Snap for 11641499 from f5d9b62fb0e250f6f941e21f1d4676baed8244c6 to build-tools-releasebuild-tools-release

Change-Id: I157050caf92ae6f34d90a34ec72fa74e97576e5c

1 files changed, 30 insertions, 119 deletions

diff --git a/include/__string b/include/__string
index 1ddeec714..b7c0767f9 100644
--- a/include/__string
+++ b/include/__string
@@ -73,126 +73,37 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 // char_traits
 
 template <class _CharT>
-struct _LIBCPP_TEMPLATE_VIS char_traits
-{
-    typedef _CharT    char_type;
-    typedef int       int_type;
-    typedef streamoff off_type;
-    typedef streampos pos_type;
-    typedef mbstate_t state_type;
-
-    static inline void _LIBCPP_CONSTEXPR_AFTER_CXX14
-        assign(char_type& __c1, const char_type& __c2) _NOEXCEPT {__c1 = __c2;}
-    static inline _LIBCPP_CONSTEXPR bool eq(char_type __c1, char_type __c2) _NOEXCEPT
-        {return __c1 == __c2;}
-    static inline _LIBCPP_CONSTEXPR bool lt(char_type __c1, char_type __c2) _NOEXCEPT
-        {return __c1 < __c2;}
-
-    static _LIBCPP_CONSTEXPR_AFTER_CXX14
-    int compare(const char_type* __s1, const char_type* __s2, size_t __n);
-    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR_AFTER_CXX14
-    size_t length(const char_type* __s);
-    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR_AFTER_CXX14
-    const char_type* find(const char_type* __s, size_t __n, const char_type& __a);
-    static char_type*       move(char_type* __s1, const char_type* __s2, size_t __n);
-    _LIBCPP_INLINE_VISIBILITY
-    static char_type*       copy(char_type* __s1, const char_type* __s2, size_t __n);
-    _LIBCPP_INLINE_VISIBILITY
-    static char_type*       assign(char_type* __s, size_t __n, char_type __a);
-
-    static inline _LIBCPP_CONSTEXPR int_type  not_eof(int_type __c) _NOEXCEPT
-        {return eq_int_type(__c, eof()) ? ~eof() : __c;}
-    static inline _LIBCPP_CONSTEXPR char_type to_char_type(int_type __c) _NOEXCEPT
-        {return char_type(__c);}
-    static inline _LIBCPP_CONSTEXPR int_type  to_int_type(char_type __c) _NOEXCEPT
-        {return int_type(__c);}
-    static inline _LIBCPP_CONSTEXPR bool      eq_int_type(int_type __c1, int_type __c2) _NOEXCEPT
-        {return __c1 == __c2;}
-    static inline _LIBCPP_CONSTEXPR int_type  eof() _NOEXCEPT
-        {return int_type(EOF);}
+struct char_traits;
+/*
+The Standard does not define the base template for char_traits because it is impossible to provide
+a correct definition for arbitrary character types. Instead, it requires implementations to provide
+specializations for predefined character types like `char`, `wchar_t` and others. We provide this as
+exposition-only to document what members a char_traits specialization should provide:
+{
+    using char_type  = _CharT;
+    using int_type   = ...;
+    using off_type   = ...;
+    using pos_type   = ...;
+    using state_type = ...;
+
+    static void assign(char_type&, const char_type&);
+    static bool eq(char_type, char_type);
+    static bool lt(char_type, char_type);
+
+    static int              compare(const char_type*, const char_type*, size_t);
+    static size_t           length(const char_type*);
+    static const char_type* find(const char_type*, size_t, const char_type&);
+    static char_type*       move(char_type*, const char_type*, size_t);
+    static char_type*       copy(char_type*, const char_type*, size_t);
+    static char_type*       assign(char_type*, size_t, char_type);
+
+    static int_type  not_eof(int_type);
+    static char_type to_char_type(int_type);
+    static int_type  to_int_type(char_type);
+    static bool      eq_int_type(int_type, int_type);
+    static int_type  eof();
 };
-
-template <class _CharT>
-_LIBCPP_CONSTEXPR_AFTER_CXX14 int
-char_traits<_CharT>::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;
-}
-
-template <class _CharT>
-inline
-_LIBCPP_CONSTEXPR_AFTER_CXX14 size_t
-char_traits<_CharT>::length(const char_type* __s)
-{
-    size_t __len = 0;
-    for (; !eq(*__s, char_type(0)); ++__s)
-        ++__len;
-    return __len;
-}
-
-template <class _CharT>
-inline
-_LIBCPP_CONSTEXPR_AFTER_CXX14 const _CharT*
-char_traits<_CharT>::find(const char_type* __s, size_t __n, const char_type& __a)
-{
-    for (; __n; --__n)
-    {
-        if (eq(*__s, __a))
-            return __s;
-        ++__s;
-    }
-    return 0;
-}
-
-template <class _CharT>
-_CharT*
-char_traits<_CharT>::move(char_type* __s1, const char_type* __s2, size_t __n)
-{
-    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;
-}
-
-template <class _CharT>
-inline
-_CharT*
-char_traits<_CharT>::copy(char_type* __s1, const char_type* __s2, size_t __n)
-{
-    _LIBCPP_ASSERT(__s2 < __s1 || __s2 >= __s1+__n, "char_traits::copy overlapped range");
-    char_type* __r = __s1;
-    for (; __n; --__n, ++__s1, ++__s2)
-        assign(*__s1, *__s2);
-    return __r;
-}
-
-template <class _CharT>
-inline
-_CharT*
-char_traits<_CharT>::assign(char_type* __s, size_t __n, char_type __a)
-{
-    char_type* __r = __s;
-    for (; __n; --__n, ++__s)
-        assign(*__s, __a);
-    return __r;
-}
+*/
 
 // char_traits<char>