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include/boost/fixed_string/detail/fixed_string.hpp

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+//
+// Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// 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)
+//
+// Official repository: https://github.com/boostorg/fixed_string
+//
+
+#ifndef BOOST_FIXED_STRING_DETAIL_FIXED_STRING_HPP
+#define BOOST_FIXED_STRING_DETAIL_FIXED_STRING_HPP
+
+#include <boost/assert.hpp>
+#include <boost/core/ignore_unused.hpp>
+#include <iterator>
+#include <type_traits>
+
+namespace boost {
+namespace fixed_string {
+namespace detail {
+
+// Because k-ballo said so
+template<class T>
+using is_input_iterator =
+    std::integral_constant<bool,
+        ! std::is_integral<T>::value>;
+
+template<class CharT, class Traits>
+int
+lexicographical_compare(
+    CharT const* s1, std::size_t n1,
+    CharT const* s2, std::size_t n2)
+{
+    if(n1 < n2)
+        return Traits::compare(
+            s1, s2, n1) <= 0 ? -1 : 1;
+    if(n1 > n2)
+        return Traits::compare(
+            s1, s2, n2) >= 0 ? 1 : -1;
+    return Traits::compare(s1, s2, n1);
+}
+
+template<class CharT, class Traits>
+int
+lexicographical_compare(
+    basic_string_view<CharT, Traits> s1,
+    CharT const* s2, std::size_t n2)
+{
+    return detail::lexicographical_compare<
+        CharT, Traits>(s1.data(), s1.size(), s2, n2);
+}
+
+template<class CharT, class Traits>
+int
+lexicographical_compare(
+    basic_string_view<CharT, Traits> s1,
+    basic_string_view<CharT, Traits> s2)
+{
+    return detail::lexicographical_compare<CharT, Traits>(
+        s1.data(), s1.size(), s2.data(), s2.size());
+}
+
+// Maximum number of characters in the decimal
+// representation of a binary number. This includes
+// the potential minus sign.
+//
+inline
+std::size_t constexpr
+max_digits(std::size_t bytes)
+{
+    return static_cast<std::size_t>(
+        bytes * 2.41) + 1 + 1;
+}
+
+template<class CharT, class Integer, class Traits>
+CharT*
+raw_to_string(
+    CharT* buf, Integer x, std::true_type)
+{
+    if(x == 0)
+    {
+        Traits::assign(*--buf, '0');
+        return buf;
+    }
+    if(x < 0)
+    {
+        x = -x;
+        for(;x > 0; x /= 10)
+            Traits::assign(*--buf ,
+                "0123456789"[x % 10]);
+        Traits::assign(*--buf, '-');
+        return buf;
+    }
+    for(;x > 0; x /= 10)
+        Traits::assign(*--buf ,
+            "0123456789"[x % 10]);
+    return buf;
+}
+
+template<class CharT, class Integer, class Traits>
+CharT*
+raw_to_string(
+    CharT* buf, Integer x, std::false_type)
+{
+    if(x == 0)
+    {
+        *--buf = '0';
+        return buf;
+    }
+    for(;x > 0; x /= 10)
+        Traits::assign(*--buf ,
+            "0123456789"[x % 10]);
+    return buf;
+}
+
+template<
+    class CharT,
+    class Integer,
+    class Traits = std::char_traits<CharT>>
+CharT*
+raw_to_string(CharT* last, std::size_t size, Integer i)
+{
+    boost::ignore_unused(size);
+    BOOST_ASSERT(size >= max_digits(sizeof(Integer)));
+    return raw_to_string<CharT, Integer, Traits>(
+        last, i, std::is_signed<Integer>{});
+}
+
+} // detail
+} // fixed_string
+} // boost
+
+#endif