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clang-p2996/libcxx/include/charconv
Louis Dionne 2eadbc8614 [libc++] Rework the whole availability markup implementation 
Currently, vendor-specific availability markup is enabled by default.
This means that even when building against trunk libc++, the headers
will by default prevent you from using some features that were not
released in the dylib on your target platform. This is a source of
frustration since people building libc++ from sources are usually not
trying to use some vendor's released dylib.

For that reason, I've been thinking for a long time that availability
annotations should be off by default, which is the primary change that
this commit enables.

In addition, it reworks the implementation to make it easier for new
vendors to add availability annotations for their platform, and it
refreshes the documentation to reflect the current state of the codebase.

Finally, a CMake configuration option is added to control whether
availability annotations should be turned on for the flavor of libc++
being created. The intent is for vendors like Apple to turn it on, and
for the upstream libc++ to leave it off (the default).

Differential Revision: https://reviews.llvm.org/D90843
2020-11-05 12:28:52 -05:00

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// -*- C++ -*-
//===------------------------------ charconv ------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP_CHARCONV
#define _LIBCPP_CHARCONV
/*
charconv synopsis
namespace std {
// floating-point format for primitive numerical conversion
enum class chars_format {
scientific = unspecified,
fixed = unspecified,
hex = unspecified,
general = fixed | scientific
};
// 23.20.2, primitive numerical output conversion
struct to_chars_result {
char* ptr;
errc ec;
};
to_chars_result to_chars(char* first, char* last, see below value,
int base = 10);
to_chars_result to_chars(char* first, char* last, float value);
to_chars_result to_chars(char* first, char* last, double value);
to_chars_result to_chars(char* first, char* last, long double value);
to_chars_result to_chars(char* first, char* last, float value,
chars_format fmt);
to_chars_result to_chars(char* first, char* last, double value,
chars_format fmt);
to_chars_result to_chars(char* first, char* last, long double value,
chars_format fmt);
to_chars_result to_chars(char* first, char* last, float value,
chars_format fmt, int precision);
to_chars_result to_chars(char* first, char* last, double value,
chars_format fmt, int precision);
to_chars_result to_chars(char* first, char* last, long double value,
chars_format fmt, int precision);
// 23.20.3, primitive numerical input conversion
struct from_chars_result {
const char* ptr;
errc ec;
};
from_chars_result from_chars(const char* first, const char* last,
see below& value, int base = 10);
from_chars_result from_chars(const char* first, const char* last,
float& value,
chars_format fmt = chars_format::general);
from_chars_result from_chars(const char* first, const char* last,
double& value,
chars_format fmt = chars_format::general);
from_chars_result from_chars(const char* first, const char* last,
long double& value,
chars_format fmt = chars_format::general);
} // namespace std
*/
#include <__config>
#include <__availability>
#include <__errc>
#include <type_traits>
#include <limits>
#include <stdint.h>
#include <string.h>
#include <math.h>
#include <__debug>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
_LIBCPP_BEGIN_NAMESPACE_STD
namespace __itoa {
_LIBCPP_AVAILABILITY_TO_CHARS _LIBCPP_FUNC_VIS char* __u64toa(uint64_t __value, char* __buffer) _NOEXCEPT;
_LIBCPP_AVAILABILITY_TO_CHARS _LIBCPP_FUNC_VIS char* __u32toa(uint32_t __value, char* __buffer) _NOEXCEPT;
}
#ifndef _LIBCPP_CXX03_LANG
enum class _LIBCPP_ENUM_VIS chars_format
{
scientific = 0x1,
fixed = 0x2,
hex = 0x4,
general = fixed | scientific
};
struct _LIBCPP_TYPE_VIS to_chars_result
{
char* ptr;
errc ec;
};
struct _LIBCPP_TYPE_VIS from_chars_result
{
const char* ptr;
errc ec;
};
void to_chars(char*, char*, bool, int = 10) = delete;
void from_chars(const char*, const char*, bool, int = 10) = delete;
namespace __itoa
{
static _LIBCPP_CONSTEXPR uint64_t __pow10_64[] = {
UINT64_C(0),
UINT64_C(10),
UINT64_C(100),
UINT64_C(1000),
UINT64_C(10000),
UINT64_C(100000),
UINT64_C(1000000),
UINT64_C(10000000),
UINT64_C(100000000),
UINT64_C(1000000000),
UINT64_C(10000000000),
UINT64_C(100000000000),
UINT64_C(1000000000000),
UINT64_C(10000000000000),
UINT64_C(100000000000000),
UINT64_C(1000000000000000),
UINT64_C(10000000000000000),
UINT64_C(100000000000000000),
UINT64_C(1000000000000000000),
UINT64_C(10000000000000000000),
};
static _LIBCPP_CONSTEXPR uint32_t __pow10_32[] = {
UINT32_C(0), UINT32_C(10), UINT32_C(100),
UINT32_C(1000), UINT32_C(10000), UINT32_C(100000),
UINT32_C(1000000), UINT32_C(10000000), UINT32_C(100000000),
UINT32_C(1000000000),
};
template <typename _Tp, typename = void>
struct _LIBCPP_HIDDEN __traits_base
{
using type = uint64_t;
#if !defined(_LIBCPP_COMPILER_MSVC)
static _LIBCPP_INLINE_VISIBILITY int __width(_Tp __v)
{
auto __t = (64 - __builtin_clzll(__v | 1)) * 1233 >> 12;
return __t - (__v < __pow10_64[__t]) + 1;
}
#endif
_LIBCPP_AVAILABILITY_TO_CHARS
static _LIBCPP_INLINE_VISIBILITY char* __convert(_Tp __v, char* __p)
{
return __u64toa(__v, __p);
}
static _LIBCPP_INLINE_VISIBILITY decltype(__pow10_64)& __pow() { return __pow10_64; }
};
template <typename _Tp>
struct _LIBCPP_HIDDEN
__traits_base<_Tp, decltype(void(uint32_t{declval<_Tp>()}))>
{
using type = uint32_t;
#if !defined(_LIBCPP_COMPILER_MSVC)
static _LIBCPP_INLINE_VISIBILITY int __width(_Tp __v)
{
auto __t = (32 - __builtin_clz(__v | 1)) * 1233 >> 12;
return __t - (__v < __pow10_32[__t]) + 1;
}
#endif
_LIBCPP_AVAILABILITY_TO_CHARS
static _LIBCPP_INLINE_VISIBILITY char* __convert(_Tp __v, char* __p)
{
return __u32toa(__v, __p);
}
static _LIBCPP_INLINE_VISIBILITY decltype(__pow10_32)& __pow() { return __pow10_32; }
};
template <typename _Tp>
inline _LIBCPP_INLINE_VISIBILITY bool
__mul_overflowed(unsigned char __a, _Tp __b, unsigned char& __r)
{
auto __c = __a * __b;
__r = __c;
return __c > (numeric_limits<unsigned char>::max)();
}
template <typename _Tp>
inline _LIBCPP_INLINE_VISIBILITY bool
__mul_overflowed(unsigned short __a, _Tp __b, unsigned short& __r)
{
auto __c = __a * __b;
__r = __c;
return __c > (numeric_limits<unsigned short>::max)();
}
template <typename _Tp>
inline _LIBCPP_INLINE_VISIBILITY bool
__mul_overflowed(_Tp __a, _Tp __b, _Tp& __r)
{
static_assert(is_unsigned<_Tp>::value, "");
#if !defined(_LIBCPP_COMPILER_MSVC)
return __builtin_mul_overflow(__a, __b, &__r);
#else
bool __did = __b && ((numeric_limits<_Tp>::max)() / __b) < __a;
__r = __a * __b;
return __did;
#endif
}
template <typename _Tp, typename _Up>
inline _LIBCPP_INLINE_VISIBILITY bool
__mul_overflowed(_Tp __a, _Up __b, _Tp& __r)
{
return __mul_overflowed(__a, static_cast<_Tp>(__b), __r);
}
template <typename _Tp>
struct _LIBCPP_HIDDEN __traits : __traits_base<_Tp>
{
static _LIBCPP_CONSTEXPR int digits = numeric_limits<_Tp>::digits10 + 1;
using __traits_base<_Tp>::__pow;
using typename __traits_base<_Tp>::type;
// precondition: at least one non-zero character available
static _LIBCPP_INLINE_VISIBILITY char const*
__read(char const* __p, char const* __ep, type& __a, type& __b)
{
type __cprod[digits];
int __j = digits - 1;
int __i = digits;
do
{
if (!('0' <= *__p && *__p <= '9'))
break;
__cprod[--__i] = *__p++ - '0';
} while (__p != __ep && __i != 0);
__a = __inner_product(__cprod + __i + 1, __cprod + __j, __pow() + 1,
__cprod[__i]);
if (__mul_overflowed(__cprod[__j], __pow()[__j - __i], __b))
--__p;
return __p;
}
template <typename _It1, typename _It2, class _Up>
static _LIBCPP_INLINE_VISIBILITY _Up
__inner_product(_It1 __first1, _It1 __last1, _It2 __first2, _Up __init)
{
for (; __first1 < __last1; ++__first1, ++__first2)
__init = __init + *__first1 * *__first2;
return __init;
}
};
} // namespace __itoa
template <typename _Tp>
inline _LIBCPP_INLINE_VISIBILITY _Tp
__complement(_Tp __x)
{
static_assert(is_unsigned<_Tp>::value, "cast to unsigned first");
return _Tp(~__x + 1);
}
template <typename _Tp>
inline _LIBCPP_INLINE_VISIBILITY typename make_unsigned<_Tp>::type
__to_unsigned(_Tp __x)
{
return static_cast<typename make_unsigned<_Tp>::type>(__x);
}
template <typename _Tp>
_LIBCPP_AVAILABILITY_TO_CHARS
inline _LIBCPP_INLINE_VISIBILITY to_chars_result
__to_chars_itoa(char* __first, char* __last, _Tp __value, true_type)
{
auto __x = __to_unsigned(__value);
if (__value < 0 && __first != __last)
{
*__first++ = '-';
__x = __complement(__x);
}
return __to_chars_itoa(__first, __last, __x, false_type());
}
template <typename _Tp>
_LIBCPP_AVAILABILITY_TO_CHARS
inline _LIBCPP_INLINE_VISIBILITY to_chars_result
__to_chars_itoa(char* __first, char* __last, _Tp __value, false_type)
{
using __tx = __itoa::__traits<_Tp>;
auto __diff = __last - __first;
#if !defined(_LIBCPP_COMPILER_MSVC)
if (__tx::digits <= __diff || __tx::__width(__value) <= __diff)
return {__tx::__convert(__value, __first), errc(0)};
else
return {__last, errc::value_too_large};
#else
if (__tx::digits <= __diff)
return {__tx::__convert(__value, __first), {}};
else
{
char __buf[__tx::digits];
auto __p = __tx::__convert(__value, __buf);
auto __len = __p - __buf;
if (__len <= __diff)
{
memcpy(__first, __buf, __len);
return {__first + __len, {}};
}
else
return {__last, errc::value_too_large};
}
#endif
}
template <typename _Tp>
_LIBCPP_AVAILABILITY_TO_CHARS
inline _LIBCPP_INLINE_VISIBILITY to_chars_result
__to_chars_integral(char* __first, char* __last, _Tp __value, int __base,
true_type)
{
auto __x = __to_unsigned(__value);
if (__value < 0 && __first != __last)
{
*__first++ = '-';
__x = __complement(__x);
}
return __to_chars_integral(__first, __last, __x, __base, false_type());
}
template <typename _Tp>
_LIBCPP_AVAILABILITY_TO_CHARS
inline _LIBCPP_INLINE_VISIBILITY to_chars_result
__to_chars_integral(char* __first, char* __last, _Tp __value, int __base,
false_type)
{
if (__base == 10)
return __to_chars_itoa(__first, __last, __value, false_type());
auto __p = __last;
while (__p != __first)
{
auto __c = __value % __base;
__value /= __base;
*--__p = "0123456789abcdefghijklmnopqrstuvwxyz"[__c];
if (__value == 0)
break;
}
auto __len = __last - __p;
if (__value != 0 || !__len)
return {__last, errc::value_too_large};
else
{
memmove(__first, __p, __len);
return {__first + __len, {}};
}
}
template <typename _Tp, typename enable_if<is_integral<_Tp>::value, int>::type = 0>
_LIBCPP_AVAILABILITY_TO_CHARS
inline _LIBCPP_INLINE_VISIBILITY to_chars_result
to_chars(char* __first, char* __last, _Tp __value)
{
return __to_chars_itoa(__first, __last, __value, is_signed<_Tp>());
}
template <typename _Tp, typename enable_if<is_integral<_Tp>::value, int>::type = 0>
_LIBCPP_AVAILABILITY_TO_CHARS
inline _LIBCPP_INLINE_VISIBILITY to_chars_result
to_chars(char* __first, char* __last, _Tp __value, int __base)
{
_LIBCPP_ASSERT(2 <= __base && __base <= 36, "base not in [2, 36]");
return __to_chars_integral(__first, __last, __value, __base,
is_signed<_Tp>());
}
template <typename _It, typename _Tp, typename _Fn, typename... _Ts>
inline _LIBCPP_INLINE_VISIBILITY from_chars_result
__sign_combinator(_It __first, _It __last, _Tp& __value, _Fn __f, _Ts... __args)
{
using __tl = numeric_limits<_Tp>;
decltype(__to_unsigned(__value)) __x;
bool __neg = (__first != __last && *__first == '-');
auto __r = __f(__neg ? __first + 1 : __first, __last, __x, __args...);
switch (__r.ec)
{
case errc::invalid_argument:
return {__first, __r.ec};
case errc::result_out_of_range:
return __r;
default:
break;
}
if (__neg)
{
if (__x <= __complement(__to_unsigned(__tl::min())))
{
__x = __complement(__x);
memcpy(&__value, &__x, sizeof(__x));
return __r;
}
}
else
{
if (__x <= (__tl::max)())
{
__value = __x;
return __r;
}
}
return {__r.ptr, errc::result_out_of_range};
}
template <typename _Tp>
inline _LIBCPP_INLINE_VISIBILITY bool
__in_pattern(_Tp __c)
{
return '0' <= __c && __c <= '9';
}
struct _LIBCPP_HIDDEN __in_pattern_result
{
bool __ok;
int __val;
explicit _LIBCPP_INLINE_VISIBILITY operator bool() const { return __ok; }
};
template <typename _Tp>
inline _LIBCPP_INLINE_VISIBILITY __in_pattern_result
__in_pattern(_Tp __c, int __base)
{
if (__base <= 10)
return {'0' <= __c && __c < '0' + __base, __c - '0'};
else if (__in_pattern(__c))
return {true, __c - '0'};
else if ('a' <= __c && __c < 'a' + __base - 10)
return {true, __c - 'a' + 10};
else
return {'A' <= __c && __c < 'A' + __base - 10, __c - 'A' + 10};
}
template <typename _It, typename _Tp, typename _Fn, typename... _Ts>
inline _LIBCPP_INLINE_VISIBILITY from_chars_result
__subject_seq_combinator(_It __first, _It __last, _Tp& __value, _Fn __f,
_Ts... __args)
{
auto __find_non_zero = [](_It __first, _It __last) {
for (; __first != __last; ++__first)
if (*__first != '0')
break;
return __first;
};
auto __p = __find_non_zero(__first, __last);
if (__p == __last || !__in_pattern(*__p, __args...))
{
if (__p == __first)
return {__first, errc::invalid_argument};
else
{
__value = 0;
return {__p, {}};
}
}
auto __r = __f(__p, __last, __value, __args...);
if (__r.ec == errc::result_out_of_range)
{
for (; __r.ptr != __last; ++__r.ptr)
{
if (!__in_pattern(*__r.ptr, __args...))
break;
}
}
return __r;
}
template <typename _Tp, typename enable_if<is_unsigned<_Tp>::value, int>::type = 0>
inline _LIBCPP_INLINE_VISIBILITY from_chars_result
__from_chars_atoi(const char* __first, const char* __last, _Tp& __value)
{
using __tx = __itoa::__traits<_Tp>;
using __output_type = typename __tx::type;
return __subject_seq_combinator(
__first, __last, __value,
[](const char* __first, const char* __last,
_Tp& __value) -> from_chars_result {
__output_type __a, __b;
auto __p = __tx::__read(__first, __last, __a, __b);
if (__p == __last || !__in_pattern(*__p))
{
__output_type __m = (numeric_limits<_Tp>::max)();
if (__m >= __a && __m - __a >= __b)
{
__value = __a + __b;
return {__p, {}};
}
}
return {__p, errc::result_out_of_range};
});
}
template <typename _Tp, typename enable_if<is_signed<_Tp>::value, int>::type = 0>
inline _LIBCPP_INLINE_VISIBILITY from_chars_result
__from_chars_atoi(const char* __first, const char* __last, _Tp& __value)
{
using __t = decltype(__to_unsigned(__value));
return __sign_combinator(__first, __last, __value, __from_chars_atoi<__t>);
}
template <typename _Tp, typename enable_if<is_unsigned<_Tp>::value, int>::type = 0>
inline _LIBCPP_INLINE_VISIBILITY from_chars_result
__from_chars_integral(const char* __first, const char* __last, _Tp& __value,
int __base)
{
if (__base == 10)
return __from_chars_atoi(__first, __last, __value);
return __subject_seq_combinator(
__first, __last, __value,
[](const char* __p, const char* __last, _Tp& __value,
int __base) -> from_chars_result {
using __tl = numeric_limits<_Tp>;
auto __digits = __tl::digits / log2f(float(__base));
_Tp __a = __in_pattern(*__p++, __base).__val, __b = 0;
for (int __i = 1; __p != __last; ++__i, ++__p)
{
if (auto __c = __in_pattern(*__p, __base))
{
if (__i < __digits - 1)
__a = __a * __base + __c.__val;
else
{
if (!__itoa::__mul_overflowed(__a, __base, __a))
++__p;
__b = __c.__val;
break;
}
}
else
break;
}
if (__p == __last || !__in_pattern(*__p, __base))
{
if ((__tl::max)() - __a >= __b)
{
__value = __a + __b;
return {__p, {}};
}
}
return {__p, errc::result_out_of_range};
},
__base);
}
template <typename _Tp, typename enable_if<is_signed<_Tp>::value, int>::type = 0>
inline _LIBCPP_INLINE_VISIBILITY from_chars_result
__from_chars_integral(const char* __first, const char* __last, _Tp& __value,
int __base)
{
using __t = decltype(__to_unsigned(__value));
return __sign_combinator(__first, __last, __value,
__from_chars_integral<__t>, __base);
}
template <typename _Tp, typename enable_if<is_integral<_Tp>::value, int>::type = 0>
inline _LIBCPP_INLINE_VISIBILITY from_chars_result
from_chars(const char* __first, const char* __last, _Tp& __value)
{
return __from_chars_atoi(__first, __last, __value);
}
template <typename _Tp, typename enable_if<is_integral<_Tp>::value, int>::type = 0>
inline _LIBCPP_INLINE_VISIBILITY from_chars_result
from_chars(const char* __first, const char* __last, _Tp& __value, int __base)
{
_LIBCPP_ASSERT(2 <= __base && __base <= 36, "base not in [2, 36]");
return __from_chars_integral(__first, __last, __value, __base);
}
#endif // _LIBCPP_CXX03_LANG
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS
#endif // _LIBCPP_CHARCONV
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