// file      : butl/utility -*- C++ -*-
// copyright : Copyright (c) 2014-2015 Code Synthesis Ltd
// license   : MIT; see accompanying LICENSE file

#ifndef BUTL_UTILITY
#define BUTL_UTILITY

#include <cstring> // strcmp

namespace butl
{
  // Key comparators (i.e., to be used in sets, maps, etc).
  //
  struct compare_c_string
  {
    bool operator() (const char* x, const char* y) const
    {
      return std::strcmp (x, y) < 0;
    }
  };

  struct compare_pointer_target
  {
    template <typename P>
    bool operator() (const P& x, const P& y) const {return *x < *y;}
  };

  // Support for reverse iteration using range-based for-loop:
  //
  // for (... : reverse_iterate (x)) ...
  //
  template <typename T>
  class reverse_range
  {
    T& x_;

  public:
    reverse_range (T& x): x_ (x) {}

    auto begin () -> decltype (this->x_.rbegin ()) {return x_.rbegin ();}
    auto end () -> decltype (this->x_.rend ()) {return x_.rend ();}
  };

  template <typename T>
  inline reverse_range<T>
  reverse_iterate (T& x) {return reverse_range<T> (x);}

  template <typename T>
  inline reverse_range<const T>
  reverse_iterate (const T& x) {return reverse_range<const T> (x);}
}

#endif // BUTL_UTILITY