diff --git a/src/include/utils.h b/src/include/utils.h
index 4c21022..028de36 100644
--- a/src/include/utils.h
+++ b/src/include/utils.h
@@ -3,6 +3,7 @@
 #include <cstdint>
 #include <string>
 #include <string_view>
+#include <utility>
 typedef uint64_t hash_t;
 inline hash_t SplitMix64Hash(const std::string &str) noexcept {
   // constexpr static char salt1[10] = "mL;]-=eT";
@@ -12,7 +13,8 @@ inline hash_t SplitMix64Hash(const std::string &str) noexcept {
   // str = salt1 + str + salt2;
   hash_t ret = 0;
   int i = 0;
-  for (; i + 8 <= str.length(); i += 8) {
+  size_t len = str.length();
+  for (; i + 8 <= len; i += 8) {
     ret ^= *reinterpret_cast<const hash_t *>(str.c_str() + i);
     ret ^= *reinterpret_cast<const hash_t *>(inner_salt + (i & 15));
     ret += 0x9e3779b97f4a7c15;
@@ -20,7 +22,7 @@ inline hash_t SplitMix64Hash(const std::string &str) noexcept {
     ret = (ret ^ (ret >> 27)) * 0x94d049bb133111eb;
     ret ^= ret >> 31;
   }
-  for (; i < str.length(); ++i) {
+  for (; i < len; ++i) {
     ret ^= str[i];
     ret ^= inner_salt[i & 15];
     ret += 0x9e3779b97f4a7c15;
@@ -38,7 +40,8 @@ inline hash_t SplitMix64Hash(const std::string_view &str) noexcept {
   // str = salt1 + str + salt2;
   hash_t ret = 0;
   int i = 0;
-  for (; i + 8 <= str.length(); i += 8) {
+  size_t len = str.length();
+  for (; i + 8 <= len; i += 8) {
     ret ^= *reinterpret_cast<const hash_t *>(str.data() + i);
     ret ^= *reinterpret_cast<const hash_t *>(inner_salt + (i & 15));
     ret += 0x9e3779b97f4a7c15;
@@ -46,7 +49,7 @@ inline hash_t SplitMix64Hash(const std::string_view &str) noexcept {
     ret = (ret ^ (ret >> 27)) * 0x94d049bb133111eb;
     ret ^= ret >> 31;
   }
-  for (; i < str.length(); ++i) {
+  for (; i < len; ++i) {
     ret ^= str[i];
     ret ^= inner_salt[i & 15];
     ret += 0x9e3779b97f4a7c15;
@@ -56,4 +59,70 @@ inline hash_t SplitMix64Hash(const std::string_view &str) noexcept {
   }
   return ret;
 }
+
+/**
+ * Note that in our system, all the dates are within the year 2024.
+ */
+inline std::pair<uint8_t, uint8_t> RetrieveReadableDate(int day_id) {
+  // the day_id is 0-based, that is, 2024-01-01 is day 0.
+  // clang-format off
+  static const uint8_t month_lookup[366] = {
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+    2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+    3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
+    4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
+    5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
+    6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
+    7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+    8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+    9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
+    10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10,
+    11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11,
+    12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12
+  };
+
+  static const uint8_t day_lookup[366] = {
+    1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
+    1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
+    1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
+    1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30,
+    1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
+    1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30,
+    1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
+    1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
+    1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30,
+    1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
+    1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30,
+    1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31
+  };
+  // clang-format on
+
+  return std::make_pair(month_lookup[day_id], day_lookup[day_id]);
+}
+
+inline int GetCompactDate(int month, int day) {
+  // the day_id is 0-based, that is, 2024-01-01 is day 0.
+  // clang-format off
+  static const int lookup[12] = {
+    0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335
+  };
+  // clang-format on
+  return lookup[month - 1] + day - 1;
+}
+
+inline void RetrieveReadableTimeStamp(int full_time_stamp, int &month, int &day, int &hour, int &minute) {
+  int day_id = full_time_stamp / 1440;
+  int minute_id = full_time_stamp % 1440;
+  std::pair<uint8_t, uint8_t> date = RetrieveReadableDate(day_id);
+  month = date.first;
+  day = date.second;
+  hour = minute_id / 60;
+  minute = minute_id % 60;
+}
+
+
+inline int GetFullTimeStamp(int month, int day, int hour, int minute) {
+  int day_id = GetCompactDate(month, day);
+  return day_id * 1440 + hour * 60 + minute;
+}
 #endif
\ No newline at end of file
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 02b52e9..56c0b49 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -23,4 +23,5 @@ if(ENABLE_ADVANCED_FEATURE)
   add_executable(snapshot_test snapshot_test.cpp)
   target_link_libraries(snapshot_test storage dataguard GTest::gtest_main spdlog::spdlog)
 endif()
-add_executable(hash_collision_test hash_collision_test.cpp)
\ No newline at end of file
+add_executable(hash_collision_test hash_collision_test.cpp)
+add_executable(utils_test utils_test.cpp)
\ No newline at end of file
diff --git a/test/utils_test.cpp b/test/utils_test.cpp
new file mode 100644
index 0000000..e6a265b
--- /dev/null
+++ b/test/utils_test.cpp
@@ -0,0 +1,25 @@
+#include "../src/include/utils.h"
+#include <cassert>
+#include <iostream>
+int main() {
+  int time_stamp = 0;
+  for (int i = 0; i <= 365; i++) {
+    std::pair<int, int> date = RetrieveReadableDate(i);
+    std::cout << i << " " << date.first << " " << date.second << std::endl;
+    assert(GetCompactDate(date.first, date.second) == i);
+    for (int j = 0; j < 1440; j++) {
+      int std_hour = j / 60;
+      int std_minute = j % 60;
+      int out_month, out_day, out_hour, out_minute;
+      assert(time_stamp == i * 1440 + j);
+      RetrieveReadableTimeStamp(time_stamp, out_month, out_day, out_hour, out_minute);
+      assert(out_month == date.first);
+      assert(out_day == date.second);
+      assert(out_minute == std_minute);
+      assert(out_hour == std_hour);
+      assert(GetFullTimeStamp(out_month, out_day, out_hour, out_minute) == time_stamp);
+      time_stamp++;
+    }
+  }
+  return 0;
+}
\ No newline at end of file