From 775d25573bac4b009dd393db12eaeb5a8e8e1130 Mon Sep 17 00:00:00 2001
From: Beman Dawes <bdawes@acm.org>
Date: Sun, 25 Nov 2007 18:07:19 +0000
Subject: [PATCH] Full merge from trunk at revision 41356 of entire boost-root
 tree.

[SVN r41369]
---
 include/boost/pending/ct_if.hpp        | 104 +++++--------------------
 include/boost/pending/integer_log2.hpp |   9 ++-
 2 files changed, 24 insertions(+), 89 deletions(-)

diff --git a/include/boost/pending/ct_if.hpp b/include/boost/pending/ct_if.hpp
index 2f8540d..a9b801e 100644
--- a/include/boost/pending/ct_if.hpp
+++ b/include/boost/pending/ct_if.hpp
@@ -3,107 +3,39 @@
 // accompanying file LICENSE_1_0.txt or copy at
 // http://www.boost.org/LICENSE_1_0.txt)
 
-// The ct_if implementation that avoids partial specialization is
-// based on the IF class by Ulrich W. Eisenecker and Krzysztof
-// Czarnecki.
+// This header replaces the implementation of ct_if that preceded the
+// introduction of Boost.MPL with a facade that defers to that reviewed and
+// accepted library.
+
+// Author: Ronald Garcia
+// Date: 20 October, 2006
+
 
 #ifndef BOOST_CT_IF_HPP
 #define BOOST_CT_IF_HPP
 
-#include <boost/config.hpp>
 
-/*
-  There is a bug in the Borland compiler with regards to using
-  integers to specialize templates. This made it hard to use ct_if in
-  the graph library. Changing from 'ct_if' to 'ct_if_t' fixed the
-  problem.
-*/
+// A stub implementation in terms of Boost.MPL
 
-#include <boost/type_traits/integral_constant.hpp> // true_type and false_type
+#include <boost/mpl/if.hpp>
+#include <boost/mpl/not.hpp>
+#include <boost/mpl/and.hpp>
+// true_type and false_type are used by applications of ct_if
+#include <boost/type_traits/integral_constant.hpp> 
 
 namespace boost {
 
-  struct ct_if_error { };
-
   template <class A, class B>
-  struct ct_and { typedef false_type type; };
-  template <> struct ct_and<true_type,true_type> { typedef true_type type; };
+  struct ct_and : boost::mpl::and_<A,B> {};
 
-  template <class A> struct ct_not { typedef ct_if_error type; };
-  template <> struct ct_not<true_type> { typedef false_type type; };
-  template <> struct ct_not<false_type> { typedef true_type type; };
+  template <class A>
+  struct ct_not : mpl::not_<A> {};
 
-#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
-
-// agurt, 15/sep/02: in certain cases Borland has problems with
-// choosing the right 'ct_if' specialization even though 'cond' 
-// _does_ equal '1'; the easiest way to fix it is to make first 
-// 'ct_if' non-type template parameter boolean.
-#if !defined(__BORLANDC__)
   template <bool cond, class A, class B>
-  struct ct_if { typedef ct_if_error type; };
-  template <class A, class B>
-  struct ct_if<true, A, B> { typedef A type; };
-  template <class A, class B>
-  struct ct_if<false, A, B> { typedef B type; };
-#else
-  template <bool cond, class A, class B>
-  struct ct_if { typedef A type; };
-  template <class A, class B>
-  struct ct_if<false, A, B> { typedef B type; };
-#endif
+  struct ct_if : mpl::if_c<cond,A,B> {};
 
   template <class cond, class A, class B>
-  struct ct_if_t { typedef ct_if_error type; };
-  template <class A, class B>
-  struct ct_if_t<true_type, A, B> { typedef A type; };
-  template <class A, class B>
-  struct ct_if_t<false_type, A, B> { typedef B type; };
-
-#else
-
-  namespace detail {
-
-    template <int condition, class A, class B> struct IF;
-    template <int condition> struct SlectSelector;
-    struct SelectFirstType;
-    struct SelectSecondType;
-    
-    struct SelectFirstType {
-      template<class A, class B>
-      struct Template {        typedef A type; };
-    };
-    
-    struct SelectSecondType {
-      template<class A, class B>
-      struct Template { typedef B type; };
-    };
-    
-    template<int condition>
-    struct SlectSelector {
-      typedef SelectFirstType type;
-    };
-    
-    template <>
-    struct SlectSelector<0> {
-      typedef SelectSecondType type;
-    };
-
-  } // namespace detail
-    
-  template<int condition, class A, class B>
-  struct ct_if
-  {
-    typedef typename detail::SlectSelector<condition>::type Selector;
-    typedef typename Selector::template Template<A, B>::type type;
-  };
-  
-  template <class cond, class A, class B>
-  struct ct_if_t { 
-    typedef typename ct_if<cond::value, A, B>::type type;
-  };
-
-#endif
+  struct ct_if_t : mpl::if_<cond,A,B> {};
 
 } // namespace boost
 
diff --git a/include/boost/pending/integer_log2.hpp b/include/boost/pending/integer_log2.hpp
index fd8e446..15fd8b5 100644
--- a/include/boost/pending/integer_log2.hpp
+++ b/include/boost/pending/integer_log2.hpp
@@ -12,14 +12,17 @@
 //          http://www.boost.org/LICENSE_1_0.txt)
 //
 // ------------------------------------------------------
-
+//
+// $Id$
 
 
 #ifndef BOOST_INTEGER_LOG2_HPP_GP_20030301
 #define BOOST_INTEGER_LOG2_HPP_GP_20030301
 
-#include <cassert>
-#include <climits> // actually used for Borland only
+#include <assert.h>
+#ifdef __BORLANDC__
+#include <climits>
+#endif
 #include "boost/limits.hpp"
 #include "boost/config.hpp"