feat: datetime,uuid

include/cpputils/datetime.h

@@ -0,0 +1,65 @@
+#pragma once
+
+#include <chrono>
+#include <cstdint>
+#include <iomanip>
+#include <sstream>
+#include <string>
+
+namespace cpputils {
+namespace datetime {
+
+inline auto print_iso8601_utc(std::chrono::system_clock::time_point tp)
+    -> std::string {
+  time_t t = std::chrono::system_clock::to_time_t(tp);
+  std::tm utc_tm = *std::gmtime(&t);
+  std::ostringstream oss;
+  oss << std::put_time(&utc_tm, "%Y-%m-%dT%H:%M:%SZ");
+  return oss.str();
+};
+
+inline auto print_iso8601_local(std::chrono::system_clock::time_point tp)
+    -> std::string {
+  std::time_t time = std::chrono::system_clock::to_time_t(tp);
+  std::tm local_tm = *std::localtime(&time);
+  std::ostringstream oss;
+  oss << std::put_time(&local_tm, "%Y-%m-%dT%H:%M:%S");
+  return oss.str();
+}
+
+inline int64_t now() {
+  return static_cast<int64_t>(
+      std::chrono::duration_cast<std::chrono::milliseconds>(
+          std::chrono::system_clock::now().time_since_epoch())
+          .count());
+}
+
+inline std::chrono::system_clock::time_point to_time_point(
+    int64_t timestamp_ms) {
+  return std::chrono::system_clock::time_point(
+      std::chrono::milliseconds(timestamp_ms));
+}
+
+inline int64_t to_timestamp(std::chrono::system_clock::time_point tp) {
+  return std::chrono::duration_cast<std::chrono::milliseconds>(
+             tp.time_since_epoch())
+      .count();
+}
+
+inline int64_t to_timestamp_seconds(std::chrono::system_clock::time_point tp) {
+  return std::chrono::duration_cast<std::chrono::seconds>(tp.time_since_epoch())
+      .count();
+}
+
+template <typename Duration>
+inline int64_t add_to_timestamp(int64_t timestamp, Duration duration) {
+  auto time_point = std::chrono::system_clock::time_point(
+      std::chrono::milliseconds(timestamp));
+  time_point += duration;
+  return std::chrono::duration_cast<std::chrono::milliseconds>(
+             time_point.time_since_epoch())
+      .count();
+}
+
+}  // namespace datetime
+}  // namespace cpputils

include/cpputils/uuid.h

@@ -0,0 +1,53 @@
+#pragma once
+
+#include <array>
+#include <atomic>
+#include <cstdint>
+#include <random>
+#include <string>
+
+namespace cpputils {
+namespace uuid {
+
+extern std::string uuidToString(std::array<uint8_t, 16> const& uuid) noexcept;
+
+class V4 {
+ private:
+  std::mt19937_64 rng;
+
+  inline uint64_t random64() { return rng(); }
+
+ public:
+  inline V4() : rng(std::random_device{}()) {}
+
+  std::array<uint8_t, 16> generate();
+};
+
+class V7 {
+
+ private:
+  std::atomic<int64_t> last_timestamp{0};
+  std::atomic<uint8_t> sequence{0};
+  std::mt19937_64 rng;
+
+  inline uint64_t random64() { return rng(); }
+
+  uint8_t next_sequence(int64_t current_timestamp);
+
+ public:
+  inline V7() : rng(std::random_device{}()) {}
+
+  static inline uint64_t get_timestamp_from_uuid(
+      std::array<uint8_t, 16> const& uuid) noexcept {
+    uint64_t timestamp = 0;
+    for (size_t i = 0; i < 6; ++i) {
+      timestamp = (timestamp << 8) | uuid[i];
+    }
+    return timestamp;
+  }
+
+  std::array<uint8_t, 16> generate();
+};
+
+}  // namespace uuid
+}  // namespace cpputils