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Diffstat (limited to 'include/std/util/impl/iterator.h')
| -rw-r--r-- | include/std/util/impl/iterator.h | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/include/std/util/impl/iterator.h b/include/std/util/impl/iterator.h new file mode 100644 index 00000000..fdb03145 --- /dev/null +++ b/include/std/util/impl/iterator.h @@ -0,0 +1,149 @@ +/* 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 |
