Uuid.hpp

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// This is a C++ification of the libuuid code, less the code that actually
// creates UUIDs, which is most of it and we don't need at this time.

#pragma once

#include <cstdint>
#include <string>
#include <iomanip>

#include "pdal_util_export.hpp"

#include "Inserter.hpp"
#include "Extractor.hpp"

namespace pdal
{

#pragma pack(push)
#pragma pack(1)
struct uuid
{
    uuid()
    { clear(); }

    uint32_t time_low;
    uint16_t time_mid;
    uint16_t time_hi_and_version;
    uint16_t clock_seq;
    uint8_t node[6];

    void clear()
    { memset(this, 0, sizeof(struct uuid)); }
};
#pragma pack(pop)

inline bool operator < (const uuid& u1, const uuid& u2)
{
    if (u1.time_low != u2.time_low)
        return u1.time_low < u2.time_low;
    if (u1.time_mid != u2.time_mid)
        return u1.time_mid < u2.time_mid;
    if (u1.time_hi_and_version != u2.time_hi_and_version)
        return u1.time_hi_and_version < u2.time_hi_and_version;
    for (size_t i = 0; i < sizeof(u1.node); ++i)
        if (u1.node[i] != u2.node[i])
            return u1.node[i] < u2.node[i];
    return false;
}

class PDAL_DLL Uuid
{
    friend inline bool operator < (const Uuid& u1, const Uuid& u2);
public:
    Uuid()
        {}
    Uuid(const char *c)
        { unpack(c); }
    Uuid(const std::string& s)
        { parse(s); }

    void clear()
        { m_data.clear(); }
    void unpack(const char *c)
    {
        BeExtractor e(c, 10);

        e >> m_data.time_low >> m_data.time_mid >>
            m_data.time_hi_and_version >> m_data.clock_seq;
        c += 10;
        std::copy(c, c + 6, m_data.node);
    }

    void pack(char *c) const
    {
        BeInserter i(c, 10);

        i << m_data.time_low << m_data.time_mid <<
            m_data.time_hi_and_version << m_data.clock_seq;
        c += 10;
        std::copy(m_data.node, m_data.node + 6, c);
    }

    bool parse(const std::string& s)
    {
        if (s.length() != 36)
            return false;

        // Format validation.
        const char *cp = s.data();
        for (size_t i = 0; i < 36; i++) {
            if ((i == 8) || (i == 13) || (i == 18) || (i == 23))
            {
                if (*cp != '-')
                    return false;
            }
            else if (!isxdigit(*cp))
                return false;
            ++cp;
        }

        cp = s.data();
        m_data.time_low = strtoul(cp, NULL, 16);
        m_data.time_mid = (uint16_t)strtoul(cp + 9, NULL, 16);
        m_data.time_hi_and_version = (uint16_t)strtoul(cp + 14, NULL, 16);
        m_data.clock_seq = (uint16_t)strtoul(cp + 19, NULL, 16);

        // Extract bytes as pairs of hex digits.
        cp = s.data() + 24;
        char buf[3];
        buf[2] = 0;
        for (size_t i = 0; i < 6; i++) {
            buf[0] = *cp++;
            buf[1] = *cp++;
            m_data.node[i] = (uint8_t)strtoul(buf, NULL, 16);
        }
        return true;
    }

    std::string unparse() const
    {
        std::stringstream out;

        out << std::hex << std::uppercase << std::setfill('0');
        out << std::setw(8) << m_data.time_low << '-';
        out << std::setw(4) << m_data.time_mid << '-';
        out << std::setw(4) << m_data.time_hi_and_version << '-';
        out << std::setw(2) << (m_data.clock_seq >> 8);
        out << std::setw(2) << (m_data.clock_seq & 0xFF) << '-';
        for (size_t i = 0; i < 6; ++i)
            out << std::setw(2) << (int)m_data.node[i];
        return out.str();
    }

    std::string toString() const
        { return unparse(); }

    bool empty() const
    { return isNull(); }

    bool isNull() const
    {
        const char *c = (const char *)&m_data;
        for (size_t i = 0; i < sizeof(m_data); ++i)
            if (*c++ != 0)
                return false;
        return true;
    }

    static constexpr size_t size()
        { return sizeof(m_data); }

private:
    uuid m_data;
};

inline bool operator == (const Uuid& u1, const Uuid& u2)
{
    return !(u1 < u2) && !(u2 < u1);
}

inline bool operator < (const Uuid& u1, const Uuid& u2)
{
    return u1.m_data < u2.m_data;
}

inline std::ostream& operator << (std::ostream& out, const Uuid& u)
{
    out << u.toString();
    return out;
}

inline std::istream& operator >> (std::istream& in, Uuid& u)
{
    std::string s;
    in >> s;
    if (!u.parse(s))
        in.setstate(std::ios::failbit);
    return in;
}

} // namespace pdal