[boost][range] - ticket 5544 - fix for termination of irange.

[SVN r72070]

include/boost/range/irange.hpp

@@ -216,9 +216,10 @@ namespace boost
 
         typedef typename range_detail::integer_iterator_with_step<Integer> iterator_t;
 
-        const std::ptrdiff_t last_step
-            = (static_cast<std::ptrdiff_t>(last) - static_cast<std::ptrdiff_t>(first))
-            / (static_cast<std::ptrdiff_t>(step_size));
+        const std::ptrdiff_t l = static_cast<std::ptrdiff_t>(last);
+        const std::ptrdiff_t f = static_cast<std::ptrdiff_t>(first);
+        const std::ptrdiff_t sz = static_cast<std::ptrdiff_t>(step_size);
+        const std::ptrdiff_t last_step = (l + ((l-f) % sz) - f) / sz;
 
         return strided_integer_range<Integer>(
             iterator_t(first, 0, step_size),

test/Jamfile.v2

@@ -156,5 +156,6 @@ test-suite range :
 	[ range-test std_container ]
 	[ range-test string ]
 	[ range-test sub_range ]
+	[ range-test ticket_5544_terminate_irange ]
     ;
 

test/irange.cpp

@@ -81,7 +81,6 @@ namespace boost
     void test_irange(int first, int last, int step_size)
     {
         BOOST_ASSERT( step_size != 0 );
-        BOOST_ASSERT( (last - first) % step_size == 0 );
         test_irange_impl<signed char>(first, last, step_size);
         test_irange_impl<unsigned char>(first, last, step_size);
         test_irange_impl<signed short>(first, last, step_size);
@@ -114,8 +113,16 @@ namespace boost
         test_irange(10, 0, -1);
         test_irange(0, 2, 2);
         test_irange(2, 0, -2);
+        test_irange(0, 9, 2);
         test_irange(10, 20, 5);
         test_irange(20, 10, -5);
+        
+        test_irange(0, 0, 3);
+        test_irange(0, 1, 3);
+        test_irange(0, 2, 3);
+        test_irange(0, 3, 3);
+        test_irange(0, 4, 3);
+        test_irange(0, 10, 3);
     }
 } // namespace boost
 

test/ticket_5544_terminate_irange.cpp

@@ -0,0 +1,47 @@
+// Boost.Range library
+//
+//  Copyright Neil Groves 2011. Use, modification and
+//  distribution is 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)
+//
+//
+// For more information, see http://www.boost.org/libs/range/
+//
+#include <boost/range/irange.hpp>
+#include <boost/range/algorithm_ext/push_back.hpp>
+
+#include <boost/test/test_tools.hpp>
+#include <boost/test/unit_test.hpp>
+
+#include <vector>
+
+namespace boost
+{
+    namespace
+    {
+        void test_irange_termination()
+        {
+            std::vector<int> reference;
+            for (int i = 0; i < 9; i += 2)
+                reference.push_back(i);
+                
+            std::vector<int> actual;
+            boost::push_back(actual, boost::irange(0,9,2));
+            
+            BOOST_CHECK_EQUAL_COLLECTIONS(actual.begin(), actual.end(),
+                                          reference.begin(), reference.end());
+        }
+    }
+}
+
+boost::unit_test::test_suite*
+init_unit_test_suite(int argc, char* argv[])
+{
+    boost::unit_test::test_suite* test
+        = BOOST_TEST_SUITE( "RangeTestSuite.ticket_5544" );
+
+    test->add( BOOST_TEST_CASE( &boost::test_irange_termination ) );
+
+    return test;
+}