[boost] stl extensions

From: Toon Knapen (toon.knapen_at_[hidden])
Date: 2002-10-01 03:06:42

I've been using my own std::is_sorted, std::iota etc. on compilers/stl's that 
do not provide these extensions (snippet below). OTOH, I've seen that 
boost/detail/algorithm does the same thing (but here all these are defined in 
the boost namespace, not the std namespace).

Now I think it would be interesting to provide these extensions for all stl's 
that do not include these to improve portabilitity of C++ programs. Should 
boost/detail/algorithm.hpp be used for this (but in that case the header 
should directly be in the boost includes and not in a 'detail' subdirectory) 
or would it be better to define these in the std namespace ?

#if defined(__ICC)
#define FEMTOWN_NO_IS_SORTED
#endif

#if (__GNUC__ >= 3) && ( __GNUC_MINOR__ >= 1 )
#define FEMTOWN_NO_IS_SORTED
#define FEMTOWN_NO_IOTA
#endif

#if (__IBMCPP__) 
#define FEMTOWN_NO_IS_SORTED
#define FEMTOWN_NO_IOTA
#endif

namespace std {

#if defined( FEMTOWN_NO_IS_SORTED )

  // copied from g++-v3 in gcc-2.95.3
  template <class _ForwardIter>
  bool is_sorted(_ForwardIter __first, _ForwardIter __last)
  {
    if (__first == __last)
      return true;
    
    _ForwardIter __next = __first;
    for (++__next; __next != __last; __first = __next, ++__next) {
      if (*__next < *__first)
        return false;
    }
    
    return true;
  }

  template <class _ForwardIter, class _StrictWeakOrdering>
  bool is_sorted(_ForwardIter __first, _ForwardIter __last,
                 _StrictWeakOrdering __comp)
  {
    if (__first == __last)
      return true;
    
    _ForwardIter __next = __first;
    for (++__next; __next != __last; __first = __next, ++__next) {
      if (__comp(*__next, *__first))
        return false;
    }
    
    return true;
  }

#endif // NO_IS_SORTED

#if defined( FEMTOWN_NO_IOTA )

  // copied from gcc-3.0.4
  template <class _ForwardIter, class _Tp>
  void 
  iota(_ForwardIter __first, _ForwardIter __last, _Tp __value)
  {
    while (__first != __last)
      *__first++ = __value++;
  }
  
#endif // NO_IOTA

} // namespace std