/// <summary>Initialize bit reader.</summary>
/// <remarks>
/// Initialize bit reader.
/// <para> Initialisation turns bit reader to a ready state. Also a number of bytes is prefetched to
/// accumulator. Because of that this method may block until enough data could be read from input.</para>
/// </remarks>
/// <param name="br">BitReader POJO</param>
/// <param name="input">data source</param>
internal static void Init(BitReader br, Stream input)
{
if (br._input != null)
{
throw new InvalidOperationException("Bit reader already has associated input stream");
}
IntReader.Init(br._intReader, br._byteBuffer, br._intBuffer);
br._input = input;
br._accumulator = 0;
br._bitOffset = 64;
br._intOffset = Capacity;
br._endOfStreamReached = false;
Prepare(br);
}
/* Number of bytes in unfinished "int" item. */
/// <summary>Fills up the input buffer.</summary>
/// <remarks>
/// Fills up the input buffer.
/// <para> No-op if there are at least 36 bytes present after current position.</para>
/// <para> After encountering the end of the input stream, 64 additional zero bytes are copied to the buffer.</para>
/// </remarks>
internal static void ReadMoreInput(BitReader br)
{
// TODO: Split to check and read; move read outside of decoding loop.
if (br._intOffset <= Capacity - 9)
{
return;
}
if (br._endOfStreamReached)
{
if (IntAvailable(br) >= -2)
{
return;
}
throw new BrotliRuntimeException("No more input");
}
int readOffset = br._intOffset << 2;
int bytesRead = ByteReadSize - readOffset;
Array.Copy(br._byteBuffer, readOffset, br._byteBuffer, 0, bytesRead);
br._intOffset = 0;
try
{
while (bytesRead < ByteReadSize)
{
int len = br._input.Read(br._byteBuffer, bytesRead, ByteReadSize - bytesRead);
// EOF is -1 in Java, but 0 in C#.
if (len <= 0)
{
br._endOfStreamReached = true;
br._tailBytes = bytesRead;
bytesRead += 3;
break;
}
bytesRead += len;
}
}
catch (IOException e)
{
throw new BrotliRuntimeException("Failed to read input", e);
}
IntReader.Convert(br._intReader, bytesRead >> 2);
}
