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Diffstat (limited to 'src/corelib/text/qutf8stringview.h')
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1 files changed, 329 insertions, 0 deletions
diff --git a/src/corelib/text/qutf8stringview.h b/src/corelib/text/qutf8stringview.h new file mode 100644 index 00000000000..a197d14a63a --- /dev/null +++ b/src/corelib/text/qutf8stringview.h @@ -0,0 +1,329 @@ +/**************************************************************************** +** +** Copyright (C) 2020 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Marc Mutz <marc.mutz@kdab.com> +** Contact: http://www.qt.io/licensing/ +** +** This file is part of the QtCore module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** Commercial License Usage +** Licensees holding valid commercial Qt licenses may use this file in +** accordance with the commercial license agreement provided with the +** Software or, alternatively, in accordance with the terms contained in +** a written agreement between you and The Qt Company. For licensing terms +** and conditions see https://www.qt.io/terms-conditions. For further +** information use the contact form at https://www.qt.io/contact-us. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 3 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL3 included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 3 requirements +** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 2.0 or (at your option) the GNU General +** Public license version 3 or any later version approved by the KDE Free +** Qt Foundation. The licenses are as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 +** included in the packaging of this file. Please review the following +** information to ensure the GNU General Public License requirements will +** be met: https://www.gnu.org/licenses/gpl-2.0.html and +** https://www.gnu.org/licenses/gpl-3.0.html. +** +** $QT_END_LICENSE$ +** +****************************************************************************/ +#ifndef QUTF8STRINGVIEW_H +#define QUTF8STRINGVIEW_H + +#include <QtCore/qstringalgorithms.h> +#include <QtCore/qarraydata.h> // for QContainerImplHelper + +#include <string> + +QT_BEGIN_NAMESPACE + +template <bool> class QBasicUtf8StringView; +class QByteArray; +class QLatin1String; + +namespace QtPrivate { +template <typename Char> +using IsCompatibleChar8TypeHelper = std::disjunction< +#ifdef __cpp_char8_t + std::is_same<Char, char8_t>, +#endif + std::is_same<Char, char>, + std::is_same<Char, uchar>, + std::is_same<Char, signed char> + >; +template <typename Char> +using IsCompatibleChar8Type + = IsCompatibleChar8TypeHelper<std::remove_cv_t<std::remove_reference_t<Char>>>; + +template <typename Pointer> +struct IsCompatiblePointer8Helper : std::false_type {}; +template <typename Char> +struct IsCompatiblePointer8Helper<Char*> + : IsCompatibleChar8Type<Char> {}; +template <typename Pointer> +using IsCompatiblePointer8 + = IsCompatiblePointer8Helper<std::remove_cv_t<std::remove_reference_t<Pointer>>>; + +template <typename T, typename Enable = void> +struct IsContainerCompatibleWithQUtf8StringView : std::false_type {}; + +template <typename T> +struct IsContainerCompatibleWithQUtf8StringView<T, std::enable_if_t<std::conjunction_v< + // lacking concepts and ranges, we accept any T whose std::data yields a suitable pointer ... + IsCompatiblePointer8<decltype(std::data(std::declval<const T &>()))>, + // ... and that has a suitable size ... + std::is_convertible< + decltype(std::size(std::declval<const T &>())), + qsizetype + >, + // ... and it's a range as it defines an iterator-like API + IsCompatibleChar8Type<typename std::iterator_traits< + decltype(std::begin(std::declval<const T &>()))>::value_type + >, + std::is_convertible< + decltype( std::begin(std::declval<const T &>()) != std::end(std::declval<const T &>()) ), + bool + >, + + // This needs to be treated specially due to the empty vs null distinction + std::negation<std::is_same<std::decay_t<T>, QByteArray>>, + + // This has a compatible value_type, but explicitly a different encoding + std::negation<std::is_same<std::decay_t<T>, QLatin1String>>, + + // Don't make an accidental copy constructor + std::negation<std::disjunction< + std::is_same<std::decay_t<T>, QBasicUtf8StringView<true>>, + std::is_same<std::decay_t<T>, QBasicUtf8StringView<false>> + >> + >>> : std::true_type {}; + +struct hide_char8_t { +#ifdef __cpp_char8_t + using type = char8_t; +#endif +}; + +struct wrap_char { using type = char; }; + +} // namespace QtPrivate + +template <bool UseChar8T> +class QBasicUtf8StringView +{ +public: + using storage_type = typename std::conditional<UseChar8T, + QtPrivate::hide_char8_t, + QtPrivate::wrap_char + >::type::type; + typedef const storage_type value_type; + typedef qptrdiff difference_type; + typedef qsizetype size_type; + typedef value_type &reference; + typedef value_type &const_reference; + typedef value_type *pointer; + typedef value_type *const_pointer; + + typedef pointer iterator; + typedef const_pointer const_iterator; + typedef std::reverse_iterator<iterator> reverse_iterator; + typedef std::reverse_iterator<const_iterator> const_reverse_iterator; + +private: + template <typename Char> + using if_compatible_char = std::enable_if_t<QtPrivate::IsCompatibleChar8Type<Char>::value, bool>; + + template <typename Pointer> + using if_compatible_pointer = std::enable_if_t<QtPrivate::IsCompatiblePointer8<Pointer>::value, bool>; + + template <typename T> + using if_compatible_qstring_like = std::enable_if_t<std::is_same_v<T, QByteArray>, bool>; + + template <typename T> + using if_compatible_container = std::enable_if_t<QtPrivate::IsContainerCompatibleWithQUtf8StringView<T>::value, bool>; + + template <typename Container> + static constexpr qsizetype lengthHelperContainer(const Container &c) noexcept + { + return qsizetype(std::size(c)); + } + + // Note: Do not replace with std::size(const Char (&)[N]), cause the result + // will be of by one. + template <typename Char, size_t N> + static constexpr qsizetype lengthHelperContainer(const Char (&)[N]) noexcept + { + return qsizetype(N - 1); + } + + template <typename Char> + static const storage_type *castHelper(const Char *str) noexcept + { return reinterpret_cast<const storage_type*>(str); } + static constexpr const storage_type *castHelper(const storage_type *str) noexcept + { return str; } + +public: + constexpr QBasicUtf8StringView() noexcept + : m_data(nullptr), m_size(0) {} + constexpr QBasicUtf8StringView(std::nullptr_t) noexcept + : QBasicUtf8StringView() {} + + template <typename Char, if_compatible_char<Char> = true> + constexpr QBasicUtf8StringView(const Char *str, qsizetype len) + : m_data(castHelper(str)), + m_size((Q_ASSERT(len >= 0), Q_ASSERT(str || !len), len)) {} + + template <typename Char, if_compatible_char<Char> = true> + constexpr QBasicUtf8StringView(const Char *f, const Char *l) + : QBasicUtf8StringView(f, l - f) {} + +#ifdef Q_CLANG_QDOC + template <typename Char, size_t N> + constexpr QBasicUtf8StringView(const Char (&array)[N]) noexcept; + + template <typename Char> + constexpr QBasicUtf8StringView(const Char *str) noexcept; +#else + template <typename Pointer, if_compatible_pointer<Pointer> = true> + constexpr QBasicUtf8StringView(const Pointer &str) noexcept + : QBasicUtf8StringView(str, + str ? std::char_traits<std::remove_cv_t<std::remove_pointer_t<Pointer>>>::length(str) : 0) {} +#endif + +#ifdef Q_CLANG_QDOC + QBasicUtf8StringView(const QByteArray &str) noexcept; +#else + template <typename String, if_compatible_qstring_like<String> = true> + QBasicUtf8StringView(const String &str) noexcept + : QBasicUtf8StringView(str.isNull() ? nullptr : str.data(), qsizetype(str.size())) {} +#endif + + template <typename Container, if_compatible_container<Container> = true> + constexpr QBasicUtf8StringView(const Container &c) noexcept + : QBasicUtf8StringView(std::data(c), lengthHelperContainer(c)) {} + +#ifdef __cpp_char8_t + constexpr QBasicUtf8StringView(QBasicUtf8StringView<!UseChar8T> other) + : QBasicUtf8StringView(other.data(), other.size()) {} +#endif + + [[nodiscard]] inline QString toString() const; // defined in qstring.h + + [[nodiscard]] constexpr qsizetype size() const noexcept { return m_size; } + [[nodiscard]] const_pointer data() const noexcept { return reinterpret_cast<const_pointer>(m_data); } +#ifdef __cpp_char8_t + [[nodiscard]] const char8_t *utf8() const noexcept { return reinterpret_cast<const char8_t*>(m_data); } +#endif + + [[nodiscard]] constexpr storage_type operator[](qsizetype n) const + { return Q_ASSERT(n >= 0), Q_ASSERT(n < size()), m_data[n]; } + + // + // QString API + // + + [[nodiscard]] constexpr storage_type at(qsizetype n) const { return (*this)[n]; } + + [[nodiscard]] + constexpr QBasicUtf8StringView mid(qsizetype pos, qsizetype n = -1) const + { + using namespace QtPrivate; + auto result = QContainerImplHelper::mid(size(), &pos, &n); + return result == QContainerImplHelper::Null ? QBasicUtf8StringView() : QBasicUtf8StringView(m_data + pos, n); + } + [[nodiscard]] + constexpr QBasicUtf8StringView left(qsizetype n) const + { + if (size_t(n) >= size_t(size())) + n = size(); + return QBasicUtf8StringView(m_data, n); + } + [[nodiscard]] + constexpr QBasicUtf8StringView right(qsizetype n) const + { + if (size_t(n) >= size_t(size())) + n = size(); + return QBasicUtf8StringView(m_data + m_size - n, n); + } + + [[nodiscard]] constexpr QBasicUtf8StringView sliced(qsizetype pos) const + { verify(pos); return QBasicUtf8StringView{m_data + pos, m_size - pos}; } + [[nodiscard]] constexpr QBasicUtf8StringView sliced(qsizetype pos, qsizetype n) const + { verify(pos, n); return QBasicUtf8StringView(m_data + pos, n); } + [[nodiscard]] constexpr QBasicUtf8StringView first(qsizetype n) const + { verify(n); return QBasicUtf8StringView(m_data, n); } + [[nodiscard]] constexpr QBasicUtf8StringView last(qsizetype n) const + { verify(n); return QBasicUtf8StringView(m_data + m_size - n, n); } + [[nodiscard]] constexpr QBasicUtf8StringView chopped(qsizetype n) const + { verify(n); return QBasicUtf8StringView(m_data, m_size - n); } + + constexpr void truncate(qsizetype n) + { verify(n); m_size = n; } + constexpr void chop(qsizetype n) + { verify(n); m_size -= n; } + + // + // STL compatibility API: + // + [[nodiscard]] const_iterator begin() const noexcept { return data(); } + [[nodiscard]] const_iterator end() const noexcept { return data() + size(); } + [[nodiscard]] const_iterator cbegin() const noexcept { return begin(); } + [[nodiscard]] const_iterator cend() const noexcept { return end(); } + [[nodiscard]] const_reverse_iterator rbegin() const noexcept { return const_reverse_iterator(end()); } + [[nodiscard]] const_reverse_iterator rend() const noexcept { return const_reverse_iterator(begin()); } + [[nodiscard]] const_reverse_iterator crbegin() const noexcept { return rbegin(); } + [[nodiscard]] const_reverse_iterator crend() const noexcept { return rend(); } + + [[nodiscard]] constexpr bool empty() const noexcept { return size() == 0; } + [[nodiscard]] constexpr storage_type front() const { return Q_ASSERT(!empty()), m_data[0]; } + [[nodiscard]] constexpr storage_type back() const { return Q_ASSERT(!empty()), m_data[m_size - 1]; } + + // + // Qt compatibility API: + // + [[nodiscard]] constexpr bool isNull() const noexcept { return !m_data; } + [[nodiscard]] constexpr bool isEmpty() const noexcept { return empty(); } +#if QT_DEPRECATED_SINCE(6, 0) + [[nodiscard]] + Q_DECL_DEPRECATED_X("Use size() and port callers to qsizetype.") + constexpr int length() const /* not nothrow! */ + { return Q_ASSERT(int(size()) == size()), int(size()); } +#endif +private: + Q_ALWAYS_INLINE constexpr void verify(qsizetype pos, qsizetype n = 0) const + { + Q_ASSERT(pos >= 0); + Q_ASSERT(pos <= size()); + Q_ASSERT(n >= 0); + Q_ASSERT(n <= size() - pos); + } + const storage_type *m_data; + qsizetype m_size; +}; +template <bool UseChar8T> +Q_DECLARE_TYPEINFO_BODY(QBasicUtf8StringView<UseChar8T>, Q_PRIMITIVE_TYPE); + +QT_BEGIN_NO_CHAR8_T_NAMESPACE +using QUtf8StringView = QBasicUtf8StringView<false>; +QT_END_NO_CHAR8_T_NAMESPACE + +QT_BEGIN_HAS_CHAR8_T_NAMESPACE +using QUtf8StringView = QBasicUtf8StringView<true>; +QT_END_HAS_CHAR8_T_NAMESPACE + +template <typename QStringLike, std::enable_if_t<std::is_same_v<QStringLike, QByteArray>, bool> = true> +[[nodiscard]] inline q_no_char8_t::QUtf8StringView qToUtf8StringViewIgnoringNull(const QStringLike &s) noexcept +{ return q_no_char8_t::QUtf8StringView(s.data(), s.size()); } + +QT_END_NAMESPACE + +#endif /* QUTF8STRINGVIEW_H */ |