public void HashCore(byte[] data, int start, int length)
{
if (data == null)
{
throw new ArgumentNullException("data");
}
if (start < 0)
{
throw new ArgumentException("start");
}
if (length < 0)
{
throw new ArgumentException("length");
}
if (length == 0)
{
return;
}
// avoid copying data unless required (API limitation)
if (start == 0)
{
MHashWrapper.mhash(handle, data, (IntPtr)length);
}
else
{
byte[] partial = new byte [length];
Buffer.BlockCopy(data, start, partial, 0, length);
MHashWrapper.mhash(handle, partial, (IntPtr)length);
}
}
public void Initialize()
{
if (handle == IntPtr.Zero)
{
GC.ReRegisterForFinalize(this);
}
handle = MHashWrapper.mhash_init(type);
}
public void Dispose()
{
if (handle != IntPtr.Zero)
{
// this frees the hashing structure, but allocates the digest
IntPtr digest = MHashWrapper.mhash_end(handle);
// so we still have a second free to make to complete dispose
Marshal.FreeHGlobal(digest);
handle = IntPtr.Zero;
GC.SuppressFinalize(this);
}
}
public MHashHelper(MHashId type)
{
this.type = type;
handle = MHashWrapper.mhash_init(type);
if (handle == IntPtr.Zero)
{
string msg = String.Format("Unknown mhash id '{0}'.", type);
throw new CryptographicException(msg);
}
blocksize = (int)MHashWrapper.mhash_get_block_size(type);
}
public byte[] HashFinal()
{
byte[] result = new byte [blocksize];
IntPtr digest = MHashWrapper.mhash_end(handle);
try {
Marshal.Copy(digest, result, 0, blocksize);
}
finally {
Marshal.FreeHGlobal(digest);
handle = IntPtr.Zero;
}
return(result);
}
