public static byte[] Encode(byte[] src)
{
/* quick & dirty format80 encoder -- only uses raw copy operator, terminated with a zero-run. */
/* this does not produce good compression, but it's valid format80 */
var ctx = new FastByteReader(src);
var ms = new MemoryStream();
do
{
var len = Math.Min(ctx.Remaining(), 0x3F);
ms.WriteByte((byte)(0x80 | len));
while (len-- > 0)
{
ms.WriteByte(ctx.ReadByte());
}
}while (!ctx.Done());
ms.WriteByte(0x80); // terminator -- 0-length run.
return(ms.ToArray());
}
public static byte[] Encode(byte[] src)
{
/* quick & dirty format80 encoder -- only uses raw copy operator, terminated with a zero-run. */
/* this does not produce good compression, but it's valid format80 */
var ctx = new FastByteReader(src);
var ms = new MemoryStream();
do
{
var len = Math.Min(ctx.Remaining(), 0x3F);
ms.WriteByte((byte)(0x80 | len));
while (len-- > 0)
ms.WriteByte(ctx.ReadByte());
}
while (!ctx.Done());
ms.WriteByte(0x80); // terminator -- 0-length run.
return ms.ToArray();
}
public static int DecodeInto(byte[] src, byte[] dest)
{
var ctx = new FastByteReader(src);
var destIndex = 0;
while (true)
{
var i = ctx.ReadByte();
if ((i & 0x80) == 0)
{
// case 2
var secondByte = ctx.ReadByte();
var count = ((i & 0x70) >> 4) + 3;
var rpos = ((i & 0xf) << 8) + secondByte;
ReplicatePrevious(dest, destIndex, destIndex - rpos, count);
destIndex += count;
}
else if ((i & 0x40) == 0)
{
// case 1
var count = i & 0x3F;
if (count == 0)
return destIndex;
ctx.CopyTo(dest, destIndex, count);
destIndex += count;
}
else
{
var count3 = i & 0x3F;
if (count3 == 0x3E)
{
// case 4
var count = ctx.ReadWord();
var color = ctx.ReadByte();
for (var end = destIndex + count; destIndex < end; destIndex++)
dest[destIndex] = color;
}
else if (count3 == 0x3F)
{
// case 5
var count = ctx.ReadWord();
var srcIndex = ctx.ReadWord();
if (srcIndex >= destIndex)
throw new NotImplementedException("srcIndex >= destIndex {0} {1}".F(srcIndex, destIndex));
for (var end = destIndex + count; destIndex < end; destIndex++)
dest[destIndex] = dest[srcIndex++];
}
else
{
// case 3
var count = count3 + 3;
var srcIndex = ctx.ReadWord();
if (srcIndex >= destIndex)
throw new NotImplementedException("srcIndex >= destIndex {0} {1}".F(srcIndex, destIndex));
for (var end = destIndex + count; destIndex < end; destIndex++)
dest[destIndex] = dest[srcIndex++];
}
}
}
}
public static int DecodeInto(byte[] src, byte[] dest, int srcOffset = 0, bool reverse = false)
{
var ctx = new FastByteReader(src, srcOffset);
var destIndex = 0;
while (true)
{
var i = ctx.ReadByte();
if ((i & 0x80) == 0)
{
// case 2
var secondByte = ctx.ReadByte();
var count = ((i & 0x70) >> 4) + 3;
var rpos = ((i & 0xf) << 8) + secondByte;
if (destIndex + count > dest.Length)
{
return(destIndex);
}
ReplicatePrevious(dest, destIndex, destIndex - rpos, count);
destIndex += count;
}
else if ((i & 0x40) == 0)
{
// case 1
var count = i & 0x3F;
if (count == 0)
{
return(destIndex);
}
ctx.CopyTo(dest, destIndex, count);
destIndex += count;
}
else
{
var count3 = i & 0x3F;
if (count3 == 0x3E)
{
// case 4
var count = ctx.ReadWord();
var color = ctx.ReadByte();
for (var end = destIndex + count; destIndex < end; destIndex++)
{
dest[destIndex] = color;
}
}
else if (count3 == 0x3F)
{
// case 5
var count = ctx.ReadWord();
var srcIndex = reverse ? destIndex - ctx.ReadWord() : ctx.ReadWord();
if (srcIndex >= destIndex)
{
throw new NotImplementedException("srcIndex >= destIndex {0} {1}".F(srcIndex, destIndex));
}
for (var end = destIndex + count; destIndex < end; destIndex++)
{
dest[destIndex] = dest[srcIndex++];
}
}
else
{
// case 3
var count = count3 + 3;
var srcIndex = reverse ? destIndex - ctx.ReadWord() : ctx.ReadWord();
if (srcIndex >= destIndex)
{
throw new NotImplementedException("srcIndex >= destIndex {0} {1}".F(srcIndex, destIndex));
}
for (var end = destIndex + count; destIndex < end; destIndex++)
{
dest[destIndex] = dest[srcIndex++];
}
}
}
}
}
public static int DecodeInto(byte[] src, byte[] dest)
{
var ctx = new FastByteReader(src);
int destIndex = 0;
while (true)
{
byte i = ctx.ReadByte();
if ((i & 0x80) == 0)
{
// case 2
byte secondByte = ctx.ReadByte();
int count = ((i & 0x70) >> 4) + 3;
int rpos = ((i & 0xf) << 8) + secondByte;
ReplicatePrevious(dest, destIndex, destIndex - rpos, count);
destIndex += count;
}
else if ((i & 0x40) == 0)
{
// case 1
int count = i & 0x3F;
if (count == 0)
{
return(destIndex);
}
ctx.CopyTo(dest, destIndex, count);
destIndex += count;
}
else
{
int count3 = i & 0x3F;
if (count3 == 0x3E)
{
// case 4
int count = ctx.ReadWord();
byte color = ctx.ReadByte();
for (int end = destIndex + count; destIndex < end; destIndex++)
{
dest[destIndex] = color;
}
}
else if (count3 == 0x3F)
{
// case 5
int count = ctx.ReadWord();
int srcIndex = ctx.ReadWord();
if (srcIndex >= destIndex)
{
throw new NotImplementedException(string.Format("srcIndex >= destIndex {0} {1}", srcIndex, destIndex));
}
for (int end = destIndex + count; destIndex < end; destIndex++)
{
dest[destIndex] = dest[srcIndex++];
}
}
else
{
// case 3
int count = count3 + 3;
int srcIndex = ctx.ReadWord();
if (srcIndex >= destIndex)
{
throw new NotImplementedException(string.Format("srcIndex >= destIndex {0} {1}", srcIndex, destIndex));
}
for (int end = destIndex + count; destIndex < end; destIndex++)
{
dest[destIndex] = dest[srcIndex++];
}
}
}
}
}
public static int EncodeInto(byte[] src, byte[] dest)
{
/* quick & dirty format80 encoder -- only uses raw copy operator, terminated with a zero-run. */
/* this does not produce good compression, but it's valid format80 */
var destIndex = 0;
var ctx = new FastByteReader(src);
do
{
var len = Math.Min(ctx.Remaining(), 0x3F);
dest[destIndex++] = (byte)(0x80 | len);
if (len > 0)
ctx.CopyTo(dest, destIndex, len);
}
while (!ctx.Done());
return destIndex;
}