OpenLCP/uuid/uuid.h

/*
  uuid.h

  Copyright (c) 2021 Kevin Matz (kevin.matz@gmail.com)

  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  SOFTWARE.
*/
#pragma once

#include <cstdint>
#include <cstring>
#include <string>

// RFC4122 A Universally Unique IDentifier (UUID) URN Namespace
namespace UUID {

/**
 * @brief The Type enum
 */
enum Type {
  NCS,      // Reserved, NCS backward compatibility.
  RFC4122,  // The variant specified in this document.
  MS,       // Reserved, Microsoft Corporation backward compatibility
  RESVERED, // Reserved for future definition.
  NIL
};


/**
 * @brief The RFC4122Version enum
 */
enum RFC4122Version {
  VOID = 0b0000,
  TIME = 0b0001, // The time-based version specified in this document.
  DCE  = 0b0010, // DCE Security version, with embedded POSIX UIDs.
  MD5  = 0b0011, // The name-based version that uses MD5 hashing.
  RAND = 0b0100, // The randomly or pseudo-randomly generated version.
  SHA1 = 0b0101  // The name-based version that uses SHA-1 hashing.
};


/**
 * @brief The Namespace enum
 */
enum Namespace {
  DNS, // the name string is a fully-qualified domain name.
  URL, // the name string is a URL.
  OID, // the name string is an ISO OID.
  X500 // the name string is an X.500 DN in DER or a text output format.
};


/**
 * @brief The NCSFields struct
 */
struct NCSFields {
  uint64_t time : 48;
  uint16_t res;
  uint8_t  family;
  uint64_t node : 56;
}__attribute__((packed));


/**
 * @brief The RFC4122Fields struct
 */
struct RFC4122Fields {
  uint32_t time_low;
  uint16_t time_mid;
  uint16_t time_hi_version;
  uint8_t  clock_seq_hi_variant;
  uint8_t  clock_seq_low;
  uint16_t node_low;
  uint32_t node_high;
}__attribute__((packed));


/**
 * @brief UUID_TICKS_BETWEEK_EPOCH
 * The number of 100 ns ticks between the Gregorian epoch `1582-10-15 00:00:00`
 * and the Unix epoch `1970-01-01 00:00:00`.
 */
static const uint64_t UUID_TICKS_BETWEEK_EPOCH = 122192928000000000;


// extern const std::string NAMESPACE_DNS;
// extern const std::string NAMESPACE_URL;
// extern const std::string NAMESPACE_OID;
// extern const std::string NAMESPACE_X500;


/**
 * @brief The uuid class
 */
class uuid {
public:
  uuid();
  uuid(const uuid&);
  uuid(const uint8_t * raw) : uuid() { fromArray_(raw);    };
  uuid(const char * c_str)   : uuid() { fromCstring_(c_str); };
  uuid(std::string str)     : uuid() { fromString_(str);   };
  ~uuid();

  // accessors
  const uint8_t * bytes()    const { return raw_;       };
        Type      type()     const { return type_;      };
        uint16_t  version()  const { return version_;   };
        uint64_t  time()     const { return timestamp_; };
        uint16_t  sequence() const { return clock_seq_; };
        uint64_t  node()     const { return node_;      };

  // output
  std::string hex() const;   // '12345678123456781234567812345678'
  std::string string() const;// '{12345678-1234-5678-1234-567812345678}'
  std::string urn() const;   // 'urn:uuid:12345678-1234-5678-1234-567812345678'

  // creators
  virtual uint16_t uuid1(uint64_t node, uint16_t clock_seq);
//  virtual void uuid3(Namespace, std::string) {};
  virtual void uuid4();      // very low quality of random
//  virtual void uuid5(Namespace, std::string) {};

  // operator overloads
  uuid& operator= (const uuid& other);
  friend bool operator== (const uuid&, const uuid&);

  // typecast overload
  operator const uint8_t *   () const { return raw_;     };
  operator const std::string () const { return string(); };

private:
  uint8_t* raw_;
  Type     type_;
  uint16_t version_;
  uint64_t timestamp_;
  uint16_t clock_seq_;
  uint64_t node_;

  void fromArray_(const uint8_t *);
  void fromCstring_(const char *);
  void fromString_(std::string);

  void setType_();
  void setBytes_();
  void setNCSBytes_();
  void setRFC4122Bytes_();

  void setFields_();
  void setNCSFields_();
  void setRFC4122Fields_();

  uint64_t now_();
};

} // namespace UUID


namespace std
{
  template<>
  /**
   * @brief The hash struct specialization for UUID::uuid
   */
  struct hash<UUID::uuid>
  {
    /**
     * @brief operator ()
     * @param id
     * @return
     */
    size_t operator()(UUID::uuid const& id) const noexcept
    {
      return std::hash<std::string>{}(id.hex());
    }
  };
} // namespace std