Added thirdparty: boost library

2026-08-23 23:58:08 +00:00 · 2024-01-06 19:55:56 +02:00
parent bf49f439e1
commit bccd1e7051
15683 changed files with 3239840 additions and 0 deletions
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+/*=============================================================================
+    Copyright (c) 2001-2014 Joel de Guzman
+    Copyright (c) 2001-2011 Hartmut Kaiser
+
+    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_X3_CAST_CHAR_NOVEMBER_10_2006_0907AM)
+#define BOOST_SPIRIT_X3_CAST_CHAR_NOVEMBER_10_2006_0907AM
+
+#include <boost/type_traits/is_signed.hpp>
+#include <boost/type_traits/make_unsigned.hpp>
+#include <boost/type_traits/make_signed.hpp>
+
+namespace boost { namespace spirit { namespace x3 { namespace detail
+{
+    // Here's the thing... typical encodings (except ASCII) deal with unsigned
+    // integers > 127 (ASCII uses only 127). Yet, most char and wchar_t are signed.
+    // Thus, a char with value > 127 is negative (e.g. char 233 is -23). When you
+    // cast this to an unsigned int with 32 bits, you get 4294967273!
+    //
+    // The trick is to cast to an unsigned version of the source char first
+    // before casting to the target. {P.S. Don't worry about the code, the
+    // optimizer will optimize the if-else branches}
+
+    template <typename TargetChar, typename SourceChar>
+    TargetChar cast_char(SourceChar ch)
+    {
+#if defined(_MSC_VER)
+# pragma warning(push)
+# pragma warning(disable: 4127) // conditional expression is constant
+#endif
+        if (is_signed<TargetChar>::value != is_signed<SourceChar>::value)
+        {
+            if (is_signed<SourceChar>::value)
+            {
+                 // source is signed, target is unsigned
+                typedef typename make_unsigned<SourceChar>::type USourceChar;
+                return TargetChar(USourceChar(ch));
+            }
+            else
+            {
+                 // source is unsigned, target is signed
+                typedef typename make_signed<SourceChar>::type SSourceChar;
+                return TargetChar(SSourceChar(ch));
+            }
+        }
+        else
+        {
+            // source and target has same signedness
+            return TargetChar(ch); // just cast
+        }
+#if defined(_MSC_VER)
+# pragma warning(pop)
+#endif
+    }
+}}}}
+
+#endif
+
+