1 files changed, 176 insertions, 0 deletions
diff --git a/src/corelib/text/qstringconverter_base.h b/src/corelib/text/qstringconverter_base.h
new file mode 100644
index 0000000000..d6b6fcb484
--- /dev/null
+++ b/src/corelib/text/qstringconverter_base.h
@@ -0,0 +1,176 @@
+// Copyright (C) 2022 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#ifndef QSTRINGCONVERTER_BASE_H
+#define QSTRINGCONVERTER_BASE_H
+
+#if 0
+// QStringConverter(Base) class are handled in qstringconverter
+#pragma qt_sync_stop_processing
+#endif
+
+#include <optional>
+
+#include <QtCore/qglobal.h> // QT_{BEGIN,END}_NAMESPACE
+#include <QtCore/qflags.h> // Q_DECLARE_FLAGS
+#include <QtCore/qcontainerfwd.h>
+
+#include <cstring>
+
+QT_BEGIN_NAMESPACE
+
+class QByteArrayView;
+class QChar;
+class QByteArrayView;
+class QStringView;
+
+class QStringConverterBase
+{
+public:
+    enum class Flag {
+        Default = 0,
+        Stateless = 0x1,
+        ConvertInvalidToNull = 0x2,
+        WriteBom = 0x4,
+        ConvertInitialBom = 0x8,
+        UsesIcu = 0x10,
+    };
+    Q_DECLARE_FLAGS(Flags, Flag)
+
+    struct State {
+        constexpr State(Flags f = Flag::Default) noexcept
+            : flags(f), state_data{0, 0, 0, 0} {}
+        ~State() { clear(); }
+
+        State(State &&other) noexcept
+            : flags(other.flags),
+              remainingChars(other.remainingChars),
+              invalidChars(other.invalidChars),
+              state_data{other.state_data[0], other.state_data[1],
+                         other.state_data[2], other.state_data[3]},
+              clearFn(other.clearFn)
+        { other.clearFn = nullptr; }
+        State &operator=(State &&other) noexcept
+        {
+            clear();
+            flags = other.flags;
+            remainingChars = other.remainingChars;
+            invalidChars = other.invalidChars;
+            std::memmove(state_data, other.state_data, sizeof state_data); // self-assignment-safe
+            clearFn = other.clearFn;
+            other.clearFn = nullptr;
+            return *this;
+        }
+        Q_CORE_EXPORT void clear() noexcept;
+        Q_CORE_EXPORT void reset() noexcept;
+
+        Flags flags;
+        int internalState = 0;
+        qsizetype remainingChars = 0;
+        qsizetype invalidChars = 0;
+
+        union {
+            uint state_data[4];
+            void *d[2];
+        };
+        using ClearDataFn = void (*)(State *) noexcept;
+        ClearDataFn clearFn = nullptr;
+    private:
+        Q_DISABLE_COPY(State)
+    };
+protected:
+    ~QStringConverterBase() = default;
+};
+Q_DECLARE_OPERATORS_FOR_FLAGS(QStringConverterBase::Flags)
+
+class QStringConverter : public QStringConverterBase
+{
+public:
+
+    enum Encoding {
+        Utf8,
+#ifndef QT_BOOTSTRAPPED
+        Utf16,
+        Utf16LE,
+        Utf16BE,
+        Utf32,
+        Utf32LE,
+        Utf32BE,
+#endif
+        Latin1,
+        System,
+        LastEncoding = System
+    };
+#ifdef Q_QDOC
+    // document the flags here
+    enum class Flag {
+        Default = 0,
+        Stateless = 0x1,
+        ConvertInvalidToNull = 0x2,
+        WriteBom = 0x4,
+        ConvertInitialBom = 0x8,
+        UsesIcu = 0x10,
+    };
+    Q_DECLARE_FLAGS(Flags, Flag)
+#endif
+
+protected:
+
+    struct Interface
+    {
+        using DecoderFn = QChar * (*)(QChar *out, QByteArrayView in, State *state);
+        using LengthFn = qsizetype (*)(qsizetype inLength);
+        using EncoderFn = char * (*)(char *out, QStringView in, State *state);
+        const char *name = nullptr;
+        DecoderFn toUtf16 = nullptr;
+        LengthFn toUtf16Len = nullptr;
+        EncoderFn fromUtf16 = nullptr;
+        LengthFn fromUtf16Len = nullptr;
+    };
+
+    constexpr QStringConverter() noexcept
+        : iface(nullptr)
+    {}
+    constexpr explicit QStringConverter(Encoding encoding, Flags f)
+        : iface(&encodingInterfaces[qsizetype(encoding)]), state(f)
+    {}
+    constexpr explicit QStringConverter(const Interface *i) noexcept
+        : iface(i)
+    {}
+    Q_CORE_EXPORT explicit QStringConverter(const char *name, Flags f);
+
+
+    ~QStringConverter() = default;
+
+public:
+    QStringConverter(QStringConverter &&) = default;
+    QStringConverter &operator=(QStringConverter &&) = default;
+
+    bool isValid() const noexcept { return iface != nullptr; }
+
+    void resetState() noexcept
+    {
+        state.reset();
+    }
+    bool hasError() const noexcept { return state.invalidChars != 0; }
+
+    Q_CORE_EXPORT const char *name() const noexcept;
+
+    Q_CORE_EXPORT static std::optional<Encoding> encodingForName(const char *name) noexcept;
+    Q_CORE_EXPORT static const char *nameForEncoding(Encoding e);
+    Q_CORE_EXPORT static std::optional<Encoding>
+    encodingForData(QByteArrayView data, char16_t expectedFirstCharacter = 0) noexcept;
+    Q_CORE_EXPORT static std::optional<Encoding> encodingForHtml(QByteArrayView data);
+
+    Q_CORE_EXPORT static QStringList availableCodecs();
+
+protected:
+    const Interface *iface;
+    State state;
+private:
+    Q_CORE_EXPORT static const Interface encodingInterfaces[Encoding::LastEncoding + 1];
+};
+
+QT_END_NAMESPACE
+
+#endif