///////////////////////////// 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.
internal static int read_entropy_vars(WavpackStream wps, WavpackMetadata wpmd)
{
byte[] byteptr = wpmd.data;
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 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.
internal static int get_words(long nsamples, long flags, words_data w, Bitstream bs, int[] buffer, int bufferStartPos)
{
entropy_data[] c = w.c;
int csamples;
int buffer_counter = bufferStartPos;
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, high, mid;
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 = (int)(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)
{
int 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 = (int)(bs.bc - ((ones_count = ones_count_table[next8]) + 1));
bs.sr = bs.sr >> (int)(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;
// for c# I replace the division by DIV0 with >> 7
c[entidx].median[0] -= (((c[entidx].median[0] + (DIV0 - 2)) >> 7) * 2);
}
else
{
low = (((c[entidx].median[0]) >> 4) + 1);
// for c# I replace the division by DIV0 with >> 7
c[entidx].median[0] += ((c[entidx].median[0] + DIV0) >> 7) * 5;
if (ones_count == 1)
{
high = low + (((c[entidx].median[1]) >> 4) + 1) - 1;
// for c# I replace the division by DIV1 with >> 6
c[entidx].median[1] -= ((c[entidx].median[1] + (DIV1 - 2)) >> 6) * 2;
}
else
{
low += (((c[entidx].median[1]) >> 4) + 1);
// for c# I replace the division by DIV1 with >> 6
c[entidx].median[1] += ((c[entidx].median[1] + DIV1) >> 6) * 5;
if (ones_count == 2)
{
high = low + (((c[entidx].median[2]) >> 4) + 1) - 1;
// for c# I replace the division by DIV2 with >> 5
c[entidx].median[2] -= ((c[entidx].median[2] + (DIV2 - 2)) >> 5) * 2;
}
else
{
low += (ones_count - 2) * (((c[entidx].median[2]) >> 4) + 1);
high = low + (((c[entidx].median[2]) >> 4) + 1) - 1;
// for c# I replace the division by DIV2 with >> 5
c[entidx].median[2] += ((c[entidx].median[2] + DIV2) >> 5) * 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);
}
}
// 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.
internal 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);
}
