/*
  * RealAudio Lossless decoder
  *
  * Copyright (c) 2012 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
  */
 
 /**
  * @file
  * This is a decoder for Real Audio Lossless format.
  * Dedicated to the mastermind behind it, Ralph Wiggum.
  */
 

 #include "libavutil/attributes.h"

 #include "libavutil/channel_layout.h"

 #include "avcodec.h"
 #include "get_bits.h"
 #include "golomb.h"

 #include "internal.h"

 #include "unary.h"
 #include "ralfdata.h"
 
 #define FILTER_NONE 0
 #define FILTER_RAW  642
 
 typedef struct VLCSet {
     VLC filter_params;
     VLC bias;
     VLC coding_mode;
     VLC filter_coeffs[10][11];
     VLC short_codes[15];
     VLC long_codes[125];
 } VLCSet;
 
 #define RALF_MAX_PKT_SIZE 8192
 
 typedef struct RALFContext {
     int version;
     int max_frame_size;
     VLCSet sets[3];
     int32_t channel_data[2][4096];
 
     int     filter_params;   ///< combined filter parameters for the current channel data
     int     filter_length;   ///< length of the filter for the current channel data
     int     filter_bits;     ///< filter precision for the current channel data
     int32_t filter[64];
 
     int     bias[2];         ///< a constant value added to channel data after filtering
 
     int num_blocks;          ///< number of blocks inside the frame
     int sample_offset;
     int block_size[1 << 12]; ///< size of the blocks
     int block_pts[1 << 12];  ///< block start time (in milliseconds)
 
     uint8_t pkt[16384];
     int     has_pkt;
 } RALFContext;
 
 #define MAX_ELEMS 644 // no RALF table uses more than that
 

 static av_cold int init_ralf_vlc(VLC *vlc, const uint8_t *data, int elems)

 {
     uint8_t  lens[MAX_ELEMS];
     uint16_t codes[MAX_ELEMS];
     int counts[17], prefixes[18];
     int i, cur_len;
     int max_bits = 0;

     int nb = 0;

 
     for (i = 0; i <= 16; i++)
         counts[i] = 0;
     for (i = 0; i < elems; i++) {

         cur_len  = (nb ? *data & 0xF : *data >> 4) + 1;

         counts[cur_len]++;
         max_bits = FFMAX(max_bits, cur_len);
         lens[i]  = cur_len;

         data    += nb;
         nb      ^= 1;

     }
     prefixes[1] = 0;
     for (i = 1; i <= 16; i++)
         prefixes[i + 1] = (prefixes[i] + counts[i]) << 1;
 
     for (i = 0; i < elems; i++)
         codes[i] = prefixes[lens[i]]++;
 
     return ff_init_vlc_sparse(vlc, FFMIN(max_bits, 9), elems,
                               lens, 1, 1, codes, 2, 2, NULL, 0, 0, 0);
 }
 
 static av_cold int decode_close(AVCodecContext *avctx)
 {
     RALFContext *ctx = avctx->priv_data;
     int i, j, k;
 
     for (i = 0; i < 3; i++) {
         ff_free_vlc(&ctx->sets[i].filter_params);
         ff_free_vlc(&ctx->sets[i].bias);
         ff_free_vlc(&ctx->sets[i].coding_mode);
         for (j = 0; j < 10; j++)
             for (k = 0; k < 11; k++)
                 ff_free_vlc(&ctx->sets[i].filter_coeffs[j][k]);
         for (j = 0; j < 15; j++)
             ff_free_vlc(&ctx->sets[i].short_codes[j]);
         for (j = 0; j < 125; j++)
             ff_free_vlc(&ctx->sets[i].long_codes[j]);
     }
 
     return 0;
 }
 
 static av_cold int decode_init(AVCodecContext *avctx)
 {
     RALFContext *ctx = avctx->priv_data;
     int i, j, k;
     int ret;
 
     if (avctx->extradata_size < 24 || memcmp(avctx->extradata, "LSD:", 4)) {
         av_log(avctx, AV_LOG_ERROR, "Extradata is not groovy, dude\n");
         return AVERROR_INVALIDDATA;
     }
 
     ctx->version = AV_RB16(avctx->extradata + 4);
     if (ctx->version != 0x103) {

         avpriv_request_sample(avctx, "Unknown version %X", ctx->version);

         return AVERROR_PATCHWELCOME;
     }
 
     avctx->channels    = AV_RB16(avctx->extradata + 8);
     avctx->sample_rate = AV_RB32(avctx->extradata + 12);
     if (avctx->channels < 1 || avctx->channels > 2
         || avctx->sample_rate < 8000 || avctx->sample_rate > 96000) {
         av_log(avctx, AV_LOG_ERROR, "Invalid coding parameters %d Hz %d ch\n",
                avctx->sample_rate, avctx->channels);
         return AVERROR_INVALIDDATA;
     }

     avctx->sample_fmt     = AV_SAMPLE_FMT_S16P;

     avctx->channel_layout = (avctx->channels == 2) ? AV_CH_LAYOUT_STEREO
                                                    : AV_CH_LAYOUT_MONO;
 
     ctx->max_frame_size = AV_RB32(avctx->extradata + 16);
     if (ctx->max_frame_size > (1 << 20) || !ctx->max_frame_size) {
         av_log(avctx, AV_LOG_ERROR, "invalid frame size %d\n",
                ctx->max_frame_size);
     }
     ctx->max_frame_size = FFMAX(ctx->max_frame_size, avctx->sample_rate);
 
     for (i = 0; i < 3; i++) {
         ret = init_ralf_vlc(&ctx->sets[i].filter_params, filter_param_def[i],
                             FILTERPARAM_ELEMENTS);
         if (ret < 0) {
             decode_close(avctx);
             return ret;
         }
         ret = init_ralf_vlc(&ctx->sets[i].bias, bias_def[i], BIAS_ELEMENTS);
         if (ret < 0) {
             decode_close(avctx);
             return ret;
         }
         ret = init_ralf_vlc(&ctx->sets[i].coding_mode, coding_mode_def[i],
                             CODING_MODE_ELEMENTS);
         if (ret < 0) {
             decode_close(avctx);
             return ret;
         }
         for (j = 0; j < 10; j++) {
             for (k = 0; k < 11; k++) {
                 ret = init_ralf_vlc(&ctx->sets[i].filter_coeffs[j][k],
                                     filter_coeffs_def[i][j][k],
                                     FILTER_COEFFS_ELEMENTS);
                 if (ret < 0) {
                     decode_close(avctx);
                     return ret;
                 }
             }
         }
         for (j = 0; j < 15; j++) {
             ret = init_ralf_vlc(&ctx->sets[i].short_codes[j],
                                 short_codes_def[i][j], SHORT_CODES_ELEMENTS);
             if (ret < 0) {
                 decode_close(avctx);
                 return ret;
             }
         }
         for (j = 0; j < 125; j++) {
             ret = init_ralf_vlc(&ctx->sets[i].long_codes[j],
                                 long_codes_def[i][j], LONG_CODES_ELEMENTS);
             if (ret < 0) {
                 decode_close(avctx);
                 return ret;
             }
         }
     }
 
     return 0;
 }
 
 static inline int extend_code(GetBitContext *gb, int val, int range, int bits)
 {
     if (val == 0) {
         val = -range - get_ue_golomb(gb);
     } else if (val == range * 2) {
         val =  range + get_ue_golomb(gb);
     } else {
         val -= range;
     }
     if (bits)
         val = (val << bits) | get_bits(gb, bits);
     return val;
 }
 
 static int decode_channel(RALFContext *ctx, GetBitContext *gb, int ch,
                           int length, int mode, int bits)
 {
     int i, t;
     int code_params;
     VLCSet *set = ctx->sets + mode;
     VLC *code_vlc; int range, range2, add_bits;
     int *dst = ctx->channel_data[ch];
 
     ctx->filter_params = get_vlc2(gb, set->filter_params.table, 9, 2);
     ctx->filter_bits   = (ctx->filter_params - 2) >> 6;
     ctx->filter_length = ctx->filter_params - (ctx->filter_bits << 6) - 1;
 
     if (ctx->filter_params == FILTER_RAW) {
         for (i = 0; i < length; i++)
             dst[i] = get_bits(gb, bits);
         ctx->bias[ch] = 0;
         return 0;
     }
 
     ctx->bias[ch] = get_vlc2(gb, set->bias.table, 9, 2);
     ctx->bias[ch] = extend_code(gb, ctx->bias[ch], 127, 4);
 
     if (ctx->filter_params == FILTER_NONE) {
         memset(dst, 0, sizeof(*dst) * length);
         return 0;
     }
 
     if (ctx->filter_params > 1) {
         int cmode = 0, coeff = 0;
         VLC *vlc = set->filter_coeffs[ctx->filter_bits] + 5;
 
         add_bits = ctx->filter_bits;
 
         for (i = 0; i < ctx->filter_length; i++) {
             t = get_vlc2(gb, vlc[cmode].table, vlc[cmode].bits, 2);
             t = extend_code(gb, t, 21, add_bits);
             if (!cmode)
                 coeff -= 12 << add_bits;
             coeff = t - coeff;
             ctx->filter[i] = coeff;
 
             cmode = coeff >> add_bits;
             if (cmode < 0) {
                 cmode = -1 - av_log2(-cmode);
                 if (cmode < -5)
                     cmode = -5;
             } else if (cmode > 0) {
                 cmode =  1 + av_log2(cmode);
                 if (cmode > 5)
                     cmode = 5;
             }
         }
     }
 
     code_params = get_vlc2(gb, set->coding_mode.table, set->coding_mode.bits, 2);
     if (code_params >= 15) {
         add_bits = av_clip((code_params / 5 - 3) / 2, 0, 10);
         if (add_bits > 9 && (code_params % 5) != 2)
             add_bits--;
         range    = 10;
         range2   = 21;
         code_vlc = set->long_codes + code_params - 15;
     } else {
         add_bits = 0;
         range    = 6;
         range2   = 13;
         code_vlc = set->short_codes + code_params;
     }
 
     for (i = 0; i < length; i += 2) {
         int code1, code2;
 
         t = get_vlc2(gb, code_vlc->table, code_vlc->bits, 2);
         code1 = t / range2;
         code2 = t % range2;
         dst[i]     = extend_code(gb, code1, range, 0) << add_bits;
         dst[i + 1] = extend_code(gb, code2, range, 0) << add_bits;
         if (add_bits) {
             dst[i]     |= get_bits(gb, add_bits);
             dst[i + 1] |= get_bits(gb, add_bits);
         }
     }
 
     return 0;
 }
 
 static void apply_lpc(RALFContext *ctx, int ch, int length, int bits)
 {
     int i, j, acc;
     int *audio = ctx->channel_data[ch];
     int bias = 1 << (ctx->filter_bits - 1);
     int max_clip = (1 << bits) - 1, min_clip = -max_clip - 1;
 
     for (i = 1; i < length; i++) {
         int flen = FFMIN(ctx->filter_length, i);
 
         acc = 0;
         for (j = 0; j < flen; j++)
             acc += ctx->filter[j] * audio[i - j - 1];
         if (acc < 0) {
             acc = (acc + bias - 1) >> ctx->filter_bits;
             acc = FFMAX(acc, min_clip);
         } else {
             acc = (acc + bias) >> ctx->filter_bits;
             acc = FFMIN(acc, max_clip);
         }
         audio[i] += acc;
     }
 }
 

 static int decode_block(AVCodecContext *avctx, GetBitContext *gb,
                         int16_t *dst0, int16_t *dst1)

 {
     RALFContext *ctx = avctx->priv_data;
     int len, ch, ret;
     int dmode, mode[2], bits[2];
     int *ch0, *ch1;
     int i, t, t2;
 
     len = 12 - get_unary(gb, 0, 6);
 
     if (len <= 7) len ^= 1; // codes for length = 6 and 7 are swapped
     len = 1 << len;
 
     if (ctx->sample_offset + len > ctx->max_frame_size) {
         av_log(avctx, AV_LOG_ERROR,
                "Decoder's stomach is crying, it ate too many samples\n");
         return AVERROR_INVALIDDATA;
     }
 
     if (avctx->channels > 1)
         dmode = get_bits(gb, 2) + 1;
     else
         dmode = 0;
 
     mode[0] = (dmode == 4) ? 1 : 0;
     mode[1] = (dmode >= 2) ? 2 : 0;
     bits[0] = 16;
     bits[1] = (mode[1] == 2) ? 17 : 16;
 
     for (ch = 0; ch < avctx->channels; ch++) {
         if ((ret = decode_channel(ctx, gb, ch, len, mode[ch], bits[ch])) < 0)
             return ret;
         if (ctx->filter_params > 1 && ctx->filter_params != FILTER_RAW) {
             ctx->filter_bits += 3;
             apply_lpc(ctx, ch, len, bits[ch]);
         }
         if (get_bits_left(gb) < 0)
             return AVERROR_INVALIDDATA;
     }
     ch0 = ctx->channel_data[0];
     ch1 = ctx->channel_data[1];
     switch (dmode) {
     case 0:
         for (i = 0; i < len; i++)

             dst0[i] = ch0[i] + ctx->bias[0];

         break;
     case 1:
         for (i = 0; i < len; i++) {

             dst0[i] = ch0[i] + ctx->bias[0];
             dst1[i] = ch1[i] + ctx->bias[1];

         }
         break;
     case 2:
         for (i = 0; i < len; i++) {
             ch0[i] += ctx->bias[0];

             dst0[i] = ch0[i];
             dst1[i] = ch0[i] - (ch1[i] + ctx->bias[1]);

         }
         break;
     case 3:
         for (i = 0; i < len; i++) {
             t  = ch0[i] + ctx->bias[0];
             t2 = ch1[i] + ctx->bias[1];

             dst0[i] = t + t2;
             dst1[i] = t;

         }
         break;
     case 4:
         for (i = 0; i < len; i++) {
             t  =   ch1[i] + ctx->bias[1];
             t2 = ((ch0[i] + ctx->bias[0]) << 1) | (t & 1);

             dst0[i] = (t2 + t) / 2;
             dst1[i] = (t2 - t) / 2;

         }
         break;
     }
 
     ctx->sample_offset += len;
 
     return 0;
 }
 
 static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr,
                         AVPacket *avpkt)
 {
     RALFContext *ctx = avctx->priv_data;

     AVFrame *frame   = data;

     int16_t *samples0;
     int16_t *samples1;

     int ret;
     GetBitContext gb;
     int table_size, table_bytes, i;
     const uint8_t *src, *block_pointer;
     int src_size;
     int bytes_left;
 
     if (ctx->has_pkt) {
         ctx->has_pkt = 0;
         table_bytes = (AV_RB16(avpkt->data) + 7) >> 3;
         if (table_bytes + 3 > avpkt->size || avpkt->size > RALF_MAX_PKT_SIZE) {
             av_log(avctx, AV_LOG_ERROR, "Wrong packet's breath smells of wrong data!\n");
             return AVERROR_INVALIDDATA;
         }
         if (memcmp(ctx->pkt, avpkt->data, 2 + table_bytes)) {
             av_log(avctx, AV_LOG_ERROR, "Wrong packet tails are wrong!\n");
             return AVERROR_INVALIDDATA;
         }
 
         src      = ctx->pkt;
         src_size = RALF_MAX_PKT_SIZE + avpkt->size;
         memcpy(ctx->pkt + RALF_MAX_PKT_SIZE, avpkt->data + 2 + table_bytes,
                avpkt->size - 2 - table_bytes);
     } else {
         if (avpkt->size == RALF_MAX_PKT_SIZE) {
             memcpy(ctx->pkt, avpkt->data, avpkt->size);
             ctx->has_pkt   = 1;
             *got_frame_ptr = 0;
 
             return avpkt->size;
         }
         src      = avpkt->data;
         src_size = avpkt->size;
     }
 

     frame->nb_samples = ctx->max_frame_size;

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

         return ret;

     samples0 = (int16_t *)frame->data[0];
     samples1 = (int16_t *)frame->data[1];

 
     if (src_size < 5) {
         av_log(avctx, AV_LOG_ERROR, "too short packets are too short!\n");
         return AVERROR_INVALIDDATA;
     }
     table_size  = AV_RB16(src);
     table_bytes = (table_size + 7) >> 3;
     if (src_size < table_bytes + 3) {
         av_log(avctx, AV_LOG_ERROR, "short packets are short!\n");
         return AVERROR_INVALIDDATA;
     }
     init_get_bits(&gb, src + 2, table_size);
     ctx->num_blocks = 0;
     while (get_bits_left(&gb) > 0) {
         ctx->block_size[ctx->num_blocks] = get_bits(&gb, 15);
         if (get_bits1(&gb)) {
             ctx->block_pts[ctx->num_blocks] = get_bits(&gb, 9);
         } else {
             ctx->block_pts[ctx->num_blocks] = 0;
         }
         ctx->num_blocks++;
     }
 
     block_pointer = src      + table_bytes + 2;
     bytes_left    = src_size - table_bytes - 2;
     ctx->sample_offset = 0;
     for (i = 0; i < ctx->num_blocks; i++) {
         if (bytes_left < ctx->block_size[i]) {
             av_log(avctx, AV_LOG_ERROR, "I'm pedaling backwards\n");
             break;
         }
         init_get_bits(&gb, block_pointer, ctx->block_size[i] * 8);

         if (decode_block(avctx, &gb, samples0 + ctx->sample_offset,
                                      samples1 + ctx->sample_offset) < 0) {

             av_log(avctx, AV_LOG_ERROR, "Sir, I got carsick in your office. Not decoding the rest of packet.\n");
             break;
         }
         block_pointer += ctx->block_size[i];
         bytes_left    -= ctx->block_size[i];
     }
 

     frame->nb_samples = ctx->sample_offset;
     *got_frame_ptr    = ctx->sample_offset > 0;

 
     return avpkt->size;
 }
 
 static void decode_flush(AVCodecContext *avctx)
 {
     RALFContext *ctx = avctx->priv_data;
 
     ctx->has_pkt = 0;
 }
 
 
 AVCodec ff_ralf_decoder = {
     .name           = "ralf",

     .long_name      = NULL_IF_CONFIG_SMALL("RealAudio Lossless"),

     .type           = AVMEDIA_TYPE_AUDIO,

     .id             = AV_CODEC_ID_RALF,

     .priv_data_size = sizeof(RALFContext),
     .init           = decode_init,
     .close          = decode_close,
     .decode         = decode_frame,
     .flush          = decode_flush,
     .capabilities   = CODEC_CAP_DR1,

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

 };