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sbc.c

/*
 *
 *  Bluetooth low-complexity, subband codec (SBC) library
 *
 *  Copyright (C) 2004-2006  Marcel Holtmann <marcel@holtmann.org>
 *  Copyright (C) 2004-2005  Henryk Ploetz <henryk@ploetzli.ch>
 *  Copyright (C) 2005-2006  Brad Midgley <bmidgley@xmission.com>
 *
 *
 *  This library 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.
 *
 *  This library 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 this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

/* todo items:

  use a log2 table for byte integer scale factors calculation (sum log2 results for high and low bytes)
  fill bitpool by 16 bits instead of one at a time in bits allocation/bitpool generation
  port to the dsp 
  don't consume more bytes than passed into the encoder

*/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdio.h>
#include <errno.h>
#include <stdint.h>
#include <malloc.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>


#include "sbc_math.h"
#include "sbc_tables.h"

#include "sbc.h"

#define SBC_SYNCWORD    0x9C

/* sampling frequency */
#define SBC_FS_16 0x00
#define SBC_FS_32 0x01
#define SBC_FS_44 0x02
#define SBC_FS_48 0x03

/* nrof_blocks */
#define SBC_NB_4  0x00
#define SBC_NB_8  0x01
#define SBC_NB_12 0x02
#define SBC_NB_16 0x03

/* channel mode */
#define SBC_CM_MONO           0x00
#define SBC_CM_DUAL_CHANNEL   0x01
#define SBC_CM_STEREO         0x02
#define SBC_CM_JOINT_STEREO   0x03

/* allocation mode */
#define SBC_AM_LOUDNESS       0x00
#define SBC_AM_SNR            0x01

/* subbands */
#define SBC_SB_4  0x00
#define SBC_SB_8  0x01

/* This structure contains an unpacked SBC frame. 
   Yes, there is probably quite some unused space herein */
struct sbc_frame {
      uint16_t sampling_frequency;  /* in kHz */
      uint8_t blocks;
      enum {
            MONO        = SBC_CM_MONO,
            DUAL_CHANNEL      = SBC_CM_DUAL_CHANNEL,
            STEREO            = SBC_CM_STEREO,
            JOINT_STEREO      = SBC_CM_JOINT_STEREO
      } channel_mode;
      uint8_t channels;
      enum {
            LOUDNESS    = SBC_AM_LOUDNESS,
            SNR         = SBC_AM_SNR
      } allocation_method;
      uint8_t subbands;
      uint8_t bitpool;
      uint8_t join;                       /* bit number x set means joint stereo has been used in subband x */
      uint8_t scale_factor[2][8];         /* only the lower 4 bits of every element are to be used */
      uint16_t audio_sample[16][2][8];    /* raw integer subband samples in the frame */

      int32_t sb_sample_f[16][2][8];
      int32_t sb_sample[16][2][8];        /* modified subband samples */
      int16_t pcm_sample[2][16*8];        /* original pcm audio samples */
};

struct sbc_decoder_state {
      int subbands;
      int32_t V[2][170];
      int offset[2][16];
};

struct sbc_encoder_state {
      int subbands;
      int32_t X[2][80];
};

/*
 * Calculates the CRC-8 of the first len bits in data
 */
static const uint8_t crc_table[256] = {
      0x00, 0x1D, 0x3A, 0x27, 0x74, 0x69, 0x4E, 0x53,
      0xE8, 0xF5, 0xD2, 0xCF, 0x9C, 0x81, 0xA6, 0xBB,
      0xCD, 0xD0, 0xF7, 0xEA, 0xB9, 0xA4, 0x83, 0x9E,
      0x25, 0x38, 0x1F, 0x02, 0x51, 0x4C, 0x6B, 0x76,
      0x87, 0x9A, 0xBD, 0xA0, 0xF3, 0xEE, 0xC9, 0xD4,
      0x6F, 0x72, 0x55, 0x48, 0x1B, 0x06, 0x21, 0x3C,
      0x4A, 0x57, 0x70, 0x6D, 0x3E, 0x23, 0x04, 0x19,
      0xA2, 0xBF, 0x98, 0x85, 0xD6, 0xCB, 0xEC, 0xF1,
      0x13, 0x0E, 0x29, 0x34, 0x67, 0x7A, 0x5D, 0x40,
      0xFB, 0xE6, 0xC1, 0xDC, 0x8F, 0x92, 0xB5, 0xA8,
      0xDE, 0xC3, 0xE4, 0xF9, 0xAA, 0xB7, 0x90, 0x8D,
      0x36, 0x2B, 0x0C, 0x11, 0x42, 0x5F, 0x78, 0x65,
      0x94, 0x89, 0xAE, 0xB3, 0xE0, 0xFD, 0xDA, 0xC7,
      0x7C, 0x61, 0x46, 0x5B, 0x08, 0x15, 0x32, 0x2F,
      0x59, 0x44, 0x63, 0x7E, 0x2D, 0x30, 0x17, 0x0A,
      0xB1, 0xAC, 0x8B, 0x96, 0xC5, 0xD8, 0xFF, 0xE2,
      0x26, 0x3B, 0x1C, 0x01, 0x52, 0x4F, 0x68, 0x75,
      0xCE, 0xD3, 0xF4, 0xE9, 0xBA, 0xA7, 0x80, 0x9D,
      0xEB, 0xF6, 0xD1, 0xCC, 0x9F, 0x82, 0xA5, 0xB8,
      0x03, 0x1E, 0x39, 0x24, 0x77, 0x6A, 0x4D, 0x50,
      0xA1, 0xBC, 0x9B, 0x86, 0xD5, 0xC8, 0xEF, 0xF2,
      0x49, 0x54, 0x73, 0x6E, 0x3D, 0x20, 0x07, 0x1A,
      0x6C, 0x71, 0x56, 0x4B, 0x18, 0x05, 0x22, 0x3F,
      0x84, 0x99, 0xBE, 0xA3, 0xF0, 0xED, 0xCA, 0xD7,
      0x35, 0x28, 0x0F, 0x12, 0x41, 0x5C, 0x7B, 0x66,
      0xDD, 0xC0, 0xE7, 0xFA, 0xA9, 0xB4, 0x93, 0x8E,
      0xF8, 0xE5, 0xC2, 0xDF, 0x8C, 0x91, 0xB6, 0xAB,
      0x10, 0x0D, 0x2A, 0x37, 0x64, 0x79, 0x5E, 0x43,
      0xB2, 0xAF, 0x88, 0x95, 0xC6, 0xDB, 0xFC, 0xE1,
      0x5A, 0x47, 0x60, 0x7D, 0x2E, 0x33, 0x14, 0x09,
      0x7F, 0x62, 0x45, 0x58, 0x0B, 0x16, 0x31, 0x2C,
      0x97, 0x8A, 0xAD, 0xB0, 0xE3, 0xFE, 0xD9, 0xC4
};

static uint8_t sbc_crc8(const uint8_t * data, size_t len)
{
      uint8_t crc = 0x0f;
      size_t i;
      uint8_t octet;

      for (i = 0; i < len / 8; i++)
            crc = crc_table[crc ^ data[i]];

      octet = data[i];
      for (i = 0; i < len % 8; i++) {
            char bit = ((octet ^ crc) & 0x80) >> 7;

            crc = ((crc & 0x7f) << 1) ^ (bit ? 0x1d : 0);

            octet = octet << 1;
      }

      return crc;
}

/*
 * Code straight from the spec to calculate the bits array 
 * Takes a pointer to the frame in question, a pointer to the bits array and the sampling frequency (as 2 bit integer)
 */
static void sbc_calculate_bits(const struct sbc_frame *frame, int (*bits)[8], uint8_t sf)
{
      if (frame->channel_mode == MONO || frame->channel_mode == DUAL_CHANNEL) {
            int bitneed[2][8], loudness, max_bitneed, bitcount, slicecount, bitslice;
            int ch, sb;

            for (ch = 0; ch < frame->channels; ch++) {
                  if (frame->allocation_method == SNR) {
                        for (sb = 0; sb < frame->subbands; sb++) {
                              bitneed[ch][sb] = frame->scale_factor[ch][sb];
                        }
                  } else {
                        for (sb = 0; sb < frame->subbands; sb++) {
                              if (frame->scale_factor[ch][sb] == 0) {
                                    bitneed[ch][sb] = -5;
                              } else {
                                    if (frame->subbands == 4) {
                                          loudness = frame->scale_factor[ch][sb] - sbc_offset4[sf][sb];
                                    } else {
                                          loudness = frame->scale_factor[ch][sb] - sbc_offset8[sf][sb];
                                    }
                                    if (loudness > 0) {
                                          bitneed[ch][sb] = loudness / 2;
                                    } else {
                                          bitneed[ch][sb] = loudness;
                                    }
                              }
                        }
                  }

                  max_bitneed = 0;
                  for (sb = 0; sb < frame->subbands; sb++) {
                        if (bitneed[ch][sb] > max_bitneed)
                              max_bitneed = bitneed[ch][sb];
                  }

                  bitcount = 0;
                  slicecount = 0;
                  bitslice = max_bitneed + 1;
                  do {
                        bitslice--;
                        bitcount += slicecount;
                        slicecount = 0;
                        for (sb = 0; sb < frame->subbands; sb++) {
                              if ((bitneed[ch][sb] > bitslice + 1) && (bitneed[ch][sb] < bitslice + 16)) {
                                    slicecount++;
                              } else if (bitneed[ch][sb] == bitslice + 1) {
                                    slicecount += 2;
                              }
                        }
                  } while (bitcount + slicecount < frame->bitpool);

                  if (bitcount + slicecount == frame->bitpool) {
                        bitcount += slicecount;
                        bitslice--;
                  }

                  for (sb = 0; sb < frame->subbands; sb++) {
                        if (bitneed[ch][sb] < bitslice + 2) {
                              bits[ch][sb] = 0;
                        } else {
                              bits[ch][sb] = bitneed[ch][sb] - bitslice;
                              if (bits[ch][sb] > 16)
                                    bits[ch][sb] = 16;
                        }
                  }

                  sb = 0;
                  while (bitcount < frame->bitpool && sb < frame->subbands) {
                        if ((bits[ch][sb] >= 2) && (bits[ch][sb] < 16)) {
                              bits[ch][sb]++;
                              bitcount++;
                        } else if ((bitneed[ch][sb] == bitslice + 1) && (frame->bitpool > bitcount + 1)) {
                              bits[ch][sb] = 2;
                              bitcount += 2;
                        }
                        sb++;
                  }

                  sb = 0;
                  while (bitcount < frame->bitpool && sb < frame->subbands) {
                        if (bits[ch][sb] < 16) {
                              bits[ch][sb]++;
                              bitcount++;
                        }
                        sb++;
                  }

            }

      } else if (frame->channel_mode == STEREO || frame->channel_mode == JOINT_STEREO) {
            int bitneed[2][8], loudness, max_bitneed, bitcount, slicecount, bitslice;
            int ch, sb;

            if (frame->allocation_method == SNR) {
                  for (ch = 0; ch < 2; ch++) {
                        for (sb = 0; sb < frame->subbands; sb++) {
                              bitneed[ch][sb] = frame->scale_factor[ch][sb];
                        }
                  }
            } else {
                  for (ch = 0; ch < 2; ch++) {
                        for (sb = 0; sb < frame->subbands; sb++) {
                              if (frame->scale_factor[ch][sb] == 0) {
                                    bitneed[ch][sb] = -5;
                              } else {
                                    if (frame->subbands == 4) {
                                          loudness = frame->scale_factor[ch][sb] - sbc_offset4[sf][sb];
                                    } else {
                                          loudness = frame->scale_factor[ch][sb] - sbc_offset8[sf][sb];
                                    }
                                    if (loudness > 0) {
                                          bitneed[ch][sb] = loudness / 2;
                                    } else {
                                          bitneed[ch][sb] = loudness;
                                    }
                              }
                        }
                  }
            }

            max_bitneed = 0;
            for (ch = 0; ch < 2; ch++) {
                  for (sb = 0; sb < frame->subbands; sb++) {
                        if (bitneed[ch][sb] > max_bitneed)
                              max_bitneed = bitneed[ch][sb];
                  }
            }

            bitcount = 0;
            slicecount = 0;
            bitslice = max_bitneed + 1;
            do {
                  bitslice--;
                  bitcount += slicecount;
                  slicecount = 0;
                  for (ch = 0; ch < 2; ch++) {
                        for (sb = 0; sb < frame->subbands; sb++) {
                              if ((bitneed[ch][sb] > bitslice + 1) && (bitneed[ch][sb] < bitslice + 16)) {
                                    slicecount++;
                              } else if (bitneed[ch][sb] == bitslice + 1) {
                                    slicecount += 2;
                              }
                        }
                  }
            } while (bitcount + slicecount < frame->bitpool);
            if (bitcount + slicecount == frame->bitpool) {
                  bitcount += slicecount;
                  bitslice--;
            }

            for (ch = 0; ch < 2; ch++) {
                  for (sb = 0; sb < frame->subbands; sb++) {
                        if (bitneed[ch][sb] < bitslice + 2) {
                              bits[ch][sb] = 0;
                        } else {
                              bits[ch][sb] = bitneed[ch][sb] - bitslice;
                              if (bits[ch][sb] > 16)
                                    bits[ch][sb] = 16;
                        }
                  }
            }

            ch = 0;
            sb = 0;
            while ((bitcount < frame->bitpool) && (sb < frame->subbands)) {
                  if ((bits[ch][sb] >= 2) && (bits[ch][sb] < 16)) {
                        bits[ch][sb]++;
                        bitcount++;
                  } else if ((bitneed[ch][sb] == bitslice + 1) && (frame->bitpool > bitcount + 1)) {
                        bits[ch][sb] = 2;
                        bitcount += 2;
                  }
                  if (ch == 1) {
                        ch = 0;
                        sb++;
                  } else {
                        ch = 1;
                  }
            }

            ch = 0;
            sb = 0;
            while ((bitcount < frame->bitpool) && (sb < frame->subbands)) {
                  if (bits[ch][sb] < 16) {
                        bits[ch][sb]++;
                        bitcount++;
                  }
                  if (ch == 1) {
                        ch = 0;
                        sb++;
                  } else {
                        ch = 1;
                  }
            }

      }

}

/* 
 * Unpacks a SBC frame at the beginning of the stream in data,
 * which has at most len bytes into frame.
 * Returns the length in bytes of the packed frame, or a negative
 * value on error. The error codes are:
 *
 *  -1   Data stream too short
 *  -2   Sync byte incorrect
 *  -3   CRC8 incorrect
 *  -4   Bitpool value out of bounds
 */
static int sbc_unpack_frame(const uint8_t * data, struct sbc_frame *frame, size_t len)
{
      int consumed;
      /* Will copy the parts of the header that are relevant to crc calculation here */
      uint8_t crc_header[11] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
      int crc_pos = 0;
      int32_t temp;

      uint8_t sf;       /* sampling_frequency, temporarily needed as array index */

      int ch, sb, blk, bit;   /* channel, subband, block and bit standard counters */
      int bits[2][8];         /* bits distribution */
      int levels[2][8]; /* levels derived from that */

      if (len < 4)
            return -1;

      if (data[0] != SBC_SYNCWORD)
            return -2;

      sf = (data[1] >> 6) & 0x03;
      switch (sf) {
      case SBC_FS_16:
            frame->sampling_frequency = 16000;
            break;
      case SBC_FS_32:
            frame->sampling_frequency = 32000;
            break;
      case SBC_FS_44:
            frame->sampling_frequency = 44100;
            break;
      case SBC_FS_48:
            frame->sampling_frequency = 48000;
            break;
      }

      switch ((data[1] >> 4) & 0x03) {
      case SBC_NB_4:
            frame->blocks = 4;
            break;
      case SBC_NB_8:
            frame->blocks = 8;
            break;
      case SBC_NB_12:
            frame->blocks = 12;
            break;
      case SBC_NB_16:
            frame->blocks = 16;
            break;
      }

      frame->channel_mode = (data[1] >> 2) & 0x03;
      switch (frame->channel_mode) {
      case MONO:
            frame->channels = 1;
            break;
      case DUAL_CHANNEL:      /* fall-through */
      case STEREO:
      case JOINT_STEREO:
            frame->channels = 2;
            break;
      }

      frame->allocation_method = (data[1] >> 1) & 0x01;

      frame->subbands = (data[1] & 0x01) ? 8 : 4;

      frame->bitpool = data[2];

      if (((frame->channel_mode == MONO || frame->channel_mode == DUAL_CHANNEL)
           && frame->bitpool > 16 * frame->subbands)
          || ((frame->channel_mode == STEREO || frame->channel_mode == JOINT_STEREO)
            && frame->bitpool > 32 * frame->subbands))
            return -4;

      /* data[3] is crc, we're checking it later */

      consumed = 32;

      crc_header[0] = data[1];
      crc_header[1] = data[2];
      crc_pos = 16;

      if (frame->channel_mode == JOINT_STEREO) {
            if (len * 8 < consumed + frame->subbands)
                  return -1;

            frame->join = 0x00;
            for (sb = 0; sb < frame->subbands - 1; sb++) {
                  frame->join |= ((data[4] >> (7 - sb)) & 0x01) << sb;
            }
            if (frame->subbands == 4) {
                  crc_header[crc_pos / 8] = data[4] & 0xf0;
            } else {
                  crc_header[crc_pos / 8] = data[4];
            }

            consumed += frame->subbands;
            crc_pos += frame->subbands;
      }

      if (len * 8 < consumed + (4 * frame->subbands * frame->channels))
            return -1;

      for (ch = 0; ch < frame->channels; ch++) {
            for (sb = 0; sb < frame->subbands; sb++) {
                  /* FIXME assert(consumed % 4 == 0); */
                  frame->scale_factor[ch][sb] = (data[consumed >> 3] >> (4 - (consumed & 0x7))) & 0x0F;
                  crc_header[crc_pos >> 3] |= frame->scale_factor[ch][sb] << (4 - (crc_pos & 0x7));

                  consumed += 4;
                  crc_pos += 4;
            }
      }

      if (data[3] != sbc_crc8(crc_header, crc_pos))
            return -3;

      sbc_calculate_bits(frame, bits, sf);

      for (blk = 0; blk < frame->blocks; blk++) {
            for (ch = 0; ch < frame->channels; ch++) {
                  for (sb = 0; sb < frame->subbands; sb++) {
                        frame->audio_sample[blk][ch][sb] = 0;
                        if (bits[ch][sb] == 0)
                              continue;

                        for (bit = 0; bit < bits[ch][sb]; bit++) {
                              int b;      /* A bit */
                              if (consumed > len * 8)
                                    return -1;

                              b = (data[consumed >> 3] >> (7 - (consumed & 0x7))) & 0x01;
                              frame->audio_sample[blk][ch][sb] |= b << (bits[ch][sb] - bit - 1);

                              consumed++;
                        }
                  }
            }
      }

      for (ch = 0; ch < frame->channels; ch++) {
            for (sb = 0; sb < frame->subbands; sb++) {
                  levels[ch][sb] = (1 << bits[ch][sb]) - 1;
            }
      }

      for (blk = 0; blk < frame->blocks; blk++) {
            for (ch = 0; ch < frame->channels; ch++) {
                  for (sb = 0; sb < frame->subbands; sb++) {
                        if (levels[ch][sb] > 0) {
                              frame->sb_sample[blk][ch][sb] = 
                                    (((frame->audio_sample[blk][ch][sb] << 16) | 0x8000) / levels[ch][sb]) - 0x8000; 

                              frame->sb_sample[blk][ch][sb] >>= 3;
                              frame->sb_sample[blk][ch][sb] = (frame->sb_sample[blk][ch][sb] << (frame->scale_factor[ch][sb] + 1)); // Q13 

                        } else {
                              frame->sb_sample[blk][ch][sb] = 0;
                        }
                  }
            }
      }

      if (frame->channel_mode == JOINT_STEREO) {
            for (blk = 0; blk < frame->blocks; blk++) {
                  for (sb = 0; sb < frame->subbands; sb++) {
                        if (frame->join & (0x01 << sb)) {
                              temp = frame->sb_sample[blk][0][sb] + frame->sb_sample[blk][1][sb];
                              frame->sb_sample[blk][1][sb] = frame->sb_sample[blk][0][sb] - frame->sb_sample[blk][1][sb];
                              frame->sb_sample[blk][0][sb] = temp;
                        }
                  }
            }
      }

      if ((consumed & 0x7) != 0)
            consumed += 8 - (consumed & 0x7);

      
      return consumed >> 3;
}

static void sbc_decoder_init(struct sbc_decoder_state *state, const struct sbc_frame *frame)
{
      int i, ch;

      memset(state->V, 0, sizeof(state->V));
      state->subbands = frame->subbands;

      for (ch = 0; ch < 2; ch++)
            for (i = 0; i < frame->subbands * 2; i++)
                  state->offset[ch][i] = (10 * i + 10);
}

static inline void sbc_synthesize_four(struct sbc_decoder_state *state,
                        struct sbc_frame *frame, int ch, int blk)
{
      int i, j, k, idx;
      sbc_extended_t res;

      for(i = 0; i < 8; i++) {
            /* Shifting */
            state->offset[ch][i]--;
            if(state->offset[ch][i] < 0) {
                  state->offset[ch][i] = 79;
                  for(j = 0; j < 9; j++) {
                        state->V[ch][j+80] = state->V[ch][j];
                  }
            }
      }
      

      for(i = 0; i < 8; i++) {
            /* Distribute the new matrix value to the shifted position */
            SBC_FIXED_0(res);
            for (j = 0; j < 4; j++) {
                  MULA(res, synmatrix4[i][j], frame->sb_sample[blk][ch][j]);
            }
            state->V[ch][state->offset[ch][i]] = SCALE4_STAGED1(res);
      }

      /* Compute the samples */
      for(idx = 0, i = 0; i < 4; i++) {
            k = (i + 4) & 0xf;
            SBC_FIXED_0(res);
            for(j = 0; j < 10; idx++) {
            MULA(res, state->V[ch][state->offset[ch][i]+j++], sbc_proto_4_40m0[idx]);
                  MULA(res, state->V[ch][state->offset[ch][k]+j++], sbc_proto_4_40m1[idx]);
            }
            /* Store in output */
            frame->pcm_sample[ch][blk * 4 + i] = SCALE4_STAGED2(res); // Q0
      }
}

static inline void sbc_synthesize_eight(struct sbc_decoder_state *state,
                        struct sbc_frame *frame, int ch, int blk)
{
      int i, j, k, idx;
      sbc_extended_t res;

      for(i = 0; i < 16; i++) {
            /* Shifting */
            state->offset[ch][i]--;
            if(state->offset[ch][i] < 0) {
                  state->offset[ch][i] = 159;
                  for(j = 0; j < 9; j++) {
                        state->V[ch][j+160] = state->V[ch][j]; 
                  }
            }
      }

      for(i = 0; i < 16; i++) {
            /* Distribute the new matrix value to the shifted position */
            SBC_FIXED_0(res);
            for (j = 0; j < 8; j++) {
                  MULA(res, synmatrix8[i][j], frame->sb_sample[blk][ch][j]); // Q28 = Q15 * Q13
            }
            state->V[ch][state->offset[ch][i]] = SCALE8_STAGED1(res); // Q10
      }
      

      /* Compute the samples */
      for(idx = 0, i = 0; i < 8; i++) {
            k = (i + 8) & 0xf;
            SBC_FIXED_0(res);
            for(j = 0; j < 10; idx++) {
                  MULA(res, state->V[ch][state->offset[ch][i]+j++], sbc_proto_8_80m0[idx]);
                  MULA(res, state->V[ch][state->offset[ch][k]+j++], sbc_proto_8_80m1[idx]);
            }
            /* Store in output */
            frame->pcm_sample[ch][blk * 8 + i] = SCALE8_STAGED2(res); // Q0

      }
}

static int sbc_synthesize_audio(struct sbc_decoder_state *state, struct sbc_frame *frame)
{
      int ch, blk;
      
      switch (frame->subbands) {
      case 4:
            for (ch = 0; ch < frame->channels; ch++) {
                  for (blk = 0; blk < frame->blocks; blk++)
                        sbc_synthesize_four(state, frame, ch, blk);
            }
            return frame->blocks * 4;

      case 8:
            for (ch = 0; ch < frame->channels; ch++) {
                  for (blk = 0; blk < frame->blocks; blk++)
                        sbc_synthesize_eight(state, frame, ch, blk);
            }
            return frame->blocks * 8;

      default:
            return -EIO;
      }
}

static void sbc_encoder_init(struct sbc_encoder_state *state, const struct sbc_frame *frame)
{
      memset(&state->X, 0, sizeof(state->X));
      state->subbands = frame->subbands;
}

static inline void _sbc_analyze_four(const int32_t *in, int32_t *out)
{

      sbc_extended_t res;
      sbc_extended_t t[8];

      out[0] = out[1] = out[2] = out[3] = 0;

      MUL(res, _sbc_proto_4[0], (in[8] - in[32])); // Q18
      MULA(res, _sbc_proto_4[1], (in[16] - in[24]));
      t[0] = SCALE4_STAGE1(res); // Q8

      MUL(res, _sbc_proto_4[2], in[1]);
      MULA(res, _sbc_proto_4[3], in[9]);
      MULA(res, _sbc_proto_4[4], in[17]);
      MULA(res, _sbc_proto_4[5], in[25]);
      MULA(res, _sbc_proto_4[6], in[33]);
      t[1] = SCALE4_STAGE1(res);

      MUL(res, _sbc_proto_4[7], in[2]);
      MULA(res, _sbc_proto_4[8], in[10]);
      MULA(res, _sbc_proto_4[9], in[18]);
      MULA(res, _sbc_proto_4[10], in[26]);
      MULA(res, _sbc_proto_4[11], in[34]);
      t[2] = SCALE4_STAGE1(res);

      MUL(res, _sbc_proto_4[12], in[3]);
      MULA(res, _sbc_proto_4[13], in[11]);
      MULA(res, _sbc_proto_4[14], in[19]);
      MULA(res, _sbc_proto_4[15], in[27]);
      MULA(res, _sbc_proto_4[16], in[35]);
      t[3] = SCALE4_STAGE1(res);

      MUL(res, _sbc_proto_4[17], in[4]);
      MULA(res, _sbc_proto_4[18], (in[12] + in[28]));
      MULA(res, _sbc_proto_4[19], in[20]);
      MULA(res, _sbc_proto_4[17], in[36]);
      t[4] = SCALE4_STAGE1(res);

      MUL(res, _sbc_proto_4[16], in[5]);
      MULA(res, _sbc_proto_4[15], in[13]);
      MULA(res, _sbc_proto_4[14], in[21]);
      MULA(res, _sbc_proto_4[13], in[29]);
      MULA(res, _sbc_proto_4[12], in[37]);
      t[5] = SCALE4_STAGE1(res);

      MUL(res, _sbc_proto_4[11], in[6]);
      MULA(res, _sbc_proto_4[10], in[14]);
      MULA(res, _sbc_proto_4[9], in[22]);
      MULA(res, _sbc_proto_4[8], in[30]);
      MULA(res, _sbc_proto_4[7], in[38]);
      t[6] = SCALE4_STAGE1(res);

      MUL(res, _sbc_proto_4[6], in[7]);
      MULA(res, _sbc_proto_4[5], in[15]);
      MULA(res, _sbc_proto_4[4], in[23]);
      MULA(res, _sbc_proto_4[3], in[31]);
      MULA(res, _sbc_proto_4[2], in[39]);
      t[7] = SCALE4_STAGE1(res);

      MUL(res, _anamatrix4[0], t[0]);
      MULA(res, _anamatrix4[1], t[1]);
      MULA(res, _anamatrix4[2], t[2]);
      MULA(res, _anamatrix4[1], t[3]);
      MULA(res, _anamatrix4[0], t[4]);
      MULA(res, _anamatrix4[3], t[5]);
      MULA(res, -_anamatrix4[3], t[7]);
      out[0] = SCALE4_STAGE2(res); // Q0
      
      MUL(res, -_anamatrix4[0], t[0]);
      MULA(res, _anamatrix4[3], t[1]);
      MULA(res, _anamatrix4[2], t[2]);
      MULA(res, _anamatrix4[3], t[3]);
      MULA(res, -_anamatrix4[0], t[4]);
      MULA(res, -_anamatrix4[1], t[5]);
      MULA(res, _anamatrix4[1], t[7]);
      out[1] = SCALE4_STAGE2(res);


      MUL(res, -_anamatrix4[0], t[0]);
      MULA(res, -_anamatrix4[3], t[1]);
      MULA(res, _anamatrix4[2], t[2]);
      MULA(res, -_anamatrix4[3], t[3]);
      MULA(res, -_anamatrix4[0], t[4]);
      MULA(res, _anamatrix4[1], t[5]);
      MULA(res, -_anamatrix4[1], t[7]);
      out[2] = SCALE4_STAGE2(res);

      MUL(res, _anamatrix4[0], t[0]);
      MULA(res, -_anamatrix4[1], t[1]);
      MULA(res, _anamatrix4[2], t[2]);
      MULA(res, -_anamatrix4[1], t[3]);
      MULA(res, _anamatrix4[0], t[4]);
      MULA(res, -_anamatrix4[3], t[5]);
      MULA(res, _anamatrix4[3], t[7]);
      out[3] = SCALE4_STAGE2(res);
}
static inline void sbc_analyze_four(struct sbc_encoder_state *state,
                        struct sbc_frame *frame, int ch, int blk)
{
      int i;
      /* Input 4 New Audio Samples */
      for (i = 39; i >= 4; i--)
            state->X[ch][i] = state->X[ch][i - 4];
      for (i = 3; i >= 0; i--)
            state->X[ch][i] = frame->pcm_sample[ch][blk * 4 + (3 - i)];
      _sbc_analyze_four(state->X[ch], frame->sb_sample_f[blk][ch]);
}

static inline void _sbc_analyze_eight(const int32_t *in, int32_t *out)
{
      sbc_extended_t res;
      sbc_extended_t t[8];

      out[0] = out[1] = out[2] = out[3] = out[4] = out[5] = out[6] = out[7] = 0;
      
      MUL(res,  _sbc_proto_8[0], (in[16] - in[64])); // Q18 = Q18 * Q0
      MULA(res, _sbc_proto_8[1], (in[32] - in[48]));
      MULA(res, _sbc_proto_8[2], in[4]);
      MULA(res, _sbc_proto_8[3], in[20]);
      MULA(res, _sbc_proto_8[4], in[36]);
      MULA(res, _sbc_proto_8[5], in[52]);
      t[0] = SCALE8_STAGE1(res); // Q10

      MUL(res,   _sbc_proto_8[6], in[2]);
      MULA(res,  _sbc_proto_8[7], in[18]);
      MULA(res,  _sbc_proto_8[8], in[34]);
      MULA(res,  _sbc_proto_8[9], in[50]);
      MULA(res, _sbc_proto_8[10], in[66]);
      t[1] = SCALE8_STAGE1(res);

      MUL(res,  _sbc_proto_8[11], in[1]);
      MULA(res, _sbc_proto_8[12], in[17]);
      MULA(res, _sbc_proto_8[13], in[33]);
      MULA(res, _sbc_proto_8[14], in[49]);
      MULA(res, _sbc_proto_8[15], in[65]);
      MULA(res, _sbc_proto_8[16], in[3]);
      MULA(res, _sbc_proto_8[17], in[19]);
      MULA(res, _sbc_proto_8[18], in[35]);
      MULA(res, _sbc_proto_8[19], in[51]);
      MULA(res, _sbc_proto_8[20], in[67]);
      t[2] = SCALE8_STAGE1(res);

      MUL(res,   _sbc_proto_8[21], in[5]);
      MULA(res,  _sbc_proto_8[22], in[21]);
      MULA(res,  _sbc_proto_8[23], in[37]);
      MULA(res,  _sbc_proto_8[24], in[53]);
      MULA(res,  _sbc_proto_8[25], in[69]);
      MULA(res, -_sbc_proto_8[15], in[15]);
      MULA(res, -_sbc_proto_8[14], in[31]);
      MULA(res, -_sbc_proto_8[13], in[47]);
      MULA(res, -_sbc_proto_8[12], in[63]);
      MULA(res, -_sbc_proto_8[11], in[79]);
      t[3] = SCALE8_STAGE1(res);

      MUL(res,   _sbc_proto_8[26], in[6]);
      MULA(res,  _sbc_proto_8[27], in[22]);
      MULA(res,  _sbc_proto_8[28], in[38]);
      MULA(res,  _sbc_proto_8[29], in[54]);
      MULA(res,  _sbc_proto_8[30], in[70]);
      MULA(res, -_sbc_proto_8[10], in[14]);
      MULA(res,  -_sbc_proto_8[9], in[30]);
      MULA(res,  -_sbc_proto_8[8], in[46]);
      MULA(res,  -_sbc_proto_8[7], in[62]);
      MULA(res,  -_sbc_proto_8[6], in[78]);
      t[4] = SCALE8_STAGE1(res);

      MUL(res,   _sbc_proto_8[31], in[7]);
      MULA(res,  _sbc_proto_8[32], in[23]);
      MULA(res,  _sbc_proto_8[33], in[39]);
      MULA(res,  _sbc_proto_8[34], in[55]);
      MULA(res,  _sbc_proto_8[35], in[71]);
      MULA(res, -_sbc_proto_8[20], in[13]);
      MULA(res, -_sbc_proto_8[19], in[29]);
      MULA(res, -_sbc_proto_8[18], in[45]);
      MULA(res, -_sbc_proto_8[17], in[61]);
      MULA(res, -_sbc_proto_8[16], in[77]);
      t[5] = SCALE8_STAGE1(res);

      MUL(res,   _sbc_proto_8[36], (in[8] + in[72]));
      MULA(res,  _sbc_proto_8[37], in[24]);
      MULA(res,  _sbc_proto_8[38], in[40]);
      MULA(res,  _sbc_proto_8[37], in[56]);
      MULA(res, -_sbc_proto_8[39], in[12]);
      MULA(res,  -_sbc_proto_8[5], in[28]);
      MULA(res,  -_sbc_proto_8[4], in[44]);
      MULA(res,  -_sbc_proto_8[3], in[60]);
      MULA(res,  -_sbc_proto_8[2], in[76]);
      t[6] = SCALE8_STAGE1(res);

      MUL(res,   _sbc_proto_8[35], in[9]);
      MULA(res,  _sbc_proto_8[34], in[25]);
      MULA(res,  _sbc_proto_8[33], in[41]);
      MULA(res,  _sbc_proto_8[32], in[57]);
      MULA(res,  _sbc_proto_8[31], in[73]);
      MULA(res, -_sbc_proto_8[25], in[11]);
      MULA(res, -_sbc_proto_8[24], in[27]);
      MULA(res, -_sbc_proto_8[23], in[43]);
      MULA(res, -_sbc_proto_8[22], in[59]);
      MULA(res, -_sbc_proto_8[21], in[75]);
      t[7] = SCALE8_STAGE1(res);

      MUL(res, _anamatrix8[0], t[0]); // = Q14 * Q10
      MULA(res, _anamatrix8[7], t[1]);
      MULA(res, _anamatrix8[2], t[2]);
      MULA(res, _anamatrix8[3], t[3]);
      MULA(res, _anamatrix8[6], t[4]);
      MULA(res, _anamatrix8[4], t[5]);
      MULA(res, _anamatrix8[1], t[6]);
      MULA(res, _anamatrix8[5], t[7]);
      out[0] = SCALE8_STAGE2(res); // Q0

      MUL(res, _anamatrix8[1], t[0]);
      MULA(res, _anamatrix8[7], t[1]);
      MULA(res, _anamatrix8[3], t[2]);
      MULA(res, -_anamatrix8[5], t[3]);
      MULA(res, -_anamatrix8[6], t[4]);
      MULA(res, -_anamatrix8[2], t[5]);
      MULA(res, -_anamatrix8[0], t[6]);
      MULA(res, -_anamatrix8[4], t[7]);
      out[1] = SCALE8_STAGE2(res);

      MUL(res, -_anamatrix8[1], t[0]);
      MULA(res, _anamatrix8[7], t[1]);
      MULA(res, _anamatrix8[4], t[2]);
      MULA(res, -_anamatrix8[2], t[3]);
      MULA(res, -_anamatrix8[6], t[4]);
      MULA(res, _anamatrix8[5], t[5]);
      MULA(res, _anamatrix8[0], t[6]);
      MULA(res, _anamatrix8[3], t[7]);
      out[2] = SCALE8_STAGE2(res);

      MUL(res, -_anamatrix8[0], t[0]);
      MULA(res, _anamatrix8[7], t[1]);
      MULA(res, _anamatrix8[5], t[2]);
      MULA(res, -_anamatrix8[4], t[3]);
      MULA(res, _anamatrix8[6], t[4]);
      MULA(res, _anamatrix8[3], t[5]);
      MULA(res, -_anamatrix8[1], t[6]);
      MULA(res, -_anamatrix8[2], t[7]);
      out[3] = SCALE8_STAGE2(res);

      MUL(res, -_anamatrix8[0], t[0]);
      MULA(res, _anamatrix8[7], t[1]);
      MULA(res, -_anamatrix8[5], t[2]);
      MULA(res, _anamatrix8[4], t[3]);
      MULA(res, _anamatrix8[6], t[4]);
      MULA(res, -_anamatrix8[3], t[5]);
      MULA(res, -_anamatrix8[1], t[6]);
      MULA(res, _anamatrix8[2], t[7]);
      out[4] = SCALE8_STAGE2(res);

      MUL(res, -_anamatrix8[1], t[0]);
      MULA(res, _anamatrix8[7], t[1]);
      MULA(res, -_anamatrix8[4], t[2]);
      MULA(res, _anamatrix8[2], t[3]);
      MULA(res, -_anamatrix8[6], t[4]);
      MULA(res, -_anamatrix8[5], t[5]);
      MULA(res, _anamatrix8[0], t[6]);
      MULA(res, -_anamatrix8[3], t[7]);
      out[5] = SCALE8_STAGE2(res);

      MUL(res, _anamatrix8[1], t[0]);
      MULA(res, _anamatrix8[7], t[1]);
      MULA(res, -_anamatrix8[3], t[2]);
      MULA(res, _anamatrix8[5], t[3]);
      MULA(res, -_anamatrix8[6], t[4]);
      MULA(res, _anamatrix8[2], t[5]);
      MULA(res, -_anamatrix8[0], t[6]);
      MULA(res, _anamatrix8[4], t[7]);
      out[6] = SCALE8_STAGE2(res);

      MUL(res, _anamatrix8[0], t[0]);
      MULA(res, _anamatrix8[7], t[1]);
      MULA(res, -_anamatrix8[2], t[2]);
      MULA(res, -_anamatrix8[3], t[3]);
      MULA(res, _anamatrix8[6], t[4]);
      MULA(res, -_anamatrix8[4], t[5]);
      MULA(res, _anamatrix8[1], t[6]);
      MULA(res, -_anamatrix8[5], t[7]);
      out[7] = SCALE8_STAGE2(res);
}

static inline void sbc_analyze_eight(struct sbc_encoder_state *state,
                             struct sbc_frame *frame, int ch, int blk)
{
      int i;

      /* Input 8 Audio Samples */
      for (i = 79; i >= 8; i--)
            state->X[ch][i] = state->X[ch][i - 8];
      for (i = 7; i >= 0; i--)
            state->X[ch][i] = frame->pcm_sample[ch][blk * 8 + (7 - i)];
      _sbc_analyze_eight(state->X[ch], frame->sb_sample_f[blk][ch]);
}

static int sbc_analyze_audio(struct sbc_encoder_state *state, struct sbc_frame *frame)
{
      int ch, blk;

      switch (frame->subbands) {
      case 4:
            for (ch = 0; ch < frame->channels; ch++)
                  for (blk = 0; blk < frame->blocks; blk++) {
                        sbc_analyze_four(state, frame, ch, blk);
                  }
            return frame->blocks * 4;

      case 8:
            for (ch = 0; ch < frame->channels; ch++)
                  for (blk = 0; blk < frame->blocks; blk++) {
                        sbc_analyze_eight(state, frame, ch, blk);
                  }
            return frame->blocks * 8;

      default:
            return -EIO;
      }
}

/*
 * Packs the SBC frame from frame into the memory at data. At most len
 * bytes will be used, should more memory be needed an appropriate 
 * error code will be returned. Returns the length of the packed frame
 * on success or a negative value on error. 
 *
 * The error codes are:
 * -1 Not enough memory reserved
 * -2 Unsupported sampling rate
 * -3 Unsupported number of blocks
 * -4 Unsupported number of subbands
 * -5 Bitpool value out of bounds
 * -99 not implemented
 */

static int sbc_pack_frame(uint8_t * data, struct sbc_frame *frame, size_t len)
{
      int produced;
      /* Will copy the header parts for CRC-8 calculation here */
      uint8_t crc_header[11] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
      int crc_pos = 0;

      uint8_t sf;       /* Sampling frequency as temporary value for table lookup */

      int ch, sb, blk, bit;   /* channel, subband, block and bit counters */
      int bits[2][8];         /* bits distribution */
      int levels[2][8]; /* levels are derived from that */

      u_int32_t scalefactor[2][8];  /* derived from frame->scale_factor */

      if (len < 4) {
            return -1;
      }

      /* Clear first 4 bytes of data (that's the constant length part of the SBC header) */
      memset(data, 0, 4);

      data[0] = SBC_SYNCWORD;

      if (frame->sampling_frequency == 16000) {
            data[1] |= (SBC_FS_16 & 0x03) << 6;
            sf = SBC_FS_16;
      } else if (frame->sampling_frequency == 32000) {
            data[1] |= (SBC_FS_32 & 0x03) << 6;
            sf = SBC_FS_32;
      } else if (frame->sampling_frequency == 44100) {
            data[1] |= (SBC_FS_44 & 0x03) << 6;
            sf = SBC_FS_44;
      } else if (frame->sampling_frequency == 48000) {
            data[1] |= (SBC_FS_48 & 0x03) << 6;
            sf = SBC_FS_48;
      } else {
            return -2;
      }

      switch (frame->blocks) {
      case 4:
            data[1] |= (SBC_NB_4 & 0x03) << 4;
            break;
      case 8:
            data[1] |= (SBC_NB_8 & 0x03) << 4;
            break;
      case 12:
            data[1] |= (SBC_NB_12 & 0x03) << 4;
            break;
      case 16:
            data[1] |= (SBC_NB_16 & 0x03) << 4;
            break;
      default:
            return -3;
            break;
      }

      data[1] |= (frame->channel_mode & 0x03) << 2;

      data[1] |= (frame->allocation_method & 0x01) << 1;

      switch (frame->subbands) {
      case 4:
            /* Nothing to do */
            break;
      case 8:
            data[1] |= 0x01;
            break;
      default:
            return -4;
            break;
      }

      data[2] = frame->bitpool;
      if (((frame->channel_mode == MONO || frame->channel_mode == DUAL_CHANNEL)
           && frame->bitpool > 16 * frame->subbands)
          || ((frame->channel_mode == STEREO || frame->channel_mode == JOINT_STEREO)
            && frame->bitpool > 32 * frame->subbands)) {
            return -5;
      }

      /* Can't fill in crc yet */

      produced = 32;

      crc_header[0] = data[1];
      crc_header[1] = data[2];
      crc_pos = 16;

      for (ch = 0; ch < frame->channels; ch++) {
            for (sb = 0; sb < frame->subbands; sb++) {
                  frame->scale_factor[ch][sb] = 0;
                  scalefactor[ch][sb] = 2;
                  for (blk = 0; blk < frame->blocks; blk++) {
                        while (scalefactor[ch][sb] < fabs(frame->sb_sample_f[blk][ch][sb])) {
                              frame->scale_factor[ch][sb]++;
                              scalefactor[ch][sb] *= 2;
                        }
                  }
            }
      }

      if (frame->channel_mode == JOINT_STEREO) {
            int32_t sb_sample_j[16][2][7]; /* like frame->sb_sample but joint stereo */
            int scalefactor_j[2][7], scale_factor_j[2][7]; /* scalefactor and scale_factor in joint case */

            /* Calculate joint stereo signal */
            for (sb = 0; sb < frame->subbands - 1; sb++) {
                  for (blk = 0; blk < frame->blocks; blk++) {
                        sb_sample_j[blk][0][sb] = (frame->sb_sample_f[blk][0][sb] +  frame->sb_sample_f[blk][1][sb]) >> 1;
                        sb_sample_j[blk][1][sb] = (frame->sb_sample_f[blk][0][sb] -  frame->sb_sample_f[blk][1][sb]) >> 1;
                  }
            }

            /* calculate scale_factor_j and scalefactor_j for joint case */
            for (ch = 0; ch < 2; ch++) {
                  for (sb = 0; sb < frame->subbands - 1; sb++) {
                        scale_factor_j[ch][sb] = 0;
                        scalefactor_j[ch][sb] = 2;
                        for (blk = 0; blk < frame->blocks; blk++) {
                              while (scalefactor_j[ch][sb] < fabs(sb_sample_j[blk][ch][sb])) {
                                    scale_factor_j[ch][sb]++;
                                    scalefactor_j[ch][sb] *= 2;
                              }
                        }
                  }
            }

            /* decide which subbands to join */
            frame->join = 0;
            for (sb = 0; sb < frame->subbands - 1; sb++) {
                  if ((scalefactor[0][sb] + scalefactor[1][sb]) >
                              (scalefactor_j[0][sb] + scalefactor_j[1][sb]) ) {
                        /* use joint stereo for this subband */
                        frame->join |= 1 << sb;
                        frame->scale_factor[0][sb] = scale_factor_j[0][sb];
                        frame->scale_factor[1][sb] = scale_factor_j[1][sb];
                        scalefactor[0][sb] = scalefactor_j[0][sb];
                        scalefactor[1][sb] = scalefactor_j[1][sb];
                        for (blk = 0; blk < frame->blocks; blk++) {
                              frame->sb_sample_f[blk][0][sb] = sb_sample_j[blk][0][sb];
                              frame->sb_sample_f[blk][1][sb] = sb_sample_j[blk][1][sb];
                        }
                  }
            }

            if (len * 8 < produced + frame->subbands)
                  return -1;

            data[4] = 0;
            for (sb = 0; sb < frame->subbands - 1; sb++) {
                  data[4] |= ((frame->join >> sb) & 0x01) << (7 - sb);
            }
            if (frame->subbands == 4) {
                  crc_header[crc_pos / 8] = data[4] & 0xf0;
            } else {
                  crc_header[crc_pos / 8] = data[4];
            }
 
            produced += frame->subbands;
            crc_pos += frame->subbands;
      }

      if (len * 8 < produced + (4 * frame->subbands * frame->channels))
            return -1;

      for (ch = 0; ch < frame->channels; ch++) {
            for (sb = 0; sb < frame->subbands; sb++) {
                  if (produced % 8 == 0)
                        data[produced / 8] = 0;
                  data[produced / 8] |= ((frame->scale_factor[ch][sb] & 0x0F) << (4 - (produced % 8)));
                  crc_header[crc_pos / 8] |= ((frame->scale_factor[ch][sb] & 0x0F) << (4 - (crc_pos % 8)));

                  produced += 4;
                  crc_pos += 4;
            }
      }

      data[3] = sbc_crc8(crc_header, crc_pos);

      sbc_calculate_bits(frame, bits, sf);

      for (ch = 0; ch < frame->channels; ch++) {
            for (sb = 0; sb < frame->subbands; sb++) {
                  levels[ch][sb] = (1 << bits[ch][sb]) - 1;
            }
      }

      for (blk = 0; blk < frame->blocks; blk++) {
            for (ch = 0; ch < frame->channels; ch++) {
                  for (sb = 0; sb < frame->subbands; sb++) {
                        if (levels[ch][sb] > 0) {
                              frame->audio_sample[blk][ch][sb] =
                                    (uint16_t) ((((frame->sb_sample_f[blk][ch][sb]*levels[ch][sb]) >> (frame->scale_factor[ch][sb] + 1)) +
                                    levels[ch][sb]) >> 1);
                        } else {
                              frame->audio_sample[blk][ch][sb] = 0;
                        }
                  }
            }
      }

      for (blk = 0; blk < frame->blocks; blk++) {
            for (ch = 0; ch < frame->channels; ch++) {
                  for (sb = 0; sb < frame->subbands; sb++) {
                        if (bits[ch][sb] != 0) {
                              for (bit = 0; bit < bits[ch][sb]; bit++) {
                                    int b;      /* A bit */
                                    if (produced > len * 8) {
                                          return -1;
                                    }
                                    if (produced % 8 == 0) {
                                          data[produced / 8] = 0;
                                    }
                                    b = ((frame->audio_sample[blk][ch][sb]) >> (bits[ch][sb] - bit -
                                                                      1)) & 0x01;
                                    data[produced / 8] |= b << (7 - (produced % 8));
                                    produced++;
                              }
                        }
                  }
            }
      }

      if (produced % 8 != 0) {
            produced += 8 - (produced % 8);
      }

      return produced / 8;
}

struct sbc_priv {
      int init;
      struct sbc_frame frame;
      struct sbc_decoder_state dec_state;
      struct sbc_encoder_state enc_state;
};

int sbc_init(sbc_t *sbc, unsigned long flags)
{
      if (!sbc)
            return -EIO;

      memset(sbc, 0, sizeof(sbc_t));

      sbc->priv = malloc(sizeof(struct sbc_priv));
      if (!sbc->priv)
            return -ENOMEM;

      memset(sbc->priv, 0, sizeof(struct sbc_priv));

      sbc->rate = 44100;
      sbc->channels = 2;
      sbc->joint = 0;
      sbc->subbands = 8;
      sbc->blocks = 16;
      sbc->bitpool = 32;

      return 0;
}

int sbc_decode(sbc_t *sbc, void *data, int count)
{
      struct sbc_priv *priv;
      char *ptr;
      int i, ch, framelen, samples;

      if (!sbc)
            return -EIO;

      priv = sbc->priv;

      framelen = sbc_unpack_frame(data, &priv->frame, count);
      

      if (!priv->init) {
            sbc_decoder_init(&priv->dec_state, &priv->frame);
            priv->init = 1;

            sbc->rate = priv->frame.sampling_frequency;
            sbc->channels = priv->frame.channels;
            sbc->subbands = priv->frame.subbands;
            sbc->blocks = priv->frame.blocks;
            sbc->bitpool = priv->frame.bitpool;
      }

      samples = sbc_synthesize_audio(&priv->dec_state, &priv->frame);

      if (!sbc->data) {
            sbc->size = samples * priv->frame.channels * 2;
            sbc->data = malloc(sbc->size);
      }

      if (sbc->size < samples * priv->frame.channels * 2) {
            sbc->size = samples * priv->frame.channels * 2;
            sbc->data = realloc(sbc->data, sbc->size);
      }

      if (!sbc->data) {
            sbc->size = 0;
            return -ENOMEM;
      }

      ptr = sbc->data;

      for (i = 0; i < samples; i++) {
            for (ch = 0; ch < priv->frame.channels; ch++) {
                  int16_t s;
                  s = priv->frame.pcm_sample[ch][i];
                  *ptr++ = (s & 0xff00) >> 8;
                  *ptr++ = (s & 0x00ff);
            }
      }

      sbc->len = samples * priv->frame.channels * 2;

      return framelen;
}

int sbc_encode(sbc_t *sbc, void *data, int count)
{
      struct sbc_priv *priv;
      char *ptr;
      int i, ch, framelen, samples;

      if (!sbc)
            return -EIO;

      priv = sbc->priv;

      if (!priv->init) {
            priv->frame.sampling_frequency = sbc->rate;
            priv->frame.channels = sbc->channels;

            if (sbc->channels > 1) {
                  if (sbc->joint)
                        priv->frame.channel_mode = JOINT_STEREO;
                  else
                        priv->frame.channel_mode = STEREO;
            } else
                  priv->frame.channel_mode = MONO;

            priv->frame.allocation_method = SNR;
            priv->frame.subbands = sbc->subbands;
            priv->frame.blocks = sbc->blocks;
            priv->frame.bitpool = sbc->bitpool;

            sbc_encoder_init(&priv->enc_state, &priv->frame);
            priv->init = 1;
      }

      ptr = data;

      for (i = 0; i < priv->frame.subbands * priv->frame.blocks; i++) {
            for (ch = 0; ch < sbc->channels; ch++) {
                  int16_t s = (ptr[0] & 0xff) << 8 | (ptr[1] & 0xff);
                  ptr += 2;
                  priv->frame.pcm_sample[ch][i] = s;
            }
      }

      samples = sbc_analyze_audio(&priv->enc_state, &priv->frame);

      if (!sbc->data) {
            sbc->size = 1024;
            sbc->data = malloc(sbc->size);
      }

      if (!sbc->data) {
            sbc->size = 0;
            return -ENOMEM;
      }

      framelen = sbc_pack_frame(sbc->data, &priv->frame, sbc->size);

      sbc->len = framelen;

      sbc->duration = (1000000 * priv->frame.subbands * priv->frame.blocks) / sbc->rate;

      return samples * sbc->channels * 2;
}

void sbc_finish(sbc_t *sbc)
{
      if (!sbc)
            return;

      if (sbc->data)
            free(sbc->data);

      if (sbc->priv)
            free(sbc->priv);

      memset(sbc, 0, sizeof(sbc_t));
}

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