From: Eric Niebler (eric_at_[hidden])
Date: 2008-01-24 16:04:03
Eric Niebler wrote:
> Aries Tao wrote:
>> hi everybody,I use boost.xpressive to search email address in a binary
>> file which size is 10*1024*1024 bytes. every bytes is 0x6f in that
>> file.boost.xpressive is inefficient. anyone can help me? thanks!
>> the code is below:
> <snip>
>
> I've done some investigation, and I've discovered a couple of things...
Correct file attached now...
-- Eric Niebler Boost Consulting www.boost-consulting.com
///////////////////////////////////////////////////////////////////////////////
// main.hpp
//
// Copyright 2007 Eric Niebler. Distributed under the Boost
// Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
#include <cstring>
#include <iostream>
#include <boost/regex.hpp>
int main()
{
std::size_t const Mb = 1048576; // 1Mb
char *begin = new char[Mb];
char *end = begin + Mb;
std::memset(begin, 0x6f, 1048576);
char const *pattern = "([a-z#~_\\.!\\#$%\\^&\\*\\(\\)\\-]+@[a-z#_\\-]+\\.[a-z#_\\-\\.]+)";
try
{
using namespace boost;
regex token(pattern);
// fast, doesn't throw:
cregex_iterator cur(begin, end, token);
// slow, throws on memory exhaustion:
regex_search(begin, end, token);
}
catch(std::exception const &e)
{
std::cout << "boost.regex error: " << e.what() << std::endl;
}
return 0;
}