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Another Flake optimization

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This commit is contained in:
Grigory Chudov
2013-03-26 19:50:44 -04:00
parent 55af6e181a
commit 76111a5c6e
4 changed files with 55 additions and 13 deletions
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4
CUETools.Codecs.FLACCL/FLACCLWriter.cs
View File

@@ -1060,8 +1060,8 @@ namespace CUETools.Codecs.FLACCL
void output_frame_footer(FlacFrame frame)
{
frame.writer.flush();
ushort crc = Crc16.ComputeChecksum(0, frame.writer.Buffer, frame.writer_offset, frame.writer.Length - frame.writer_offset);
frame.writer.writebits(16, crc);
ushort crc = frame.writer.get_crc16();
frame.writer.writebits(16, crc);
frame.writer.flush();
}

4
CUETools.Codecs.FLAKE/FlakeWriter.cs
View File

@@ -1443,8 +1443,8 @@ new int[] { // 30
void output_frame_footer(BitWriter bitwriter)
{
bitwriter.flush();
ushort crc = Crc16.ComputeChecksum(0, frame_buffer, 0, bitwriter.Length);
bitwriter.writebits(16, crc);
ushort crc = bitwriter.get_crc16();
bitwriter.writebits(16, crc);
bitwriter.flush();
}

54
CUETools.Codecs/BitWriter.cs
View File

@@ -4,6 +4,7 @@ namespace CUETools.Codecs
{
public class BitWriter
{
private ushort crc16_m;
private ulong bit_buf_m;
private int bit_left_m;
private byte[] buffer;
@@ -39,6 +40,11 @@ namespace CUETools.Codecs
}
}
public ushort get_crc16()
{
return crc16_m;
}
public BitWriter(byte[] buf, int pos, int len)
{
buffer = buf;
@@ -47,6 +53,7 @@ namespace CUETools.Codecs
buf_end = pos + len;
bit_left_m = 64;
bit_buf_m = 0;
crc16_m = 0;
eof = false;
}
@@ -55,6 +62,7 @@ namespace CUETools.Codecs
buf_ptr_m = buf_start;
bit_left_m = 64;
bit_buf_m = 0;
crc16_m = 0;
eof = false;
}
@@ -76,8 +84,13 @@ namespace CUETools.Codecs
flush();
byte start_val = old_pos % 8 != 0 ? buffer[start] : (byte)0;
fixed (byte* buf1 = &buffer[0])
{
if (old_pos % 8 != 0)
crc16_m = Crc16.Substract(crc16_m, 0, 1);
crc16_m = Crc16.ComputeChecksum(crc16_m, buf + start1, end - start);
AudioSamples.MemCpy(buf1 + start, buf + start1, end - start);
buffer[start] |= start_val;
buf1[start] |= start_val;
}
buf_ptr_m = end;
if ((old_pos + len) % 8 != 0)
writebits((old_pos + len) % 8, buf[end1] >> (8 - ((old_pos + len) % 8)));
@@ -126,11 +139,6 @@ namespace CUETools.Codecs
//assert(bits == 32 || val < (1U << bits));
if (bits == 0 || eof) return;
if ((buf_ptr_m + 3) >= buf_end)
{
eof = true;
return;
}
if (bits <= bit_left_m)
{
bit_left_m -= bits;
@@ -141,6 +149,21 @@ namespace CUETools.Codecs
ulong bb = bit_buf_m | (val >> (bits - bit_left_m));
if (buffer != null)
{
if (buf_ptr_m + 8 > buf_end)
{
eof = true;
return;
}
crc16_m = (ushort)((crc16_m << 8) ^ Crc16.table[(crc16_m >> 8) ^ (byte)(bb >> 56)]);
crc16_m = (ushort)((crc16_m << 8) ^ Crc16.table[(crc16_m >> 8) ^ (byte)(bb >> 48)]);
crc16_m = (ushort)((crc16_m << 8) ^ Crc16.table[(crc16_m >> 8) ^ (byte)(bb >> 40)]);
crc16_m = (ushort)((crc16_m << 8) ^ Crc16.table[(crc16_m >> 8) ^ (byte)(bb >> 32)]);
crc16_m = (ushort)((crc16_m << 8) ^ Crc16.table[(crc16_m >> 8) ^ (byte)(bb >> 24)]);
crc16_m = (ushort)((crc16_m << 8) ^ Crc16.table[(crc16_m >> 8) ^ (byte)(bb >> 16)]);
crc16_m = (ushort)((crc16_m << 8) ^ Crc16.table[(crc16_m >> 8) ^ (byte)(bb >> 8)]);
crc16_m = (ushort)((crc16_m << 8) ^ Crc16.table[(crc16_m >> 8) ^ (byte)(bb )]);
buffer[buf_ptr_m + 7] = (byte)(bb & 0xFF); bb >>= 8;
buffer[buf_ptr_m + 6] = (byte)(bb & 0xFF); bb >>= 8;
buffer[buf_ptr_m + 5] = (byte)(bb & 0xFF); bb >>= 8;
@@ -251,6 +274,8 @@ namespace CUETools.Codecs
byte* buf = &fixedbuf[buf_ptr_m];
ulong bit_buf = bit_buf_m;
int bit_left = bit_left_m;
ushort crc16 = crc16_m;
fixed (ushort *crc16_t = Crc16.table)
for (int i = count; i > 0; i--)
{
int v = *(residual++);
@@ -268,6 +293,7 @@ namespace CUETools.Codecs
return;
}
#endif
crc16 = (ushort)((crc16 << 8) ^ crc16_t[(crc16 >> 8) ^ (byte)(bit_buf >> 56)]);
*(buf++) = (byte)(bit_buf >> 56);
bit_buf <<= 8;
bits -= 8;
@@ -292,6 +318,15 @@ namespace CUETools.Codecs
}
#endif
crc16 = (ushort)((crc16 << 8) ^ crc16_t[(crc16 >> 8) ^ (byte)(bb >> 56)]);
crc16 = (ushort)((crc16 << 8) ^ crc16_t[(crc16 >> 8) ^ (byte)(bb >> 48)]);
crc16 = (ushort)((crc16 << 8) ^ crc16_t[(crc16 >> 8) ^ (byte)(bb >> 40)]);
crc16 = (ushort)((crc16 << 8) ^ crc16_t[(crc16 >> 8) ^ (byte)(bb >> 32)]);
crc16 = (ushort)((crc16 << 8) ^ crc16_t[(crc16 >> 8) ^ (byte)(bb >> 24)]);
crc16 = (ushort)((crc16 << 8) ^ crc16_t[(crc16 >> 8) ^ (byte)(bb >> 16)]);
crc16 = (ushort)((crc16 << 8) ^ crc16_t[(crc16 >> 8) ^ (byte)(bb >> 8)]);
crc16 = (ushort)((crc16 << 8) ^ crc16_t[(crc16 >> 8) ^ (byte)(bb)]);
*(buf++) = (byte)(bb >> 56);
*(buf++) = (byte)(bb >> 48);
*(buf++) = (byte)(bb >> 40);
@@ -304,6 +339,7 @@ namespace CUETools.Codecs
bit_buf = val << bit_left;
}
}
crc16_m = crc16;
buf_ptr_m = (int)(buf - fixedbuf);
bit_buf_m = bit_buf;
bit_left_m = bit_left;
@@ -319,7 +355,11 @@ namespace CUETools.Codecs
break;
}
if (buffer != null)
buffer[buf_ptr_m] = (byte)(bit_buf_m >> 56);
{
byte b = (byte)(bit_buf_m >> 56);
crc16_m = (ushort)((crc16_m << 8) ^ Crc16.table[(crc16_m >> 8) ^ b]);
buffer[buf_ptr_m] = b;
}
buf_ptr_m++;
bit_buf_m <<= 8;
bit_left_m += 8;

6
CUETools.Codecs/CRC/CRC16.cs
View File

@@ -17,8 +17,10 @@ namespace CUETools.Codecs
public static unsafe ushort ComputeChecksum(ushort crc, byte* bytes, int count)
{
fixed (ushort* t = table)
for (int i = count; i > 0; i--)
crc = (ushort)((crc << 8) ^ t[(crc >> 8) ^ *(bytes++)]);
for (int i = count; i > 0; i--)
{
crc = (ushort)((crc << 8) ^ t[(crc >> 8) ^ *(bytes++)]);
}
return crc;
}