experimental/string_view
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// Components for manipulating non-owning sequences of characters -*- C++ -*-
// Copyright (C) 2013-2024 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
/** @file experimental/string_view
* This is a TS C++ Library header.
* @ingroup libfund-ts
*/
//
// N3762 basic_string_view library
//
#ifndef _GLIBCXX_EXPERIMENTAL_STRING_VIEW
#define _GLIBCXX_EXPERIMENTAL_STRING_VIEW 1
#pragma GCC system_header
#include <bits/requires_hosted.h> // experimental is currently omitted
#if __cplusplus >= 201402L
#include <string>
#include <limits>
#include <bits/ranges_base.h> // enable_borrowed_range, enable_view
#include <experimental/bits/lfts_config.h>
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
namespace experimental
{
inline namespace fundamentals_v1
{
#define __cpp_lib_experimental_string_view 201411
/**
* @class basic_string_view <experimental/string_view>
* @brief A non-owning reference to a string.
*
* @ingroup strings
* @ingroup sequences
* @ingroup libfund-ts
*
* @tparam _CharT Type of character
* @tparam _Traits Traits for character type, defaults to
* char_traits<_CharT>.
*
* A basic_string_view looks like this:
*
* @code
* _CharT* _M_str
* size_t _M_len
* @endcode
*/
template<typename _CharT, typename _Traits = std::char_traits<_CharT>>
class basic_string_view
{
public:
// types
using traits_type = _Traits;
using value_type = _CharT;
using pointer = _CharT*;
using const_pointer = const _CharT*;
using reference = _CharT&;
using const_reference = const _CharT&;
using const_iterator = const _CharT*;
using iterator = const_iterator;
using const_reverse_iterator = std::reverse_iterator<const_iterator>;
using reverse_iterator = const_reverse_iterator;
using size_type = size_t;
using difference_type = ptrdiff_t;
static constexpr size_type npos = size_type(-1);
// [string.view.cons], construct/copy
constexpr
basic_string_view() noexcept
: _M_len{0}, _M_str{nullptr}
{ }
constexpr basic_string_view(const basic_string_view&) noexcept = default;
template<typename _Allocator>
basic_string_view(const basic_string<_CharT, _Traits,
_Allocator>& __str) noexcept
: _M_len{__str.length()}, _M_str{__str.data()}
{ }
constexpr basic_string_view(const _CharT* __str)
: _M_len{__str == nullptr ? 0 : traits_type::length(__str)},
_M_str{__str}
{ }
constexpr basic_string_view(const _CharT* __str, size_type __len)
: _M_len{__len},
_M_str{__str}
{ }
basic_string_view&
operator=(const basic_string_view&) noexcept = default;
// [string.view.iterators], iterators
constexpr const_iterator
begin() const noexcept
{ return this->_M_str; }
constexpr const_iterator
end() const noexcept
{ return this->_M_str + this->_M_len; }
constexpr const_iterator
cbegin() const noexcept
{ return this->_M_str; }
constexpr const_iterator
cend() const noexcept
{ return this->_M_str + this->_M_len; }
const_reverse_iterator
rbegin() const noexcept
{ return const_reverse_iterator(this->end()); }
const_reverse_iterator
rend() const noexcept
{ return const_reverse_iterator(this->begin()); }
const_reverse_iterator
crbegin() const noexcept
{ return const_reverse_iterator(this->end()); }
const_reverse_iterator
crend() const noexcept
{ return const_reverse_iterator(this->begin()); }
// [string.view.capacity], capacity
constexpr size_type
size() const noexcept
{ return this->_M_len; }
constexpr size_type
length() const noexcept
{ return _M_len; }
constexpr size_type
max_size() const noexcept
{
return (npos - sizeof(size_type) - sizeof(void*))
/ sizeof(value_type) / 4;
}
_GLIBCXX_NODISCARD constexpr bool
empty() const noexcept
{ return this->_M_len == 0; }
// [string.view.access], element access
constexpr const _CharT&
operator[](size_type __pos) const
{
__glibcxx_assert(__pos < this->_M_len);
return *(this->_M_str + __pos);
}
constexpr const _CharT&
at(size_type __pos) const
{
return __pos < this->_M_len
? *(this->_M_str + __pos)
: (__throw_out_of_range_fmt(__N("basic_string_view::at: __pos "
"(which is %zu) >= this->size() "
"(which is %zu)"),
__pos, this->size()),
*this->_M_str);
}
constexpr const _CharT&
front() const
{
__glibcxx_assert(this->_M_len > 0);
return *this->_M_str;
}
constexpr const _CharT&
back() const
{
__glibcxx_assert(this->_M_len > 0);
return *(this->_M_str + this->_M_len - 1);
}
constexpr const _CharT*
data() const noexcept
{ return this->_M_str; }
// [string.view.modifiers], modifiers:
constexpr void
remove_prefix(size_type __n)
{
__glibcxx_assert(this->_M_len >= __n);
this->_M_str += __n;
this->_M_len -= __n;
}
constexpr void
remove_suffix(size_type __n)
{ this->_M_len -= __n; }
constexpr void
swap(basic_string_view& __sv) noexcept
{
auto __tmp = *this;
*this = __sv;
__sv = __tmp;
}
// [string.view.ops], string operations:
template<typename _Allocator>
explicit operator basic_string<_CharT, _Traits, _Allocator>() const
{
return { this->_M_str, this->_M_len };
}
template<typename _Allocator = std::allocator<_CharT>>
basic_string<_CharT, _Traits, _Allocator>
to_string(const _Allocator& __alloc = _Allocator()) const
{
return { this->_M_str, this->_M_len, __alloc };
}
size_type
copy(_CharT* __str, size_type __n, size_type __pos = 0) const
{
__glibcxx_requires_string_len(__str, __n);
if (__pos > this->_M_len)
__throw_out_of_range_fmt(__N("basic_string_view::copy: __pos "
"(which is %zu) > this->size() "
"(which is %zu)"),
__pos, this->size());
size_type __rlen{std::min(__n, size_type{this->_M_len - __pos})};
for (auto __begin = this->_M_str + __pos,
__end = __begin + __rlen; __begin != __end;)
*__str++ = *__begin++;
return __rlen;
}
// [string.view.ops], string operations:
constexpr basic_string_view
substr(size_type __pos = 0, size_type __n = npos) const
{
return __pos <= this->_M_len
? basic_string_view{this->_M_str + __pos,
std::min(__n, size_type{this->_M_len - __pos})}
: (__throw_out_of_range_fmt(__N("basic_string_view::substr: __pos "
"(which is %zu) > this->size() "
"(which is %zu)"),
__pos, this->size()), basic_string_view{});
}
constexpr int
compare(basic_string_view __str) const noexcept
{
int __ret = traits_type::compare(this->_M_str, __str._M_str,
std::min(this->_M_len, __str._M_len));
if (__ret == 0)
__ret = _S_compare(this->_M_len, __str._M_len);
return __ret;
}
constexpr int
compare(size_type __pos1, size_type __n1, basic_string_view __str) const
{ return this->substr(__pos1, __n1).compare(__str); }
constexpr int
compare(size_type __pos1, size_type __n1,
basic_string_view __str, size_type __pos2, size_type __n2) const
{ return this->substr(__pos1, __n1).compare(__str.substr(__pos2, __n2)); }
constexpr int
compare(const _CharT* __str) const noexcept
{ return this->compare(basic_string_view{__str}); }
constexpr int
compare(size_type __pos1, size_type __n1, const _CharT* __str) const
{ return this->substr(__pos1, __n1).compare(basic_string_view{__str}); }
constexpr int
compare(size_type __pos1, size_type __n1,
const _CharT* __str, size_type __n2) const
{
return this->substr(__pos1, __n1)
.compare(basic_string_view(__str, __n2));
}
constexpr size_type
find(basic_string_view __str, size_type __pos = 0) const noexcept
{ return this->find(__str._M_str, __pos, __str._M_len); }
constexpr size_type
find(_CharT __c, size_type __pos=0) const noexcept;
constexpr size_type
find(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
constexpr size_type
find(const _CharT* __str, size_type __pos=0) const noexcept
{ return this->find(__str, __pos, traits_type::length(__str)); }
constexpr size_type
rfind(basic_string_view __str, size_type __pos = npos) const noexcept
{ return this->rfind(__str._M_str, __pos, __str._M_len); }
constexpr size_type
rfind(_CharT __c, size_type __pos = npos) const noexcept;
constexpr size_type
rfind(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
constexpr size_type
rfind(const _CharT* __str, size_type __pos = npos) const noexcept
{ return this->rfind(__str, __pos, traits_type::length(__str)); }
constexpr size_type
find_first_of(basic_string_view __str, size_type __pos = 0) const noexcept
{ return this->find_first_of(__str._M_str, __pos, __str._M_len); }
constexpr size_type
find_first_of(_CharT __c, size_type __pos = 0) const noexcept
{ return this->find(__c, __pos); }
constexpr size_type
find_first_of(const _CharT* __str, size_type __pos, size_type __n) const;
constexpr size_type
find_first_of(const _CharT* __str, size_type __pos = 0) const noexcept
{ return this->find_first_of(__str, __pos, traits_type::length(__str)); }
constexpr size_type
find_last_of(basic_string_view __str,
size_type __pos = npos) const noexcept
{ return this->find_last_of(__str._M_str, __pos, __str._M_len); }
constexpr size_type
find_last_of(_CharT __c, size_type __pos=npos) const noexcept
{ return this->rfind(__c, __pos); }
constexpr size_type
find_last_of(const _CharT* __str, size_type __pos, size_type __n) const;
constexpr size_type
find_last_of(const _CharT* __str, size_type __pos = npos) const noexcept
{ return this->find_last_of(__str, __pos, traits_type::length(__str)); }
constexpr size_type
find_first_not_of(basic_string_view __str,
size_type __pos = 0) const noexcept
{ return this->find_first_not_of(__str._M_str, __pos, __str._M_len); }
constexpr size_type
find_first_not_of(_CharT __c, size_type __pos = 0) const noexcept;
constexpr size_type
find_first_not_of(const _CharT* __str,
size_type __pos, size_type __n) const;
constexpr size_type
find_first_not_of(const _CharT* __str, size_type __pos = 0) const noexcept
{
return this->find_first_not_of(__str, __pos,
traits_type::length(__str));
}
constexpr size_type
find_last_not_of(basic_string_view __str,
size_type __pos = npos) const noexcept
{ return this->find_last_not_of(__str._M_str, __pos, __str._M_len); }
constexpr size_type
find_last_not_of(_CharT __c, size_type __pos = npos) const noexcept;
constexpr size_type
find_last_not_of(const _CharT* __str,
size_type __pos, size_type __n) const;
constexpr size_type
find_last_not_of(const _CharT* __str,
size_type __pos = npos) const noexcept
{
return this->find_last_not_of(__str, __pos,
traits_type::length(__str));
}
private:
static constexpr int
_S_compare(size_type __n1, size_type __n2) noexcept
{
return difference_type(__n1 - __n2) > std::numeric_limits<int>::max()
? std::numeric_limits<int>::max()
: difference_type(__n1 - __n2) < std::numeric_limits<int>::min()
? std::numeric_limits<int>::min()
: static_cast<int>(difference_type(__n1 - __n2));
}
size_t _M_len;
const _CharT* _M_str;
};
// [string.view.comparison], non-member basic_string_view comparison functions
// Several of these functions use type_identity_t to create a non-deduced
// context, so that only one argument participates in template argument
// deduction and the other argument gets implicitly converted to the deduced
// type (see N3766).
template<typename _CharT, typename _Traits>
constexpr bool
operator==(basic_string_view<_CharT, _Traits> __x,
basic_string_view<_CharT, _Traits> __y) noexcept
{ return __x.size() == __y.size() && __x.compare(__y) == 0; }
template<typename _CharT, typename _Traits>
constexpr bool
operator==(basic_string_view<_CharT, _Traits> __x,
__type_identity_t<basic_string_view<_CharT, _Traits>> __y)
noexcept
{ return __x.size() == __y.size() && __x.compare(__y) == 0; }
template<typename _CharT, typename _Traits>
constexpr bool
operator==(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
basic_string_view<_CharT, _Traits> __y) noexcept
{ return __x.size() == __y.size() && __x.compare(__y) == 0; }
template<typename _CharT, typename _Traits>
constexpr bool
operator!=(basic_string_view<_CharT, _Traits> __x,
basic_string_view<_CharT, _Traits> __y) noexcept
{ return !(__x == __y); }
template<typename _CharT, typename _Traits>
constexpr bool
operator!=(basic_string_view<_CharT, _Traits> __x,
__type_identity_t<basic_string_view<_CharT, _Traits>> __y)
noexcept
{ return !(__x == __y); }
template<typename _CharT, typename _Traits>
constexpr bool
operator!=(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
basic_string_view<_CharT, _Traits> __y) noexcept
{ return !(__x == __y); }
template<typename _CharT, typename _Traits>
constexpr bool
operator< (basic_string_view<_CharT, _Traits> __x,
basic_string_view<_CharT, _Traits> __y) noexcept
{ return __x.compare(__y) < 0; }
template<typename _CharT, typename _Traits>
constexpr bool
operator< (basic_string_view<_CharT, _Traits> __x,
__type_identity_t<basic_string_view<_CharT, _Traits>> __y)
noexcept
{ return __x.compare(__y) < 0; }
template<typename _CharT, typename _Traits>
constexpr bool
operator< (__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
basic_string_view<_CharT, _Traits> __y) noexcept
{ return __x.compare(__y) < 0; }
template<typename _CharT, typename _Traits>
constexpr bool
operator> (basic_string_view<_CharT, _Traits> __x,
basic_string_view<_CharT, _Traits> __y) noexcept
{ return __x.compare(__y) > 0; }
template<typename _CharT, typename _Traits>
constexpr bool
operator> (basic_string_view<_CharT, _Traits> __x,
__type_identity_t<basic_string_view<_CharT, _Traits>> __y)
noexcept
{ return __x.compare(__y) > 0; }
template<typename _CharT, typename _Traits>
constexpr bool
operator> (__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
basic_string_view<_CharT, _Traits> __y) noexcept
{ return __x.compare(__y) > 0; }
template<typename _CharT, typename _Traits>
constexpr bool
operator<=(basic_string_view<_CharT, _Traits> __x,
basic_string_view<_CharT, _Traits> __y) noexcept
{ return __x.compare(__y) <= 0; }
template<typename _CharT, typename _Traits>
constexpr bool
operator<=(basic_string_view<_CharT, _Traits> __x,
__type_identity_t<basic_string_view<_CharT, _Traits>> __y)
noexcept
{ return __x.compare(__y) <= 0; }
template<typename _CharT, typename _Traits>
constexpr bool
operator<=(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
basic_string_view<_CharT, _Traits> __y) noexcept
{ return __x.compare(__y) <= 0; }
template<typename _CharT, typename _Traits>
constexpr bool
operator>=(basic_string_view<_CharT, _Traits> __x,
basic_string_view<_CharT, _Traits> __y) noexcept
{ return __x.compare(__y) >= 0; }
template<typename _CharT, typename _Traits>
constexpr bool
operator>=(basic_string_view<_CharT, _Traits> __x,
__type_identity_t<basic_string_view<_CharT, _Traits>> __y)
noexcept
{ return __x.compare(__y) >= 0; }
template<typename _CharT, typename _Traits>
constexpr bool
operator>=(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
basic_string_view<_CharT, _Traits> __y) noexcept
{ return __x.compare(__y) >= 0; }
// [string.view.io], Inserters and extractors
template<typename _CharT, typename _Traits>
inline basic_ostream<_CharT, _Traits>&
operator<<(basic_ostream<_CharT, _Traits>& __os,
basic_string_view<_CharT,_Traits> __str)
{ return __ostream_insert(__os, __str.data(), __str.size()); }
// basic_string_view typedef names
using string_view = basic_string_view<char>;
using wstring_view = basic_string_view<wchar_t>;
#ifdef _GLIBCXX_USE_CHAR8_T
using u8string_view = basic_string_view<char8_t>;
#endif
using u16string_view = basic_string_view<char16_t>;
using u32string_view = basic_string_view<char32_t>;
} // namespace fundamentals_v1
} // namespace experimental
// [string.view.hash], hash support:
template<typename _Tp>
struct hash;
template<>
struct hash<experimental::string_view>
: public __hash_base<size_t, experimental::string_view>
{
size_t
operator()(const experimental::string_view& __str) const noexcept
{ return std::_Hash_impl::hash(__str.data(), __str.length()); }
};
template<>
struct __is_fast_hash<hash<experimental::string_view>> : std::false_type
{ };
template<>
struct hash<experimental::wstring_view>
: public __hash_base<size_t, wstring>
{
size_t
operator()(const experimental::wstring_view& __s) const noexcept
{ return std::_Hash_impl::hash(__s.data(),
__s.length() * sizeof(wchar_t)); }
};
template<>
struct __is_fast_hash<hash<experimental::wstring_view>> : std::false_type
{ };
#ifdef _GLIBCXX_USE_CHAR8_T
template<>
struct hash<experimental::u8string_view>
: public __hash_base<size_t, experimental::u8string_view>
{
size_t
operator()(const experimental::u8string_view& __s) const noexcept
{ return std::_Hash_impl::hash(__s.data(), __s.length()); }
};
template<>
struct __is_fast_hash<hash<experimental::u8string_view>> : std::false_type
{ };
#endif
template<>
struct hash<experimental::u16string_view>
: public __hash_base<size_t, experimental::u16string_view>
{
size_t
operator()(const experimental::u16string_view& __s) const noexcept
{ return std::_Hash_impl::hash(__s.data(),
__s.length() * sizeof(char16_t)); }
};
template<>
struct __is_fast_hash<hash<experimental::u16string_view>> : std::false_type
{ };
template<>
struct hash<experimental::u32string_view>
: public __hash_base<size_t, experimental::u32string_view>
{
size_t
operator()(const experimental::u32string_view& __s) const noexcept
{ return std::_Hash_impl::hash(__s.data(),
__s.length() * sizeof(char32_t)); }
};
template<>
struct __is_fast_hash<hash<experimental::u32string_view>> : std::false_type
{ };
namespace experimental
{
// I added these EMSR.
inline namespace literals
{
inline namespace string_view_literals
{
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wliteral-suffix"
inline constexpr basic_string_view<char>
operator""sv(const char* __str, size_t __len) noexcept
{ return basic_string_view<char>{__str, __len}; }
inline constexpr basic_string_view<wchar_t>
operator""sv(const wchar_t* __str, size_t __len) noexcept
{ return basic_string_view<wchar_t>{__str, __len}; }
#ifdef _GLIBCXX_USE_CHAR8_T
inline constexpr basic_string_view<char8_t>
operator""sv(const char8_t* __str, size_t __len) noexcept
{ return basic_string_view<char8_t>{__str, __len}; }
#endif
inline constexpr basic_string_view<char16_t>
operator""sv(const char16_t* __str, size_t __len) noexcept
{ return basic_string_view<char16_t>{__str, __len}; }
inline constexpr basic_string_view<char32_t>
operator""sv(const char32_t* __str, size_t __len) noexcept
{ return basic_string_view<char32_t>{__str, __len}; }
#pragma GCC diagnostic pop
} // namespace string_literals
} // namespace literals
} // namespace experimental
#if __cpp_lib_concepts
namespace ranges
{
// Opt-in to borrowed_range concept
template<typename _CharT, typename _Traits>
inline constexpr bool
enable_borrowed_range<experimental::basic_string_view<_CharT, _Traits>>
= true;
// Opt-in to view concept
template<typename _CharT, typename _Traits>
inline constexpr bool
enable_view<experimental::basic_string_view<_CharT, _Traits>> = true;
}
#endif
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#include <experimental/bits/string_view.tcc>
#endif // __cplusplus <= 201103L
#endif // _GLIBCXX_EXPERIMENTAL_STRING_VIEW