALIDDATA;

                goto error;

            }

            value = (unary << k) + get_bits(&gb, k);

        } else

            value = unary;

        // FIXME: copy paste from original

        switch (depth) {

        case 1:

            rice->sum1 += value - (rice->sum1 >> 4);

            if (rice->k1 > 0 && rice->sum1 < ff_tta_shift_16[rice->k1])

                rice->k1--;

            else if (rice->sum1 > ff_tta_shift_16[rice->k1 + 1])

                rice->k1++;

            value += ff_tta_shift_1[rice->k0];

        default:

            rice->sum0 += value - (rice->sum0 >> 4);

            if (rice->k0 > 0 && rice->sum0 < ff_tta_shift_16[rice->k0])

                rice->k0--;

            else if (rice->sum0 > ff_tta_shift_16[rice->k0 + 1])

                rice->k0++;

        }

        // extract coded value

        *p = 1 + ((value >> 1) ^ ((value & 1) - 1));

        // run hybrid filter

        s->dsp.filter_process(filter->qm, filter->dx, filter->dl, &filter->error, p,

                              filter->shift, filter->round);

        // fixed order prediction

#define PRED(x, k) (int32_t)((((uint64_t)(x) << (k)) - (x)) >> (k))

        switch (s->bps) {

        case 1: *p += PRED(*predictor, 4); break;

        case 2:

        case 3: *p += PRED(*predictor, 5); break;

        case 4: *p +=      *predictor;     break;

        }

        *predictor = *p;

        // flip channels

        if (cur_chan < (s->channels-1))

            cur_chan++;

        else {

            // decorrelate in case of multiple channels

            if (s->channels > 1) {

                int32_t *r = p - 1;

                for (*p += *r / 2; r > (int32_t*)p - s->channels; r--)

                    *r = *(r + 1) - (unsigned)*r;

            }

            cur_chan = 0;

            i++;

            // check for last frame

            if (i == s->last_frame_length && get_bits_left(&gb) / 8 == 4) {

                frame->nb_samples = framelen = s->last_frame_length;

                break;

            }

        }

    }

    align_get_bits(&gb);

    if (get_bits_left(&gb) < 32) {

        ret = AVERROR_INVALIDDATA;

        goto error;

    }

    skip_bits_long(&gb, 32); // frame crc

    // convert to output buffer

    switch (s->bps) {

    case 1: {

        uint8_t *samples = (uint8_t *)frame->data[0];

        p = s->decode_buffer;

        for (i = 0; i < framelen * s->channels; i++)

            samples[i] = p[i] + 0x80;

        break;

        }

    case 2: {

        int16_t *samples = (int16_t *)frame->data[0];

        p = s->decode_buffer;

        for (i = 0; i < framelen * s->channels; i++)

            samples[i] = p[i];

        break;

        }

    case 3: {

        // shift samples for 24-bit sample format

        int32_t *samples = (int32_t *)frame->data[0];

        for (i = 0; i < framelen * s->channels; i++)

            samples[i] = samples[i] * 256U;

        // reset decode buffer

        s->decode_buffer = NULL;

        break;

        }

    }

    *got_frame_ptr = 1;

    return buf_size;

error:

    // reset decode buffer

    if (s->bps == 3)

        s->decode_buffer = NULL;

    return ret;

}

static av_cold int tta_decode_close(AVCodecContext *avctx)

{

    TTAContext *s = avctx->priv_data;

    if (s->bps < 3)

        av_freep(&s->decode_buffer);

    s->decode_buffer = NULL;

    av_freep(&s->ch_ctx);

    return 0;

}

#define OFFSET(x) offsetof(TTAContext, x)

#define DEC (AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_AUDIO_PARAM)

static const AVOption options[] = {

    { "password", "Set decoding password", OFFSET(pass), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, DEC },

    { NULL },

};

static const AVClass tta_decoder_class = {

    .class_name = "TTA Decoder",

    .item_name  = av_default_item_name,

    .option     = options,

    .version    = LIBAVUTIL_VERSION_INT,

};

const FFCodec ff_tta_decoder = {

    .p.name         = "tta",

    CODEC_LONG_NAME("TTA (True Audio)"),

    .p.type         = AVMEDIA_TYPE_AUDIO,

    .p.id           = AV_CODEC_ID_TTA,

    .priv_data_size = sizeof(TTAContext),

    .init           = tta_decode_init,

    .close          = tta_decode_close,

    FF_CODEC_DECODE_CB(tta_decode_frame),

    .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS | AV_CODEC_CAP_CHANNEL_CONF,

    .p.priv_class   = &tta_decoder_class,

    .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,

};