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optimizations

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This commit is contained in:
chudov
2009-12-24 16:09:20 +00:00
parent 1bd39f81b5
commit c9c6d7b545
4 changed files with 713 additions and 245 deletions
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50
CUETools.Codecs/BitReader.cs
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@@ -96,7 +96,21 @@ namespace CUETools.Codecs
}
}
public BitReader()
{
buffer = null;
pos = 0;
len = 0;
_bitaccumulator = 0;
cache = 0;
}
public BitReader(byte* _buffer, int _pos, int _len)
{
Reset(_buffer, _pos, _len);
}
public void Reset(byte* _buffer, int _pos, int _len)
{
buffer = _buffer;
pos = _pos;
@@ -126,6 +140,16 @@ namespace CUETools.Codecs
cache = peek4();
}
/* skip up to 16 bits */
public void skipbits16(int bits)
{
cache <<= bits;
int new_accumulator = (_bitaccumulator + bits);
pos += (new_accumulator >> 3);
_bitaccumulator = (new_accumulator & 7);
cache |= ((((uint)buffer[pos + 2] << 8) + (uint)buffer[pos + 3]) << _bitaccumulator);
}
/* skip up to 8 bits */
public void skipbits8(int bits)
{
@@ -288,6 +312,7 @@ namespace CUETools.Codecs
{
fixed (byte* unary_table = byte_to_unary_table)
{
uint mask = (1U << k) - 1;
if (k == 0)
for (int i = n; i > 0; i--)
*(r++) = read_unary_signed();
@@ -303,9 +328,26 @@ namespace CUETools.Codecs
bits = unary_table[cache >> 24];
msbs += bits;
}
skipbits8((int)(msbs & 7) + 1);
uint uval = (msbs << k) | (cache >> (32 - k));
skipbits8(k);
int btsk = k + (int)bits + 1;
uint uval = (msbs << k) | ((cache >> (32 - btsk)) & mask);
skipbits16(btsk);
*(r++) = (int)(uval >> 1 ^ -(int)(uval & 1));
}
else if (k <= 16)
for (int i = n; i > 0; i--)
{
//*(r++) = read_rice_signed((int)k);
uint bits = unary_table[cache >> 24];
uint msbs = bits;
while (bits == 8)
{
skipbits8(8);
bits = unary_table[cache >> 24];
msbs += bits;
}
int btsk = k + (int)bits + 1;
uint uval = (msbs << k) | ((cache >> (32 - btsk)) & mask);
skipbits(btsk);
*(r++) = (int)(uval >> 1 ^ -(int)(uval & 1));
}
else
@@ -321,7 +363,7 @@ namespace CUETools.Codecs
msbs += bits;
}
skipbits8((int)(msbs & 7) + 1);
uint uval = (msbs << k) | (cache >> (32 - k));
uint uval = (msbs << k) | ((cache >> (32 - k)));
skipbits(k);
*(r++) = (int)(uval >> 1 ^ -(int)(uval & 1));
}