CODEWITHSUNDEEP
c++c
walter
walter

Reputation: 823

How to find a byte array inside another byte array

I cannot use strstr, memchr because array can contains any number of \0 chars, is there are any efficient ways to do that? I have to find all positions (indexes) or pointers.

Upvotes: 0

Views: 3222

Answers (4)

Dmitry Ivanov
Dmitry Ivanov

Reputation: 585

Works normally for me

bool BinScanner::FindSequence(const unsigned char * pSeq, unsigned long ulSeqSize)
{
    const unsigned char* pFindRes = std::search(pCurr, pEnd, pSeq, pSeq+ulSeqSize);
    if (pFindRes != pEnd)
    {
        return true;
    }
}

Upvotes: 0

Kerrek SB
Kerrek SB

Reputation: 477070

Piece of cake in C++:

#include <string>

const std::string needle = get_byte_sequence();
const std::string haystack = get_data();


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

// found if pos != std::string::npos

Another option is to use a generic algorithm:

#include <algorithm>

std::string::const_iterator it = std::search(data.begin(), data.end(), needle.begin(), needle.end());

if (it != data.end())
{
  // needle found at position std::distance(data.begin(), it);
}
else
{
  // needle not found
}

Bear in mind that C++ string objects can contain arbitrary data. To create a string from a byte buffer, pass its size to the constructor:

char buf[200];   // fill with your data; possibly full of zeros!

std::string s(buf, 200); // no problem

Upvotes: 6

bert-jan
bert-jan

Reputation: 968

If you expect to encounter null-characters, use the standard function memcmp(const void *, const void *, size_t).

Upvotes: 0

Michael Krelin - hacker
Michael Krelin - hacker

Reputation: 143099

Perhaps, you should look at std::search? (there is also memem, but I don't think it's extremely portable).

Upvotes: 1

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