/****************************************************************************
**
** Copyright (C) 1992-2005 Trolltech AS. All rights reserved.
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** This file may be used under the terms of the GNU General Public
** License version 2.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of
** this file.  Please review the following information to ensure GNU
** General Public Licensing requirements will be met:
** http://www.trolltech.com/products/qt/opensource.html
**
** If you are unsure which license is appropriate for your use, please
** review the following information:
** http://www.trolltech.com/products/qt/licensing.html or contact the
** sales department at sales@trolltech.com.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
****************************************************************************/

#include "qplatformdefs.h"

#include "qtranslator.h"

#ifndef QT_NO_TRANSLATION

#include "qfileinfo.h"
#include "qstring.h"
#include "qcoreapplication.h"
#include "qdatastream.h"
#include "qfile.h"
#include "qmap.h"
#include "qalgorithms.h"
#include "qhash.h"
#include "qglobal.h"

#if defined(Q_OS_UNIX)
#define QT_USE_MMAP
#endif

// most of the headers below are already included in qplatformdefs.h
// also this lacks Large File support but that's probably irrelevant
#if defined(QT_USE_MMAP)
// for mmap
#include <sys/mman.h>
#include <errno.h>
#endif

#include <stdlib.h>

#include "qobject_p.h"

enum Tag { Tag_End = 1, Tag_SourceText16, Tag_Translation, Tag_Context16,
           Tag_Hash, Tag_SourceText, Tag_Context, Tag_Comment,
           Tag_Obsolete1 };
/*
$ mcookie
3cb86418caef9c95cd211cbf60a1bddd
$
*/

// magic number for the file
static const int MagicLength = 16;
static const uchar magic[MagicLength] = {
    0x3c, 0xb8, 0x64, 0x18, 0xca, 0xef, 0x9c, 0x95,
    0xcd, 0x21, 0x1c, 0xbf, 0x60, 0xa1, 0xbd, 0xdd
};

static bool match(const uchar* found, const char* target, uint len)
{
    // 0 means anything, "" means empty
    return !found || qstrncmp((const char *)found, target, len) == 0 && target[len] == '\0';
}

static uint elfHash(const char * name)
{
    const uchar *k;
    uint h = 0;
    uint g;

    if (name) {
        k = (const uchar *) name;
        while (*k) {
            h = (h << 4) + *k++;
            if ((g = (h & 0xf0000000)) != 0)
                h ^= g >> 24;
            h &= ~g;
        }
    }
    if (!h)
        h = 1;
    return h;
}

extern bool qt_detectRTLLanguage();

class QTranslatorPrivate : public QObjectPrivate
{
    Q_DECLARE_PUBLIC(QTranslator)
public:
    enum { Contexts = 0x2f, Hashes = 0x42, Messages = 0x69 };

    QTranslatorPrivate() : used_mmap(0), unmapPointer(0), unmapLength(0),
       messageArray(0), offsetArray(0), contextArray(0), messageLength(0),
       offsetLength(0), contextLength(0) {}

    // for mmap'ed files, this is what needs to be unmapped.
    uint used_mmap : 1;
    char *unmapPointer;
    unsigned int unmapLength;

    // for squeezed but non-file data, this is what needs to be deleted
    const uchar *messageArray;
    const uchar *offsetArray;
    const uchar *contextArray;
    uint messageLength;
    uint offsetLength;
    uint contextLength;

    bool do_load(const uchar *data, int len);

    void clear();
};


/*!
    \class QTranslator

    \brief The QTranslator class provides internationalization support for text
    output.

    \ingroup i18n
    \ingroup environment
    \mainclass

    An object of this class contains a set of translations from a
    source language to a target language. QTranslator provides
    functions to look up translations in a translation file.
    Translation files are created using \l{Qt Linguist}.

    The most common use of QTranslator is to: load a translation
    file, install it using QApplication::installTranslator(), and use
    it via QObject::tr(). Here's the \c main() function from the
    \l{linguist/hellotr}{Hello tr()} example:

    \quotefromfile linguist/hellotr/main.cpp
    \skipto main(
    \printuntil }

    Note that the translator must be created \e before the
    application's widgets.

    Most applications will never need to do anything else with this
    class. The other functions provided by this class are useful for
    applications that work on translator files.

    It is possible to lookup a translation using translate() (as tr()
    and QApplication::translate() do). The translate() function takes
    up to three parameters:

    \list
    \o The \e context - usually the class name for the tr() caller.
    \o The \e {source text} - usually the argument to tr().
    \o The \e comment - an optional comment that helps disambiguate
       different uses of the same text in the same context.
    \endlist

    For example, the "Cancel" in a dialog might have "Anuluj" when the
    program runs in Polish (in this case the source text would be
    "Cancel"). The context would (normally) be the dialog's class
    name; there would normally be no comment, and the translated text
    would be "Anuluj".

    But it's not always so simple. The Spanish version of a printer
    dialog with settings for two-sided printing and binding would
    probably require both "Activado" and "Activada" as translations
    for "Enabled". In this case the source text would be "Enabled" in
    both cases, and the context would be the dialog's class name, but
    the two items would have disambiguating comments such as
    "two-sided printing" for one and "binding" for the other. The
    comment enables the translator to choose the appropriate gender
    for the Spanish version, and enables Qt to distinguish between
    translations.

    \sa QApplication::installTranslator(), QApplication::removeTranslator(),
        QObject::tr(), QApplication::translate()
*/

/*!
    Constructs an empty message file object with parent \a parent that
    is not connected to any file.
*/

QTranslator::QTranslator(QObject * parent)
    : QObject(*new QTranslatorPrivate, parent)
{
}

#ifdef QT3_SUPPORT
/*!
    \overload
    \obsolete
 */
QTranslator::QTranslator(QObject * parent, const char * name)
    : QObject(*new QTranslatorPrivate, parent)
{
    setObjectName(QString::fromAscii(name));
}
#endif

/*!
    Destroys the object and frees any allocated resources.
*/

QTranslator::~QTranslator()
{
    if (QCoreApplication::instance())
        QCoreApplication::instance()->removeTranslator(this);
    Q_D(QTranslator);
    d->clear();
}

/*!
    Loads \a filename + \a suffix (".qm" if the \a suffix is
    not specified), which may be an absolute file name or relative
    to \a directory. The previous contents of this translator object
    is discarded.

    If the file name does not exist, other file names are tried
    in the following order:

    \list 1
    \o File name without \a suffix appended.
    \o File name with text after a character in \a search_delimiters
       stripped ("_." is the default for \a search_delimiters if it is
       an empty string) and \a suffix.
    \o File name stripped without \a suffix appended.
    \o File name stripped further, etc.
    \endlist

    For example, an application running in the fr_CA locale
    (French-speaking Canada) might call load("foo.fr_ca",
    "/opt/foolib"). load() would then try to open the first existing
    readable file from this list:

    \list 1
    \o \c /opt/foolib/foo.fr_ca.qm
    \o \c /opt/foolib/foo.fr_ca
    \o \c /opt/foolib/foo.fr.qm
    \o \c /opt/foolib/foo.fr
    \o \c /opt/foolib/foo.qm
    \o \c /opt/foolib/foo
    \endlist
*/

bool QTranslator::load(const QString & filename, const QString & directory,
                       const QString & search_delimiters,
                       const QString & suffix)
{
    Q_D(QTranslator);
    d->clear();

    QString prefix;

    const int l = filename.size();
    if (!((l > 0 && filename[0] == QLatin1Char('/'))
#ifdef Q_WS_WIN
          || (l >= 2 && filename[0].isLetter() && filename[1] == QLatin1Char(':'))
          || (l >= 1 && filename[0] == QLatin1Char('\\'))
#endif
            )) {
        prefix = directory;
    }

    if (prefix.length()) {
        if (prefix[int(prefix.length()-1)] != QLatin1Char('/'))
            prefix += QLatin1Char('/');
    }

    QString fname = filename;
    QString realname;
    QString delims;
    delims = search_delimiters.isNull() ? QString::fromLatin1("_.") : search_delimiters;

    for (;;) {
        QFileInfo fi;

        realname = prefix + fname + (suffix.isNull() ? QString::fromLatin1(".qm") : suffix);
        fi.setFile(realname);
        if (fi.isReadable())
            break;

        realname = prefix + fname;
        fi.setFile(realname);
        if (fi.isReadable())
            break;

        int rightmost = 0;
        for (int i = 0; i < (int)delims.length(); i++) {
            int k = fname.lastIndexOf(delims[i]);
            if (k > rightmost)
                rightmost = k;
        }

        // no truncations? fail
        if (rightmost == 0)
            return false;

        fname.truncate(rightmost);
    }

    // realname is now the fully qualified name of a readable file.

    bool ok = false;

#ifdef QT_USE_MMAP

#ifndef MAP_FILE
#define MAP_FILE 0
#endif
#ifndef MAP_FAILED
#define MAP_FAILED -1
#endif

    int fd = -1;
    if (!realname.startsWith(QLatin1Char(':')))
        fd = QT_OPEN(QFile::encodeName(realname), O_RDONLY,
#if defined(Q_OS_WIN)
                     _S_IREAD | _S_IWRITE
#else
                     0666
#endif
            );
    if (fd >= 0) {
        struct stat st;
        if (!fstat(fd, &st)) {
            char *ptr;
            ptr = reinterpret_cast<char *>(
                mmap(0, st.st_size,             // any address, whole file
                     PROT_READ,                 // read-only memory
                     MAP_FILE | MAP_PRIVATE,    // swap-backed map from file
                     fd, 0));                   // from offset 0 of fd
            if (ptr && ptr != reinterpret_cast<char *>(MAP_FAILED)) {
                d->used_mmap = true;
                d->unmapPointer = ptr;
                d->unmapLength = st.st_size;
                ok = true;
            }
        }
        ::close(fd);
    }
#endif // QT_USE_MMAP

    if (!ok) {
        QFile file(realname);
        if (!file.exists())
            return false;
        d->unmapLength = file.size();
        d->unmapPointer = new char[d->unmapLength];

        if (file.open(QIODevice::ReadOnly))
            ok = (d->unmapLength == (uint)file.read(d->unmapPointer, d->unmapLength));

        if (!ok) {
            delete [] d->unmapPointer;
            d->unmapPointer = 0;
            d->unmapLength = 0;
            return false;
        }
    }

    return d->do_load(reinterpret_cast<const uchar *>(d->unmapPointer), d->unmapLength);
}

/*!
  \overload
  \fn bool QTranslator::load(const uchar *data, int len)

  Loads the .qm file data \a data of length \a len into the
  translator.

  The data is not copied. The caller must be able to guarantee that \a data
  will not be deleted or modified.
*/
bool QTranslator::load(const uchar *data, int len)
{
    Q_D(QTranslator);
    d->clear();
    return d->do_load(data, len);
}

static quint8 read8(const uchar *data)
{
    return *data;
}

static quint16 read16(const uchar *data)
{
    return (data[0] << 8) | (data[1]);
}

static quint32 read32(const uchar *data)
{
    return (data[0] << 24)
        | (data[1] << 16)
        | (data[2] << 8)
        | (data[3]);
}

bool QTranslatorPrivate::do_load(const uchar *data, int len)
{
    if (len < MagicLength || memcmp(data, magic, MagicLength) != 0) {
        clear();
        return false;
    }

    bool ok = true;
    const uchar *end = data + len;

    data += MagicLength;

    while (data < end - 4) {
        quint8 tag = read8(data++);
        quint32 blockLen = read32(data);
        data += 4;
        if (!tag || !blockLen)
            break;
        if (data + blockLen > end) {
            ok = false;
            break;
        }

        if (tag == QTranslatorPrivate::Contexts) {
            contextArray = data;
            contextLength = blockLen;
        } else if (tag == QTranslatorPrivate::Hashes) {
            offsetArray = data;
            offsetLength = blockLen;
        } else if (tag == QTranslatorPrivate::Messages) {
            messageArray = data;
            messageLength = blockLen;
        }

        data += blockLen;
    }

    return ok;
}

/*!
    Empties this translator of all contents.

    This function works with stripped translator files.
*/

void QTranslatorPrivate::clear()
{
    if (unmapPointer && unmapLength) {
#if defined(QT_USE_MMAP)
        if(used_mmap)
            munmap(unmapPointer, unmapLength);
        else
#else
            delete [] unmapPointer;
#endif
        unmapPointer = 0;
        unmapLength = 0;
    }

    messageArray = 0;
    contextArray = 0;
    offsetArray = 0;
    messageLength = 0;
    contextLength = 0;
    offsetLength = 0;

    QEvent ev(QEvent::LanguageChange);
    QCoreApplication::sendEvent(QCoreApplication::instance(), &ev);
}


static QString getMessage(const uchar *m, const uchar *end, const char *context, const char *sourceText, const char *comment)
{
    const uchar *tn = 0;
    uint tn_length = 0;

    for (;;) {
        uchar tag = 0;
        if (m < end)
            tag = read8(m++);
        switch((Tag)tag) {
        case Tag_End:
            goto end;
        case Tag_Translation:
            tn_length = read32(m);
            if (tn_length % 1)
                return QString();
            m += 4;
            if (tn_length == 0xffffffff)
                return QString();
            tn = m;
            m += tn_length;
            break;
        case Tag_Hash:
            m += 4;
            break;
        case Tag_SourceText: {
            quint32 len = read32(m);
            m += 4;
            if (!match(m, sourceText, len))
                return QString();
            m += len;
        }
            break;
        case Tag_Context: {
            quint32 len = read32(m);
            m += 4;
            if (*m && !match(m, context, len))
                return QString();
            m += len;
        }
            break;
        case Tag_Comment: {
            quint32 len = read32(m);
            m += 4;
            if (*m && !match(m, comment, len))
                return QString();
            m += len;
        }
            break;
        default:
            return QString();
        }
    }
end:
    if (!tn)
        return QString();
    QString str = QString::fromUtf16((const ushort *)tn, tn_length/2);
    if (QSysInfo::ByteOrder == QSysInfo::LittleEndian) {
        for (int i = 0; i < str.length(); ++i)
            str[i] = QChar((str.at(i).unicode() >> 8) + ((str.at(i).unicode() << 8) & 0xff00));
    }
    return str;
}


/*!
    Returns the translation for the key (\a context, \a sourceText,
    \a comment). If none is found, also tries (\a context, \a
    sourceText, ""). If that still fails, returns an empty string.

    \sa load()
*/
QString QTranslator::translate(const char *context, const char *sourceText, const char *comment) const
{
    Q_D(const QTranslator);
    if (context == 0)
        context = "";
    if (sourceText == 0)
        sourceText = "";
    if (comment == 0)
        comment = "";

    if (!d->offsetLength)
        return QString();

    /*
        Check if the context belongs to this QTranslator. If many
        translators are installed, this step is necessary.
    */
    if (d->contextLength) {
        quint16 hTableSize = read16(d->contextArray);
        uint g = elfHash(context) % hTableSize;
        const uchar *c = d->contextArray + 2 + (g << 1);
        quint16 off = read16(c);
        c += 2;
        if (off == 0)
            return QString();
        c = d->contextArray + (2 + (hTableSize << 1) + (off << 1));

        for (;;) {
            quint8 len = read8(c++);
            if (len == 0)
                return QString();
            if (match(c, context, len))
                break;
            c += len;
        }
    }

    size_t numItems = d->offsetLength / (2 * sizeof(quint32));
    if (!numItems)
        return QString();

    for (;;) {
        quint32 h = elfHash(QByteArray(sourceText) + comment);

        const uchar *start = d->offsetArray;
        const uchar *end = start + ((numItems-1) << 3);
        while (start <= end) {
            const uchar *middle = start + (((end - start) >> 4) << 3);
            uint hash = read32(middle);
            if (h == hash) {
                start = middle;
                break;
            } else if (hash < h) {
                start = middle + 8;
            } else {
                end = middle - 8;
            }
        }

        if (start <= end) {
            // go back on equal key
            while (start != d->offsetArray && read32(start) == read32(start-8))
                start -= 8;

            while (start < d->offsetArray + d->offsetLength) {
                quint32 rh = read32(start);
                start += 4;
                if (rh != h)
                    break;
                quint32 ro = read32(start);
                start += 4;
                QString tn = getMessage(d->messageArray + ro, d->messageArray + d->messageLength, context, sourceText, comment);
                if (!tn.isNull())
                    return tn;
            }
        }
        if (!comment[0])
            break;
        comment = "";
    }
    return QString();
}

/*!
    Returns true if this translator is empty, otherwise returns false.
    This function works with stripped and unstripped translation files.
*/
bool QTranslator::isEmpty() const
{
    Q_D(const QTranslator);
    return !d->unmapPointer && !d->unmapLength && !d->messageArray &&
           !d->offsetArray && !d->contextArray;
}


/*!
    \fn QString QTranslator::find(const char *context, const char *sourceText, const char * comment = 0) const

    Use translate(\a context, \a sourceText, \a comment) instead.
*/

#endif // QT_NO_TRANSLATION
