/*
  * SBC parser
  *
  * Copyright (C) 2017  Aurelien Jacobs <aurel@gnuage.org>
  *
  * 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 "sbc.h"
 #include "parser.h"
 
 typedef struct SBCParseContext {
     ParseContext pc;
     uint8_t header[3];
     int header_size;
     int buffered_size;
 } SBCParseContext;
 
 static int sbc_parse_header(AVCodecParserContext *s, AVCodecContext *avctx,
                             const uint8_t *data, size_t len)
 {
     static const int sample_rates[4] = { 16000, 32000, 44100, 48000 };
     int sr, blocks, mode, subbands, bitpool, channels, joint;
     int length;
 
     if (len < 3)
         return -1;
 
     if (data[0] == MSBC_SYNCWORD && data[1] == 0 && data[2] == 0) {
         avctx->channels = 1;
         avctx->sample_fmt = AV_SAMPLE_FMT_S16;
         avctx->sample_rate = 16000;
         avctx->frame_size = 120;
         s->duration = avctx->frame_size;
         return 57;
     }
 
     if (data[0] != SBC_SYNCWORD)
         return -2;
 
     sr       =   (data[1] >> 6) & 0x03;
     blocks   = (((data[1] >> 4) & 0x03) + 1) << 2;
     mode     =   (data[1] >> 2) & 0x03;
     subbands = (((data[1] >> 0) & 0x01) + 1) << 2;
     bitpool  = data[2];
 
     channels = mode == SBC_MODE_MONO ? 1 : 2;
     joint    = mode == SBC_MODE_JOINT_STEREO;
 
     length = 4 + (subbands * channels) / 2
              + ((((mode == SBC_MODE_DUAL_CHANNEL) + 1) * blocks * bitpool
                  + (joint * subbands)) + 7) / 8;
 
     avctx->channels = channels;
     avctx->sample_fmt = AV_SAMPLE_FMT_S16;
     avctx->sample_rate = sample_rates[sr];
     avctx->frame_size = subbands * blocks;
     s->duration = avctx->frame_size;
     return length;
 }
 
 static int sbc_parse(AVCodecParserContext *s, AVCodecContext *avctx,
                      const uint8_t **poutbuf, int *poutbuf_size,
                      const uint8_t *buf, int buf_size)
 {
     SBCParseContext *pc = s->priv_data;
     int next;
 
     if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
         next = buf_size;
     } else {
         if (pc->header_size) {
             memcpy(pc->header + pc->header_size, buf,
                    sizeof(pc->header) - pc->header_size);
             next = sbc_parse_header(s, avctx, pc->header, sizeof(pc->header))
                  - pc->buffered_size;
             pc->header_size = 0;
         } else {
             next = sbc_parse_header(s, avctx, buf, buf_size);
             if (next >= buf_size)
                 next = -1;
         }
 
         if (next < 0) {
             pc->header_size = FFMIN(sizeof(pc->header), buf_size);
             memcpy(pc->header, buf, pc->header_size);
             pc->buffered_size = buf_size;
             next = END_NOT_FOUND;
         }
 
         if (ff_combine_frame(&pc->pc, next, &buf, &buf_size) < 0) {
             *poutbuf      = NULL;
             *poutbuf_size = 0;
             return buf_size;
         }
     }
 
     *poutbuf      = buf;
     *poutbuf_size = buf_size;
     return next;
 }
 
 AVCodecParser ff_sbc_parser = {
     .codec_ids      = { AV_CODEC_ID_SBC },
     .priv_data_size = sizeof(SBCParseContext),
     .parser_parse   = sbc_parse,
     .parser_close   = ff_parse_close,
 };