// Port of the ChannelBuffer struct from tclIO.h/tclIO.c
// and associated functionality
//
// Included in SQLite3 port to C# for use in testharness only;  2008 Noah B Hart
//$Header$

using System;
namespace tcl.lang
{

  class ChannelBuffer
  {

    // The next position into which a character
    // will be put in the buffer.

    internal int nextAdded;

    // Position of next byte to be removed
    // from the buffer.

    internal int nextRemoved;

    // How big is the buffer?

    internal int bufLength;

    // Next buffer in chain.

    internal ChannelBuffer next;

    // The actual bytes stored in the buffer

    internal byte[] buf;

    // A channel buffer has BUFFER_PADDING bytes extra at beginning to
    // hold any bytes of a native-encoding character that got split by
    // the end of the previous buffer and need to be moved to the
    // beginning of the next buffer to make a contiguous string so it
    // can be converted to UTF-8.
    //
    // A channel buffer has BUFFER_PADDING bytes extra at the end to
    // hold any bytes of a native-encoding character (generated from a
    // UTF-8 character) that overflow past the end of the buffer and
    // need to be moved to the next buffer.

    internal const int BUFFER_PADDING = 16;

    /// <summary> AllocChannelBuffer -> ChannelBuffer
    /// 
    /// Create a new ChannelBuffer object
    /// </summary>

    internal ChannelBuffer( int length )
    {
      int n;

      n = length + BUFFER_PADDING + BUFFER_PADDING;
      buf = new byte[n];
      nextAdded = BUFFER_PADDING;
      nextRemoved = BUFFER_PADDING;
      bufLength = length + BUFFER_PADDING;
      next = null;
    }
  }
}