1 files changed, 83 insertions, 0 deletions
diff --git a/zlib/contrib/dotzlib/DotZLib/CircularBuffer.cs b/zlib/contrib/dotzlib/DotZLib/CircularBuffer.cs
new file mode 100644
index 000000000..16997e906
--- /dev/null
+++ b/zlib/contrib/dotzlib/DotZLib/CircularBuffer.cs
@@ -0,0 +1,83 @@
+//
+// © Copyright Henrik Ravn 2004
+//
+// Use, modification and distribution are subject to the Boost Software License, Version 1.0. 
+// (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+using System;
+using System.Diagnostics;
+
+namespace DotZLib
+{
+
+	/// <summary>
+	/// This class implements a circular buffer
+	/// </summary>
+	internal class CircularBuffer
+	{
+        #region Private data
+        private int _capacity;
+        private int _head;
+        private int _tail;
+        private int _size;
+        private byte[] _buffer;
+        #endregion
+
+        public CircularBuffer(int capacity)
+        {    
+            Debug.Assert( capacity > 0 );
+            _buffer = new byte[capacity];
+            _capacity = capacity;
+            _head = 0;
+            _tail = 0;
+            _size = 0;
+        }
+
+        public int Size { get { return _size; } }
+
+        public int Put(byte[] source, int offset, int count)
+        {
+            Debug.Assert( count > 0 );
+            int trueCount = Math.Min(count, _capacity - Size);
+            for (int i = 0; i < trueCount; ++i)
+                _buffer[(_tail+i) % _capacity] = source[offset+i];
+            _tail += trueCount;
+            _tail %= _capacity;
+            _size += trueCount;
+            return trueCount;
+        }
+
+        public bool Put(byte b)
+        {
+            if (Size == _capacity) // no room
+                return false;
+            _buffer[_tail++] = b;
+            _tail %= _capacity;
+            ++_size;
+            return true;
+        }
+
+        public int Get(byte[] destination, int offset, int count)
+        {
+            int trueCount = Math.Min(count,Size);
+            for (int i = 0; i < trueCount; ++i)
+                destination[offset + i] = _buffer[(_head+i) % _capacity];
+            _head += trueCount;
+            _head %= _capacity;
+            _size -= trueCount;
+            return trueCount;
+        }
+
+        public int Get()
+        {
+            if (Size == 0)
+                return -1;
+
+            int result = (int)_buffer[_head++ % _capacity];
+            --_size;
+            return result;
+        }
+
+    }
+}