Christoph Ruegg
14 years ago
9 changed files with 140 additions and 54 deletions
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// <copyright file="Adler32.cs" company="Math.NET">
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// Math.NET Numerics, part of the Math.NET Project
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// http://numerics.mathdotnet.com
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// http://github.com/mathnet/mathnet-numerics
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// http://mathnetnumerics.codeplex.com
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//
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// Copyright (c) 2013 Math.NET
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//
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// Permission is hereby granted, free of charge, to any person
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// obtaining a copy of this software and associated documentation
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// files (the "Software"), to deal in the Software without
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// restriction, including without limitation the rights to use,
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// copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the
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// Software is furnished to do so, subject to the following
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// conditions:
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// The above copyright notice and this permission notice shall be
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// included in all copies or substantial portions of the Software.
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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// OTHER DEALINGS IN THE SOFTWARE.
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// </copyright>
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/* This code is a port and simplification of |
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adler32.c -- compute the Adler-32 checksum of a data stream |
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Copyright (C) 1995-2011 Mark Adler |
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zlib license: |
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Copyright (C) 1995-2012 Jean-loup Gailly and Mark Adler |
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This software is provided 'as-is', without any express or implied |
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warranty. In no event will the authors be held liable for any damages |
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arising from the use of this software. |
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Permission is granted to anyone to use this software for any purpose, |
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including commercial applications, and to alter it and redistribute it |
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freely, subject to the following restrictions: |
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1. The origin of this software must not be misrepresented; you must not |
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claim that you wrote the original software. If you use this software |
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in a product, an acknowledgment in the product documentation would be |
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appreciated but is not required. |
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2. Altered source versions must be plainly marked as such, and must not be |
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misrepresented as being the original software. |
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3. This notice may not be removed or altered from any source distribution. |
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Jean-loup Gailly Mark Adler |
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jloup@gzip.org madler@alumni.caltech.edu |
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*/ |
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namespace MathNet.Numerics.LinearAlgebra.IO.Matlab |
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{ |
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internal static class Adler32 |
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{ |
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/* largest prime smaller than 65536 */ |
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const int Base = 65521; |
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/* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */ |
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const int Nmax = 5552; |
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/// <summary>
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/// Computes the Adler-32 checksum of the given data.
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/// </summary>
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/// <param name="data">The data to create the checksum.</param>
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/// <returns>The checksum</returns>
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public static uint Compute(byte[] data) |
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{ |
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uint adler = 1; |
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uint sum2 = 0; |
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var len = data.Length; |
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var offset = 0; |
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while (len > 0) |
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{ |
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var tlen = len < Nmax ? len : Nmax; |
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len -= tlen; |
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do |
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{ |
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adler += data[offset++]; |
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sum2 += adler; |
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} while (--tlen > 0); |
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adler %= Base; |
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sum2 %= Base; |
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} |
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return adler | (sum2 << 16); |
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} |
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} |
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} |
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