byte []数组模式搜索 [英] byte[] array pattern search

问题描述

任何人都知道来搜索字节模式/匹配在byte []数组，然后返回的位置的良好和有效的方式。

Anyone know a good and effective way to search/match for a byte pattern in an byte[] array and then return the positions.

例如

字节[] =模式新的字节[] { 12,3,5,76,8,0,6,125 };

byte[] pattern = new byte[] {12,3,5,76,8,0,6,125};

字节[] = toBeSearched新的字节[] {23,36,43,76,125,56,34,234,12,3,5,76,8,0,6,125,234,56,211,122,22,4,7,89,76,64,12,3,5,76,8,0,6,125}

byte[] toBeSearched = new byte[] {23,36,43,76,125,56,34,234,12,3,5,76,8,0,6,125,234,56,211,122,22,4,7,89,76,64,12,3,5,76,8,0,6,125}

推荐答案

我建议的东西，不涉及创建字符串数组复制或不安全code：

May I suggest something that doesn't involve creating strings, copying arrays or unsafe code:

using System;
using System.Collections.Generic;

static class ByteArrayRocks {

    static readonly int [] Empty = new int [0];

    public static int [] Locate (this byte [] self, byte [] candidate)
    {
        if (IsEmptyLocate (self, candidate))
            return Empty;

        var list = new List<int> ();

        for (int i = 0; i < self.Length; i++) {
            if (!IsMatch (self, i, candidate))
                continue;

            list.Add (i);
        }

        return list.Count == 0 ? Empty : list.ToArray ();
    }

    static bool IsMatch (byte [] array, int position, byte [] candidate)
    {
        if (candidate.Length > (array.Length - position))
            return false;

        for (int i = 0; i < candidate.Length; i++)
            if (array [position + i] != candidate [i])
                return false;

        return true;
    }

    static bool IsEmptyLocate (byte [] array, byte [] candidate)
    {
        return array == null
            || candidate == null
            || array.Length == 0
            || candidate.Length == 0
            || candidate.Length > array.Length;
    }

    static void Main ()
    {
        var data = new byte [] { 23, 36, 43, 76, 125, 56, 34, 234, 12, 3, 5, 76, 8, 0, 6, 125, 234, 56, 211, 122, 22, 4, 7, 89, 76, 64, 12, 3, 5, 76, 8, 0, 6, 125 };
        var pattern = new byte [] { 12, 3, 5, 76, 8, 0, 6, 125 };

        foreach (var position in data.Locate (pattern))
            Console.WriteLine (position);
    }
}

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修改（由IAbstract） - 搬到这里的帖子内容，因为它是不是答案的

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Edit (by IAbstract) - moving contents of post here since it is not an answer

出于好奇，我创建了一个小的基准与不同的答案。

Out of curiosity, I've created a small benchmark with the different answers.

下面是一百万次迭代的结果：

Here are the results for a million iterations:

solution [Locate]:            00:00:00.7714027
solution [FindAll]:           00:00:03.5404399
solution [SearchBytePattern]: 00:00:01.1105190
solution [MatchBytePattern]:  00:00:03.0658212

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