Added missing includes, remove C++11 requirement, other code cleanup.

Also, use Boost.Swap instead of the direct unqualified call to std::swap
and boost::enable_if_c instead of std::enable_if.

doc/modular_arithmetic/extended_euclidean.qbk

@@ -38,8 +38,6 @@ The extended Euclidean algorithm solves the integer relation /mx + ny/ = gcd(/m/
     int y = res.y;
     // mx + ny = gcd(m,n) should now hold
 
-Unlike most of the library, the extended Euclidean algorithm requires C++11 features.
-
 [endsect]
 
 [section References]

include/boost/integer/extended_euclidean.hpp

@@ -9,6 +9,8 @@
 #include <limits>
 #include <stdexcept>
 #include <boost/throw_exception.hpp>
+#include <boost/core/swap.hpp>
+#include <boost/core/enable_if.hpp>
 
 namespace boost { namespace integer {
 
@@ -16,27 +18,27 @@ namespace boost { namespace integer {
 // Solves mx + ny = gcd(m,n). Returns tuple with (gcd(m,n), x, y).
 
 template<class Z>
-struct euclidean_result_t {
+struct euclidean_result_t
+{
     Z gcd;
     Z x;
     Z y;
 };
 
 template<class Z>
-euclidean_result_t<typename std::enable_if<std::numeric_limits< Z >::is_signed, Z>::type>
+typename boost::enable_if_c< std::numeric_limits< Z >::is_signed, euclidean_result_t< Z > >::type
 extended_euclidean(Z m, Z n)
 {
     if (m < 1 || n < 1)
     {
-        BOOST_THROW_EXCEPTION(std::domain_error("Arguments must be strictly positive."));
+        BOOST_THROW_EXCEPTION(std::domain_error("extended_euclidean: arguments must be strictly positive"));
     }
 
     bool swapped = false;
     if (m < n)
     {
         swapped = true;
-      using std::swap;
-      swap(m, n);
+        boost::swap(m, n);
     }
     Z u0 = m;
     Z u1 = 1;
@@ -61,11 +63,20 @@ extended_euclidean(Z m, Z n)
         v2 = w2;
     }
 
-    if (swapped)
+    euclidean_result_t< Z > result;
+    result.gcd = u0;
+    if (!swapped)
     {
-        return {u0, u2, u1};
+        result.x = u1;
+        result.y = u2;
     }
-    return {u0, u1, u2};
+    else
+    {
+        result.x = u2;
+        result.y = u1;
+    }
+
+    return result;
 }
 
 }}

include/boost/integer/mod_inverse.hpp

@@ -8,7 +8,8 @@
 #define BOOST_INTEGER_MOD_INVERSE_HPP
 #include <stdexcept>
 #include <boost/throw_exception.hpp>
-#include <boost/optional.hpp>
+#include <boost/none.hpp>
+#include <boost/optional/optional.hpp>
 #include <boost/integer/extended_euclidean.hpp>
 
 namespace boost { namespace integer {
@@ -25,7 +26,7 @@ boost::optional<Z> mod_inverse(Z a, Z modulus)
 {
     if (modulus < 2)
     {
-        BOOST_THROW_EXCEPTION(std::domain_error("Modulus must be > 1."));
+        BOOST_THROW_EXCEPTION(std::domain_error("mod_inverse: modulus must be > 1"));
     }
     // make sure a < modulus:
     a = a % modulus;
@@ -34,7 +35,7 @@ boost::optional<Z> mod_inverse(Z a, Z modulus)
         // a doesn't have a modular multiplicative inverse:
         return boost::none;
     }
-    euclidean_result_t<Z> u = extended_euclidean(a, modulus);
+    boost::integer::euclidean_result_t<Z> u = boost::integer::extended_euclidean(a, modulus);
     if (u.gcd > 1)
     {
         return boost::none;

test/Jamfile.v2

@@ -17,8 +17,8 @@ test-suite integer
         [ run integer_mask_test.cpp ]
         [ run static_log2_test.cpp ]
         [ run static_min_max_test.cpp ]
-        [ run extended_euclidean_test.cpp : : : [ requires cxx11_unified_initialization_syntax sfinae_expr ] ]
-        [ run mod_inverse_test.cpp : : : [ requires cxx11_unified_initialization_syntax sfinae_expr ]  ]
+        [ run extended_euclidean_test.cpp ]
+        [ run mod_inverse_test.cpp ]
         [ compile integer_traits_include_test.cpp ]
         [ compile integer_include_test.cpp ]
         [ compile integer_mask_include_test.cpp ]