public bool WriteTo2(WriteBuffer buffer)
{
// 0. init header
// 1. loop on header
// 2. loop on Key, if any
// 3. loop on Data, if any
// 4. done
switch (state)
{
case STATE_INITIAL:
PrepareHeader();
state = STATE_WRITE_HEADER;
goto case STATE_WRITE_HEADER;
case STATE_WRITE_HEADER:
writeOffset += buffer.Append(header, writeOffset, headerLength - writeOffset);
if (writeOffset < headerLength)
{
return(true);
}
if (Key.Length > 0)
{
writeOffset = 0;
state = STATE_WRITE_KEY;
goto case STATE_WRITE_KEY;
}
goto case STATE_PREPARE_BODY;
case STATE_WRITE_KEY:
writeOffset += buffer.Append(Key.Array, writeOffset, Key.Length - writeOffset);
if (writeOffset < Key.Length)
{
return(true);
}
goto case STATE_PREPARE_BODY;
case STATE_PREPARE_BODY:
if (Data.Count > 0)
{
writeOffset = 0;
state = STATE_WRITE_BODY;
goto case STATE_WRITE_BODY;
}
break;
case STATE_WRITE_BODY:
writeOffset += buffer.Append(Data.Array, Data.Offset + writeOffset, Data.Count - writeOffset);
if (writeOffset < Data.Count)
{
return(true);
}
break;
}
state = STATE_DONE;
return(false);
}
private static ReadBuffer UnpackSequences(ReadBuffer packedData, byte seqMarker)
{
var remaining = packedData;
var result = new WriteBuffer();
while (remaining.Length > 0)
{
var value = remaining[0];
remaining = remaining.Drop(1);
if (value != seqMarker)
{
result.Append(value);
}
else
{
var sequence = remaining.TakeUntil(seqMarker);
var count = remaining[sequence.Length + 1];
for (int i = 0; i < count; i++)
{
result.Append(sequence);
}
remaining = remaining.Drop(sequence.Length + 2);
}
}
return(result.ToReadBuffer());
}
public bool WriteTo(WriteBuffer buffer)
{
// 0. init header
// 1. loop on header
// 2. loop on Key, if any
// 3. loop on Data, if any
// 4. done
switch (state)
{
case STATE_INITIAL: goto init;
case STATE_WRITE_HEADER: goto write_header;
case STATE_WRITE_KEY: goto write_key;
case STATE_WRITE_BODY: goto write_body;
default: return false;
}
// TODO put these inside switch..case
init:
PrepareHeader();
state = STATE_WRITE_HEADER;
write_header:
writeOffset += buffer.Append(header, writeOffset, headerLength - writeOffset);
if (writeOffset < headerLength) return true;
if (Key.Length > 0)
{
writeOffset = 0;
state = STATE_WRITE_KEY;
}
else goto pre_body;
write_key:
writeOffset += buffer.Append(Key.Array, writeOffset, Key.Length - writeOffset);
if (writeOffset < Key.Length) return true;
pre_body:
if (Data.Count > 0)
{
writeOffset = 0;
state = STATE_WRITE_BODY;
}
else goto done;
write_body:
writeOffset += buffer.Append(Data.Array, Data.Offset + writeOffset, Data.Count - writeOffset);
if (writeOffset < Data.Count) return true;
done:
state = STATE_DONE;
return false;
}
private static ReadBuffer UnpackRLE(ReadBuffer packedData)
{
int escCount = packedData[0] & 0x7f;
var escCodes = packedData.Slice(1, escCount);
var rleData = packedData.Drop(escCount + 1);
var escLookup = new byte[0x100];
for (int i = 0; i < escCount; i++)
{
escLookup[escCodes[i]] = (byte)(i + 1);
}
bool compressed = (packedData[0] & 0x80) == 0;
var encodedData = compressed ? UnpackSequences(rleData, escCodes[1]) : rleData;
var result = new WriteBuffer();
while (encodedData.Length > 0)
{
var code = escLookup[encodedData[0]];
switch (code)
{
case 0:
result.Append(encodedData[0]);
encodedData = encodedData.Drop(1);
break;
case 1:
result.AppendRepeat(encodedData[2], encodedData[1]);
encodedData = encodedData.Drop(3);
break;
case 3:
result.AppendRepeat(encodedData[3], encodedData[1] + (((int)encodedData[2]) << 8));
encodedData = encodedData.Drop(4);
break;
default:
result.AppendRepeat(encodedData[1], code - 1);
encodedData = encodedData.Drop(2);
break;
}
}
return(result.ToReadBuffer());
}
private static ReadBuffer UnpackVLE(ReadBuffer packedData)
{
var widthsCount = packedData[0];
var widths = packedData.Slice(1, widthsCount);
var alphabetCount = widths.Select(val => (int)val).Sum();
var alphabet = packedData.Slice(1 + widthsCount, alphabetCount);
var dictionary = new HuffmanTree(widths, alphabet);
var stream = EnumerateBits(packedData.Drop(1 + widthsCount + alphabetCount));
var result = new WriteBuffer();
while (true)
{
int value = dictionary.DecodeByte(stream);
if (value < 0)
{
break;
}
result.Append((byte)value);
}
return(result.ToReadBuffer());
}
public bool WriteTo2(WriteBuffer buffer)
{
// 0. init header
// 1. loop on header
// 2. loop on Key, if any
// 3. loop on Data, if any
// 4. done
switch (state)
{
case STATE_INITIAL:
PrepareHeader();
state = STATE_WRITE_HEADER;
goto case STATE_WRITE_HEADER;
case STATE_WRITE_HEADER:
writeOffset += buffer.Append(header, writeOffset, headerLength - writeOffset);
if (writeOffset < headerLength) return true;
if (Key.Length > 0)
{
writeOffset = 0;
state = STATE_WRITE_KEY;
goto case STATE_WRITE_KEY;
}
goto case STATE_PREPARE_BODY;
case STATE_WRITE_KEY:
writeOffset += buffer.Append(Key.Array, writeOffset, Key.Length - writeOffset);
if (writeOffset < Key.Length) return true;
goto case STATE_PREPARE_BODY;
case STATE_PREPARE_BODY:
if (Data.Count > 0)
{
writeOffset = 0;
state = STATE_WRITE_BODY;
goto case STATE_WRITE_BODY;
}
break;
case STATE_WRITE_BODY:
writeOffset += buffer.Append(Data.Array, Data.Offset + writeOffset, Data.Count - writeOffset);
if (writeOffset < Data.Count) return true;
break;
}
state = STATE_DONE;
return false;
}
public bool WriteTo(WriteBuffer buffer)
{
// 0. init header
// 1. loop on header
// 2. loop on Key, if any
// 3. loop on Data, if any
// 4. done
switch (state)
{
case STATE_INITIAL: goto init;
case STATE_WRITE_HEADER: goto write_header;
case STATE_WRITE_KEY: goto write_key;
case STATE_WRITE_BODY: goto write_body;
default: return(false);
}
// TODO put these inside switch..case
init:
PrepareHeader();
state = STATE_WRITE_HEADER;
write_header:
writeOffset += buffer.Append(header, writeOffset, headerLength - writeOffset);
if (writeOffset < headerLength)
{
return(true);
}
if (Key.Length > 0)
{
writeOffset = 0;
state = STATE_WRITE_KEY;
}
else
{
goto pre_body;
}
write_key:
writeOffset += buffer.Append(Key.Array, writeOffset, Key.Length - writeOffset);
if (writeOffset < Key.Length)
{
return(true);
}
pre_body:
if (Data.Count > 0)
{
writeOffset = 0;
state = STATE_WRITE_BODY;
}
else
{
goto done;
}
write_body:
writeOffset += buffer.Append(Data.Array, Data.Offset + writeOffset, Data.Count - writeOffset);
if (writeOffset < Data.Count)
{
return(true);
}
done:
state = STATE_DONE;
return(false);
}