Further chasing of non-standard std::char_traits implementations

thirdparty/compoundfilereader/compoundfilereader.h

@@ -37,6 +37,136 @@
 #include <stdexcept>
 #include <functional>
 
+/***********************************************************************************************************************
+ * If we are compiling on Apple with Clang >= 17, the version of LLVM no longer includes a generic template for
+ * char_traits for char types which are not specified in the C++ standard. We define our own here for types required by
+ * the JSON library.
+ *
+ * From: https://github.com/llvm/llvm-project/commit/c3668779c13596e223c26fbd49670d18cd638c40
+ *
+ * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+ * See https://llvm.org/LICENSE.txt for license information.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ *
+ **********************************************************************************************************************/
+
+#ifdef __APPLE__
+#if __clang_major__ >= 17
+
+template <>
+struct std::char_traits<uint16_t>
+{
+    using char_type = uint16_t;
+    using int_type = int;
+    using off_type = std::streamoff;
+    using pos_type = std::streampos;
+    using state_type = mbstate_t;
+
+    static inline void assign( char_type& __c1, const char_type& __c2 ) noexcept { __c1 = __c2; }
+
+    static inline bool eq( char_type __c1, char_type __c2 ) noexcept { return __c1 == __c2; }
+
+    static inline bool lt( char_type __c1, char_type __c2 ) noexcept { return __c1 < __c2; }
+
+    static constexpr int compare( const char_type* __s1, const char_type* __s2, size_t __n )
+    {
+        for( ; __n; --__n, ++__s1, ++__s2 )
+        {
+            if( lt( *__s1, *__s2 ) )
+                return -1;
+
+            if( lt( *__s2, *__s1 ) )
+                return 1;
+        }
+
+        return 0;
+    }
+
+    static size_t length( const char_type* __s )
+    {
+        size_t __len = 0;
+
+        for( ; !eq( *__s, char_type( 0 ) ); ++__s )
+            ++__len;
+
+        return __len;
+    }
+
+    static constexpr const char_type* find( const char_type* __s, size_t __n, const char_type& __a )
+    {
+        for( ; __n; --__n )
+        {
+            if( eq( *__s, __a ) )
+                return __s;
+            ++__s;
+        }
+
+        return nullptr;
+    }
+
+    static constexpr char_type* move( char_type* __s1, const char_type* __s2, size_t __n )
+    {
+        if( __n == 0 )
+            return __s1;
+
+        char_type* __r = __s1;
+
+        if( __s1 < __s2 )
+        {
+            for( ; __n; --__n, ++__s1, ++__s2 )
+                assign( *__s1, *__s2 );
+        }
+        else if( __s2 < __s1 )
+        {
+            __s1 += __n;
+            __s2 += __n;
+
+            for( ; __n; --__n )
+                assign( *--__s1, *--__s2 );
+        }
+
+        return __r;
+    }
+
+    static constexpr char_type* copy( char_type* __s1, const char_type* __s2, size_t __n )
+    {
+        char_type* __r = __s1;
+
+        for( ; __n; --__n, ++__s1, ++__s2 )
+            assign( *__s1, *__s2 );
+
+        return __r;
+    }
+
+    static char_type* assign( char_type* __s, size_t __n, char_type __a )
+    {
+        char_type* __r = __s;
+
+        for( ; __n; --__n, ++__s )
+            assign( *__s, __a );
+
+        return __r;
+    }
+
+    static inline constexpr int_type not_eof( int_type __c ) noexcept
+    {
+        return eq_int_type( __c, eof() ) ? ~eof() : __c;
+    }
+
+    static inline char_type to_char_type( int_type __c ) noexcept { return char_type( __c ); }
+
+    static inline int_type to_int_type( char_type __c ) noexcept { return static_cast<int_type>( __c ); }
+
+    static inline constexpr bool eq_int_type( int_type __c1, int_type __c2 ) noexcept { return __c1 == __c2; }
+
+    static inline constexpr int_type eof() noexcept { return static_cast<int_type>( EOF ); }
+};
+
+#endif
+#endif
+
+/**********************************************************************************************************************/
+
 namespace CFB
 {
     struct CFBException : public std::runtime_error