cannam@128: //
cannam@128: // © Copyright Henrik Ravn 2004
cannam@128: //
cannam@128: // Use, modification and distribution are subject to the Boost Software License, Version 1.0.
cannam@128: // (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
cannam@128: //
cannam@128: 
cannam@128: using System;
cannam@128: using System.Diagnostics;
cannam@128: 
cannam@128: namespace DotZLib
cannam@128: {
cannam@128: 
cannam@128: 	/// <summary>
cannam@128: 	/// This class implements a circular buffer
cannam@128: 	/// </summary>
cannam@128: 	internal class CircularBuffer
cannam@128: 	{
cannam@128:         #region Private data
cannam@128:         private int _capacity;
cannam@128:         private int _head;
cannam@128:         private int _tail;
cannam@128:         private int _size;
cannam@128:         private byte[] _buffer;
cannam@128:         #endregion
cannam@128: 
cannam@128:         public CircularBuffer(int capacity)
cannam@128:         {
cannam@128:             Debug.Assert( capacity > 0 );
cannam@128:             _buffer = new byte[capacity];
cannam@128:             _capacity = capacity;
cannam@128:             _head = 0;
cannam@128:             _tail = 0;
cannam@128:             _size = 0;
cannam@128:         }
cannam@128: 
cannam@128:         public int Size { get { return _size; } }
cannam@128: 
cannam@128:         public int Put(byte[] source, int offset, int count)
cannam@128:         {
cannam@128:             Debug.Assert( count > 0 );
cannam@128:             int trueCount = Math.Min(count, _capacity - Size);
cannam@128:             for (int i = 0; i < trueCount; ++i)
cannam@128:                 _buffer[(_tail+i) % _capacity] = source[offset+i];
cannam@128:             _tail += trueCount;
cannam@128:             _tail %= _capacity;
cannam@128:             _size += trueCount;
cannam@128:             return trueCount;
cannam@128:         }
cannam@128: 
cannam@128:         public bool Put(byte b)
cannam@128:         {
cannam@128:             if (Size == _capacity) // no room
cannam@128:                 return false;
cannam@128:             _buffer[_tail++] = b;
cannam@128:             _tail %= _capacity;
cannam@128:             ++_size;
cannam@128:             return true;
cannam@128:         }
cannam@128: 
cannam@128:         public int Get(byte[] destination, int offset, int count)
cannam@128:         {
cannam@128:             int trueCount = Math.Min(count,Size);
cannam@128:             for (int i = 0; i < trueCount; ++i)
cannam@128:                 destination[offset + i] = _buffer[(_head+i) % _capacity];
cannam@128:             _head += trueCount;
cannam@128:             _head %= _capacity;
cannam@128:             _size -= trueCount;
cannam@128:             return trueCount;
cannam@128:         }
cannam@128: 
cannam@128:         public int Get()
cannam@128:         {
cannam@128:             if (Size == 0)
cannam@128:                 return -1;
cannam@128: 
cannam@128:             int result = (int)_buffer[_head++ % _capacity];
cannam@128:             --_size;
cannam@128:             return result;
cannam@128:         }
cannam@128: 
cannam@128:     }
cannam@128: }