Re: [Boost-users] usage cregex_iterator

From: Winson Yung (winson.yung_at_[hidden])
Date: 2006-08-10 13:29:48

Sure, that's why I have the checking first in the while () statement. Was
that not enought?

while (i < 100 && h1 != h2)
{
    nextPos[i] = (*h1).position(0);
    h1++;
    i++;
}

On 8/10/06, John Maddock <john_at_[hidden]> wrote:
>
> Winson Yung wrote:
> >> Thanks John, I was going to ask about this magic '1' number thing. I
> >> think I found an example somewhere like this, but appearantely it
> >> was wrong. I was having so much difficulty using the
> >> cregex_iterator, even without the last match flag, the same code was
> >> asserting when it was walking through the iterator to get the
> >> posistion(0). Here is an example of the calltrace when assert
> >> happened:
> >>
> >> _assert(void * 0x0067a74c `string', void * 0x0067a758 `string',
> >> unsigned int 253) line 256
> >> boost::shared_ptr<boost::regex_iterator_implementation<char const
> >> *,char,boost::regex_traits<char,boost::w32_regex_traits<char> > >
> >>>>> operator->() line 253 + 31 bytes
> >> boost::regex_iterator<char const
> >> *,char,boost::regex_traits<char,boost::w32_regex_traits<char> >
> >>>>> operator*() line 129 + 37 bytes
> >> CDownloadProgressDlg::ExtractReportKeyStats(unsigned char *
> >> 0x02470040, unsigned __int64 1292879, unsigned char 205) line 1386 +
> >> 8 bytes CDownloadProgressDlg::ExtractReportKeyStats(const char *
> >> 0x010ed664, unsigned char 205) line 1333 + 36 bytes
>
> You are trying to dereference an iterator that doesn't point to anything.
>
> You must ensure it is not equal to the end-of-sequence-iterator before
> dereferencing it.  Same as with any other iterator.
>
> >> Question here are:
> >>
> >> 1) do I need to put parensis around like this to instantiate regex
> >> obj like the following?
> >>
> >> expr("(hello world here)", regex_constants::perl |
> >> regex_constants::icase);
>
> Not unless you want a marked sub-expression no.
>
> >> 2) say pBuf has something like the following, will my sample code
> >> get the position of the matching on line 1, 3, 5?
> >>
> >> hello skjdfskldjf hello world here  kjsfsdf
> >> w3423422 sfsdfsfs hello hello  kjkjkjkjkl
> >> world world hello world here 23432423
> >> 3333333333333332334234244436435353
> >> hello world here -----------------------------------
>
> It will find three matches, the positions will be relative to the start of
> the buffer, *not* the start of the current line.  Boost.Regex generally
> isn't interested in lines (other than matching ^ and $), it considers \n
> as
> just another character.
>
> John.
>
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