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#include "qv4identifier_p.h"
#include "qv4identifiertable_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(int numBits)
    : size(0)
    , numBits(numBits)
{
    refCount.store(1);
    alloc = primeForNumBits(numBits);
    entries = (IdentifierHashEntry *)malloc(alloc*sizeof(IdentifierHashEntry));
    memset(entries, 0, alloc*sizeof(IdentifierHashEntry));
}

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));
}

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

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


IdentifierHashEntry *IdentifierHashBase::addEntry(const Identifier *identifier)
{
    // 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)
                continue;
            uint idx = e.identifier->hashValue % newAlloc;
            while (newEntries[idx].identifier) {
                ++idx;
                idx %= newAlloc;
            }
            newEntries[idx] = e;
        }
        free(d->entries);
        d->entries = newEntries;
        d->alloc = newAlloc;
    }

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

const IdentifierHashEntry *IdentifierHashBase::lookup(const Identifier *identifier) const
{
    if (!d)
        return 0;
    Q_ASSERT(d->entries);

    uint idx = identifier->hashValue % d->alloc;
    while (1) {
        if (!d->entries[idx].identifier)
            return 0;
        if (d->entries[idx].identifier == identifier)
            return d->entries + idx;
        ++idx;
        idx %= d->alloc;
    }
}

const IdentifierHashEntry *IdentifierHashBase::lookup(const QString &str) const
{
    if (!d)
        return 0;
    Q_ASSERT(d->entries);

    uint hash = String::createHashValue(str.constData(), str.length(), Q_NULLPTR);
    uint idx = hash % d->alloc;
    while (1) {
        if (!d->entries[idx].identifier)
            return 0;
        if (d->entries[idx].identifier->string == str)
            return d->entries + idx;
        ++idx;
        idx %= d->alloc;
    }
}

const IdentifierHashEntry *IdentifierHashBase::lookup(String *str) const
{
    if (!d)
        return 0;
    if (str->d()->identifier)
        return lookup(str->d()->identifier);
    return lookup(str->toQString());
}

const Identifier *IdentifierHashBase::toIdentifier(const QString &str) const
{
    Q_ASSERT(d);
    return d->identifierTable->identifier(str);
}

const Identifier *IdentifierHashBase::toIdentifier(Heap::String *str) const
{
    Q_ASSERT(d);
    return d->identifierTable->identifier(str);
}


}

QT_END_NAMESPACE