qstring.cpp

奇趣公司比较新的qt/emd版本

    const uchar *c = (uchar *) other.latin1();

    if (!c || *c == 0)
        return false;

    while (*c) {
        if (uc == e || *uc != *c)
            break;
        ++uc;
        ++c;
    }
    return (uc == e ? *c : *uc < *c);
}

/*! \fn bool QString::operator<(const QByteArray &other) const

    \overload

    The \a other byte array is converted to a QString using the
    fromAscii() function.

    You can disable this operator by defining \c
    QT_NO_CAST_FROM_ASCII when you compile your applications. This
    can be useful if you want to ensure that all user-visible strings
    go through QObject::tr(), for example.
*/

/*! \fn bool QString::operator<(const char *other) const

    \overload

    The \a other const char pointer is converted to a QString using
    the fromAscii() function.

    You can disable this operator by defining \c
    QT_NO_CAST_FROM_ASCII when you compile your applications. This
    can be useful if you want to ensure that all user-visible strings
    go through QObject::tr(), for example.
*/

/*! \fn bool QString::operator<=(const QString &other) const

    Returns true if this string is lexically less than or equal to
    string \a other; otherwise returns false.

    The comparison is based exclusively on the numeric Unicode values
    of the characters and is very fast, but is not what a human would
    expect. Consider sorting user-interface strings with
    localeAwareCompare().
*/

/*! \fn bool QString::operator<=(const QLatin1String &other) const

    \overload
*/

/*! \fn bool QString::operator<=(const QByteArray &other) const

    \overload

    The \a other byte array is converted to a QString using the
    fromAscii() function.

    You can disable this operator by defining \c
    QT_NO_CAST_FROM_ASCII when you compile your applications. This
    can be useful if you want to ensure that all user-visible strings
    go through QObject::tr(), for example.
*/

/*! \fn bool QString::operator<=(const char *other) const

    \overload

    The \a other const char pointer is converted to a QString using
    the fromAscii() function.

    You can disable this operator by defining \c
    QT_NO_CAST_FROM_ASCII when you compile your applications. This
    can be useful if you want to ensure that all user-visible strings
    go through QObject::tr(), for example.
*/

/*! \fn bool QString::operator>(const QString &other) const

    Returns true if this string is lexically greater than string \a
    other; otherwise returns false.

    The comparison is based exclusively on the numeric Unicode values
    of the characters and is very fast, but is not what a human would
    expect. Consider sorting user-interface strings with
    localeAwareCompare().
*/

/*!
    \overload
*/
bool QString::operator>(const QLatin1String &other) const
{
    const ushort *uc = d->data;;
    const ushort *e = uc + d->size;
    const uchar *c = (uchar *) other.latin1();

    if (!c || *c == '\0')
        return !isEmpty();

    while (*c) {
        if (uc == e || *uc != *c)
            break;
        ++uc;
        ++c;
    }
    return (uc == e ? false : *uc > *c);
}

/*! \fn bool QString::operator>(const QByteArray &other) const

    \overload

    The \a other byte array is converted to a QString using the
    fromAscii() function.

    You can disable this operator by defining \c
    QT_NO_CAST_FROM_ASCII when you compile your applications. This
    can be useful if you want to ensure that all user-visible strings
    go through QObject::tr(), for example.
*/

/*! \fn bool QString::operator>(const char *other) const

    \overload

    The \a other const char pointer is converted to a QString using
    the fromAscii() function.

    You can disable this operator by defining \c QT_NO_CAST_FROM_ASCII
    when you compile your applications. This can be useful if you want
    to ensure that all user-visible strings go through QObject::tr(),
    for example.
*/

/*! \fn bool QString::operator>=(const QString &other) const

    Returns true if this string is lexically greater than or equal to
    string \a other; otherwise returns false.

    The comparison is based exclusively on the numeric Unicode values
    of the characters and is very fast, but is not what a human would
    expect. Consider sorting user-interface strings with
    localeAwareCompare().
*/

/*! \fn bool QString::operator>=(const QLatin1String &other) const

    \overload
*/

/*! \fn bool QString::operator>=(const QByteArray &other) const

    \overload

    The \a other byte array is converted to a QString using the
    fromAscii() function.

    You can disable this operator by defining \c QT_NO_CAST_FROM_ASCII
    when you compile your applications. This can be useful if you want
    to ensure that all user-visible strings go through QObject::tr(),
    for example.
*/

/*! \fn bool QString::operator>=(const char *other) const

    \overload

    The \a other const char pointer is converted to a QString using
    the fromAscii() function.

    You can disable this operator by defining \c
    QT_NO_CAST_FROM_ASCII when you compile your applications. This
    can be useful if you want to ensure that all user-visible strings
    go through QObject::tr(), for example.
*/

/*! \fn bool QString::operator!=(const QString &other) const

    Returns true if this string is not equal to string \a other;
    otherwise returns false.

    The comparison is based exclusively on the numeric Unicode values
    of the characters and is very fast, but is not what a human would
    expect. Consider sorting user-interface strings with
    localeAwareCompare().
*/

/*! \fn bool QString::operator!=(const QLatin1String &other) const

    \overload
*/

/*! \fn bool QString::operator!=(const QByteArray &other) const

    \overload

    The \a other byte array is converted to a QString using the
    fromAscii() function.

    You can disable this operator by defining \c QT_NO_CAST_FROM_ASCII
    when you compile your applications. This can be useful if you want
    to ensure that all user-visible strings go through QObject::tr(),
    for example.
*/

/*! \fn bool QString::operator!=(const char *other) const

    \overload

    The \a other const char pointer is converted to a QString using
    the fromAscii() function.

    You can disable this operator by defining \c
    QT_NO_CAST_FROM_ASCII when you compile your applications. This
    can be useful if you want to ensure that all user-visible strings
    go through QObject::tr(), for example.
*/

#define REHASH(a) \
    if (sl_minus_1 < (int)sizeof(int) * CHAR_BIT)       \
        hashHaystack -= (a) << sl_minus_1; \
    hashHaystack <<= 1

/*!
    Returns the index position of the first occurrence of the string
    \a str in this string, searching forward from index position \a
    from. Returns -1 if \a str is not found.

    If \a cs is Qt::CaseSensitive (the default), the search is
    case sensitive; otherwise the search is case insensitive.

    Example:

    \quotefromfile snippets/qstring/main.cpp
    \skipto Widget::indexOfFunction()
    \skipto QString x
    \printuntil  x.indexOf(y, 11)

    If \a from is -1, the search starts at the last character; if it
    is -2, at the next to last character and so on.

    \sa lastIndexOf(), contains(), count()
*/
int QString::indexOf(const QString &str, int from, Qt::CaseSensitivity cs) const
{
    const int l = d->size;
    const int sl = str.d->size;
    if (from < 0)
        from += l;
    if (uint(sl + from) > (uint)l)
        return -1;
    if (!sl)
        return from;
    if (!l)
        return -1;

    if (sl == 1)
        return indexOf(QChar(str.d->data[0]), from, cs);

    /*
        We use the Boyer-Moore algorithm in cases where the overhead
        for the skip table should pay off, otherwise we use a simple
        hash function.
    */
    if (l > 500 && sl > 5)
        return QStringMatcher(str, cs).indexIn(*this, from);

    /*
        We use some hashing for efficiency's sake. Instead of
        comparing strings, we compare the hash value of str with that
        of a part of this QString. Only if that matches, we call
        ucstrncmp() or ucstrnicmp().
    */
    const ushort *needle = str.d->data;
    const ushort *haystack = d->data + from;
    const ushort *end = d->data + (l-sl);
    const int sl_minus_1 = sl-1;
    int hashNeedle = 0, hashHaystack = 0, idx;

    if (cs == Qt::CaseSensitive) {
        for (idx = 0; idx < sl; ++idx) {
            hashNeedle = ((hashNeedle<<1) + needle[idx]);
            hashHaystack = ((hashHaystack<<1) + haystack[idx]);
        }
        hashHaystack -= haystack[sl_minus_1];

        while (haystack <= end) {
            hashHaystack += haystack[sl_minus_1];
            if (hashHaystack == hashNeedle
                 && ucstrncmp((const QChar *)needle, (const QChar *)haystack, sl) == 0)
                return haystack - d->data;

            REHASH(*haystack);
            ++haystack;
        }
    } else {
        const ushort *haystack_start = d->data;
        for (idx = 0; idx < sl; ++idx) {
            hashNeedle = (hashNeedle<<1) + foldCase(needle + idx, needle);
            hashHaystack = (hashHaystack<<1) + foldCase(haystack + idx, haystack_start);
        }
        hashHaystack -= foldCase(haystack + sl_minus_1, haystack_start);

        while (haystack <= end) {
            hashHaystack += foldCase(haystack + sl_minus_1, haystack_start);
            if (hashHaystack == hashNeedle && ucstrnicmp(needle, haystack, sl) == 0)
                return haystack - d->data;

            REHASH(foldCase(haystack, haystack_start));
            ++haystack;
        }
    }
    return -1;
}

/*!
    \overload

    Returns the index position of the first occurrence of the
    character \a ch in the string, searching forward from index
    position \a from. Returns -1 if \a ch could not be found.
*/
int QString::indexOf(QChar ch, int from, Qt::CaseSensitivity cs) const
{
    ushort c = ch.unicode();
    if (from < 0)
        from = qMax(from + d->size, 0);
    if (from  < d->size) {
        const ushort *n = d->data + from - 1;
        const ushort *e = d->data + d->size;
        if (cs == Qt::CaseSensitive) {
            while (++n != e)
                if (*n == c)
                    return  n - d->data;
        } else {
            c = foldCase(c);
            while (++n != e)
                if (foldCase(*n) == c)
                    return  n - d->data;
        }
    }
    return -1;
}

/*!
    Returns the index position of the last occurrence of the string
    \a str in this string, searching backward from index position \a
    from. If \a from is -1 (the default), the search starts at the
    last character; if \a from is -2, at the next to last character
    and so on. Returns -1 if \a str is not found.

    If \a cs is Qt::CaseSensitive (the default), the search is
    case sensitive; otherwise the search is case insensitive.

    Example:

    \quotefromfile snippets/qstring/main.cpp
    \skipto Widget::lastIndexOfFunction()
    \skipto QString x
    \printuntil x.lastIndexOf(y, 1)

    \sa indexOf(), contains(), count()
*/
int QString::lastIndexOf(const QString &str, int from, Qt::CaseSensitivity cs) const
{
    /*
        See indexOf() for explanations.
    */
    const int l = d->size;
    if (from < 0)
        from += l;
    const int sl = str.d->size;
    int delta = l-sl;
    if (from == l && sl == 0)
        return from;
    if (from < 0 || from >= l || delta < 0)
        return -1;
    if (from > delta)
        from = delta;

    if (sl == 1)
        return lastIndexOf(QChar(str.d->data[0]), from, cs);

    const ushort *needle = str.d->data;
    const ushort *haystack = d->data + from;
    const ushort *end = d->data;
    const int sl_minus_1 = sl-1;
    const ushort *n = needle+sl_minus_1;
    const ushort *h = haystack+sl_minus_1;
    int hashNeedle = 0, hashHaystack = 0, idx;

    if (cs == Qt::CaseSensitive) {
        for (idx = 0; idx < sl; ++idx) {
            hashNeedle = ((hashNeedle<<1) + *(n-idx));
            hashHaystack = ((hashHaystack<<1) + *(h-idx));
        }
        hashHaystack -= *haystack;

        while (haystack >= end) {
            hashHaystack += *haystack;
            if (hashHaystack == hashNeedle
                 && ucstrncmp((const QChar *)needle, (const QChar *)haystack, sl) == 0)
                return haystack - d->data;
            --haystack;
            REHASH(haystack[sl]);
        }
    } else {
        for (idx = 0; idx < sl; ++idx) {
            hashNeedle = ((hashNeedle<<1) + foldCase(n-idx, str.d->data));
            hashHaystack = ((hashHaystack<<1) + foldCase(h-idx, end));
        }
        hashHaystack -= foldCase(haystack, end);

        while (haystack >= end) {
            hashHaystack += foldCase(haystack, end);
            if (hashHaystack == hashNeedle && ucstrnicmp(needle, haystack, sl) == 0)
                return haystack - d->data;
            --haystack;
            REHASH(foldCase(haystack + sl, end));
        }
    }
    return -1;
}

/*! \overload

    Returns the index position of the last occurrence of the
    character \a ch, searching backward from position \a from.
*/
int QString::lastIndexOf(QChar ch, int from, Qt::CaseSensitivity cs) const
{
    ushort c = ch.unicode();
    if (from < 0)
        from += d->size;
    if (from < 0 || from >= d->size)
        return -1;
    if (from >= 0) {
        const ushort *n = d->data + from;
        const ushort *b = d->data;
        if