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#include "versitutils_p.h"
#include "qmobilityglobal.h"

#include <QMap>
#include <QTextCodec>
#include <QScopedPointer>

QTM_USE_NAMESPACE

QTextCodec* VersitUtils::m_previousCodec = 0;
QList<QByteArrayMatcher>* VersitUtils::m_newlineList = 0;
QByteArray VersitUtils::m_encodingMap[256];

/*!
 * Performs backslash escaping for line breaks (CRLFs), semicolons, backslashes and commas according
 * to RFC 2426.  This is called on parameter names and values and property values.
 * Colons ARE NOT escaped because the examples in RFC2426 suggest that they shouldn't be.
 */
void VersitUtils::backSlashEscape(QString& text)
{
    /* replaces ; with \;
                , with \,
                \ with \\
     */
    text.replace(QRegExp(QLatin1String("([;,\\\\])")), QLatin1String("\\\\1"));
    // replaces any CRLFs with \n
    text.replace(QRegExp(QLatin1String("\r\n|\r|\n")), QLatin1String("\\n"));
}

/*!
 * Removes backslash escaping for line breaks (CRLFs), colons, semicolons, backslashes and commas
 * according to RFC 2426.  This is called on parameter names and values and property values.
 * Colons ARE unescaped because the text of RFC2426 suggests that they should be.
 */
void VersitUtils::removeBackSlashEscaping(QString& text)
{
    if (!(text.startsWith(QLatin1Char('"')) && text.endsWith(QLatin1Char('"')))) {
        /* replaces \; with ;
                    \, with ,
                    \: with :
                    \\ with \
         */
        text.replace(QRegExp(QLatin1String("\\\\([;,:\\\\])")), QLatin1String("\\1"));
        // replaces \n with a CRLF
        text.replace(QLatin1String("\\n"), QLatin1String("\r\n"), Qt::CaseInsensitive);
    }
}


/*!
 * Encode \a ch with \a codec, without adding an byte-order mark
 */
QByteArray VersitUtils::encode(char ch, QTextCodec* codec)
{
    if (codec != m_previousCodec) {
        changeCodec(codec);
    }
    return m_encodingMap[(int)ch];
}

/*!
 * Encode \a ba with \a codec, without adding an byte-order mark.  \a ba is interpreted as ASCII
 */
QByteArray VersitUtils::encode(const QByteArray& ba, QTextCodec* codec)
{
    QTextCodec::ConverterState state(QTextCodec::IgnoreHeader);
    return codec->fromUnicode(QString::fromAscii(ba.data()).data(), ba.length(), &state);
}

/*!
 * Returns the list of DOS, UNIX and Mac newline characters for \a codec.
 */
QList<QByteArrayMatcher>* VersitUtils::newlineList(QTextCodec* codec)
{
    if (m_newlineList != 0 && codec == m_previousCodec) {
        return m_newlineList;
    }
    changeCodec(codec);
    return m_newlineList;
}

/*!
 * Update the cached tables of pregenerated encoded text with \a codec.
 */
void VersitUtils::changeCodec(QTextCodec* codec) {
    // Build m_encodingMap
    QChar qch;
    QTextCodec::ConverterState state(QTextCodec::IgnoreHeader);
    for (int c = 0; c < 256; c++) {
        qch = QLatin1Char(c);
        m_encodingMap[c] = codec->fromUnicode(&qch, 1, &state);
    }

    // Build m_newlineList
    if (m_newlineList != 0)
        delete m_newlineList;
    m_newlineList = new QList<QByteArrayMatcher>;
    m_newlineList->append(QByteArrayMatcher(encode("\r\n", codec)));
    m_newlineList->append(QByteArrayMatcher(encode("\n", codec)));
    m_newlineList->append(QByteArrayMatcher(encode("\r", codec)));

    m_previousCodec = codec;
}
