Function encode

3rdparty/cppzmq/zmq_addon.hpp:278–316

#endif
         >
message_t encode(const Range &parts)
{
    size_t mmsg_size = 0;

    // First pass check sizes
    for (const auto &part : parts) {
        const size_t part_size = part.size();
        if (part_size > (std::numeric_limits<std::uint32_t>::max)()) {
            // Size value must fit into uint32_t.
            throw std::range_error("Invalid size, message part too large");
        }
        const size_t count_size =
          part_size < (std::numeric_limits<std::uint8_t>::max)() ? 1 : 5;
        mmsg_size += part_size + count_size;
    }

    message_t encoded(mmsg_size);
    unsigned char *buf = encoded.data<unsigned char>();
    for (const auto &part : parts) {
        const uint32_t part_size = static_cast<uint32_t>(part.size());
        const unsigned char *part_data =
          static_cast<const unsigned char *>(part.data());

        if (part_size < (std::numeric_limits<std::uint8_t>::max)()) {
            // small part
            *buf++ = static_cast<unsigned char>(part_size);
        } else {
            // big part
            *buf++ = (std::numeric_limits<uint8_t>::max)();
            detail::write_network_order(buf, part_size);
            buf += sizeof(part_size);
        }
        std::memcpy(buf, part_data, part_size);
        buf += part_size;
    }

    assert(static_cast<size_t>(buf - encoded.data<unsigned char>()) == mmsg_size);
    return encoded;
}

/*  Decode an encoded message to multiple parts.