// Copyright (C) 2016 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 QV4ARRAYDATA_H
#define QV4ARRAYDATA_H

//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists purely as an
// implementation detail.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//

#include "qv4global_p.h"
#include "qv4managed_p.h"
#include "qv4property_p.h"
#include "qv4sparsearray_p.h"

QT_BEGIN_NAMESPACE

namespace QV4 {

#define V4_ARRAYDATA(DataClass) \
    public: \
        Q_MANAGED_CHECK \
        typedef QV4::Heap::DataClass Data; \
        static const QV4::ArrayVTable static_vtbl; \
        static inline const QV4::VTable *staticVTable() { return &static_vtbl.vTable; } \
        V4_MANAGED_SIZE_TEST \
        const Data *d() const { return static_cast<const Data *>(m()); } \
        Data *d() { return static_cast<Data *>(m()); }


struct ArrayData;

struct ArrayVTable
{
    VTable vTable;
    uint type;
    Heap::ArrayData *(*reallocate)(Object *o, uint n, bool enforceAttributes);
    ReturnedValue (*get)(const Heap::ArrayData *d, uint index);
    bool (*put)(Object *o, uint index, const Value &value);
    bool (*putArray)(Object *o, uint index, const Value *values, uint n);
    bool (*del)(Object *o, uint index);
    void (*setAttribute)(Object *o, uint index, PropertyAttributes attrs);
    void (*push_front)(Object *o, const Value *values, uint n);
    ReturnedValue (*pop_front)(Object *o);
    uint (*truncate)(Object *o, uint newLen);
    uint (*length)(const Heap::ArrayData *d);
};

namespace Heap {

#define ArrayDataMembers(class, Member) \
    Member(class, NoMark, ushort, type) \
    Member(class, NoMark, ushort, unused) \
    Member(class, NoMark, uint, offset) \
    Member(class, NoMark, PropertyAttributes *, attrs) \
    Member(class, NoMark, SparseArray *, sparse) \
    Member(class, ValueArray, ValueArray, values)

DECLARE_HEAP_OBJECT(ArrayData, Base) {
    static void markObjects(Heap::Base *base, MarkStack *stack);

    enum Type { Simple = 0, Sparse = 1, Custom = 2 };

    bool isSparse() const { return type == Sparse; }

    const ArrayVTable *vtable() const { return reinterpret_cast<const ArrayVTable *>(internalClass->vtable); }

    inline ReturnedValue get(uint i) const {
        return vtable()->get(this, i);
    }
    inline bool getProperty(uint index, Property *p, PropertyAttributes *attrs);
    inline void setProperty(EngineBase *e, uint index, const Property *p);
    inline PropertyIndex getValueOrSetter(uint index, PropertyAttributes *attrs);
    inline PropertyAttributes attributes(uint i) const;

    bool isEmpty(uint i) const {
        return get(i) == Value::emptyValue().asReturnedValue();
    }

    inline uint length() const {
        return vtable()->length(this);
    }

    void setArrayData(EngineBase *e, uint index, Value newVal) {
        values.set(e, index, newVal);
    }

    uint mappedIndex(uint index) const;
};
Q_STATIC_ASSERT(std::is_trivial_v<ArrayData>);

struct SimpleArrayData : public ArrayData {
    uint mappedIndex(uint index) const { index += offset; if (index >= values.alloc) index -= values.alloc; return index; }
    const Value &data(uint index) const { return values[mappedIndex(index)]; }
    void setData(EngineBase *e, uint index, Value newVal) {
        values.set(e, mappedIndex(index), newVal);
    }

    PropertyAttributes attributes(uint i) const {
        return attrs ? attrs[i] : Attr_Data;
    }
};
Q_STATIC_ASSERT(std::is_trivial_v<SimpleArrayData>);

struct SparseArrayData : public ArrayData {
    void destroy() {
        delete sparse;
        ArrayData::destroy();
    }

    uint mappedIndex(uint index) const {
        SparseArrayNode *n = sparse->findNode(index);
        if (!n)
            return UINT_MAX;
        return n->value;
    }

    PropertyAttributes attributes(uint i) const {
        if (!attrs)
            return Attr_Data;
        uint index = mappedIndex(i);
        return index < UINT_MAX ? attrs[index] : Attr_Data;
    }
};

}

struct Q_QML_EXPORT ArrayData : public Managed
{
    typedef Heap::ArrayData::Type Type;
    V4_MANAGED(ArrayData, Managed)
    enum {
        IsArrayData = true
    };

    uint alloc() const { return d()->values.alloc; }
    uint &alloc() { return d()->values.alloc; }
    void setAlloc(uint a) { d()->values.alloc = a; }
    Type type() const { return static_cast<Type>(d()->type); }
    void setType(Type t) { d()->type = t; }
    PropertyAttributes *attrs() const { return d()->attrs; }
    void setAttrs(PropertyAttributes *a) { d()->attrs = a; }
    const Value *arrayData() const { return d()->values.data(); }
    void setArrayData(EngineBase *e, uint index, Value newVal) {
        d()->setArrayData(e, index, newVal);
    }

    const ArrayVTable *vtable() const { return d()->vtable(); }
    bool isSparse() const { return type() == Heap::ArrayData::Sparse; }

    uint length() const {
        return d()->length();
    }

    bool hasAttributes() const {
        return attrs();
    }
    PropertyAttributes attributes(uint i) const {
        return d()->attributes(i);
    }

    bool isEmpty(uint i) const {
        return d()->isEmpty(i);
    }

    ReturnedValue get(uint i) const {
        return d()->get(i);
    }

    static void ensureAttributes(Object *o);
    static void realloc(Object *o, Type newType, uint alloc, bool enforceAttributes);

    static void sort(ExecutionEngine *engine, Object *thisObject, const Value &comparefn, uint dataLen);
    static uint append(Object *obj, ArrayObject *otherObj, uint n);
    static void insert(Object *o, uint index, const Value *v, bool isAccessor = false);
};

struct Q_QML_EXPORT SimpleArrayData : public ArrayData
{
    V4_ARRAYDATA(SimpleArrayData)
    V4_INTERNALCLASS(SimpleArrayData)

    uint mappedIndex(uint index) const { return d()->mappedIndex(index); }
    Value data(uint index) const { return d()->data(index); }

    uint &len() { return d()->values.size; }
    uint len() const { return d()->values.size; }

    static Heap::ArrayData *reallocate(Object *o, uint n, bool enforceAttributes);

    static ReturnedValue get(const Heap::ArrayData *d, uint index);
    static bool put(Object *o, uint index, const Value &value);
    static bool putArray(Object *o, uint index, const Value *values, uint n);
    static bool del(Object *o, uint index);
    static void setAttribute(Object *o, uint index, PropertyAttributes attrs);
    static void push_front(Object *o, const Value *values, uint n);
    static ReturnedValue pop_front(Object *o);
    static uint truncate(Object *o, uint newLen);
    static uint length(const Heap::ArrayData *d);
};

struct Q_QML_EXPORT SparseArrayData : public ArrayData
{
    V4_ARRAYDATA(SparseArrayData)
    V4_INTERNALCLASS(SparseArrayData)
    V4_NEEDS_DESTROY

    SparseArray *sparse() const { return d()->sparse; }
    void setSparse(SparseArray *s) { d()->sparse = s; }

    static uint allocate(Object *o, bool doubleSlot = false);
    static void free(Heap::ArrayData *d, uint idx);

    uint mappedIndex(uint index) const { return d()->mappedIndex(index); }

    static Heap::ArrayData *reallocate(Object *o, uint n, bool enforceAttributes);
    static ReturnedValue get(const Heap::ArrayData *d, uint index);
    static bool put(Object *o, uint index, const Value &value);
    static bool putArray(Object *o, uint index, const Value *values, uint n);
    static bool del(Object *o, uint index);
    static void setAttribute(Object *o, uint index, PropertyAttributes attrs);
    static void push_front(Object *o, const Value *values, uint n);
    static ReturnedValue pop_front(Object *o);
    static uint truncate(Object *o, uint newLen);
    static uint length(const Heap::ArrayData *d);
};

class ArrayElementLessThan
{
public:
    inline ArrayElementLessThan(ExecutionEngine *engine, const Value &comparefn)
        : m_engine(engine), m_comparefn(comparefn) {}

    bool operator()(Value v1, Value v2) const;

private:
    ExecutionEngine *m_engine;
    const Value &m_comparefn;
};

template <typename RandomAccessIterator, typename LessThan>
void sortHelper(RandomAccessIterator start, RandomAccessIterator end, LessThan lessThan)
{
top:
    using std::swap;

    int span = int(end - start);
    if (span < 2)
        return;

    --end;
    RandomAccessIterator low = start, high = end - 1;
    RandomAccessIterator pivot = start + span / 2;

    if (lessThan(*end, *start))
        swap(*end, *start);
    if (span == 2)
        return;

    if (lessThan(*pivot, *start))
        swap(*pivot, *start);
    if (lessThan(*end, *pivot))
        swap(*end, *pivot);
    if (span == 3)
        return;

    swap(*pivot, *end);

    while (low < high) {
        while (low < high && lessThan(*low, *end))
            ++low;

        while (high > low && lessThan(*end, *high))
            --high;

        if (low < high) {
            swap(*low, *high);
            ++low;
            --high;
        } else {
            break;
        }
    }

    if (lessThan(*low, *end))
        ++low;

    swap(*end, *low);
    sortHelper(start, low, lessThan);

    start = low + 1;
    ++end;
    goto top;
}

namespace Heap {

inline uint ArrayData::mappedIndex(uint index) const
{
    if (isSparse())
        return static_cast<const SparseArrayData *>(this)->mappedIndex(index);
    if (index >= values.size)
        return UINT_MAX;
    uint idx = static_cast<const SimpleArrayData *>(this)->mappedIndex(index);
    return values[idx].isEmpty() ? UINT_MAX : idx;
}

bool ArrayData::getProperty(uint index, Property *p, PropertyAttributes *attrs)
{
    uint mapped = mappedIndex(index);
    if (mapped == UINT_MAX) {
        *attrs = Attr_Invalid;
        return false;
    }

    *attrs = attributes(index);
    if (p) {
        p->value = *(PropertyIndex{ this, values.values + mapped });
        if (attrs->isAccessor())
            p->set = *(PropertyIndex{ this, values.values + mapped + 1 /*Object::SetterOffset*/ });
    }
    return true;
}

void ArrayData::setProperty(QV4::EngineBase *e, uint index, const Property *p)
{
    uint mapped = mappedIndex(index);
    Q_ASSERT(mapped != UINT_MAX);
    values.set(e, mapped, p->value);
    if (attributes(index).isAccessor())
        values.set(e, mapped + 1 /*QV4::Object::SetterOffset*/, p->set);
}

inline PropertyAttributes ArrayData::attributes(uint i) const
{
    if (isSparse())
        return static_cast<const SparseArrayData *>(this)->attributes(i);
    return static_cast<const SimpleArrayData *>(this)->attributes(i);
}

PropertyIndex ArrayData::getValueOrSetter(uint index, PropertyAttributes *attrs)
{
    uint idx = mappedIndex(index);
    if (idx == UINT_MAX) {
        *attrs = Attr_Invalid;
        return { nullptr, nullptr };
    }

    *attrs = attributes(index);
    if (attrs->isAccessor())
        ++idx;
    return { this, values.values + idx };
}



}

}

QT_END_NAMESPACE

#endif