/// <summary>
/// Creates a <see cref="Stream"/> wrapper that decompresses brotli data.
/// <para> For byte-by-byte reading (<see cref="ReadByte()"/>) internal buffer of specified size is
/// allocated and used.</para>
/// <para> Will block the thread until first kilobyte of data of source is available.</para>
/// </summary>
/// <param name="source">compressed data source</param>
/// <param name="byteReadBufferSize">size of internal buffer used in case of byte-by-byte reading</param>
/// <param name="customDictionary">custom dictionary data; <see langword="null"/> if not used</param>
/// <exception cref="IOException">in case of corrupted data or source stream problems</exception>
public BrotliInputStream(Stream source, int byteReadBufferSize, byte[] customDictionary)
{
if (byteReadBufferSize <= 0)
{
throw new ArgumentException("Bad buffer size:" + byteReadBufferSize);
}
else if (source == null)
{
throw new ArgumentException("source is null");
}
_buffer = new byte[byteReadBufferSize];
_remainingBufferBytes = 0;
_bufferOffset = 0;
try
{
BrotliState.SetInput(_state, source);
}
catch (BrotliRuntimeException ex)
{
throw new IOException("Brotli decoder initialization failed", ex);
}
if (customDictionary != null && customDictionary.Length != 0)
{
BrotliDecode.SetCustomDictionary(_state, customDictionary);
}
}
/// <summary><inheritDoc/></summary>
/// <exception cref="IOException"/>
public override int Read(byte[] destBuffer, int destOffset, int destLen)
{
if (destOffset < 0)
{
throw new ArgumentException("Bad offset: " + destOffset);
}
else if (destLen < 0)
{
throw new ArgumentException("Bad length: " + destLen);
}
else if (destOffset + destLen > destBuffer.Length)
{
throw new ArgumentException("Buffer overflow: " + (destOffset + destLen) + " > " + destBuffer.Length);
}
else if (destLen == 0)
{
return(0);
}
int copyLen = Math.Max(_remainingBufferBytes - _bufferOffset, 0);
if (copyLen != 0)
{
copyLen = Math.Min(copyLen, destLen);
Array.Copy(_buffer, _bufferOffset, destBuffer, destOffset, copyLen);
_bufferOffset += copyLen;
destOffset += copyLen;
destLen -= copyLen;
if (destLen == 0)
{
return(copyLen);
}
}
try
{
_state.output = destBuffer;
_state.outputOffset = destOffset;
_state.outputLength = destLen;
_state.outputUsed = 0;
BrotliDecode.Decompress(_state);
if (_state.outputUsed == 0)
{
return(-1);
}
return(_state.outputUsed + copyLen);
}
catch (BrotliRuntimeException ex)
{
throw new IOException("Brotli stream decoding failed", ex);
}
}