text: package com.wavpack.decoder;
  
  /*
  ** WordsUtils.java
  **
  ** Copyright (c) 2007 - 2008 Peter McQuillan
  **
  ** All Rights Reserved.
  **                       
  ** Distributed under the BSD Software License (see license.txt)  
  **
  */
  
  class WordsUtils {
  
  
      //////////////////////////////// local macros /////////////////////////////////
  
      static int LIMIT_ONES = 16; // maximum consecutive 1s sent for "div" data
  
      // these control the time constant "slow_level" which is used for hybrid mode
      // that controls bitrate as a function of residual level (HYBRID_BITRATE).
      static int SLS = 8;
      static int SLO = ((1 << (SLS - 1)));
  
  
      // these control the time constant of the 3 median level breakpoints
      static int DIV0 = 128; // 5/7 of samples
      static int DIV1 = 64;  // 10/49 of samples
      static int DIV2 = 32;  // 20/343 of samples
  
  
      ///////////////////////////// local table storage ////////////////////////////
  
      static char nbits_table[] =
              {
                      0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4,     // 0 - 15
                      5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,     // 16 - 31
                      6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,     // 32 - 47
                      6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,     // 48 - 63
                      7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,     // 64 - 79
                      7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,     // 80 - 95
                      7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,     // 96 - 111
                      7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,     // 112 - 127
                      8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,     // 128 - 143
                      8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,     // 144 - 159
                      8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,     // 160 - 175
                      8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,     // 176 - 191
                      8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,     // 192 - 207
                      8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,     // 208 - 223
                      8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,     // 224 - 239
                      8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8      // 240 - 255
              };
  
  
      static int log2_table[] =
              {
                      0x00, 0x01, 0x03, 0x04, 0x06, 0x07, 0x09, 0x0a, 0x0b, 0x0d, 0x0e, 0x10, 0x11, 0x12, 0x14, 0x15,
                      0x16, 0x18, 0x19, 0x1a, 0x1c, 0x1d, 0x1e, 0x20, 0x21, 0x22, 0x24, 0x25, 0x26, 0x28, 0x29, 0x2a,
                      0x2c, 0x2d, 0x2e, 0x2f, 0x31, 0x32, 0x33, 0x34, 0x36, 0x37, 0x38, 0x39, 0x3b, 0x3c, 0x3d, 0x3e,
                      0x3f, 0x41, 0x42, 0x43, 0x44, 0x45, 0x47, 0x48, 0x49, 0x4a, 0x4b, 0x4d, 0x4e, 0x4f, 0x50, 0x51,
                      0x52, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a, 0x5c, 0x5d, 0x5e, 0x5f, 0x60, 0x61, 0x62, 0x63,
                      0x64, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x74, 0x75,
                      0x76, 0x77, 0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85,
                      0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 0x90, 0x91, 0x92, 0x93, 0x94, 0x95,
                      0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, 0xa0, 0xa1, 0xa2, 0xa3, 0xa4,
                      0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, 0xb0, 0xb1, 0xb2, 0xb2,
                      0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, 0xc0, 0xc0,
                      0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xcb, 0xcb, 0xcc, 0xcd, 0xce,
                      0xcf, 0xd0, 0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd8, 0xd9, 0xda, 0xdb,
                      0xdc, 0xdc, 0xdd, 0xde, 0xdf, 0xe0, 0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe4, 0xe5, 0xe6, 0xe7, 0xe7,
                      0xe8, 0xe9, 0xea, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xee, 0xef, 0xf0, 0xf1, 0xf1, 0xf2, 0xf3, 0xf4,
                      0xf4, 0xf5, 0xf6, 0xf7, 0xf7, 0xf8, 0xf9, 0xf9, 0xfa, 0xfb, 0xfc, 0xfc, 0xfd, 0xfe, 0xff, 0xff
              };
  
  
      static int exp2_table[] =
              {
                      0x00, 0x01, 0x01, 0x02, 0x03, 0x03, 0x04, 0x05, 0x06, 0x06, 0x07, 0x08, 0x08, 0x09, 0x0a, 0x0b,
                      0x0b, 0x0c, 0x0d, 0x0e, 0x0e, 0x0f, 0x10, 0x10, 0x11, 0x12, 0x13, 0x13, 0x14, 0x15, 0x16, 0x16,
                      0x17, 0x18, 0x19, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1d, 0x1e, 0x1f, 0x20, 0x20, 0x21, 0x22, 0x23,
                      0x24, 0x24, 0x25, 0x26, 0x27, 0x28, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2c, 0x2d, 0x2e, 0x2f, 0x30,
                      0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3a, 0x3b, 0x3c, 0x3d,
                      0x3e, 0x3f, 0x40, 0x41, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x48, 0x49, 0x4a, 0x4b,
                      0x4c, 0x4d, 0x4e, 0x4f, 0x50, 0x51, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a,
                      0x5b, 0x5c, 0x5d, 0x5e, 0x5e, 0x5f, 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
                      0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,
                      0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x87, 0x88, 0x89, 0x8a,
                      0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 0x90, 0x91, 0x92, 0x93, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b,
                      0x9c, 0x9d, 0x9f, 0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad,
                      0xaf, 0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xbc, 0xbd, 0xbe, 0xbf, 0xc0,
                      0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc8, 0xc9, 0xca, 0xcb, 0xcd, 0xce, 0xcf, 0xd0, 0xd2, 0xd3, 0xd4,
                      0xd6, 0xd7, 0xd8, 0xd9, 0xdb, 0xdc, 0xdd, 0xde, 0xe0, 0xe1, 0xe2, 0xe4, 0xe5, 0xe6, 0xe8, 0xe9,
                      0xea, 0xec, 0xed, 0xee, 0xf0, 0xf1, 0xf2, 0xf4, 0xf5, 0xf6, 0xf8, 0xf9, 0xfa, 0xfc, 0xfd, 0xff
              };
  
  
      static char ones_count_table[] =
              {
                      0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5,
                      0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 6,
                      0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5,
                      0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 7,
                      0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5,
                      0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 6,
                      0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5,
                      0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 8
              };
  
  
      ///////////////////////////// executable code ////////////////////////////////
  
  
      // Read the median log2 values from the specifed metadata structure, convert
      // them back to 32-bit unsigned values and store them. If length is not
      // exactly correct then we flag and return an error.
  
      static int read_entropy_vars(WavpackStream wps, WavpackMetadata wpmd) {
          byte byteptr[] = wpmd.data; //byteptr needs to be unsigned chars, so convert to int array
          int[] b_array = new int[12];
          int i = 0;
          words_data w = new words_data();
  
          for (i = 0; i < 6; i++) {
              b_array[i] = (int) (byteptr[i] & 0xff);
          }
  
          w.holding_one = 0;
          w.holding_zero = 0;
  
          if (wpmd.byte_length != 12) {
              if ((wps.wphdr.flags & (Defines.MONO_FLAG | Defines.FALSE_STEREO)) == 0) {
                  return Defines.FALSE;
              }
          }
  
          w.c[0].median[0] = exp2s(b_array[0] + (b_array[1] << 8));
          w.c[0].median[1] = exp2s(b_array[2] + (b_array[3] << 8));
          w.c[0].median[2] = exp2s(b_array[4] + (b_array[5] << 8));
  
          if ((wps.wphdr.flags & (Defines.MONO_FLAG | Defines.FALSE_STEREO)) == 0) {
              for (i = 6; i < 12; i++) {
                  b_array[i] = (int) (byteptr[i] & 0xff);
              }
              w.c[1].median[0] = exp2s(b_array[6] + (b_array[7] << 8));
              w.c[1].median[1] = exp2s(b_array[8] + (b_array[9] << 8));
              w.c[1].median[2] = exp2s(b_array[10] + (b_array[11] << 8));
          }
  
          wps.w = w;
  
          return Defines.TRUE;
      }
  
  
      // Read the hybrid related values from the specifed metadata structure, convert
      // them back to their internal formats and store them. The extended profile
      // stuff is not implemented yet, so return an error if we get more data than
      // we know what to do with.
  
      static int read_hybrid_profile(WavpackStream wps, WavpackMetadata wpmd) {
          byte byteptr[] = wpmd.data;
          int bytecnt = wpmd.byte_length;
          int buffer_counter = 0;
          int uns_buf = 0;
          int uns_buf_plusone = 0;
  
          if ((wps.wphdr.flags & Defines.HYBRID_BITRATE) != 0) {
              uns_buf = (int) (byteptr[buffer_counter] & 0xff);
              uns_buf_plusone = (int) (byteptr[buffer_counter + 1] & 0xff);
  
              wps.w.c[0].slow_level = exp2s(uns_buf + (uns_buf_plusone << 8));
              buffer_counter = buffer_counter + 2;
  
              if ((wps.wphdr.flags & (Defines.MONO_FLAG | Defines.FALSE_STEREO)) == 0) {
                  uns_buf = (int) (byteptr[buffer_counter] & 0xff);
                  uns_buf_plusone = (int) (byteptr[buffer_counter + 1] & 0xff);
                  wps.w.c[1].slow_level = exp2s(uns_buf + (uns_buf_plusone << 8));
                  buffer_counter = buffer_counter + 2;
              }
          }
  
          uns_buf = (int) (byteptr[buffer_counter] & 0xff);
          uns_buf_plusone = (int) (byteptr[buffer_counter + 1] & 0xff);
  
          wps.w.bitrate_acc[0] = (int) (uns_buf + (uns_buf_plusone << 8)) << 16;
          buffer_counter = buffer_counter + 2;
  
          if ((wps.wphdr.flags & (Defines.MONO_FLAG | Defines.FALSE_STEREO)) == 0) {
              uns_buf = (int) (byteptr[buffer_counter] & 0xff);
              uns_buf_plusone = (int) (byteptr[buffer_counter + 1] & 0xff);
  
              wps.w.bitrate_acc[1] = (int) (uns_buf + (uns_buf_plusone << 8)) << 16;
              buffer_counter = buffer_counter + 2;
          }
  
          if (buffer_counter < bytecnt) {
              uns_buf = (int) (byteptr[buffer_counter] & 0xff);
              uns_buf_plusone = (int) (byteptr[buffer_counter + 1] & 0xff);
  
              wps.w.bitrate_delta[0] = exp2s((short) (uns_buf + (uns_buf_plusone << 8)));
              buffer_counter = buffer_counter + 2;
  
              if ((wps.wphdr.flags & (Defines.MONO_FLAG | Defines.FALSE_STEREO)) == 0) {
                  uns_buf = (int) (byteptr[buffer_counter] & 0xff);
                  uns_buf_plusone = (int) (byteptr[buffer_counter + 1] & 0xff);
                  wps.w.bitrate_delta[1] = exp2s((short) (uns_buf + (uns_buf_plusone << 8)));
                  buffer_counter = buffer_counter + 2;
              }
  
              if (buffer_counter < bytecnt)
                  return Defines.FALSE;
          } else
              wps.w.bitrate_delta[0] = wps.w.bitrate_delta[1] = 0;
  
          return Defines.TRUE;
      }
  
      // This function is called during both encoding and decoding of hybrid data to
      // update the "error_limit" variable which determines the maximum sample error
      // allowed in the main bitstream. In the HYBRID_BITRATE mode (which is the only
      // currently implemented) this is calculated from the slow_level values and the
      // bitrate accumulators. Note that the bitrate accumulators can be changing.
  
      static words_data update_error_limit(words_data w, long flags) {
          int bitrate_0 = (int) ((w.bitrate_acc[0] += w.bitrate_delta[0]) >> 16);
  
          if ((flags & (Defines.MONO_FLAG | Defines.FALSE_STEREO)) != 0) {
              if ((flags & Defines.HYBRID_BITRATE) != 0) {
                  int slow_log_0 = (int) ((w.c[0].slow_level + SLO) >> SLS);
  
                  if (slow_log_0 - bitrate_0 > -0x100)
                      w.c[0].error_limit = exp2s(slow_log_0 - bitrate_0 + 0x100);
                  else
                      w.c[0].error_limit = 0;
              } else
                  w.c[0].error_limit = exp2s(bitrate_0);
          } else {
              int bitrate_1 = (int) ((w.bitrate_acc[1] += w.bitrate_delta[1]) >> 16);
  
              if ((flags & Defines.HYBRID_BITRATE) != 0) {
                  int slow_log_0 = (int) ((w.c[0].slow_level + SLO) >> SLS);
                  int slow_log_1 = (int) ((w.c[1].slow_level + SLO) >> SLS);
  
                  if ((flags & Defines.HYBRID_BALANCE) != 0) {
                      int balance = (slow_log_1 - slow_log_0 + bitrate_1 + 1) >> 1;
  
                      if (balance > bitrate_0) {
                          bitrate_1 = bitrate_0 * 2;
                          bitrate_0 = 0;
                      } else if (-balance > bitrate_0) {
                          bitrate_0 = bitrate_0 * 2;
                          bitrate_1 = 0;
                      } else {
                          bitrate_1 = bitrate_0 + balance;
                          bitrate_0 = bitrate_0 - balance;
                      }
                  }
  
                  if (slow_log_0 - bitrate_0 > -0x100)
                      w.c[0].error_limit = exp2s(slow_log_0 - bitrate_0 + 0x100);
                  else
                      w.c[0].error_limit = 0;
  
                  if (slow_log_1 - bitrate_1 > -0x100)
                      w.c[1].error_limit = exp2s(slow_log_1 - bitrate_1 + 0x100);
                  else
                      w.c[1].error_limit = 0;
              } else {
                  w.c[0].error_limit = exp2s(bitrate_0);
                  w.c[1].error_limit = exp2s(bitrate_1);
              }
          }
  
          return w;
      }
  
  
      // Read the next word from the bitstream "wvbits" and return the value. This
      // function can be used for hybrid or lossless streams, but since an
      // optimized version is available for lossless this function would normally
      // be used for hybrid only. If a hybrid lossless stream is being read then
      // the "correction" offset is written at the specified pointer. A return value
      // of WORD_EOF indicates that the end of the bitstream was reached (all 1s) or
      // some other error occurred.
  
      static int get_words(long nsamples, long flags, words_data w, Bitstream bs, int[] buffer) {
          entropy_data[] c = w.c;
          int csamples;
          int buffer_counter = 0;
          int entidx = 1;
  
          if ((flags & (Defines.MONO_FLAG | Defines.FALSE_STEREO)) == 0) // if not mono
          {
              nsamples *= 2;
          } else {
              // it is mono
              entidx = 0;
          }
  
          for (csamples = 0; csamples < nsamples; ++csamples) {
  
              long ones_count, low, mid, high;
  
              if ((flags & (Defines.MONO_FLAG | Defines.FALSE_STEREO)) == 0) // if not mono
              {
                  if (entidx == 1)
                      entidx = 0;
                  else
                      entidx = 1;
              }
  
              if ((w.c[0].median[0] & ~1) == 0 && w.holding_zero == 0 && w.holding_one == 0
                      && (w.c[1].median[0] & ~1) == 0) {
  
                  long mask;
                  int cbits;
  
                  if (w.zeros_acc > 0) {
                      --w.zeros_acc;
  
                      if (w.zeros_acc > 0) {
                          c[entidx].slow_level -= (c[entidx].slow_level + SLO) >> SLS;
                          buffer[buffer_counter] = 0;
                          buffer_counter++;
                          continue;
                      }
                  } else {
                      cbits = 0;
                      bs = BitsUtils.getbit(bs);
  
                      while (cbits < 33 && bs.bitval > 0) {
                          cbits++;
                          bs = BitsUtils.getbit(bs);
                      }
  
                      if (cbits == 33) {
                          break;
                      }
  
                      if (cbits < 2)
                          w.zeros_acc = cbits;
                      else {
  
                          --cbits;
  
                          for (mask = 1,
                                  w.zeros_acc = 0; cbits > 0; mask <<= 1) {
                              bs = BitsUtils.getbit(bs);
  
                              if (bs.bitval > 0)
                                  w.zeros_acc |= mask;
                              cbits--;
                          }
  
                          w.zeros_acc |= mask;
                      }
  
                      if (w.zeros_acc > 0) {
  
                          c[entidx].slow_level -= (c[entidx].slow_level + SLO) >> SLS;
                          w.c[0].median[0] = 0;
                          w.c[0].median[1] = 0;
                          w.c[0].median[2] = 0;
                          w.c[1].median[0] = 0;
                          w.c[1].median[1] = 0;
                          w.c[1].median[2] = 0;
  
                          buffer[buffer_counter] = 0;
                          buffer_counter++;
                          continue;
                      }
                  }
              }
  
              if (w.holding_zero > 0)
                  ones_count = w.holding_zero = 0;
              else {
                  int next8;
                  int uns_buf;
  
                  if (bs.bc < 8) {
  
                      bs.ptr++;
                      bs.buf_index++;
  
                      if (bs.ptr == bs.end)
                          bs = BitsUtils.bs_read(bs);
  
                      uns_buf = bs.buf[bs.buf_index] & 0xff;
  
                      bs.sr = bs.sr | (uns_buf << bs.bc); // values in buffer must be unsigned
  
                      next8 = (int) (bs.sr & 0xff);
  
                      bs.bc += 8;
                  } else
                      next8 = (int) (bs.sr & 0xff);
  
                  if (next8 == 0xff) {
  
                      bs.bc -= 8;
                      bs.sr >>= 8;
  
                      ones_count = 8;
                      bs = BitsUtils.getbit(bs);
  
                      while (ones_count < (LIMIT_ONES + 1) && bs.bitval > 0) {
                          ones_count++;
                          bs = BitsUtils.getbit(bs);
                      }
  
                      if (ones_count == (LIMIT_ONES + 1)) {
                          break;
                      }
  
                      if (ones_count == LIMIT_ONES) {
                          long mask;
                          int cbits;
  
                          cbits = 0;
                          bs = BitsUtils.getbit(bs);
  
                          while (cbits < 33 && bs.bitval > 0) {
                              cbits++;
                              bs = BitsUtils.getbit(bs);
                          }
  
                          if (cbits == 33) {
                              break;
                          }
  
                          if (cbits < 2)
                              ones_count = cbits;
                          else {
                              for (mask = 1,
                                      ones_count = 0; --cbits > 0; mask <<= 1) {
                                  bs = BitsUtils.getbit(bs);
  
                                  if (bs.bitval > 0)
                                      ones_count |= mask;
                              }
                              ones_count |= mask;
                          }
  
                          ones_count += LIMIT_ONES;
                      }
                  } else {
                      bs.bc -= (ones_count = ones_count_table[next8]) + 1;
                      bs.sr = bs.sr >> ones_count + 1; // needs to be unsigned
                  }
  
                  if (w.holding_one > 0) {
                      w.holding_one = ones_count & 1;
                      ones_count = (ones_count >> 1) + 1;
                  } else {
                      w.holding_one = ones_count & 1;
                      ones_count >>= 1;
                  }
  
                  w.holding_zero = (int) (~w.holding_one & 1);
              }
  
              if ((flags & Defines.HYBRID_FLAG) > 0
                      && ((flags & (Defines.MONO_FLAG | Defines.FALSE_STEREO)) > 0 || (csamples & 1) == 0))
                  w = update_error_limit(w, flags);
  
              if (ones_count == 0) {
                  low = 0;
                  high = (((c[entidx].median[0]) >> 4) + 1) - 1;
                  c[entidx].median[0] -= (((c[entidx].median[0] + (DIV0 - 2)) / DIV0) * 2);
              } else {
                  low = (((c[entidx].median[0]) >> 4) + 1);
  
                  c[entidx].median[0] += ((c[entidx].median[0] + DIV0) / DIV0) * 5;
  
                  if (ones_count == 1) {
  
                      high = low + (((c[entidx].median[1]) >> 4) + 1) - 1;
                      c[entidx].median[1] -= ((c[entidx].median[1] + (DIV1 - 2)) / DIV1) * 2;
                  } else {
                      low += (((c[entidx].median[1]) >> 4) + 1);
                      c[entidx].median[1] += ((c[entidx].median[1] + DIV1) / DIV1) * 5;
  
                      if (ones_count == 2) {
                          high = low + (((c[entidx].median[2]) >> 4) + 1) - 1;
                          c[entidx].median[2] -= ((c[entidx].median[2] + (DIV2 - 2)) / DIV2) * 2;
                      } else {
                          low += (ones_count - 2) * (((c[entidx].median[2]) >> 4) + 1);
                          high = low + (((c[entidx].median[2]) >> 4) + 1) - 1;
                          c[entidx].median[2] += ((c[entidx].median[2] + DIV2) / DIV2) * 5;
                      }
                  }
              }
  
              mid = (high + low + 1) >> 1;
  
              if (c[entidx].error_limit == 0) {
                  mid = read_code(bs, high - low);
  
                  mid = mid + low;
              } else
                  while (high - low > c[entidx].error_limit) {
  
                      bs = BitsUtils.getbit(bs);
  
                      if (bs.bitval > 0) {
                          mid = (high + (low = mid) + 1) >> 1;
                      } else {
                          mid = ((high = mid - 1) + low + 1) >> 1;
                      }
                  }
  
              bs = BitsUtils.getbit(bs);
  
              if (bs.bitval > 0) {
                  buffer[buffer_counter] = (int) ~mid;
              } else {
                  buffer[buffer_counter] = (int) mid;
              }
  
              buffer_counter++;
  
              if ((flags & Defines.HYBRID_BITRATE) > 0)
                  c[entidx].slow_level = c[entidx].slow_level - ((c[entidx].slow_level + SLO) >> SLS) + mylog2(mid);
          }
  
          w.c = c;
  
          if ((flags & (Defines.MONO_FLAG | Defines.FALSE_STEREO)) != 0) {
              return csamples;
          } else {
              return (csamples / 2);
          }
      }
  
      static int count_bits(long av) {
          if (av < (1 << 8)) {
              return nbits_table[(int) av];
          } else {
              if (av < (1 << 16)) {
                  return nbits_table[(int) (av >>> 8)] + 8;
              } else {
                  if (av < (1 << 24)) {
                      return nbits_table[(int) (av >>> 16)] + 16;
                  } else {
                      return nbits_table[(int) (av >>> 24)] + 24;
                  }
              }
          }
      }
  
  
      // Read a single unsigned value from the specified bitstream with a value
      // from 0 to maxcode. If there are exactly a power of two number of possible
      // codes then this will read a fixed number of bits; otherwise it reads the
      // minimum number of bits and then determines whether another bit is needed
      // to define the code.
  
      static long read_code(Bitstream bs, long maxcode) {
          int bitcount = count_bits(maxcode);
          long extras = (1L << bitcount) - maxcode - 1, code;
  
          if (bitcount == 0) {
              return ((long) 0);
          }
  
          code = BitsUtils.getbits(bitcount - 1, bs);
  
          code &= (1L << (bitcount - 1)) - 1;
  
          if (code >= extras) {
  
              code = (code << 1) - extras;
  
              bs = BitsUtils.getbit(bs);
  
              if (bs.bitval > 0)
                  ++code;
          }
  
          return (code);
      }
  
  
      // The concept of a base 2 logarithm is used in many parts of WavPack. It is
      // a way of sufficiently accurately representing 32-bit signed and unsigned
      // values storing only 16 bits (actually fewer). It is also used in the hybrid
      // mode for quickly comparing the relative magnitude of large values (i.e.
      // division) and providing smooth exponentials using only addition.
  
      // These are not strict logarithms in that they become linear around zero and
      // can therefore represent both zero and negative values. They have 8 bits
      // of precision and in "roundtrip" conversions the total error never exceeds 1
      // part in 225 except for the cases of +/-115 and +/-195 (which error by 1).
  
  
      // This function returns the log2 for the specified 32-bit unsigned value.
      // The maximum value allowed is about 0xff800000 and returns 8447.
  
      static int mylog2(long avalue) {
          int dbits;
  
          if ((avalue += avalue >> 9) < (1 << 8)) {
              dbits = nbits_table[(int) avalue];
              return (dbits << 8) + log2_table[(int) (avalue << (9 - dbits)) & 0xff];
          } else {
              if (avalue < (1L << 16))
                  dbits = nbits_table[(int) (avalue >> 8)] + 8;
  
              else if (avalue < (1L << 24))
                  dbits = nbits_table[(int) (avalue >> 16)] + 16;
  
              else
                  dbits = nbits_table[(int) (avalue >> 24)] + 24;
  
              return (dbits << 8) + log2_table[(int) (avalue >> (dbits - 9)) & 0xff];
          }
      }
  
  
      // This function returns the log2 for the specified 32-bit signed value.
      // All input values are valid and the return values are in the range of
      // +/- 8192.
  
      int log2s(int value) {
          if (value < 0) {
              return -mylog2(-value);
          } else {
              return mylog2(value);
          }
      }
  
  
      // This function returns the original integer represented by the supplied
      // logarithm (at least within the provided accuracy). The log is signed,
      // but since a full 32-bit value is returned this can be used for unsigned
      // conversions as well (i.e. the input range is -8192 to +8447).
  
      static int exp2s(int log) {
          long value;
  
          if (log < 0)
              return -exp2s(-log);
  
          value = exp2_table[log & 0xff] | 0x100;
  
          if ((log >>= 8) <= 9)
              return ((int) (value >> (9 - log)));
          else
              return ((int) (value << (log - 9)));
      }
  
  
      // These two functions convert internal weights (which are normally +/-1024)
      // to and from an 8-bit signed character version for storage in metadata. The
      // weights are clipped here in the case that they are outside that range.
  
      static int restore_weight(byte weight) {
          int result;
  
          if ((result = (int) weight << 3) > 0)
              result += (result + 64) >> 7;
  
          return result;
      }
  
  }
  