cannam@89: //
cannam@89: // © Copyright Henrik Ravn 2004
cannam@89: //
cannam@89: // Use, modification and distribution are subject to the Boost Software License, Version 1.0.
cannam@89: // (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
cannam@89: //
cannam@89: 
cannam@89: using System;
cannam@89: using System.Diagnostics;
cannam@89: 
cannam@89: namespace DotZLib
cannam@89: {
cannam@89: 
cannam@89: 	/// <summary>
cannam@89: 	/// This class implements a circular buffer
cannam@89: 	/// </summary>
cannam@89: 	internal class CircularBuffer
cannam@89: 	{
cannam@89:         #region Private data
cannam@89:         private int _capacity;
cannam@89:         private int _head;
cannam@89:         private int _tail;
cannam@89:         private int _size;
cannam@89:         private byte[] _buffer;
cannam@89:         #endregion
cannam@89: 
cannam@89:         public CircularBuffer(int capacity)
cannam@89:         {
cannam@89:             Debug.Assert( capacity > 0 );
cannam@89:             _buffer = new byte[capacity];
cannam@89:             _capacity = capacity;
cannam@89:             _head = 0;
cannam@89:             _tail = 0;
cannam@89:             _size = 0;
cannam@89:         }
cannam@89: 
cannam@89:         public int Size { get { return _size; } }
cannam@89: 
cannam@89:         public int Put(byte[] source, int offset, int count)
cannam@89:         {
cannam@89:             Debug.Assert( count > 0 );
cannam@89:             int trueCount = Math.Min(count, _capacity - Size);
cannam@89:             for (int i = 0; i < trueCount; ++i)
cannam@89:                 _buffer[(_tail+i) % _capacity] = source[offset+i];
cannam@89:             _tail += trueCount;
cannam@89:             _tail %= _capacity;
cannam@89:             _size += trueCount;
cannam@89:             return trueCount;
cannam@89:         }
cannam@89: 
cannam@89:         public bool Put(byte b)
cannam@89:         {
cannam@89:             if (Size == _capacity) // no room
cannam@89:                 return false;
cannam@89:             _buffer[_tail++] = b;
cannam@89:             _tail %= _capacity;
cannam@89:             ++_size;
cannam@89:             return true;
cannam@89:         }
cannam@89: 
cannam@89:         public int Get(byte[] destination, int offset, int count)
cannam@89:         {
cannam@89:             int trueCount = Math.Min(count,Size);
cannam@89:             for (int i = 0; i < trueCount; ++i)
cannam@89:                 destination[offset + i] = _buffer[(_head+i) % _capacity];
cannam@89:             _head += trueCount;
cannam@89:             _head %= _capacity;
cannam@89:             _size -= trueCount;
cannam@89:             return trueCount;
cannam@89:         }
cannam@89: 
cannam@89:         public int Get()
cannam@89:         {
cannam@89:             if (Size == 0)
cannam@89:                 return -1;
cannam@89: 
cannam@89:             int result = (int)_buffer[_head++ % _capacity];
cannam@89:             --_size;
cannam@89:             return result;
cannam@89:         }
cannam@89: 
cannam@89:     }
cannam@89: }