ULID (Universally Unique Lexicographically Sortable Identifier)

A header-only C++20 implementation of ULID.

ULIDs are 128-bit identifiers that combine a timestamp with random data to create identifiers that are:

• Lexicographically sortable
• URL-safe
• Globally unique
• Human-readable

Features

• Header-only implementation
• Simple API
• Thread-safe
• Time-based ordering
• Optional OpenSSL support for better entropy
• Boost compatibility (via boost::uuids)

Requirements

• C++20 compatible compiler
• CMake 3.21+ (for building)
• OpenSSL (optional)
• Boost (optional)

Installation

Using CMake

git clone https://github.com/yourusername/ulid.git
cd ulid
cmake --preset release
cmake --build ./build
cmake --install ./build

Using in Your Code

#include "ulid.h"

int main() {
    // Create a ULID with current timestamp and random entropy
    ulid::ULID id = ulid::CreateNowRand();

    // Convert to string representation
    std::string str = ulid::Marshal(id);
    std::cout << "ULID: " << str << std::endl;

    // Get timestamp from ULID
    auto time_point = ulid::Time(id);
    auto time_t = std::chrono::system_clock::to_time_t(time_point);
    std::cout << "Timestamp: " << std::ctime(&time_t);

    // Convert to UUID (for database storage)
    boost::uuids::uuid uuid = ulid::MarshalUuid(id);

    // Convert back from UUID to ULID
    ulid::ULID id_from_uuid = ulid::UnmarshalBinary(uuid);

    return 0;
}

Credits

Initial Library by Suyash https://github.com/suyash/ulid Fix made to use milliseconds correctly by ChrisBove https://github.com/ChrisBove/ulid