Initial checkin of apply() and apply_if() / BoostCon 2008

library-in-a-week


[SVN r45589]

apply/test/apply_test.cpp

@@ -0,0 +1,84 @@
+/*** show that you have a forward iterator
+* more types
+* more containers*/
+
+/*
+ Copyright (C) 2008 Jesse Williamson 
+
+ Use, modification and distribution are subject to the
+ Boost Software License, Version 1.0. (See accompanying file
+ LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+*/
+
+#include <boost/test/included/test_exec_monitor.hpp>
+
+#include <boost/algorithm/apply.hpp>
+
+#include <list>
+#include <vector>
+#include <numeric>
+#include <iostream>
+
+using namespace std;
+
+using namespace boost::algorithm::sequence;
+
+int make_zero(int x)
+{
+ return 0;
+}
+
+string make_z(string x)
+{
+ return "z";
+}
+
+int test_main(int, char **)
+{
+ // Basic test:
+ {
+   vector<int> v(3);
+
+   // Should work on a single element:
+   BOOST_CHECK(apply(v.begin(), v.begin(), make_zero));
+   BOOST_CHECK(0 == accumulate(v.begin(), v.end(), 0));
+
+   v[0] = 1;
+   v[1] = 2;
+   v[2] = 3;
+   BOOST_CHECK(apply(v.begin(), v.end(), make_zero)); 
+   BOOST_CHECK(0 == accumulate(v.begin(), v.end(), 0));
+
+   // Use a conditional function (apply_if()), and do not modify the sequence:
+   v[0] = 10;
+   v[1] = 2;
+   v[2] = 10;
+   BOOST_CHECK(apply_if(v.begin(), v.end(), make_zero, std::bind1st(std::not_equal_to<int>(), 10)));
+   BOOST_CHECK(20 == accumulate(v.begin(), v.end(), 0) && 0 == v[1] && 3 == v.size());
+ }
+
+ // Basic range test:
+ {
+   vector<int> v(128);
+
+   generate(v.begin(), v.end(), rand);
+
+   BOOST_CHECK(apply(v, make_zero)); 
+
+   BOOST_CHECK(0 == accumulate(v.begin(), v.end(), 0));
+ }
+
+ {
+   list<string> ls;
+
+   const char *s[] = { "hello", "there", "world", "!\n" };	
+
+   copy(s, s + 4, back_inserter(ls));
+
+   apply(ls.begin(), ls.end(), make_z);
+
+   BOOST_CHECK(accumulate(ls.begin(), ls.end(), string()) == "zzzz");
+ }
+
+ return 0;
+}

include/boost/algorithm/apply.hpp

@@ -0,0 +1,87 @@
+/*
+
+ Copyright (C) Jesse Williamson 2008.
+	
+ Distributed under the Boost Software License, Version 1.0. (See accompanying
+ file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+*/
+
+#ifndef BOOST_ALGORITHM_APPLY_HPP
+#define BOOST_ALGORITHM_APPLY_HPP
+
+/// \file apply.hpp
+/// \brief Boost implementation of sequence-modifying algorithms.
+/// \author Jesse Williamson
+
+#include <boost/range.hpp>
+
+namespace boost { namespace algorithm { namespace sequence {
+
+/// \fn apply_if (ForwardIter begin, ForwardIter end, Mutator m, ConditionPredicate c)
+/// \brief Applies m to all elements from (begin, end) for which c is true.
+///
+/// \param begin The start of the sequence to modify
+/// \param last  One past the end of the input sequence
+/// \param m     Unary mutator function object
+/// \param c     Unary condition function object
+/// \return      The mutator function object
+///
+template <class ForwardIter, class Mutator, class ConditionPredicate>
+Mutator apply_if(ForwardIter begin, ForwardIter end, Mutator m, ConditionPredicate c)
+{
+ for (; begin != end; begin++) {
+    if (c(*begin))
+      *begin = m(*begin);
+ }
+  
+ return m; 
+}
+
+/// \fn apply_if (Range r, Mutator m, ConditionPredicate c)
+/// \brief Applies m to all elements in the range r for which c is true.
+///
+/// \param r     The range to modify
+/// \param m     Unary mutator function object
+/// \param c     Unary condition function object
+/// \return      The mutator function object
+///
+template <class ForwardReadableRange, class Mutator, class ConditionPredicate>
+Mutator apply_if(ForwardReadableRange& R, Mutator m, ConditionPredicate c)
+{
+ return apply_if(boost::begin(R), boost::end(R), m, c);
+}
+
+/// \fn apply (ForwardIter begin, ForwardIter end, Mutator m)
+/// \brief Applies m to all elements from (begin, end).
+///
+/// \param begin The start of the sequence to modify
+/// \param last  One past the end of the input sequence
+/// \param m     Unary mutator function object
+/// \return      The mutator function object
+///
+template <class ForwardIter, class Mutator>
+Mutator apply(ForwardIter begin, ForwardIter end, Mutator m)
+{
+ for (; begin != end; begin++) 
+    *begin = m(*begin);
+  
+ return m;
+}
+
+/// \fn apply (ForwardReadableRange r, Mutator m)
+/// \brief Applies m to all elements in the range r
+///
+/// \param r     The range to modify
+/// \param m     Unary mutator function object
+/// \return      The mutator function object
+///
+template <class ForwardReadableRange, class Mutator>
+Mutator apply(ForwardReadableRange& R, Mutator m)
+{
+ return apply(boost::begin(R), boost::end(R), m);
+}
+
+}}} // namespace boost::algorithm::sequence
+
+#endif // BOOST_ALGORITHM_APPLY_HPP