Function get_unzip_program

src/tz.cpp:3434–3469

Note folder can and usually does contain spaces.

// Note folder can and usually does contain spaces.
static
std::string
get_unzip_program()
{
    std::string path;

    // 7-Zip appears to note its location in the registry.
    // If that doesn't work, fall through and take a guess, but it will likely be wrong.
    HKEY hKey = nullptr;
    if (RegOpenKeyExA(HKEY_LOCAL_MACHINE, "SOFTWARE\\7-Zip", 0, KEY_READ, &hKey) == ERROR_SUCCESS)
    {
        char value_buffer[MAX_PATH + 1]; // fyi 260 at time of writing.
        // in/out parameter. Documentation say that size is a count of bytes not chars.
        DWORD size = sizeof(value_buffer) - sizeof(value_buffer[0]);
        DWORD tzi_type = REG_SZ;
        // Testing shows Path key value is "C:\Program Files\7-Zip\" i.e. always with trailing \.
        bool got_value = (RegQueryValueExA(hKey, "Path", nullptr, &tzi_type,
            reinterpret_cast<LPBYTE>(value_buffer), &size) == ERROR_SUCCESS);
        RegCloseKey(hKey); // Close now incase of throw later.
        if (got_value)
        {
            // Function does not guarantee to null terminate.
            value_buffer[size / sizeof(value_buffer[0])] = '\0';
            path = value_buffer;
            if (!path.empty())
            {
                path += "7z.exe";
                return path;
            }
        }
    }
    path += get_program_folder();
    path += folder_delimiter;
    path += "7-Zip\\7z.exe";
    return path;
}

#    if !USE_SHELL_API
static