Chris@4: //
Chris@4: // © Copyright Henrik Ravn 2004
Chris@4: //
Chris@4: // Use, modification and distribution are subject to the Boost Software License, Version 1.0.
Chris@4: // (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@4: //
Chris@4: 
Chris@4: using System;
Chris@4: using System.Diagnostics;
Chris@4: 
Chris@4: namespace DotZLib
Chris@4: {
Chris@4: 
Chris@4: 	/// <summary>
Chris@4: 	/// This class implements a circular buffer
Chris@4: 	/// </summary>
Chris@4: 	internal class CircularBuffer
Chris@4: 	{
Chris@4:         #region Private data
Chris@4:         private int _capacity;
Chris@4:         private int _head;
Chris@4:         private int _tail;
Chris@4:         private int _size;
Chris@4:         private byte[] _buffer;
Chris@4:         #endregion
Chris@4: 
Chris@4:         public CircularBuffer(int capacity)
Chris@4:         {
Chris@4:             Debug.Assert( capacity > 0 );
Chris@4:             _buffer = new byte[capacity];
Chris@4:             _capacity = capacity;
Chris@4:             _head = 0;
Chris@4:             _tail = 0;
Chris@4:             _size = 0;
Chris@4:         }
Chris@4: 
Chris@4:         public int Size { get { return _size; } }
Chris@4: 
Chris@4:         public int Put(byte[] source, int offset, int count)
Chris@4:         {
Chris@4:             Debug.Assert( count > 0 );
Chris@4:             int trueCount = Math.Min(count, _capacity - Size);
Chris@4:             for (int i = 0; i < trueCount; ++i)
Chris@4:                 _buffer[(_tail+i) % _capacity] = source[offset+i];
Chris@4:             _tail += trueCount;
Chris@4:             _tail %= _capacity;
Chris@4:             _size += trueCount;
Chris@4:             return trueCount;
Chris@4:         }
Chris@4: 
Chris@4:         public bool Put(byte b)
Chris@4:         {
Chris@4:             if (Size == _capacity) // no room
Chris@4:                 return false;
Chris@4:             _buffer[_tail++] = b;
Chris@4:             _tail %= _capacity;
Chris@4:             ++_size;
Chris@4:             return true;
Chris@4:         }
Chris@4: 
Chris@4:         public int Get(byte[] destination, int offset, int count)
Chris@4:         {
Chris@4:             int trueCount = Math.Min(count,Size);
Chris@4:             for (int i = 0; i < trueCount; ++i)
Chris@4:                 destination[offset + i] = _buffer[(_head+i) % _capacity];
Chris@4:             _head += trueCount;
Chris@4:             _head %= _capacity;
Chris@4:             _size -= trueCount;
Chris@4:             return trueCount;
Chris@4:         }
Chris@4: 
Chris@4:         public int Get()
Chris@4:         {
Chris@4:             if (Size == 0)
Chris@4:                 return -1;
Chris@4: 
Chris@4:             int result = (int)_buffer[_head++ % _capacity];
Chris@4:             --_size;
Chris@4:             return result;
Chris@4:         }
Chris@4: 
Chris@4:     }
Chris@4: }