Function writeZipImpl

src/core/ZipArchive.cpp:205–283

Shared ZIP writer. compress=false → stored (method 0); compress=true → raw-deflate (method 8). Headers carry compressed + uncompressed sizes independently; the CRC is always over the uncompressed data.

// raw-deflate (method 8). Headers carry compressed + uncompressed sizes
// independently; the CRC is always over the uncompressed data.
QByteArray writeZipImpl(const QList<ZipEntryData>& entries, bool compress)
{
    if (entries.size() > std::numeric_limits<quint16>::max())
        return {};

    QByteArray out;
    QByteArray centralDir;
    for (const ZipEntryData& entry : entries) {
        const QByteArray name = entry.name.toUtf8();
        const QByteArray& raw = entry.data;

        QByteArray deflated;
        if (compress && !rawDeflate(raw, deflated))
            return {};
        const QByteArray& payload = compress ? deflated : raw;
        const quint16 method = compress ? quint16(8) : quint16(0);

        if (name.size() > std::numeric_limits<quint16>::max()
            || raw.size() > std::numeric_limits<quint32>::max()
            || payload.size() > std::numeric_limits<quint32>::max()
            || out.size() > std::numeric_limits<quint32>::max()) {
            return {};
        }

        const quint32 localOffset = static_cast<quint32>(out.size());
        const quint32 checksum = crc32(0L, reinterpret_cast<const Bytef*>(raw.constData()),
                                       static_cast<uInt>(raw.size()));

        appendLe32(out, 0x04034b50);
        appendLe16(out, 20);
        appendLe16(out, 0);
        appendLe16(out, method);
        appendLe16(out, 0);
        appendLe16(out, 0);
        appendLe32(out, checksum);
        appendLe32(out, static_cast<quint32>(payload.size()));
        appendLe32(out, static_cast<quint32>(raw.size()));
        appendLe16(out, static_cast<quint16>(name.size()));
        appendLe16(out, 0);
        out += name;
        out += payload;

        appendLe32(centralDir, 0x02014b50);
        appendLe16(centralDir, 20);
        appendLe16(centralDir, 20);
        appendLe16(centralDir, 0);
        appendLe16(centralDir, method);
        appendLe16(centralDir, 0);
        appendLe16(centralDir, 0);
        appendLe32(centralDir, checksum);
        appendLe32(centralDir, static_cast<quint32>(payload.size()));
        appendLe32(centralDir, static_cast<quint32>(raw.size()));
        appendLe16(centralDir, static_cast<quint16>(name.size()));
        appendLe16(centralDir, 0);
        appendLe16(centralDir, 0);
        appendLe16(centralDir, 0);
        appendLe16(centralDir, 0);
        appendLe32(centralDir, 0);