lyx_mirror/src/support/lyxalgo.h
Angus Leeming 165c7cadf1 (Ling Li): re-write eliminate_duplicates to avoid initial sort.
git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@6294 a592a061-630c-0410-9148-cb99ea01b6c8
2003-02-27 13:41:22 +00:00

111 lines
2.1 KiB
C++

// -*- C++ -*-
/**
* \file lyxalgo.h
* This file is part of LyX, the document processor.
* Licence details can be found in the file COPYING.
*
* \author Lars Gullik Bjønnes
*
* Full author contact details are available in file CREDITS
*
* A variety of useful templates.
*/
#ifndef LYX_ALGO_H
#define LYX_ALGO_H
#include <utility>
#include <iterator>
#include <algorithm>
#include <set>
namespace lyx {
/// Returns true if the sequence first,last is sorted, false if not.
template <class For>
bool sorted(For first, For last)
{
if (first == last) return true;
For tmp = first;
while (++tmp != last) {
if (*tmp < *first++) return false;
}
return true;
}
/// Cmp is the same Cmp as you would pass to std::sort.
template <class For, class Cmp>
bool sorted(For first, For last, Cmp cmp)
{
if (first == last) return true;
For tmp = first;
while (++tmp != last) {
if (cmp(*tmp, *first++)) return false;
}
return true;
}
struct firster {
template <class P1, class P2>
P1 operator()(std::pair<P1, P2> const & p) {
return p.first;
}
};
/**
* copy elements in the given range to the output iterator
* if the predicate evaluates as true
*/
template <class InputIter, class OutputIter, class Func>
OutputIter copy_if(InputIter first, InputIter last,
OutputIter result, Func func)
{
for (; first != last; ++first) {
if (func(*first)) {
*result++ = *first;
}
}
return result;
}
/// A slot in replacement for std::count for systems where it is broken.
template <class Iterator, class T>
typename std::iterator_traits<Iterator>::difference_type
count (Iterator first, Iterator last, T const & value)
{
#ifdef HAVE_STD_COUNT
return std::count(first, last, value);
#else
std::iterator_traits<Iterator>::difference_type n = 0;
while (first != last)
if (*first++ == value) ++n;
return n;
#endif
}
/// Remove all duplicate entries in c.
template<class C>
void eliminate_duplicates(C & c)
{
C unique_c;
std::set<typename C::value_type> s;
for (typename C::iterator p = c.begin(); p != c.end(); ++p) {
if (s.find(*p) == s.end()) {
unique_c.push_back(*p);
s.insert(*p);
}
}
swap(c, unique_c);
}
} // namespace lyx
#endif // LYX_ALGO_H