public static void Inflate(Stream source, Stream dest, uint xor)
{
uint have;
var reader = new BinaryReader(source);
var writer = new BinaryWriter(dest);
var dataSize = reader.ReadUInt32();
var zs = new ZStream();
var size = Marshal.SizeOf(zs);
var ret = InflateInit2(ref zs, -MAXWBITS, Version(), size);
if (ret != (int)Result.OK)
{
var err = Marshal.PtrToStringAuto(zs.Msg);
throw new Exception(err);
}
IntPtr outd = Marshal.AllocHGlobal(CHUNK);
int i = 0;
do
{
var ind = reader.ReadBytes(CHUNK);
zs.AvailIn = (uint)ind.Length;
if (zs.AvailIn == 0)
{
break;
}
for (; i < 4; i++)
{
int j = i % 4;
byte key = (byte)((xor >> (8 * j)) & 0xFF);
ind[i] ^= key;
}
var nextIn = Marshal.AllocHGlobal(ind.Length);
Marshal.Copy(ind, 0, nextIn, ind.Length);
zs.NextIn = nextIn;
do
{
zs.AvailOut = CHUNK;
zs.NextOut = outd;
ret = Zlib.Inflate(ref zs, ZNOFLUSH);
if (ret != (int)Result.OK &&
ret != (int)Result.StreamEnd)
{
var err = Marshal.PtrToStringAuto(zs.Msg);
throw new Exception(err);
}
have = CHUNK - zs.AvailOut;
var buf = new byte[have];
Marshal.Copy(outd, buf, 0, (int)have);
writer.Write(buf);
} while (zs.AvailOut == 0);
Marshal.FreeHGlobal(nextIn);
} while (ret != (int)Result.StreamEnd);
Marshal.FreeHGlobal(outd);
InflateEnd(ref zs);
writer.Flush();
}
public static void Deflate(Stream source, Stream dest, uint xor, int level)
{
int ret, flush;
var length = (uint)source.Length;
var writer = new BinaryWriter(dest);
var reader = new BinaryReader(source);
writer.Write(length);
var zs = new ZStream();
zs.ZAlloc = IntPtr.Zero;
zs.ZFree = IntPtr.Zero;
zs.Opaque = IntPtr.Zero;
var size = Marshal.SizeOf(zs);
ret = DeflateInit2(
ref zs,
level,
CompressionMethod.Deflated,
-MAXWBITS,
8,
CompressionStrategy.Default,
Version(),
size);
if (ret > 0) // Z_OK = 0
{
var err = Marshal.PtrToStringAuto(zs.Msg);
throw new Exception(err);
}
IntPtr outd = Marshal.AllocHGlobal(CHUNK);
int i = 0;
do
{
var ind = reader.ReadBytes(CHUNK);
zs.AvailIn = (uint)ind.Length;
flush = (source.Position == length) ? ZFINISH : ZNOFLUSH;
var nextIn = Marshal.AllocHGlobal(ind.Length);
Marshal.Copy(ind, 0, nextIn, ind.Length);
zs.NextIn = nextIn;
do
{
zs.AvailOut = CHUNK;
zs.NextOut = outd;
ret = Zlib.Deflate(ref zs, flush);
if (ret == (int)Result.StreamError)
{
var err = Marshal.PtrToStringAuto(zs.Msg);
throw new Exception(err);
}
var have = CHUNK - zs.AvailOut;
if (have <= 0)
{
continue;
}
var buf = new byte[have];
Marshal.Copy(outd, buf, 0, (int)have);
for (; i < 4; i++)
{
int j = i % 4;
byte key = (byte)((xor >> (8 * j)) & 0xFF);
buf[i] ^= key;
}
writer.Write(buf);
} while (zs.AvailOut == 0);
Marshal.FreeHGlobal(nextIn);
} while (flush != ZFINISH);
Marshal.FreeHGlobal(outd);
DeflateEnd(ref zs);
writer.Flush();
}
