forked from boostorg/algorithm
146 lines
4.9 KiB
C++
146 lines
4.9 KiB
C++
// Boost string_algo library join.hpp header file ---------------------------//
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// Copyright Pavol Droba 2002-2006.
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//
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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// See http://www.boost.org/ for updates, documentation, and revision history.
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#ifndef BOOST_STRING_JOIN_HPP
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#define BOOST_STRING_JOIN_HPP
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#include <boost/algorithm/string/config.hpp>
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#include <boost/algorithm/string/detail/sequence.hpp>
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#include <boost/range/value_type.hpp>
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#include <boost/range/as_literal.hpp>
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/*! \file
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Defines join algorithm.
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Join algorithm is a counterpart to split algorithms.
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It joins strings from a 'list' by adding user defined separator.
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Additionally there is a version that allows simple filtering
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by providing a predicate.
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*/
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namespace boost {
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namespace algorithm {
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// join --------------------------------------------------------------//
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//! Join algorithm
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/*!
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This algorithm joins all strings in a 'list' into one long string.
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Segments are concatenated by given separator.
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\param Input A container that holds the input strings. It must be a container-of-containers.
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\param Separator A string that will separate the joined segments.
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\return Concatenated string.
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\note This function provides the strong exception-safety guarantee
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*/
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template< typename SequenceSequenceT, typename Range1T>
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inline typename range_value<SequenceSequenceT>::type
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join(
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const SequenceSequenceT& Input,
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const Range1T& Separator)
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{
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// Define working types
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typedef typename range_value<SequenceSequenceT>::type ResultT;
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typedef typename range_const_iterator<SequenceSequenceT>::type InputIteratorT;
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// Parse input
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InputIteratorT itBegin=::boost::begin(Input);
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InputIteratorT itEnd=::boost::end(Input);
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// Construct container to hold the result
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ResultT Result;
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// Append first element
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if(itBegin!=itEnd)
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{
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detail::insert(Result, ::boost::end(Result), *itBegin);
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++itBegin;
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}
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for(;itBegin!=itEnd; ++itBegin)
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{
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// Add separator
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detail::insert(Result, ::boost::end(Result), ::boost::as_literal(Separator));
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// Add element
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detail::insert(Result, ::boost::end(Result), *itBegin);
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}
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return Result;
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}
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// join_if ----------------------------------------------------------//
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//! Conditional join algorithm
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/*!
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This algorithm joins all strings in a 'list' into one long string.
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Segments are concatenated by given separator. Only segments that
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satisfy the predicate will be added to the result.
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\param Input A container that holds the input strings. It must be a container-of-containers.
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\param Separator A string that will separate the joined segments.
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\param Pred A segment selection predicate
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\return Concatenated string.
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\note This function provides the strong exception-safety guarantee
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*/
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template< typename SequenceSequenceT, typename Range1T, typename PredicateT>
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inline typename range_value<SequenceSequenceT>::type
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join_if(
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const SequenceSequenceT& Input,
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const Range1T& Separator,
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PredicateT Pred)
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{
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// Define working types
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typedef typename range_value<SequenceSequenceT>::type ResultT;
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typedef typename range_const_iterator<SequenceSequenceT>::type InputIteratorT;
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// Parse input
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InputIteratorT itBegin=::boost::begin(Input);
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InputIteratorT itEnd=::boost::end(Input);
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// Construct container to hold the result
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ResultT Result;
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// Roll to the first element that will be added
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while(itBegin!=itEnd && !Pred(*itBegin)) ++itBegin;
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// Add this element
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if(itBegin!=itEnd)
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{
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detail::insert(Result, ::boost::end(Result), *itBegin);
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++itBegin;
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}
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for(;itBegin!=itEnd; ++itBegin)
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{
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if(Pred(*itBegin))
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{
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// Add separator
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detail::insert(Result, ::boost::end(Result), ::boost::as_literal(Separator));
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// Add element
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detail::insert(Result, ::boost::end(Result), *itBegin);
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}
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}
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return Result;
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}
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} // namespace algorithm
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// pull names to the boost namespace
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using algorithm::join;
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using algorithm::join_if;
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} // namespace boost
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#endif // BOOST_STRING_JOIN_HPP
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