如何在字节数组中搜索模式?-HowtosearchinaBYTEarrayforapattern?

24  

Since you're in C++, do it the C++ way:

既然你用的是c++，那就用c++吧:

char a[] = { 0, 0, 0, 0xFC };
char Buffer[20000] = ...

std::string needle(a, a + 4);
std::string haystack(Buffer, Buffer + 20000);  // or "+ sizeof Buffer"

std::size_t n = haystack.find(needle);

if (n == std::string::npos)
{
    // not found
}
else
{
    // position is n
}

You can also use an algorithm to search the array directly:

也可以使用算法直接搜索数组:

#include 
#include 

auto it = std::search(
    std::begin(Buffer), std::end(Buffer),
    std::begin(a), std::end(a));

if (it == std::end(Buffer))
{
    // not found
}
else
{
    // subrange found at std::distance(std::begin(Buffer), it)
}

Or, in C++17, you can use a string view:

或者，在c++ 17中，可以使用字符串视图:

std::string_view sv(std::begin(Buffer), std::end(Buffer));

if (std::size_t n = sv.find(needle); n != sv.npos)
{
    // found at position n
}
else
{
    // not found
}

6  

You want something like memmem (that code is licensed with the GPL).

您需要类似memmem的东西(该代码是由GPL授权的)。

However, it should not be difficult to roll your own. Like in memmem's implementation, you need a loop that uses memchr to find the first character of your needle in the haystack, and memcmp to test each hit and see if all of your needle is there.

然而，卷你自己的卷并不难。就像在memmem的实现中一样，您需要一个循环，使用memchr在haystack中查找针头的第一个字符，并使用memcmp测试每次命中，看看您的针头是否都在那里。

2  

Try this, just needed it:

试试这个，只是需要它:

// Returns a pointer to the first byte of needle inside haystack, 
static uint8_t* bytes_find(uint8_t* haystack, size_t haystackLen, uint8_t* needle, size_t needleLen) {
    if (needleLen > haystackLen) {
        return false;
    }
    uint8_t* match = memchr(haystack, needle[0], haystackLen);
    if (match != NULL) {
        size_t remaining = haystackLen - ((uint8_t*)match - haystack);
        if (needleLen <= remaining) {
            if (memcmp(match, needle, needleLen) == 0) {
                return match;
            }
        }
    }
    return NULL;
}