[libcxx] r181548 - Implement n3607: 'equal', 'mismatch', and 'is_permutation'

[Sebastian Redl]

On 09.05.2013, at 23:14, Marshall Clow wrote:

> Author: marshall
> Date: Thu May  9 16:14:23 2013
> New Revision: 181548
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=181548&view=rev
> Log:
> Implement n3607: 'equal', 'mismatch', and 'is_permutation'
> 
> 
> template<class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
> @@ -1169,6 +1282,100 @@ is_permutation(_ForwardIterator1 __first
>     return _VSTD::is_permutation(__first1, __last1, __first2, __equal_to<__v1, __v2>());
> }
> 
> +#if _LIBCPP_STD_VER > 11
> +template<class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
> +bool
> +__is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
> +                 _ForwardIterator2 __first2, _ForwardIterator2 __last2, 
> +                 _BinaryPredicate __pred,
> +                 forward_iterator_tag, forward_iterator_tag )
> +{
> +    // shorten sequences as much as possible by lopping of any equal parts
> +    for (; __first1 != __last1 && __first2 != __last2; ++__first1, ++__first2)
> +        if (!__pred(*__first1, *__first2))
> +            goto __not_done;
> +    return __first1 == __last1 && __first2 == __last2;
> +__not_done:
> +    // __first1 != __last1 && __first2 != __last2 && *__first1 != *__first2
> +    typedef typename iterator_traits<_ForwardIterator1>::difference_type _D1;
> +    _D1 __l1 = _VSTD::distance(__first1, __last1);
> +
> +    typedef typename iterator_traits<_ForwardIterator2>::difference_type _D2;
> +    _D1 __l2 = _VSTD::distance(__first2, __last2);

_D2?