Initial commit - WPinternals 2.6

DiscUtils/Compression/MoveToFront.cs

@@ -0,0 +1,70 @@
+//
+// Copyright (c) 2008-2011, Kenneth Bell
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+//
+
+namespace DiscUtils.Compression
+{
+    internal class MoveToFront
+    {
+        private byte[] _buffer;
+
+        public MoveToFront()
+            : this(256, false)
+        {
+        }
+
+        public MoveToFront(int size, bool autoInit)
+        {
+            _buffer = new byte[size];
+
+            if (autoInit)
+            {
+                for (byte i = 0; i < size; ++i)
+                {
+                    _buffer[i] = i;
+                }
+            }
+        }
+
+        public byte Head
+        {
+            get { return _buffer[0]; }
+        }
+
+        public void Set(int pos, byte val)
+        {
+            _buffer[pos] = val;
+        }
+
+        public byte GetAndMove(int pos)
+        {
+            byte val = _buffer[pos];
+
+            for (int i = pos; i > 0; --i)
+            {
+                _buffer[i] = _buffer[i - 1];
+            }
+
+            _buffer[0] = val;
+            return val;
+        }
+    }
+}