algorithm.h

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// rak - Rakshasa's toolbox
// Copyright (C) 2005-2006, Jari Sundell
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
// 
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
// 
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//
// In addition, as a special exception, the copyright holders give
// permission to link the code of portions of this program with the
// OpenSSL library under certain conditions as described in each
// individual source file, and distribute linked combinations
// including the two.
//
// You must obey the GNU General Public License in all respects for
// all of the code used other than OpenSSL.  If you modify file(s)
// with this exception, you may extend this exception to your version
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// program, then also delete it here.
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// Contact:  Jari Sundell <[e-mail]>
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#ifndef RAK_ALGORITHM_H
#define RAK_ALGORITHM_H

#include <algorithm>
#include <functional>

namespace rak {

template <typename _InputIter, typename _Function>
_Function
for_each_pre(_InputIter __first, _InputIter __last, _Function __f) {
  _InputIter __tmp;

  while (__first != __last) {
    __tmp = __first++;
    
    __f(*__tmp);
  }

  return __f;
}

// Return a range with a distance of no more than __distance and
// between __first and __last, centered on __middle1.
template <typename _InputIter, typename _Distance>
std::pair<_InputIter, _InputIter>
advance_bidirectional(_InputIter __first, _InputIter __middle1, _InputIter __last, _Distance __distance) {
  _InputIter __middle2 = __middle1;

  do {
    if (!__distance)
      break;

    if (__middle2 != __last) {
      ++__middle2;
      --__distance;

    } else if (__middle1 == __first) {
      break;
    }

    if (!__distance)
      break;

    if (__middle1 != __first) {
      --__middle1;
      --__distance;

    } else if (__middle2 == __last) {
      break;
    }

  } while (true);

  return std::make_pair(__middle1, __middle2);
}

template <typename _Value>
struct compare_base : public std::binary_function<_Value, _Value, bool> {
  bool operator () (const _Value& complete, const _Value& base) const {
    return !complete.compare(0, base.size(), base);
  }
};

// Count the number of elements from the start of the containers to
// the first inequal element.
template <typename _InputIter>
typename std::iterator_traits<_InputIter>::difference_type
count_base(_InputIter __first1, _InputIter __last1,
	   _InputIter __first2, _InputIter __last2) {

  typename std::iterator_traits<_InputIter>::difference_type __n = 0;

  for ( ;__first1 != __last1 && __first2 != __last2; ++__first1, ++__first2, ++__n)
    if (*__first1 != *__first2)
      return __n;

  return __n;
}

template <typename _InputIter>
typename std::iterator_traits<_InputIter>::value_type
make_base(_InputIter __first, _InputIter __last) {
  if (__first == __last)
    return "";

  typename std::iterator_traits<_InputIter>::value_type __base = *__first++;

  for ( ;__first != __last; ++__first) {
    typename std::iterator_traits<_InputIter>::difference_type __pos = count_base(__base.begin(), __base.end(),
										  __first->begin(), __first->end());

    if (__pos < (typename std::iterator_traits<_InputIter>::difference_type)__base.size())
      __base.resize(__pos);
  }

  return __base;
}

}

#endif