/*
  * 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
  */
 

 #define BITSTREAM_READER_LE

 //#define DEBUG
 #include <limits.h>
 #include "avcodec.h"

 #include "get_bits.h"

 #include "internal.h"

 #include "libavutil/crc.h"

 #define FORMAT_SIMPLE    1
 #define FORMAT_ENCRYPTED 2

 #define MAX_ORDER 16
 typedef struct TTAFilter {

     int32_t shift, round, error;

     int32_t qm[MAX_ORDER];
     int32_t dx[MAX_ORDER];
     int32_t dl[MAX_ORDER];
 } TTAFilter;
 
 typedef struct TTARice {
     uint32_t k0, k1, sum0, sum1;
 } TTARice;
 
 typedef struct TTAChannel {
     int32_t predictor;
     TTAFilter filter;
     TTARice rice;
 } TTAChannel;
 

 typedef struct TTAContext {
     AVCodecContext *avctx;

     AVFrame frame;

     GetBitContext gb;

     const AVCRC *crc_table;

     int format, channels, bps;
     unsigned data_length;

     int frame_length, last_frame_length;

     int32_t *decode_buffer;

     TTAChannel *ch_ctx;

 } TTAContext;
 

 static const uint32_t shift_1[] = {

     0x00000001, 0x00000002, 0x00000004, 0x00000008,
     0x00000010, 0x00000020, 0x00000040, 0x00000080,
     0x00000100, 0x00000200, 0x00000400, 0x00000800,
     0x00001000, 0x00002000, 0x00004000, 0x00008000,
     0x00010000, 0x00020000, 0x00040000, 0x00080000,
     0x00100000, 0x00200000, 0x00400000, 0x00800000,
     0x01000000, 0x02000000, 0x04000000, 0x08000000,
     0x10000000, 0x20000000, 0x40000000, 0x80000000,
     0x80000000, 0x80000000, 0x80000000, 0x80000000,
     0x80000000, 0x80000000, 0x80000000, 0x80000000
 };
 

 static const uint32_t * const shift_16 = shift_1 + 4;

 static const int32_t ttafilter_configs[4] = {
     10,
     9,
     10,
     12

 };
 

 static void ttafilter_init(TTAFilter *c, int32_t shift) {

     memset(c, 0, sizeof(TTAFilter));
     c->shift = shift;
    c->round = shift_1[shift-1];
 //    c->round = 1 << (shift - 1);
 }
 

 static inline void ttafilter_process(TTAFilter *c, int32_t *in)
 {

     register int32_t *dl = c->dl, *qm = c->qm, *dx = c->dx, sum = c->round;

     if (c->error < 0) {
         qm[0] -= dx[0]; qm[1] -= dx[1]; qm[2] -= dx[2]; qm[3] -= dx[3];
         qm[4] -= dx[4]; qm[5] -= dx[5]; qm[6] -= dx[6]; qm[7] -= dx[7];
     } else if (c->error > 0) {
         qm[0] += dx[0]; qm[1] += dx[1]; qm[2] += dx[2]; qm[3] += dx[3];
         qm[4] += dx[4]; qm[5] += dx[5]; qm[6] += dx[6]; qm[7] += dx[7];

     }
 

     sum += dl[0] * qm[0] + dl[1] * qm[1] + dl[2] * qm[2] + dl[3] * qm[3] +
            dl[4] * qm[4] + dl[5] * qm[5] + dl[6] * qm[6] + dl[7] * qm[7];
 
     dx[0] = dx[1]; dx[1] = dx[2]; dx[2] = dx[3]; dx[3] = dx[4];
     dl[0] = dl[1]; dl[1] = dl[2]; dl[2] = dl[3]; dl[3] = dl[4];
 
     dx[4] = ((dl[4] >> 30) | 1);
     dx[5] = ((dl[5] >> 30) | 2) & ~1;
     dx[6] = ((dl[6] >> 30) | 2) & ~1;
     dx[7] = ((dl[7] >> 30) | 4) & ~3;

     c->error = *in;
     *in += (sum >> c->shift);

     dl[4] = -dl[5]; dl[5] = -dl[6];
     dl[6] = *in - dl[7]; dl[7] = *in;
     dl[5] += dl[6]; dl[4] += dl[5];

 }
 

 static void rice_init(TTARice *c, uint32_t k0, uint32_t k1)

 {
     c->k0 = k0;
     c->k1 = k1;
     c->sum0 = shift_16[k0];
     c->sum1 = shift_16[k1];
 }
 
 static int tta_get_unary(GetBitContext *gb)
 {
     int ret = 0;
 
     // count ones

     while (get_bits_left(gb) > 0 && get_bits1(gb))

         ret++;
     return ret;
 }
 

 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 av_cold int tta_decode_init(AVCodecContext * avctx)

 {
     TTAContext *s = avctx->priv_data;

     int total_frames;

 
     s->avctx = avctx;
 
     // 30bytes includes a seektable with one frame
     if (avctx->extradata_size < 30)

         return AVERROR_INVALIDDATA;

     init_get_bits(&s->gb, avctx->extradata, avctx->extradata_size * 8);

     if (show_bits_long(&s->gb, 32) == AV_RL32("TTA1"))

     {

         if (avctx->err_recognition & AV_EF_CRCCHECK) {
             s->crc_table = av_crc_get_table(AV_CRC_32_IEEE_LE);

             tta_check_crc(s, avctx->extradata, 18);

         }
 

         /* signature */

         skip_bits_long(&s->gb, 32);

         s->format = get_bits(&s->gb, 16);
         if (s->format > 2) {
             av_log(s->avctx, AV_LOG_ERROR, "Invalid format\n");

             return AVERROR_INVALIDDATA;

         }

         if (s->format == FORMAT_ENCRYPTED) {
             av_log_missing_feature(s->avctx, "Encrypted TTA", 0);

             return AVERROR_PATCHWELCOME;

         }

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

         if (s->channels > 1 && s->channels < 9)
             avctx->channel_layout = tta_channel_layouts[s->channels-2];

         avctx->bits_per_raw_sample = get_bits(&s->gb, 16);
         s->bps = (avctx->bits_per_raw_sample + 7) / 8;

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

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

         if (s->channels == 0) {
             av_log(s->avctx, AV_LOG_ERROR, "Invalid number of channels\n");
             return AVERROR_INVALIDDATA;

         } else if (avctx->sample_rate == 0) {
             av_log(s->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(s->avctx, AV_LOG_DEBUG, "format: %d chans: %d bps: %d rate: %d block: %d\n",
             s->format, avctx->channels, avctx->bits_per_coded_sample, avctx->sample_rate,

             avctx->block_align);
         av_log(s->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);

         // FIXME: seek table

         if (avctx->extradata_size <= 26 || total_frames > INT_MAX / 4 ||
             avctx->extradata_size - 26 < total_frames * 4)

             av_log(avctx, AV_LOG_WARNING, "Seek table missing or too small\n");
         else if (avctx->err_recognition & AV_EF_CRCCHECK) {

             if (tta_check_crc(s, avctx->extradata + 22, total_frames * 4))

                 return AVERROR_INVALIDDATA;
         }

         skip_bits_long(&s->gb, 32 * total_frames);

         skip_bits_long(&s->gb, 32); // CRC32 of seektable

         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;

         }
 

         if (s->bps < 3) {
             s->decode_buffer = av_mallocz(sizeof(int32_t)*s->frame_length*s->channels);
             if (!s->decode_buffer)
                 return AVERROR(ENOMEM);

         } else
             s->decode_buffer = NULL;

         s->ch_ctx = av_malloc(avctx->channels * sizeof(*s->ch_ctx));

         if (!s->ch_ctx) {
             av_freep(&s->decode_buffer);

             return AVERROR(ENOMEM);

         }

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

         return AVERROR_INVALIDDATA;

     }
 

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

     return 0;
 }
 

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

 {

     const uint8_t *buf = avpkt->data;
     int buf_size = avpkt->size;

     TTAContext *s = avctx->priv_data;

     int i, ret;

     int cur_chan = 0, framelen = s->frame_length;
     int32_t *p;

     if (avctx->err_recognition & AV_EF_CRCCHECK) {
         if (buf_size < 4 || tta_check_crc(s, buf, buf_size - 4))
             return AVERROR_INVALIDDATA;
     }
 

     init_get_bits(&s->gb, buf, buf_size*8);
 

     /* get output buffer */
     s->frame.nb_samples = framelen;

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

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

     }
 

     // decode directly to output buffer for 24-bit sample format
     if (s->bps == 3)

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

     // init per channel states
     for (i = 0; i < s->channels; i++) {
         s->ch_ctx[i].predictor = 0;

         ttafilter_init(&s->ch_ctx[i].filter, ttafilter_configs[s->bps-1]);

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

     i = 0;

     for (p = s->decode_buffer; 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 = tta_get_unary(&s->gb);
 
         if (unary == 0) {
             depth = 0;
             k = rice->k0;
         } else {
             depth = 1;
             k = rice->k1;
             unary--;

         }
 

         if (get_bits_left(&s->gb) < k) {
             ret = AVERROR_INVALIDDATA;
             goto error;
         }

         if (k) {

             if (k > MIN_CACHE_BITS) {
                 ret = AVERROR_INVALIDDATA;
                 goto error;
             }

             value = (unary << k) + get_bits(&s->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 < shift_16[rice->k1])
                 rice->k1--;
             else if(rice->sum1 > shift_16[rice->k1 + 1])
                 rice->k1++;
             value += shift_1[rice->k0];
         default:
             rice->sum0 += value - (rice->sum0 >> 4);
             if (rice->k0 > 0 && rice->sum0 < shift_16[rice->k0])
                 rice->k0--;
             else if(rice->sum0 > shift_16[rice->k0 + 1])
                 rice->k0++;
         }

         // extract coded value

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

         // run hybrid filter

         ttafilter_process(filter, p);

         // 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 > p - s->channels; r--)
                     *r = *(r + 1) - *r;

             }

             cur_chan = 0;

             i++;
             // check for last frame
             if (i == s->last_frame_length && get_bits_left(&s->gb) / 8 == 4) {
                 s->frame.nb_samples = framelen = s->last_frame_length;
                 break;
             }

         }

     }

     align_get_bits(&s->gb);

     if (get_bits_left(&s->gb) < 32) {
         ret = AVERROR_INVALIDDATA;
         goto error;
     }

     skip_bits_long(&s->gb, 32); // frame crc

     // convert to output buffer
     switch (s->bps) {
     case 1: {
         uint8_t *samples = (uint8_t *)s->frame.data[0];
         for (p = s->decode_buffer; p < s->decode_buffer + (framelen * s->channels); p++)
             *samples++ = *p + 0x80;
         break;

         }

     case 2: {

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

         for (p = s->decode_buffer; p < s->decode_buffer + (framelen * s->channels); p++)
             *samples++ = *p;
         break;
         }
     case 3: {
         // shift samples for 24-bit sample format
         int32_t *samples = (int32_t *)s->frame.data[0];
         for (p = s->decode_buffer; p < s->decode_buffer + (framelen * s->channels); p++)
             *samples++ <<= 8;
         // reset decode buffer
         s->decode_buffer = NULL;
         break;
         }
     }

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

     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_free(s->decode_buffer);
     s->decode_buffer = NULL;

     av_freep(&s->ch_ctx);

 
     return 0;
 }
 

 AVCodec ff_tta_decoder = {

     .name           = "tta",
     .type           = AVMEDIA_TYPE_AUDIO,

     .id             = AV_CODEC_ID_TTA,

     .priv_data_size = sizeof(TTAContext),
     .init           = tta_decode_init,
     .close          = tta_decode_close,
     .decode         = tta_decode_frame,

     .capabilities   = CODEC_CAP_DR1,

     .long_name      = NULL_IF_CONFIG_SMALL("TTA (True Audio)"),

 };