Initial commit - WPinternals 2.6

DiscUtils/IBuffer.cs

@@ -0,0 +1,118 @@
+//
+// 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
+{
+    using System.Collections.Generic;
+
+    /// <summary>
+    /// Interface shared by all buffers.
+    /// </summary>
+    /// <remarks>
+    /// Buffers are very similar to streams, except the buffer has no notion of
+    /// 'current position'.  All I/O operations instead specify the position, as
+    /// needed.  Buffers also support sparse behaviour.
+    /// </remarks>
+    public interface IBuffer
+    {
+        /// <summary>
+        /// Gets a value indicating whether this buffer can be read.
+        /// </summary>
+        bool CanRead { get; }
+
+        /// <summary>
+        /// Gets a value indicating whether this buffer can be modified.
+        /// </summary>
+        bool CanWrite { get; }
+
+        /// <summary>
+        /// Gets the current capacity of the buffer, in bytes.
+        /// </summary>
+        long Capacity
+        {
+            get;
+        }
+
+        /// <summary>
+        /// Gets the parts of the buffer that are stored.
+        /// </summary>
+        /// <remarks>This may be an empty enumeration if all bytes are zero.</remarks>
+        IEnumerable<StreamExtent> Extents
+        {
+            get;
+        }
+
+        /// <summary>
+        /// Reads from the buffer into a byte array.
+        /// </summary>
+        /// <param name="pos">The offset within the buffer to start reading.</param>
+        /// <param name="buffer">The destination byte array.</param>
+        /// <param name="offset">The start offset within the destination buffer.</param>
+        /// <param name="count">The number of bytes to read.</param>
+        /// <returns>The actual number of bytes read.</returns>
+        int Read(long pos, byte[] buffer, int offset, int count);
+
+        /// <summary>
+        /// Writes a byte array into the buffer.
+        /// </summary>
+        /// <param name="pos">The start offset within the buffer.</param>
+        /// <param name="buffer">The source byte array.</param>
+        /// <param name="offset">The start offset within the source byte array.</param>
+        /// <param name="count">The number of bytes to write.</param>
+        void Write(long pos, byte[] buffer, int offset, int count);
+
+        /// <summary>
+        /// Clears bytes from the buffer.
+        /// </summary>
+        /// <param name="pos">The start offset within the buffer.</param>
+        /// <param name="count">The number of bytes to clear.</param>
+        /// <remarks>
+        /// <para>Logically equivalent to writing <c>count</c> null/zero bytes to the buffer, some
+        /// implementations determine that some (or all) of the range indicated is not actually
+        /// stored.  There is no direct, automatic, correspondence to clearing bytes and them
+        /// not being represented as an 'extent' - for example, the implementation of the underlying
+        /// stream may not permit fine-grained extent storage.</para>
+        /// <para>It is always safe to call this method to 'zero-out' a section of a buffer, regardless of
+        /// the underlying buffer implementation.</para>
+        /// </remarks>
+        void Clear(long pos, int count);
+
+        /// <summary>
+        /// Flushes all data to the underlying storage.
+        /// </summary>
+        void Flush();
+
+        /// <summary>
+        /// Sets the capacity of the buffer, truncating if appropriate.
+        /// </summary>
+        /// <param name="value">The desired capacity of the buffer.</param>
+        void SetCapacity(long value);
+
+        /// <summary>
+        /// Gets the parts of a buffer that are stored, within a specified range.
+        /// </summary>
+        /// <param name="start">The offset of the first byte of interest.</param>
+        /// <param name="count">The number of bytes of interest.</param>
+        /// <returns>An enumeration of stream extents, indicating stored bytes.</returns>
+        IEnumerable<StreamExtent> GetExtentsInRange(long start, long count);
+    }
+}