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Diffstat (limited to 'src/corelib/tools/qstringview.h')
-rw-r--r-- | src/corelib/tools/qstringview.h | 307 |
1 files changed, 307 insertions, 0 deletions
diff --git a/src/corelib/tools/qstringview.h b/src/corelib/tools/qstringview.h new file mode 100644 index 0000000000..764da71d0b --- /dev/null +++ b/src/corelib/tools/qstringview.h @@ -0,0 +1,307 @@ +/**************************************************************************** +** +** Copyright (C) 2017 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 QSTRINGVIEW_H +#define QSTRINGVIEW_H + +#ifndef QT_STRINGVIEW_LEVEL +# define QT_STRINGVIEW_LEVEL 1 +#endif + +#include <QtCore/qchar.h> +#include <QtCore/qbytearray.h> +#include <QtCore/qstringliteral.h> +#include <QtCore/qstringalgorithms.h> + +#include <string> + +QT_BEGIN_NAMESPACE + +class QString; +class QStringRef; + +namespace QtPrivate { +template <typename Char> +struct IsCompatibleCharTypeHelper + : std::integral_constant<bool, + std::is_same<Char, QChar>::value || + std::is_same<Char, ushort>::value || +#if defined(Q_COMPILER_UNICODE_STRINGS) + std::is_same<Char, char16_t>::value || +#endif + (std::is_same<Char, wchar_t>::value && sizeof(wchar_t) == sizeof(QChar))> {}; +template <typename Char> +struct IsCompatibleCharType + : IsCompatibleCharTypeHelper<typename std::remove_cv<typename std::remove_reference<Char>::type>::type> {}; + +template <typename Array> +struct IsCompatibleArrayHelper : std::false_type {}; +template <typename Char, size_t N> +struct IsCompatibleArrayHelper<Char[N]> + : IsCompatibleCharType<Char> {}; +template <typename Array> +struct IsCompatibleArray + : IsCompatibleArrayHelper<typename std::remove_cv<typename std::remove_reference<Array>::type>::type> {}; + +template <typename Pointer> +struct IsCompatiblePointerHelper : std::false_type {}; +template <typename Char> +struct IsCompatiblePointerHelper<Char*> + : IsCompatibleCharType<Char> {}; +template <typename Pointer> +struct IsCompatiblePointer + : IsCompatiblePointerHelper<typename std::remove_cv<typename std::remove_reference<Pointer>::type>::type> {}; + +template <typename T> +struct IsCompatibleStdBasicStringHelper : std::false_type {}; +template <typename Char, typename...Args> +struct IsCompatibleStdBasicStringHelper<std::basic_string<Char, Args...> > + : IsCompatibleCharType<Char> {}; + +template <typename T> +struct IsCompatibleStdBasicString + : IsCompatibleStdBasicStringHelper< + typename std::remove_cv<typename std::remove_reference<T>::type>::type + > {}; + +} // namespace QtPrivate + +class QStringView +{ +public: +#if defined(Q_OS_WIN) && !defined(Q_COMPILER_UNICODE_STRINGS) + typedef wchar_t storage_type; +#else + typedef char16_t storage_type; +#endif + typedef const QChar value_type; + typedef std::ptrdiff_t difference_type; + typedef qssize_t 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 = typename std::enable_if<QtPrivate::IsCompatibleCharType<Char>::value, bool>::type; + + template <typename Array> + using if_compatible_array = typename std::enable_if<QtPrivate::IsCompatibleArray<Array>::value, bool>::type; + + template <typename Pointer> + using if_compatible_pointer = typename std::enable_if<QtPrivate::IsCompatiblePointer<Pointer>::value, bool>::type; + + template <typename T> + using if_compatible_string = typename std::enable_if<QtPrivate::IsCompatibleStdBasicString<T>::value, bool>::type; + + template <typename T> + using if_compatible_qstring_like = typename std::enable_if<std::is_same<T, QString>::value || std::is_same<T, QStringRef>::value, bool>::type; + + template <typename Char, size_t N> + static Q_DECL_CONSTEXPR qssize_t lengthHelperArray(const Char (&)[N]) Q_DECL_NOTHROW + { + return qssize_t(N - 1); + } + + template <typename Char> + static qssize_t lengthHelperPointer(const Char *str) Q_DECL_NOTHROW + { +#if defined(Q_CC_GNU) && !defined(Q_CC_CLANG) && !defined(Q_CC_INTEL) + if (__builtin_constant_p(*str)) { + qssize_t result = 0; + while (*str++) + ++result; + } +#endif + return qustrlen(reinterpret_cast<const ushort *>(str)); + } + static qssize_t lengthHelperPointer(const QChar *str) Q_DECL_NOTHROW + { + return qustrlen(reinterpret_cast<const ushort *>(str)); + } + + template <typename Char> + static const storage_type *castHelper(const Char *str) Q_DECL_NOTHROW + { return reinterpret_cast<const storage_type*>(str); } + static Q_DECL_CONSTEXPR const storage_type *castHelper(const storage_type *str) Q_DECL_NOTHROW + { return str; } + +public: + Q_DECL_CONSTEXPR QStringView() Q_DECL_NOTHROW + : m_size(0), m_data(nullptr) {} + Q_DECL_CONSTEXPR QStringView(std::nullptr_t) Q_DECL_NOTHROW + : QStringView() {} + + template <typename Char, if_compatible_char<Char> = true> + Q_DECL_CONSTEXPR QStringView(const Char *str, qssize_t len) + : m_size((Q_ASSERT(len >= 0), Q_ASSERT(str || !len), len)), + m_data(castHelper(str)) {} + + template <typename Char, if_compatible_char<Char> = true> + Q_DECL_CONSTEXPR QStringView(const Char *f, const Char *l) + : QStringView(f, l - f) {} + +#ifdef Q_QDOC + template <typename Char, size_t N> + Q_DECL_CONSTEXPR QStringView(const Char (&array)[N]) Q_DECL_NOTHROW; + + template <typename Char> + Q_DECL_CONSTEXPR QStringView(const Char *str) Q_DECL_NOTHROW; +#else + template <typename Array, if_compatible_array<Array> = true> + Q_DECL_CONSTEXPR QStringView(const Array &str) Q_DECL_NOTHROW + : QStringView(str, lengthHelperArray(str)) {} + + template <typename Pointer, if_compatible_pointer<Pointer> = true> + Q_DECL_CONSTEXPR QStringView(const Pointer &str) Q_DECL_NOTHROW + : QStringView(str, str ? lengthHelperPointer(str) : 0) {} +#endif + +#ifdef Q_QDOC + QStringView(const QString &str) Q_DECL_NOTHROW; + QStringView(const QStringRef &str) Q_DECL_NOTHROW; +#else + template <typename String, if_compatible_qstring_like<String> = true> + QStringView(const String &str) Q_DECL_NOTHROW + : QStringView(str.isNull() ? nullptr : str.data(), qssize_t(str.size())) {} +#endif + + template <typename StdBasicString, if_compatible_string<StdBasicString> = true> + QStringView(const StdBasicString &str) Q_DECL_NOTHROW + : QStringView(str.data(), qssize_t(str.size())) {} + + Q_REQUIRED_RESULT inline QString toString() const; // defined in qstring.h + + Q_REQUIRED_RESULT Q_DECL_CONSTEXPR qssize_t size() const Q_DECL_NOTHROW { return m_size; } + Q_REQUIRED_RESULT const_pointer data() const Q_DECL_NOTHROW { return reinterpret_cast<const_pointer>(m_data); } + Q_REQUIRED_RESULT Q_DECL_CONSTEXPR const storage_type *utf16() const Q_DECL_NOTHROW { return m_data; } + + Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QChar operator[](qssize_t n) const + { return Q_ASSERT(n >= 0), Q_ASSERT(n < size()), QChar(m_data[n]); } + + // + // QString API + // + + Q_REQUIRED_RESULT QByteArray toLatin1() const { return qConvertToLatin1(*this); } + Q_REQUIRED_RESULT QByteArray toUtf8() const { return qConvertToUtf8(*this); } + Q_REQUIRED_RESULT QByteArray toLocal8Bit() const { return qConvertToLocal8Bit(*this); } + Q_REQUIRED_RESULT inline QVector<uint> toUcs4() const; // defined in qvector.h + + Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QChar at(qssize_t n) const { return (*this)[n]; } + + Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QStringView mid(qssize_t pos) const + { return Q_ASSERT(pos >= 0), Q_ASSERT(pos <= size()), QStringView(m_data + pos, m_size - pos); } + Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QStringView mid(qssize_t pos, qssize_t n) const + { return Q_ASSERT(pos >= 0), Q_ASSERT(n >= 0), Q_ASSERT(pos + n <= size()), QStringView(m_data + pos, n); } + Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QStringView left(qssize_t n) const + { return Q_ASSERT(n >= 0), Q_ASSERT(n <= size()), QStringView(m_data, n); } + Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QStringView right(qssize_t n) const + { return Q_ASSERT(n >= 0), Q_ASSERT(n <= size()), QStringView(m_data + m_size - n, n); } + Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QStringView chopped(qssize_t n) const + { return Q_ASSERT(n >= 0), Q_ASSERT(n <= size()), QStringView(m_data, m_size - n); } + + Q_DECL_RELAXED_CONSTEXPR void truncate(qssize_t n) + { Q_ASSERT(n >= 0); Q_ASSERT(n <= size()); m_size = n; } + Q_DECL_RELAXED_CONSTEXPR void chop(qssize_t n) + { Q_ASSERT(n >= 0); Q_ASSERT(n <= size()); m_size -= n; } + + Q_REQUIRED_RESULT QStringView trimmed() const Q_DECL_NOTHROW { return qTrimmed(*this); } + + Q_REQUIRED_RESULT bool startsWith(QStringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const Q_DECL_NOTHROW + { return qStartsWith(*this, s, cs); } + Q_REQUIRED_RESULT inline bool startsWith(QLatin1String s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const Q_DECL_NOTHROW; + Q_REQUIRED_RESULT bool startsWith(QChar c) const Q_DECL_NOTHROW + { return !empty() && front() == c; } + Q_REQUIRED_RESULT bool startsWith(QChar c, Qt::CaseSensitivity cs) const Q_DECL_NOTHROW + { return qStartsWith(*this, QStringView(&c, 1), cs); } + + Q_REQUIRED_RESULT bool endsWith(QStringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const Q_DECL_NOTHROW + { return qEndsWith(*this, s, cs); } + Q_REQUIRED_RESULT inline bool endsWith(QLatin1String s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const Q_DECL_NOTHROW; + Q_REQUIRED_RESULT bool endsWith(QChar c) const Q_DECL_NOTHROW + { return !empty() && back() == c; } + Q_REQUIRED_RESULT bool endsWith(QChar c, Qt::CaseSensitivity cs) const Q_DECL_NOTHROW + { return qEndsWith(*this, QStringView(&c, 1), cs); } + + // + // STL compatibility API: + // + Q_REQUIRED_RESULT const_iterator begin() const Q_DECL_NOTHROW { return data(); } + Q_REQUIRED_RESULT const_iterator end() const Q_DECL_NOTHROW { return data() + size(); } + Q_REQUIRED_RESULT const_iterator cbegin() const Q_DECL_NOTHROW { return begin(); } + Q_REQUIRED_RESULT const_iterator cend() const Q_DECL_NOTHROW { return end(); } + Q_REQUIRED_RESULT const_reverse_iterator rbegin() const Q_DECL_NOTHROW { return const_reverse_iterator(end()); } + Q_REQUIRED_RESULT const_reverse_iterator rend() const Q_DECL_NOTHROW { return const_reverse_iterator(begin()); } + Q_REQUIRED_RESULT const_reverse_iterator crbegin() const Q_DECL_NOTHROW { return rbegin(); } + Q_REQUIRED_RESULT const_reverse_iterator crend() const Q_DECL_NOTHROW { return rend(); } + + Q_REQUIRED_RESULT Q_DECL_CONSTEXPR bool empty() const Q_DECL_NOTHROW { return size() == 0; } + Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QChar front() const { return Q_ASSERT(!empty()), QChar(m_data[0]); } + Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QChar back() const { return Q_ASSERT(!empty()), QChar(m_data[m_size - 1]); } + + // + // Qt compatibility API: + // + Q_REQUIRED_RESULT Q_DECL_CONSTEXPR bool isNull() const Q_DECL_NOTHROW { return !m_data; } + Q_REQUIRED_RESULT Q_DECL_CONSTEXPR bool isEmpty() const Q_DECL_NOTHROW { return empty(); } + Q_REQUIRED_RESULT Q_DECL_CONSTEXPR int length() const /* not nothrow! */ + { return Q_ASSERT(int(size()) == size()), int(size()); } + Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QChar first() const { return front(); } + Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QChar last() const { return back(); } +private: + qssize_t m_size; + const storage_type *m_data; +}; +Q_DECLARE_TYPEINFO(QStringView, Q_PRIMITIVE_TYPE); + +template <typename QStringLike, typename std::enable_if< + std::is_same<QStringLike, QString>::value || std::is_same<QStringLike, QStringRef>::value, + bool>::type = true> +inline QStringView qToStringViewIgnoringNull(const QStringLike &s) Q_DECL_NOTHROW +{ return QStringView(s.data(), s.size()); } + +QT_END_NAMESPACE + +#endif /* QSTRINGVIEW_H */ |