/*
  * ADX ADPCM codecs
  * Copyright (c) 2001,2003 BERO
  *

  * 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 "libavutil/intreadwrite.h"

 #include "avcodec.h"

 #include "adx.h"

 #include "get_bits.h"

 #include "internal.h"

 
 /**

  * @file

  * SEGA CRI adx codecs.
  *
  * Reference documents:
  * http://ku-www.ss.titech.ac.jp/~yatsushi/adx.html
  * adx2wav & wav2adx http://www.geocities.co.jp/Playtown/2004/
  */
 

 static av_cold int adx_decode_init(AVCodecContext *avctx)

 {

     ADXContext *c = avctx->priv_data;
     int ret, header_size;
 

     if (avctx->extradata_size >= 24) {
         if ((ret = avpriv_adx_decode_header(avctx, avctx->extradata,
                                             avctx->extradata_size, &header_size,
                                             c->coeff)) < 0) {
             av_log(avctx, AV_LOG_ERROR, "error parsing ADX header\n");
             return AVERROR_INVALIDDATA;
         }

         c->channels      = avctx->channels;
         c->header_parsed = 1;

     }
 

     avctx->sample_fmt = AV_SAMPLE_FMT_S16P;

 
     avcodec_get_frame_defaults(&c->frame);
     avctx->coded_frame = &c->frame;
 

     return 0;
 }
 

 /**
  * Decode 32 samples from 18 bytes.
  *
  * A 16-bit scalar value is applied to 32 residuals, which then have a
  * 2nd-order LPC filter applied to it to form the output signal for a single
  * channel.
  */

 static int adx_decode(ADXContext *c, int16_t *out, int offset,
                       const uint8_t *in, int ch)

 {

     ADXChannelState *prev = &c->prev[ch];

     GetBitContext gb;

     int scale = AV_RB16(in);

     int i;

     int s0, s1, s2, d;

     /* check if this is an EOF packet */
     if (scale & 0x8000)
         return -1;

     init_get_bits(&gb, in + 2, (BLOCK_SIZE - 2) * 8);

     out += offset;

     s1 = prev->s1;
     s2 = prev->s2;

     for (i = 0; i < BLOCK_SAMPLES; i++) {

         d  = get_sbits(&gb, 4);

         s0 = ((d << COEFF_BITS) * scale + c->coeff[0] * s1 + c->coeff[1] * s2) >> COEFF_BITS;

         s2 = s1;

         s1 = av_clip_int16(s0);

         *out++ = s1;

     }
     prev->s1 = s1;
     prev->s2 = s2;

     return 0;

 }
 

 static int adx_decode_frame(AVCodecContext *avctx, void *data,
                             int *got_frame_ptr, AVPacket *avpkt)

 {

     int buf_size        = avpkt->size;
     ADXContext *c       = avctx->priv_data;

     int16_t **samples;
     int samples_offset;

     const uint8_t *buf  = avpkt->data;

     const uint8_t *buf_end = buf + avpkt->size;

     int num_blocks, ch, ret;

 
     if (c->eof) {

         *got_frame_ptr = 0;

         return buf_size;

     }
 

     if (!c->header_parsed && buf_size >= 2 && AV_RB16(buf) == 0x8000) {

         int header_size;

         if ((ret = avpriv_adx_decode_header(avctx, buf, buf_size, &header_size,

                                             c->coeff)) < 0) {
             av_log(avctx, AV_LOG_ERROR, "error parsing ADX header\n");
             return AVERROR_INVALIDDATA;
         }

         c->channels      = avctx->channels;
         c->header_parsed = 1;
         if (buf_size < header_size)

             return AVERROR_INVALIDDATA;

         buf      += header_size;

         buf_size -= header_size;
     }

     if (!c->header_parsed)

         return AVERROR_INVALIDDATA;

     /* calculate number of blocks in the packet */

     num_blocks = buf_size / (BLOCK_SIZE * c->channels);

 
     /* if the packet is not an even multiple of BLOCK_SIZE, check for an EOF
        packet */
     if (!num_blocks || buf_size % (BLOCK_SIZE * avctx->channels)) {

         if (buf_size >= 4 && (AV_RB16(buf) & 0x8000)) {
             c->eof = 1;

             *got_frame_ptr = 0;

             return avpkt->size;

         }

         return AVERROR_INVALIDDATA;

     }

     /* get output buffer */
     c->frame.nb_samples = num_blocks * BLOCK_SAMPLES;

     if ((ret = ff_get_buffer(avctx, &c->frame)) < 0) {

         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
         return ret;
     }

     samples = (int16_t **)c->frame.extended_data;
     samples_offset = 0;

     while (num_blocks--) {

         for (ch = 0; ch < c->channels; ch++) {

             if (buf_end - buf < BLOCK_SIZE || adx_decode(c, samples[ch], samples_offset, buf, ch)) {

                 c->eof = 1;
                 buf = avpkt->data + avpkt->size;
                 break;
             }
             buf_size -= BLOCK_SIZE;
             buf      += BLOCK_SIZE;
         }

         samples_offset += BLOCK_SAMPLES;

     }

     *got_frame_ptr   = 1;
     *(AVFrame *)data = c->frame;
 

     return buf - avpkt->data;

 }
 

 static void adx_decode_flush(AVCodecContext *avctx)
 {
     ADXContext *c = avctx->priv_data;
     memset(c->prev, 0, sizeof(c->prev));
     c->eof = 0;
 }
 

 AVCodec ff_adpcm_adx_decoder = {

     .name           = "adpcm_adx",
     .type           = AVMEDIA_TYPE_AUDIO,

     .id             = AV_CODEC_ID_ADPCM_ADX,

     .priv_data_size = sizeof(ADXContext),
     .init           = adx_decode_init,
     .decode         = adx_decode_frame,

     .flush          = adx_decode_flush,

     .capabilities   = CODEC_CAP_DR1,

     .long_name      = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"),

     .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P,
                                                       AV_SAMPLE_FMT_NONE },

 };