/*

 *  Copyright (C) 2003, 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.

 *

 */

#include "config.h"

#include "Identifier.h"

#include "CallFrame.h"

#include <new> // for placement new

#include <string.h> // for strlen

#include <wtf/Assertions.h>

#include <wtf/FastMalloc.h>

#include <wtf/HashSet.h>

namespace JSC {

typedef HashMap<const char*, RefPtr<UString::Rep>, PtrHash<const char*> > LiteralIdentifierTable;

class IdentifierTable : public FastAllocBase {

public:

    ~IdentifierTable()

    {

        HashSet<UString::Rep*>::iterator end = m_table.end();

        for (HashSet<UString::Rep*>::iterator iter = m_table.begin(); iter != end; ++iter)

            (*iter)->setIdentifierTable(0);

    }

    std::pair<HashSet<UString::Rep*>::iterator, bool> add(UString::Rep* value)

    {

        std::pair<HashSet<UString::Rep*>::iterator, bool> result = m_table.add(value);

        (*result.first)->setIdentifierTable(this);

        return result;

    }

    template<typename U, typename V>

    std::pair<HashSet<UString::Rep*>::iterator, bool> add(U value)

    {

        std::pair<HashSet<UString::Rep*>::iterator, bool> result = m_table.add<U, V>(value);

        (*result.first)->setIdentifierTable(this);

        return result;

    }

    void remove(UString::Rep* r) { m_table.remove(r); }

    LiteralIdentifierTable& literalTable() { return m_literalTable; }

private:

    HashSet<UString::Rep*> m_table;

    LiteralIdentifierTable m_literalTable;

};

IdentifierTable* createIdentifierTable()

{

    return new IdentifierTable;

}

void deleteIdentifierTable(IdentifierTable* table)

{

    delete table;

}

bool Identifier::equal(const UString::Rep* r, const char* s)

{

    int length = r->len;

    const UChar* d = r->data();

    for (int i = 0; i != length; ++i)

        if (d[i] != (unsigned char)s[i])

            return false;

    return s[length] == 0;

}

bool Identifier::equal(const UString::Rep* r, const UChar* s, int length)

{

    if (r->len != length)

        return false;

    const UChar* d = r->data();

    for (int i = 0; i != length; ++i)

        if (d[i] != s[i])

            return false;

    return true;

}

struct CStringTranslator {

    static unsigned hash(const char* c)

    {

        return UString::Rep::computeHash(c);

    }

    static bool equal(UString::Rep* r, const char* s)

    {

        return Identifier::equal(r, s);

    }

    static void translate(UString::Rep*& location, const char* c, unsigned hash)

    {

        size_t length = strlen(c);

        UChar* d = static_cast<UChar*>(fastMalloc(sizeof(UChar) * length));

        for (size_t i = 0; i != length; i++)

            d[i] = static_cast<unsigned char>(c[i]); // use unsigned char to zero-extend instead of sign-extend

        UString::Rep* r = UString::Rep::create(d, static_cast<int>(length)).releaseRef();

        r->_hash = hash;

        location = r;

    }

};

PassRefPtr<UString::Rep> Identifier::add(JSGlobalData* globalData, const char* c)

{

    if (!c) {

        UString::Rep::null().hash();

        return &UString::Rep::null();

    }

    if (!c[0]) {

        UString::Rep::empty().hash();

        return &UString::Rep::empty();

    }

    if (!c[1])

        return add(globalData, globalData->smallStrings.singleCharacterStringRep(static_cast<unsigned char>(c[0])));

    IdentifierTable& identifierTable = *globalData->identifierTable;

    LiteralIdentifierTable& literalIdentifierTable = identifierTable.literalTable();

    const LiteralIdentifierTable::iterator& iter = literalIdentifierTable.find(c);

    if (iter != literalIdentifierTable.end())

        return iter->second;

    pair<HashSet<UString::Rep*>::iterator, bool> addResult = identifierTable.add<const char*, CStringTranslator>(c);

    // If the string is newly-translated, then we need to adopt it.

    // The boolean in the pair tells us if that is so.

    RefPtr<UString::Rep> addedString = addResult.second ? adoptRef(*addResult.first) : *addResult.first;

    literalIdentifierTable.add(c, addedString.get());

    return addedString.release();

}

PassRefPtr<UString::Rep> Identifier::add(ExecState* exec, const char* c)

{

    return add(&exec->globalData(), c);

}

struct UCharBuffer {

    const UChar* s;

    unsigned int length;

};

struct UCharBufferTranslator {

    static unsigned hash(const UCharBuffer& buf)

    {

        return UString::Rep::computeHash(buf.s, buf.length);

    }

    static bool equal(UString::Rep* str, const UCharBuffer& buf)

    {

        return Identifier::equal(str, buf.s, buf.length);

    }

    static void translate(UString::Rep*& location, const UCharBuffer& buf, unsigned hash)

    {

        UChar* d = static_cast<UChar*>(fastMalloc(sizeof(UChar) * buf.length));

        for (unsigned i = 0; i != buf.length; i++)

            d[i] = buf.s[i];

        UString::Rep* r = UString::Rep::create(d, buf.length).releaseRef();

        r->_hash = hash;

        location = r; 

    }

};

PassRefPtr<UString::Rep> Identifier::add(JSGlobalData* globalData, const UChar* s, int length)

{

    if (length == 1) {

        UChar c = s[0];

        if (c <= 0xFF)

            return add(globalData, globalData->smallStrings.singleCharacterStringRep(c));

    }

    if (!length) {

        UString::Rep::empty().hash();

        return &UString::Rep::empty();

    }

    UCharBuffer buf = {s, length}; 

    pair<HashSet<UString::Rep*>::iterator, bool> addResult = globalData->identifierTable->add<UCharBuffer, UCharBufferTranslator>(buf);

    // If the string is newly-translated, then we need to adopt it.

    // The boolean in the pair tells us if that is so.

    return addResult.second ? adoptRef(*addResult.first) : *addResult.first;

}

PassRefPtr<UString::Rep> Identifier::add(ExecState* exec, const UChar* s, int length)

{

    return add(&exec->globalData(), s, length);

}

PassRefPtr<UString::Rep> Identifier::addSlowCase(JSGlobalData* globalData, UString::Rep* r)

{

    ASSERT(!r->identifierTable());

    if (r->len == 1) {

        UChar c = r->data()[0];

        if (c <= 0xFF)

            r = globalData->smallStrings.singleCharacterStringRep(c);

            if (r->identifierTable()) {

#ifndef NDEBUG

                checkSameIdentifierTable(globalData, r);

#endif

                return r;

            }

    }

    if (!r->len) {

        UString::Rep::empty().hash();

        return &UString::Rep::empty();

    }

    return *globalData->identifierTable->add(r).first;

}

PassRefPtr<UString::Rep> Identifier::addSlowCase(ExecState* exec, UString::Rep* r)

{

    return addSlowCase(&exec->globalData(), r);

}

void Identifier::remove(UString::Rep* r)

{

    r->identifierTable()->remove(r);

}

#ifndef NDEBUG

void Identifier::checkSameIdentifierTable(ExecState* exec, UString::Rep* rep)

{

    ASSERT(rep->identifierTable() == exec->globalData().identifierTable);

}

void Identifier::checkSameIdentifierTable(JSGlobalData* globalData, UString::Rep* rep)

{

    ASSERT(rep->identifierTable() == globalData->identifierTable);

}

#else

void Identifier::checkSameIdentifierTable(ExecState*, UString::Rep*)

{

}

void Identifier::checkSameIdentifierTable(JSGlobalData*, UString::Rep*)

{

}

#endif

} // namespace JSC