Imported existing code

libraries/include/boost/spirit/home/qi/numeric/numeric_utils.hpp

@@ -0,0 +1,111 @@
+/*=============================================================================
+    Copyright (c) 2001-2007 Joel de Guzman
+
+    Distributed under 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)
+==============================================================================*/
+#if !defined(BOOST_SPIRIT_NUMERIC_UTILS_APR_17_2006_0830AM)
+#define BOOST_SPIRIT_NUMERIC_UTILS_APR_17_2006_0830AM
+
+#include <boost/spirit/home/qi/numeric/detail/numeric_utils.hpp>
+#include <boost/assert.hpp>
+#include <boost/mpl/assert.hpp>
+
+namespace boost { namespace spirit { namespace qi
+{
+    ///////////////////////////////////////////////////////////////////////
+    //  Extract the prefix sign (- or +), return true if a '-' was found
+    ///////////////////////////////////////////////////////////////////////
+    template <typename Iterator>
+    inline bool
+    extract_sign(Iterator& first, Iterator const& last)
+    {
+        BOOST_ASSERT(first != last); // precondition
+
+        // Extract the sign
+        bool neg = *first == '-';
+        if (neg || (*first == '+'))
+        {
+            ++first;
+            return neg;
+        }
+        return false;
+    }
+
+    ///////////////////////////////////////////////////////////////////////
+    // Low level unsigned integer parser
+    ///////////////////////////////////////////////////////////////////////
+    template <typename T, unsigned Radix, unsigned MinDigits, int MaxDigits
+      , bool Accumulate = false>
+    struct extract_uint
+    {
+        // check template parameter 'Radix' for validity
+        BOOST_MPL_ASSERT_MSG(
+            Radix == 2 || Radix == 8 || Radix == 10 || Radix == 16,
+            not_supported_radix, ());
+
+        template <typename Iterator, typename Attribute>
+        static bool call(Iterator& first, Iterator const& last, Attribute& attr)
+        {
+            typedef detail::extract_int<
+                T
+              , Radix
+              , MinDigits
+              , MaxDigits
+              , detail::positive_accumulator<Radix>
+              , Accumulate>
+            extract_type;
+
+            Iterator save = first;
+            if (!extract_type::parse(first, last, attr))
+            {
+                first = save;
+                return false;
+            }
+            return true;
+        }
+    };
+
+    ///////////////////////////////////////////////////////////////////////
+    // Low level signed integer parser
+    ///////////////////////////////////////////////////////////////////////
+    template <typename T, unsigned Radix, unsigned MinDigits, int MaxDigits>
+    struct extract_int
+    {
+        // check template parameter 'Radix' for validity
+        BOOST_MPL_ASSERT_MSG(
+            Radix == 2 || Radix == 8 || Radix == 10 || Radix == 16,
+            not_supported_radix, ());
+
+        template <typename Iterator, typename Attribute>
+        static bool call(Iterator& first, Iterator const& last, Attribute& attr)
+        {
+            if (first == last)
+                return false;
+
+            typedef detail::extract_int<
+                T, Radix, MinDigits, MaxDigits>
+            extract_pos_type;
+
+            typedef detail::extract_int<
+                T, Radix, MinDigits, MaxDigits, detail::negative_accumulator<Radix> >
+            extract_neg_type;
+
+            Iterator save = first;
+            bool hit = extract_sign(first, last);
+            if (hit)
+                hit = extract_neg_type::parse(first, last, attr);
+            else
+                hit = extract_pos_type::parse(first, last, attr);
+
+            if (!hit)
+            {
+                first = save;
+                return false;
+            }
+            return true;
+        }
+    };
+}}}
+
+#endif