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/*

 * Westwood SNDx codecs

 * Copyright (c) 2005 Konstantin Shishkov

 *

 * 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

 */

#include 

#include "libavutil/channel_layout.h"

#include "libavutil/common.h"

#include "libavutil/intreadwrite.h"

#include "avcodec.h"

#include "internal.h"

/**

 * @file

 * Westwood SNDx codecs

 *

 * Reference documents about VQA format and its audio codecs

 * can be found here:

 * http://www.multimedia.cx

 */

static const int8_t ws_adpcm_4bit[] = {

    -9, -8, -6, -5, -4, -3, -2, -1,

     0,  1,  2,  3,  4,  5,  6,  8

};

static av_cold int ws_snd_decode_init(AVCodecContext *avctx)

{

    avctx->channels       = 1;

    avctx->channel_layout = AV_CH_LAYOUT_MONO;

    avctx->sample_fmt     = AV_SAMPLE_FMT_U8;

    return 0;

}

static int ws_snd_decode_frame(AVCodecContext *avctx, void *data,

                               int *got_frame_ptr, AVPacket *avpkt)

{

    AVFrame *frame     = data;

    const uint8_t *buf = avpkt->data;

    int buf_size       = avpkt->size;

    int in_size, out_size, ret;

    int sample = 128;

    uint8_t *samples;

    uint8_t *samples_end;

    if (!buf_size)

        return 0;

    if (buf_size < 4) {

        av_log(avctx, AV_LOG_ERROR, "packet is too small\n");

        return AVERROR(EINVAL);

    }

    out_size = AV_RL16(&buf[0]);

    in_size  = AV_RL16(&buf[2]);

    buf += 4;

    if (in_size > buf_size) {

        av_log(avctx, AV_LOG_ERROR, "Frame data is larger than input buffer\n");

        return AVERROR_INVALIDDATA;

    }

    /* get output buffer */

    frame->nb_samples = out_size;

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

        return ret;

    samples     = frame->data[0];

    samples_end = samples + out_size;

    if (in_size == out_size) {

        memcpy(samples, buf, out_size);

        *got_frame_ptr = 1;

        return buf_size;

    }

    while (samples < samples_end && buf - avpkt->data < buf_size) {

        int code, smp, size;

        uint8_t count;

        code  = *buf >> 6;

        count = *buf & 0x3F;

        buf++;

        /* make sure we don't write past the output buffer */

        switch (code) {

        case 0:  smp = 4 * (count + 1);                break;

        case 1:  smp = 2 * (count + 1);                break;

        case 2:  smp = (count & 0x20) ? 1 : count + 1; break;

        default: smp = count + 1;                      break;

        }

        if (samples_end - samples < smp)

            break;

        /* make sure we don't read past the input buffer */

        size = ((code == 2 && (count & 0x20)) || code == 3) ? 0 : count + 1;

        if ((buf - avpkt->data) + size > buf_size)

            break;

        switch (code) {

        case 0: /* ADPCM 2-bit */

            for (count++; count > 0; count--) {

                code = *buf++;

                sample += ( code       & 0x3) - 2;

                sample = av_clip_uint8(sample);

                *samples++ = sample;

                sample += ((code >> 2) & 0x3) - 2;

                sample = av_clip_uint8(sample);

                *samples++ = sample;

                sample += ((code >> 4) & 0x3) - 2;

                sample = av_clip_uint8(sample);

                *samples++ = sample;

                sample +=  (code >> 6)        - 2;

                sample = av_clip_uint8(sample);

                *samples++ = sample;

            }

            break;

        case 1: /* ADPCM 4-bit */

            for (count++; count > 0; count--) {

                code = *buf++;

                sample += ws_adpcm_4bit[code & 0xF];

                sample = av_clip_uint8(sample);

                *samples++ = sample;

                sample += ws_adpcm_4bit[code >> 4];

                sample = av_clip_uint8(sample);

                *samples++ = sample;

            }

            break;

        case 2: /* no compression */

            if (count & 0x20) { /* big delta */

                int8_t t;

                t = count;

                t <<= 3;

                sample += t >> 3;

                sample = av_clip_uint8(sample);

                *samples++ = sample;

            } else { /* copy */

                memcpy(samples, buf, smp);

                samples += smp;

                buf     += smp;

                sample = buf[-1];

            }

            break;

        default: /* run */

            memset(samples, sample, smp);

            samples += smp;

        }

    }

    frame->nb_samples = samples - frame->data[0];

    *got_frame_ptr    = 1;

    return buf_size;

}

AVCodec ff_ws_snd1_decoder = {

    .name           = "ws_snd1",

    .long_name      = NULL_IF_CONFIG_SMALL("Westwood Audio (SND1)"),

    .type           = AVMEDIA_TYPE_AUDIO,

    .id             = AV_CODEC_ID_WESTWOOD_SND1,

    .init           = ws_snd_decode_init,

    .decode         = ws_snd_decode_frame,

    .capabilities   = CODEC_CAP_DR1,

};