Mega Code Archive
Copy as much data as possible for a read operation
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// Copyright (c) 2008 Interact Software Ltd.
// 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.
// Dynamic Bitmap Generation for Silverlight
//
// See http://www.codeplex.com/SlDynamicBitmap for details.
using System;
namespace InteractSw.GenerateBitmap
{
/// <summary>
/// Helpers for copying data around.
/// </summary>
class CopyUtilities
{
/// <summary>
/// Copy as much data as possible for a read operation.
/// </summary>
/// <param name="targetBuffer">Buffer to put data being read.</param>
/// <param name="targetOffset">Position from which to start putting read data.</param>
/// <param name="targetEnd">Offset at which no more data must be written.</param>
/// <param name="source">Buffer from which data is being copied.</param>
/// <param name="sourceOffset">Offset from which to start copying.</param>
/// <returns>Number of bytes copied.</returns>
/// <remarks>
/// We frequently end up needing to copy data around, and the size of the source and
/// target buffers don't necessarily match up neatly. The simple approach is to copy
/// one byte at a time, but that has dreadful perf. This works out the largest amount
/// that can be copied while still fitting into the remaining space, and without
/// attempting to copy more data than there is.
///
/// The slightly peculiar bunch of arguments comes from the fact that this fell out
/// of a refactoring exercise. It's not a wonderfully useful general-purpose method.
/// </remarks>
public static int WriteAsMuchDataAsPossible(byte[] targetBuffer, int targetOffset, int targetEnd, byte[] source, int sourceOffset)
{
int spaceInTarget = targetEnd - targetOffset;
int spaceInSource = source.Length - sourceOffset;
int toCopy = Math.Min(spaceInSource, spaceInTarget);
Array.Copy(source, sourceOffset, targetBuffer, targetOffset, toCopy);
return toCopy;
}
}
}
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