From 60030c86c8d74e40b42d11df9f6a4820ac274e29 Mon Sep 17 00:00:00 2001
From: Jonathan Turkanis <j@coderage.com>
Date: Sun, 8 Feb 2004 04:04:13 +0000
Subject: [PATCH] initial commitment

[SVN r1945]
---
 include/boost/utility/select_by_size.hpp | 67 ++++++++++++++++++++++++
 select_by_size_test.cpp                  | 56 ++++++++++++++++++++
 2 files changed, 123 insertions(+)
 create mode 100644 include/boost/utility/select_by_size.hpp
 create mode 100644 select_by_size_test.cpp

diff --git a/include/boost/utility/select_by_size.hpp b/include/boost/utility/select_by_size.hpp
new file mode 100644
index 0000000..d1d6482
--- /dev/null
+++ b/include/boost/utility/select_by_size.hpp
@@ -0,0 +1,67 @@
+// (C) Copyright Jonathan Turkanis 2004.
+// Permission to copy, use, modify, sell and distribute this software
+// is granted provided this copyright notice appears in all copies. This
+// software is provided "as is" without express or implied warranty, and
+// with no claim as to its suitability for any purpose.
+
+#ifndef BOOST_UTILITY_SELECT_BY_SIZE_HPP_INCLUDED
+#define BOOST_UTILITY_SELECT_BY_SIZE_HPP_INCLUDED
+
+#include <boost/config.hpp>                 // BOOST_STATIC_CONSTANT.
+#include <boost/mpl/int.hpp>
+#include <boost/preprocessor/cat.hpp>
+#include <boost/preprocessor/repetition/repeat.hpp>
+
+#ifndef BOOST_SELECT_BY_SIZE_MAX_CASE
+#define BOOST_SELECT_BY_SIZE_MAX_CASE 30
+#endif
+
+namespace boost { namespace utility {
+
+//--------------Definition of case_-------------------------------------------//
+
+template<unsigned N> struct case_;
+template<> struct case_<0> { char c; };
+template<unsigned N> struct case_ { char c1; case_<N - 1> c2; };
+typedef case_<true> yes_type;
+typedef case_<false> no_type;
+
+//--------------Definition of select_by_size----------------------------------//
+
+template<unsigned Size> struct select_by_size;
+
+// Specialize select_by_size for values sizeof(case_<0>), sizeof(case_<1>),
+// ..., sizeof(case_(BOOST_SELECT_BY_SIZE_MAX_CASE>).
+#define SELECT_BY_SIZE_SPEC(z, n, text)                                        \
+    namespace detail {                                                         \
+        static const int BOOST_PP_CAT(sizeof_case_, n) = sizeof(case_<n>);     \
+    }                                                                          \
+    template<>                                                                 \
+    struct select_by_size< detail::BOOST_PP_CAT(sizeof_case_, n) >             \
+        : mpl::int_<n> { };                                                    \
+    /**/
+BOOST_PP_REPEAT(BOOST_SELECT_BY_SIZE_MAX_CASE, SELECT_BY_SIZE_SPEC, _);
+#undef SELECT_BY_SIZE_SPEC
+
+} }             // End namespaces utility, boost.
+
+//--------------Definition of SELECT_BY_SIZE----------------------------------//
+
+#define BOOST_SELECT_BY_SIZE_ASSIGN(lhs, rhs) lhs = rhs
+#define BOOST_SELECT_BY_SIZE(type_, name, expr)                                \
+    BOOST_STATIC_CONSTANT(                                                     \
+        unsigned,                                                              \
+        BOOST_PP_CAT(boost_select_by_size_temp_, name) = sizeof(expr)          \
+    );                                                                         \
+    BOOST_STATIC_CONSTANT(                                                     \
+        type_,                                                                 \
+        name =                                                                 \
+            ( boost::utility::select_by_size<                                  \
+                BOOST_PP_CAT(boost_select_by_size_temp_, name)                 \
+              >::type::value )                                                 \
+    )                                                                          \
+    /**/
+
+#undef BOOST_SELECT_BY_SIZE_MAX_CASE
+
+#endif          // #ifndef BOOST_UTILITY_SELECT_BY_SIZE_HPP_INCLUDED
diff --git a/select_by_size_test.cpp b/select_by_size_test.cpp
new file mode 100644
index 0000000..0acf669
--- /dev/null
+++ b/select_by_size_test.cpp
@@ -0,0 +1,56 @@
+#include <boost/static_assert.hpp>
+#include <boost/utility/select_by_size.hpp>
+
+using boost::utility::case_;
+
+case_<0> helper(bool);
+case_<1> helper(int);
+case_<2> helper(unsigned);
+case_<3> helper(long);
+case_<4> helper(unsigned long);
+case_<5> helper(float);
+case_<6> helper(double);
+case_<7> helper(const char*);
+
+struct test {
+    BOOST_SELECT_BY_SIZE(int, v0, helper(true));
+    BOOST_SELECT_BY_SIZE(int, v1, helper(0));
+    BOOST_SELECT_BY_SIZE(int, v2, helper(0U));
+    BOOST_SELECT_BY_SIZE(int, v3, helper(0L));
+    BOOST_SELECT_BY_SIZE(int, v4, helper(0UL));
+    BOOST_SELECT_BY_SIZE(int, v5, helper(0.0F));
+    BOOST_SELECT_BY_SIZE(int, v6, helper(0.0));
+    BOOST_SELECT_BY_SIZE(int, v7, helper("hello"));
+};
+
+#include <iostream>
+
+int main()
+{
+    using namespace boost::utility;
+
+    BOOST_STATIC_ASSERT( select_by_size< sizeof(helper(true)) >::value == 0 );
+    BOOST_STATIC_ASSERT( select_by_size< sizeof(helper(0)) >::value == 1 );
+    BOOST_STATIC_ASSERT( select_by_size< sizeof(helper(0U)) >::value == 2 );
+    BOOST_STATIC_ASSERT( select_by_size< sizeof(helper(0L)) >::value == 3 );
+    BOOST_STATIC_ASSERT( select_by_size< sizeof(helper(0UL)) >::value == 4 );
+    BOOST_STATIC_ASSERT( select_by_size< sizeof(helper(0.0F)) >::value == 5 );
+    BOOST_STATIC_ASSERT( select_by_size< sizeof(helper(0.0)) >::value == 6 );
+    BOOST_STATIC_ASSERT( select_by_size< sizeof(helper("hello")) >::value == 7 );
+
+    BOOST_STATIC_ASSERT(test::v0 == 0);
+    BOOST_STATIC_ASSERT(test::v1 == 1);
+    BOOST_STATIC_ASSERT(test::v2 == 2);
+    BOOST_STATIC_ASSERT(test::v3 == 3);
+    BOOST_STATIC_ASSERT(test::v4 == 4);
+    BOOST_STATIC_ASSERT(test::v5 == 5);
+    BOOST_STATIC_ASSERT(test::v6 == 6);
+    BOOST_STATIC_ASSERT(test::v7 == 7);
+
+    return 0;
+}
+
+
+
+
+