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#include "qv4identifier_p.h"
#include "qv4identifiertable_p.h"
#include "qv4string_p.h"

QT_BEGIN_NAMESPACE

namespace QV4 {

static const uchar prime_deltas[] = {
    0,  0,  1,  3,  1,  5,  3,  3,  1,  9,  7,  5,  3,  9, 25,  3,
    1, 21,  3, 21,  7, 15,  9,  5,  3, 29, 15,  0,  0,  0,  0,  0
};

static inline int primeForNumBits(int numBits)
{
    return (1 << numBits) + prime_deltas[numBits];
}


IdentifierHashData::IdentifierHashData(IdentifierTable *table, int numBits)
    : size(0)
    , numBits(numBits)
    , identifierTable(table)
{
    refCount.store(1);
    alloc = primeForNumBits(numBits);
    entries = (IdentifierHashEntry *)malloc(alloc*sizeof(IdentifierHashEntry));
    memset(entries, 0, alloc*sizeof(IdentifierHashEntry));
    identifierTable->addIdentifierHash(this);
}

IdentifierHashData::IdentifierHashData(IdentifierHashData *other)
    : size(other->size)
    , numBits(other->numBits)
    , identifierTable(other->identifierTable)
{
    refCount.store(1);
    alloc = other->alloc;
    entries = (IdentifierHashEntry *)malloc(alloc*sizeof(IdentifierHashEntry));
    memcpy(entries, other->entries, alloc*sizeof(IdentifierHashEntry));
    identifierTable->addIdentifierHash(this);
}

IdentifierHashData::~IdentifierHashData() {
    free(entries);
    if (identifierTable)
        identifierTable->removeIdentifierHash(this);
}

IdentifierHash::IdentifierHash(ExecutionEngine *engine)
{
    d = new IdentifierHashData(engine->identifierTable, 3);
}

void IdentifierHash::detach()
{
    if (!d || d->refCount == 1)
        return;
    IdentifierHashData *newData = new IdentifierHashData(d);
    if (d && !d->refCount.deref())
        delete d;
    d = newData;
}


IdentifierHashEntry *IdentifierHash::addEntry(PropertyKey identifier)
{
    Q_ASSERT(identifier.isStringOrSymbol());

    // fill up to max 50%
    bool grow = (d->alloc <= d->size*2);

    if (grow) {
        ++d->numBits;
        int newAlloc = primeForNumBits(d->numBits);
        IdentifierHashEntry *newEntries = (IdentifierHashEntry *)malloc(newAlloc * sizeof(IdentifierHashEntry));
        memset(newEntries, 0, newAlloc*sizeof(IdentifierHashEntry));
        for (int i = 0; i < d->alloc; ++i) {
            const IdentifierHashEntry &e = d->entries[i];
            if (!e.identifier.isValid())
                continue;
            uint idx = e.identifier.id() % newAlloc;
            while (newEntries[idx].identifier.isValid()) {
                ++idx;
                idx %= newAlloc;
            }
            newEntries[idx] = e;
        }
        free(d->entries);
        d->entries = newEntries;
        d->alloc = newAlloc;
    }

    uint idx = identifier.id() % d->alloc;
    while (d->entries[idx].identifier.isValid()) {
        Q_ASSERT(d->entries[idx].identifier != identifier);
        ++idx;
        idx %= d->alloc;
    }
    d->entries[idx].identifier = identifier;
    ++d->size;
    return d->entries + idx;
}

const IdentifierHashEntry *IdentifierHash::lookup(PropertyKey identifier) const
{
    if (!d || !identifier.isStringOrSymbol())
        return nullptr;
    Q_ASSERT(d->entries);

    uint idx = identifier.id() % d->alloc;
    while (1) {
        if (!d->entries[idx].identifier.isValid())
            return nullptr;
        if (d->entries[idx].identifier == identifier)
            return d->entries + idx;
        ++idx;
        idx %= d->alloc;
    }
}

const IdentifierHashEntry *IdentifierHash::lookup(const QString &str) const
{
    if (!d)
        return nullptr;

    PropertyKey id = d->identifierTable->asPropertyKey(str);
    return lookup(id);
}

const IdentifierHashEntry *IdentifierHash::lookup(String *str) const
{
    if (!d)
        return nullptr;
    PropertyKey id = d->identifierTable->asPropertyKey(str);
    if (id.isValid())
        return lookup(id);
    return lookup(str->toQString());
}

const PropertyKey IdentifierHash::toIdentifier(const QString &str) const
{
    Q_ASSERT(d);
    return d->identifierTable->asPropertyKey(str);
}

const PropertyKey IdentifierHash::toIdentifier(Heap::String *str) const
{
    Q_ASSERT(d);
    return d->identifierTable->asPropertyKey(str);
}

QString QV4::IdentifierHash::findId(int value) const
{
    IdentifierHashEntry *e = d->entries;
    IdentifierHashEntry *end = e + d->alloc;
    while (e < end) {
        if (e->identifier.isValid() && e->value == value)
            return e->identifier.toQString();
        ++e;
    }
    return QString();
}

void IdentifierHashData::markObjects(MarkStack *markStack) const
{
    IdentifierHashEntry *e = entries;
    IdentifierHashEntry *end = e + alloc;
    while (e < end) {
        if (Heap::Base *o = e->identifier.asStringOrSymbol())
            o->mark(markStack);
        ++e;
    }
}


}

QT_END_NAMESPACE