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/* IBM_PROLOG_BEGIN_TAG */
/* This is an automatically generated prolog. */
/* */
/* $Source: src/include/util/impl/iterator.h $ */
/* */
/* OpenPOWER HostBoot Project */
/* */
/* Contributors Listed Below - COPYRIGHT 2012,2015 */
/* [+] International Business Machines Corp. */
/* */
/* */
/* Licensed under the Apache License, Version 2.0 (the "License"); */
/* you may not use this file except in compliance with the License. */
/* You may obtain a copy of the License at */
/* */
/* http://www.apache.org/licenses/LICENSE-2.0 */
/* */
/* Unless required by applicable law or agreed to in writing, software */
/* distributed under the License is distributed on an "AS IS" BASIS, */
/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or */
/* implied. See the License for the specific language governing */
/* permissions and limitations under the License. */
/* */
/* IBM_PROLOG_END_TAG */
#ifndef __UTIL_IMPL_ITERATOR_H
#define __UTIL_IMPL_ITERATOR_H
/** @file iterator.h
*
* Contains the internal implementation details of the stl <iterator> header.
*/
#include <util/traits/has_plusequals.H>
#include <util/traits/has_minus.H>
namespace Util
{
namespace __Util_Iterator_Impl
{
/**
* Template definition of an iterator advance functor.
*/
template <typename InputIterator, typename Distance,
bool HasPlusEquals> struct AdvanceImpl;
/**
* Template specialization of the advance functor for iterators
* which do not support random access.
*/
template <typename InputIterator, typename Distance>
struct AdvanceImpl<InputIterator, Distance, false>
{
static void advance(InputIterator& i, Distance n)
{
while(n--)
++i;
}
};
/**
* Template specialization of the advance functor for iterators
* which do support random access.
*/
template <typename RandomIterator, typename Distance>
struct AdvanceImpl<RandomIterator, Distance, true>
{
static void advance(RandomIterator& i, Distance n)
{
i += n;
}
};
/**
* Template wrapper function for the iterator advance.
*
* Uses the existence of a += operator on the iterator to determine
* if the random-access or non-random-access version should be used.
*/
template <typename InputIterator, typename Distance>
void advance(InputIterator& i, Distance n)
{
AdvanceImpl<InputIterator, Distance,
Util::Traits::has_plusequals<InputIterator,Distance,
InputIterator>::value
>::advance(i,n);
}
/**
* Template definition of an iterator distance functor.
*/
template <typename InputIterator, typename Distance,
bool HasMinus> struct DistanceImpl;
/**
* Template specialization of the distance functor for iterators
* which do not support random access.
*/
template <typename InputIterator, typename Distance>
struct DistanceImpl<InputIterator, Distance, false>
{
static Distance distance(InputIterator& first,
InputIterator& last)
{
Distance i = 0;
while (first != last)
{
++i;
++first;
}
return i;
}
};
/**
* Template specialization of the distance functor for iterators
* which do support random access.
*/
template <typename RandomIterator, typename Distance>
struct DistanceImpl<RandomIterator, Distance, true>
{
static Distance distance(RandomIterator& first,
RandomIterator& last)
{
return last - first;
}
};
/**
* Template wrapper function for the iterator distance.
*
* Uses the existence of a - operator on the iterator to determine
* if the random-access or non-random-access version should be used.
*/
template <typename InputIterator, typename Distance>
Distance distance(InputIterator& first,
InputIterator& last)
{
return DistanceImpl<InputIterator, Distance,
Util::Traits::has_minus<InputIterator, InputIterator,
Distance>::value
>::distance(first,last);
}
};
};
#endif
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