/*
 * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#ifdef AVOID_STATIC_CONSTRUCTORS
#define ATOMICSTRING_HIDE_GLOBALS 1
#endif

#include "AtomicString.h"

//#include "StaticConstructors.h"
#include "StringHash.h"
//#include <kjs/identifier.h>
#include <wtf/HashSet.h>

//using KJS::Identifier;
//using KJS::UString;

namespace khtml
{

static HashSet<DOMStringImpl *> *stringTable;

struct CStringTranslator {
    static unsigned hash(const char *c)
    {
        return DOMStringImpl::computeHash(c);
    }

    static bool equal(DOMStringImpl *r, const char *s)
    {
        int length = r->length();
        const QChar *d = r->unicode();
        for (int i = 0; i != length; ++i) {
            unsigned char c = s[i];
            if (d[i] != c) {
                return false;
            }
        }
        return s[length] == 0;
    }

    static void translate(DOMStringImpl *&location, const char *const &c, unsigned hash)
    {
        location = new DOMStringImpl(c, strlen(c), hash);
    }
};

bool operator==(const AtomicString &a, const char *b)
{
    DOMStringImpl *impl = a.impl();
    if ((!impl || !impl->unicode()) && !b) {
        return true;
    }
    if ((!impl || !impl->unicode()) || !b) {
        return false;
    }
    return CStringTranslator::equal(impl, b);
}

DOMStringImpl *AtomicString::add(const char *c)
{
    if (!c) {
        return nullptr;
    }
    if (!*c) {
        return DOMStringImpl::empty();
    }
    init();
    std::pair<HashSet<DOMStringImpl *>::iterator, bool> addResult = stringTable->add<const char *, CStringTranslator>(c);
    if (!addResult.second) {
        return *addResult.first;
    }
    return *addResult.first;
}

struct UCharBuffer {
    const QChar *s;
    unsigned length;
};

static inline bool equal(DOMStringImpl *string, const QChar *characters, unsigned length)
{
    if (string->length() != length) {
        return false;
    }

    /* Do it 4-bytes-at-a-time on architectures where it's safe */

    const uint32_t *stringCharacters = reinterpret_cast<const uint32_t *>(string->unicode());
    const uint32_t *bufferCharacters = reinterpret_cast<const uint32_t *>(characters);

    unsigned halfLength = length >> 1;
    for (unsigned i = 0; i != halfLength; ++i) {
        if (*stringCharacters++ != *bufferCharacters++) {
            return false;
        }
    }

    if (length & 1 &&  *reinterpret_cast<const uint16_t *>(stringCharacters) != *reinterpret_cast<const uint16_t *>(bufferCharacters)) {
        return false;
    }

    return true;
}

struct UCharBufferTranslator {
    static unsigned hash(const UCharBuffer &buf)
    {
        return DOMStringImpl::computeHash(buf.s, buf.length);
    }

    static bool equal(DOMStringImpl *const &str, const UCharBuffer &buf)
    {
        return khtml::equal(str, buf.s, buf.length);
    }

    static void translate(DOMStringImpl *&location, const UCharBuffer &buf, unsigned hash)
    {
        location = new DOMStringImpl(buf.s, buf.length, hash);
    }
};

struct HashAndCharacters {
    unsigned hash;
    const QChar *characters;
    unsigned length;
};

struct HashAndCharactersTranslator {
    static unsigned hash(const HashAndCharacters &buffer)
    {
        ASSERT(buffer.hash == DOMStringImpl::computeHash(buffer.characters, buffer.length));
        return buffer.hash;
    }

    static bool equal(DOMStringImpl *const &string, const HashAndCharacters &buffer)
    {
        return khtml::equal(string, buffer.characters, buffer.length);
    }

    static void translate(DOMStringImpl *&location, const HashAndCharacters &buffer, unsigned hash)
    {
        location = new DOMStringImpl(buffer.characters, buffer.length, hash);
    }
};

DOMStringImpl *AtomicString::add(const QChar *s, int length)
{
    if (!s) {
        return nullptr;
    }

    if (length == 0) {
        return DOMStringImpl::empty();
    }

    init();
    UCharBuffer buf = { s, static_cast<uint>(length) };
    std::pair<HashSet<DOMStringImpl *>::iterator, bool> addResult = stringTable->add<UCharBuffer, UCharBufferTranslator>(buf);
    if (!addResult.second) {
        return *addResult.first;
    }
    return *addResult.first;
}

DOMStringImpl *AtomicString::add(const QChar *s)
{
    if (!s) {
        return nullptr;
    }

    int length = 0;
    while (s[length] != QChar(0)) {
        length++;
    }

    if (length == 0) {
        return DOMStringImpl::empty();
    }

    init();
    UCharBuffer buf = {s, static_cast<uint>(length)};
    std::pair<HashSet<DOMStringImpl *>::iterator, bool> addResult = stringTable->add<UCharBuffer, UCharBufferTranslator>(buf);
    if (!addResult.second) {
        return *addResult.first;
    }
    return *addResult.first;
}

DOMStringImpl *AtomicString::add(DOMStringImpl *r)
{
    if (!r || r->m_inTable) {
        return r;
    }

    if (r->length() == 0) {
        return DOMStringImpl::empty();
    }

    init();
    DOMStringImpl *result = *stringTable->add(r).first;
    if (result == r) {
        r->m_inTable = true;
    }
    return result;
}

void AtomicString::remove(DOMStringImpl *r)
{
    stringTable->remove(r);
}

/*DOMStringImpl* AtomicString::add(const KJS::Identifier& identifier)
{
    if (identifier.isNull())
        return 0;

    UString::Rep* string = identifier.ustring().rep();
    unsigned length = string->size();
    if (!length)
        return StringImpl::empty();

    HashAndCharacters buffer = { string->computedHash(), string->data(), length };
    pair<HashSet<StringImpl*>::iterator, bool> addResult = stringTable->add<HashAndCharacters, HashAndCharactersTranslator>(buffer);
    if (!addResult.second)
        return *addResult.first;
    return adoptRef(*addResult.first);
}

PassRefPtr<StringImpl> AtomicString::add(const KJS::UString& ustring)
{
    if (ustring.isNull())
        return 0;

    UString::Rep* string = ustring.rep();
    unsigned length = string->size();
    if (!length)
        return StringImpl::empty();

    HashAndCharacters buffer = { string->hash(), string->data(), length };
    pair<HashSet<StringImpl*>::iterator, bool> addResult = stringTable->add<HashAndCharacters, HashAndCharactersTranslator>(buffer);
    if (!addResult.second)
        return *addResult.first;
    return adoptRef(*addResult.first);
}

AtomicStringImpl* AtomicString::find(const KJS::Identifier& identifier)
{
    if (identifier.isNull())
        return 0;

    UString::Rep* string = identifier.ustring().rep();
    unsigned length = string->size();
    if (!length)
        return static_cast<AtomicStringImpl*>(StringImpl::empty());

    HashAndCharacters buffer = { string->computedHash(), string->data(), length };
    HashSet<StringImpl*>::iterator iterator = stringTable->find<HashAndCharacters, HashAndCharactersTranslator>(buffer);
    if (iterator == stringTable->end())
        return 0;
    return static_cast<AtomicStringImpl*>(*iterator);
}

AtomicString::operator UString() const
{
    return m_string;
}*/

#define DEFINE_GLOBAL(type, name, ...) \
    const type name;

DEFINE_GLOBAL(AtomicString, nullAtom)
DEFINE_GLOBAL(AtomicString, emptyAtom, "")
DEFINE_GLOBAL(AtomicString, textAtom, "#text")
DEFINE_GLOBAL(AtomicString, commentAtom, "#comment")
DEFINE_GLOBAL(AtomicString, starAtom, "*")

void AtomicString::init()
{
    static bool initialized;
    if (!initialized) {
        stringTable = new HashSet<DOMStringImpl *>;

        // Use placement new to initialize the globals.
        /*new ((void*)&nullAtom) AtomicString;
        new ((void*)&emptyAtom) AtomicString("");
        new ((void*)&textAtom) AtomicString("#text");
        new ((void*)&commentAtom) AtomicString("#comment");
        new ((void*)&starAtom) AtomicString("*");*/

        initialized = true;
    }
}

}
