Chris@43: //
Chris@43: // © Copyright Henrik Ravn 2004
Chris@43: //
Chris@43: // Use, modification and distribution are subject to the Boost Software License, Version 1.0.
Chris@43: // (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@43: //
Chris@43: 
Chris@43: using System;
Chris@43: using System.Diagnostics;
Chris@43: 
Chris@43: namespace DotZLib
Chris@43: {
Chris@43: 
Chris@43: 	/// <summary>
Chris@43: 	/// This class implements a circular buffer
Chris@43: 	/// </summary>
Chris@43: 	internal class CircularBuffer
Chris@43: 	{
Chris@43:         #region Private data
Chris@43:         private int _capacity;
Chris@43:         private int _head;
Chris@43:         private int _tail;
Chris@43:         private int _size;
Chris@43:         private byte[] _buffer;
Chris@43:         #endregion
Chris@43: 
Chris@43:         public CircularBuffer(int capacity)
Chris@43:         {
Chris@43:             Debug.Assert( capacity > 0 );
Chris@43:             _buffer = new byte[capacity];
Chris@43:             _capacity = capacity;
Chris@43:             _head = 0;
Chris@43:             _tail = 0;
Chris@43:             _size = 0;
Chris@43:         }
Chris@43: 
Chris@43:         public int Size { get { return _size; } }
Chris@43: 
Chris@43:         public int Put(byte[] source, int offset, int count)
Chris@43:         {
Chris@43:             Debug.Assert( count > 0 );
Chris@43:             int trueCount = Math.Min(count, _capacity - Size);
Chris@43:             for (int i = 0; i < trueCount; ++i)
Chris@43:                 _buffer[(_tail+i) % _capacity] = source[offset+i];
Chris@43:             _tail += trueCount;
Chris@43:             _tail %= _capacity;
Chris@43:             _size += trueCount;
Chris@43:             return trueCount;
Chris@43:         }
Chris@43: 
Chris@43:         public bool Put(byte b)
Chris@43:         {
Chris@43:             if (Size == _capacity) // no room
Chris@43:                 return false;
Chris@43:             _buffer[_tail++] = b;
Chris@43:             _tail %= _capacity;
Chris@43:             ++_size;
Chris@43:             return true;
Chris@43:         }
Chris@43: 
Chris@43:         public int Get(byte[] destination, int offset, int count)
Chris@43:         {
Chris@43:             int trueCount = Math.Min(count,Size);
Chris@43:             for (int i = 0; i < trueCount; ++i)
Chris@43:                 destination[offset + i] = _buffer[(_head+i) % _capacity];
Chris@43:             _head += trueCount;
Chris@43:             _head %= _capacity;
Chris@43:             _size -= trueCount;
Chris@43:             return trueCount;
Chris@43:         }
Chris@43: 
Chris@43:         public int Get()
Chris@43:         {
Chris@43:             if (Size == 0)
Chris@43:                 return -1;
Chris@43: 
Chris@43:             int result = (int)_buffer[_head++ % _capacity];
Chris@43:             --_size;
Chris@43:             return result;
Chris@43:         }
Chris@43: 
Chris@43:     }
Chris@43: }