public static MemoryStream ReadEntry(
Stream input,
ArchiveFile.Entry entry,
ArchiveCompressionMode mode,
Endian endian)
{
switch (mode)
{
case ArchiveCompressionMode.Bogocrypt1:
{
var output = new MemoryStream();
var key = entry.BogocryptKey;
long remaining = entry.Length;
var block = new byte[1024];
while (remaining > 0)
{
var blockLength = (int)Math.Min(block.Length, remaining + 3 & ~3);
var actualBlockLength = (int)Math.Min(block.Length, remaining);
if (blockLength == 0)
{
throw new InvalidOperationException();
}
if (input.Read(block, 0, blockLength) < actualBlockLength)
{
throw new EndOfStreamException();
}
key = ArchiveFile.Bogocrypt1(block, 0, blockLength, key);
output.Write(block, 0, actualBlockLength);
remaining -= blockLength;
}
output.Position = 0;
return(output);
}
case ArchiveCompressionMode.LZW:
{
var output = new MemoryStream();
LZW.Decompress(input, entry.Length, output, endian);
output.Position = 0;
return(output);
}
case ArchiveCompressionMode.MiniZ:
{
ISAAC isaac = null;
var outputBytes = new byte[entry.Length];
var outputOffset = 0;
var blockBytes = new byte[0x800];
long remaining = entry.Length;
bool isCompressed = true;
bool isLastBlock;
do
{
var blockFlags = input.ReadValueU32(endian);
var blockLength = (int)(blockFlags & ~0x80000000u);
isLastBlock = (blockFlags & 0x80000000u) != 0;
if (blockLength > blockBytes.Length)
{
throw new InvalidOperationException();
}
if (input.Read(blockBytes, 0, blockLength) != blockLength)
{
throw new EndOfStreamException();
}
if (isCompressed == false || (isLastBlock == false && blockLength == 1024))
{
isCompressed = false;
if (isaac == null)
{
isaac = entry.GetISAAC();
}
int seed = 0;
for (int o = 0; o < blockLength; o++)
{
if ((o & 3) != 0)
{
seed >>= 8;
}
else
{
seed = isaac.Value();
}
blockBytes[o] ^= (byte)seed;
}
Array.Copy(blockBytes, 0, outputBytes, outputOffset, blockLength);
outputOffset += blockLength;
remaining -= blockLength;
}
else
{
using (var temp = new MemoryStream(blockBytes, false))
{
var zlib = new InflaterInputStream(temp, new Inflater(true));
var read = zlib.Read(outputBytes, outputOffset, (int)Math.Min(remaining, 1024));
outputOffset += read;
remaining -= read;
}
}
}while (isLastBlock == false);
return(new MemoryStream(outputBytes));
}
case ArchiveCompressionMode.Bogocrypt2:
{
var blockBytes = new byte[1024];
var output = new MemoryStream();
long remaining = entry.Length;
while (remaining >= 4)
{
var blockLength = (int)Math.Min(blockBytes.Length, remaining);
if (input.Read(blockBytes, 0, blockLength) != blockLength)
{
throw new EndOfStreamException();
}
ArchiveFile.Bogocrypt2(blockBytes, 0, blockLength);
output.Write(blockBytes, 0, blockLength);
remaining -= blockLength;
}
if (remaining > 0)
{
output.WriteFromStream(input, remaining);
}
output.Position = 0;
return(output);
}
default:
{
throw new NotSupportedException();
}
}
}
