Extended next/prior using patch from Daniel Walker (Daniel.Walker-at-bowneglobal.com)

[SVN r21382]

test/next_prior_test.cpp

@@ -0,0 +1,79 @@
+// Boost test program for next() and prior() utilities.
+
+// Copyright 2003 Daniel Walker.  Use, modification, and distribution
+// are subject to the Boost Software License, Version 1.0. (See
+// accompanying file LICENSE_1_0.txt or a copy at
+// http://www.boost.org/LICENSE_1_0.txt.)
+
+// See http://www.boost.org/libs/utility for documentation.
+
+// Revision History 13 Dec 2003 Initial Version (Daniel Walker)
+
+// next() and prior() are replacements for operator+ and operator- for
+// non-random-access iterators. The semantics of these operators are
+// such that after executing j = i + n, std::distance(i, j) equals
+// n. Tests are provided to ensure next() has the same
+// result. Parallel tests are provided for prior(). The tests call
+// next() and prior() several times. next() and prior() are very
+// simple functions, though, and it would be very strange if these
+// tests were to fail.
+
+#define BOOST_INCLUDE_MAIN
+#include <boost/test/test_tools.hpp>
+
+#include <list>
+#include <vector>
+
+#include <boost/next_prior.hpp>
+
+template<class RandomAccessIterator, class ForwardIterator>
+bool plus_one_test(RandomAccessIterator first, RandomAccessIterator last, ForwardIterator first2)
+{
+    RandomAccessIterator i = first;
+    ForwardIterator j = first2;
+    while(i != last)
+        i = i + 1, j = boost::next(j);
+    return std::distance(first, i) == std::distance(first2, j);
+}
+
+template<class RandomAccessIterator, class ForwardIterator>
+bool plus_n_test(RandomAccessIterator first, RandomAccessIterator last, ForwardIterator first2)
+{
+    RandomAccessIterator i = first;
+    ForwardIterator j = first2;
+    for(int n = 0; i != last; ++n)
+        i = first + n, j = boost::next(first2, n);
+    return std::distance(first, i) == std::distance(first2, j);
+}
+
+template<class RandomAccessIterator, class BidirectionalIterator>
+bool minus_one_test(RandomAccessIterator first, RandomAccessIterator last, BidirectionalIterator last2)
+{
+    RandomAccessIterator i = last;
+    BidirectionalIterator j = last2;
+    while(i != first)
+        i = i - 1, j = boost::prior(j);
+    return std::distance(i, last) == std::distance(j, last2);
+}
+
+template<class RandomAccessIterator, class BidirectionalIterator>
+bool minus_n_test(RandomAccessIterator first, RandomAccessIterator last, BidirectionalIterator last2)
+{
+    RandomAccessIterator i = last;
+    BidirectionalIterator j = last2;
+    for(int n = 0; i != first; ++n)
+        i = last - n, j = boost::prior(last2, n);
+    return std::distance(i, last) == std::distance(j, last2);
+}
+
+int test_main(int, char*[])
+{
+    std::vector<int> x(8);
+    std::list<int> y(x.begin(), x.end());
+
+    BOOST_REQUIRE(plus_one_test(x.begin(), x.end(), y.begin()));
+    BOOST_REQUIRE(plus_n_test(x.begin(), x.end(), y.begin()));
+    BOOST_REQUIRE(minus_one_test(x.begin(), x.end(), y.end()));
+    BOOST_REQUIRE(minus_n_test(x.begin(), x.end(), y.end()));
+    return 0;
+}