improve AM/PM handling and extend the test cases (#15)

Author: mguludag

include/mgutility/chrono/parse.hpp

@@ -396,7 +396,7 @@ MGUTILITY_CNSTXPR auto parse_timezone_offset(detail::tm &result,
  */
 MGUTILITY_CNSTXPR auto parse_am_pm(detail::tm &result, string_view date_str,
                                    uint32_t &next) -> std::errc {
-  if (next + 2 > date_str.size()) {
+  if (next + 2 > date_str.size() || result.tm_hour < 1 || result.tm_hour > 12) {
     return std::errc::invalid_argument;
   }
   if (date_str.substr(next, 2) == "AM") {

tests/test_chrono_parse.cpp

@@ -10,48 +10,73 @@ auto to_milliseconds(T time_point) -> std::chrono::milliseconds {
   return std::chrono::duration_cast<std::chrono::milliseconds>(time_point.time_since_epoch());
 }
 
-TEST_CASE("testing the iso8601 parsing") {
+TEST_CASE("Basic ISO 8601 Parsing") {
   using std::chrono::milliseconds;
 
   CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T}", "2023-04-30T16:22:18")) == milliseconds(1682871738000));
+  CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T}", "2022-12-31T23:59:59")) == milliseconds(1672531199000));
+  CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T}", "2023-01-01T00:00:00")) == milliseconds(1672531200000));
+  CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T}", "2023-05-01T00:00:00")) == milliseconds(1682899200000));
+}
+
+TEST_CASE("Timezone Offset Handling") {
+  using std::chrono::milliseconds;
+
   CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T%z}", "2023-04-30T16:22:18Z")) == milliseconds(1682871738000));
   CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T%z}", "2023-04-30T18:22:18+0200")) == milliseconds(1682871738000));
   CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T%z}", "2023-04-30T16:22:18-0200")) == milliseconds(1682878938000));
-  CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T.%f}", "2023-04-30T16:22:18.500")) == milliseconds(1682871738500));
-  CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T.%f%z}", "2023-04-30T16:22:18.500+0100")) == milliseconds(1682868138500));
-
-  REQUIRE_THROWS(mgutility::chrono::parse("{:%FT%T", "2023-04-30T16:22:18"));
-  REQUIRE_THROWS(mgutility::chrono::parse("%FT%T}", "2023-04-30T16:22:18"));
-  REQUIRE_THROWS(mgutility::chrono::parse("{%F %T}", "2023-04-30T16:22:18"));
-  REQUIRE_THROWS(mgutility::chrono::parse("{:%F %T}", "2023-04-30T16:22:18"));
-
+  CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T%z}", "2016-02-29T05:00:00-0000")) == milliseconds(1456722000000));
+  CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T%z}", "2016-02-29T23:59:59+0000")) == milliseconds(1456790399000));
+  CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T%z}", "2016-02-29T12:00:00-1200")) == milliseconds(1456790400000));
+}
 
-  // Leap year: Feb 29 should work in a leap year
-CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T}", "2020-02-29T12:00:00")) == milliseconds(1582977600000));
+TEST_CASE("AM/PM Handling") {
+  using std::chrono::milliseconds;
 
-// Non-leap year: Feb 29 should not exist
-REQUIRE_THROWS(mgutility::chrono::parse("{:%FT%T}", "2021-02-29T12:00:00"));
+  CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%H:%M:%S %p}", "2023-04-30T12:00:00 AM")) == milliseconds(1682812800000));
+  CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%H:%M:%S %p}", "2023-04-30T12:00:00 PM")) == milliseconds(1682856000000));
+  CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%H:%M:%S %p}", "2023-04-30T11:59:59 PM")) == milliseconds(1682899199000));
+  CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%H:%M:%S %p}", "2023-04-30T01:00:00 AM")) == milliseconds(1682816400000));
+  CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%H:%M:%S %p}", "2023-04-30T01:00:00 PM")) == milliseconds(1682859600000));
+}
 
-// Leap year, with timezone offset: UTC should equal local time with -0000
-CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T%z}", "2016-02-29T05:00:00-0000")) == milliseconds(1456722000000));
+TEST_CASE("Fractional Seconds") {
+  using std::chrono::milliseconds;
 
-// February 28 + 1 day (should rollover to Mar 1 on non-leap year)
-CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T}", "2021-03-01T00:00:00")) == milliseconds(1614556800000));
+  CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T.%f}", "2023-04-30T16:22:18.1")) == milliseconds(1682871738100)); // 100ms
+  CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T.%f}", "2023-04-30T16:22:18.123")) == milliseconds(1682871738123)); // 123ms
+  CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T.%f}", "2023-04-30T16:22:18.123456")) == milliseconds(1682871738123)); // 123ms (truncated)
+}
 
-// Year rollover: Dec 31 to Jan 1
-CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T}", "2022-12-31T23:59:59")) == milliseconds(1672531199000));
-CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T}", "2023-01-01T00:00:00")) == milliseconds(1672531200000));
+TEST_CASE("Combined AM/PM, Fractional Seconds, and Timezone") {
+  using std::chrono::milliseconds;
 
-// Month boundary rollover: Apr 30 + 1 day == May 1
-CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T}", "2023-05-01T00:00:00")) == milliseconds(1682899200000));
+  CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T.%f %p}", "2023-04-30T11:59:59.500 PM")) == milliseconds(1682899199500));
+  CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T.%f %p}", "2023-04-30T01:20:00.123 AM")) == milliseconds(1682817600123));
+  CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T.%f %p %z}", "2023-04-30T11:59:59.500 PM +0100")) == milliseconds(1682895599500));
+  CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T.%f %p %z}", "2023-04-30T01:20:00.123 AM -0200")) == milliseconds(1682824800123));
+  CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T %p %z}", "2023-04-30T01:20:00 PM +0200")) == milliseconds(1682853600000));
+  CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T %p %z}", "2023-04-30T01:20:00 AM -0200")) == milliseconds(1682824800000));
+}
 
-// Invalid date: April 31
-REQUIRE_THROWS(mgutility::chrono::parse("{:%FT%T}", "2023-04-31T12:00:00"));
+TEST_CASE("Leap Year and Date Boundaries") {
+  using std::chrono::milliseconds;
 
-// Edge timezone: Feb 29 with offset
-CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T%z}", "2016-02-29T23:59:59+0000")) == milliseconds(1456790399000));
-CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T%z}", "2016-02-29T12:00:00-1200")) == milliseconds(1456790400000));
+  CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T}", "2020-02-29T12:00:00")) == milliseconds(1582977600000)); // Leap year
+  CHECK(to_milliseconds(mgutility::chrono::parse("{:%FT%T}", "2021-03-01T00:00:00")) == milliseconds(1614556800000)); // Feb 28 + 1 day
+}
 
-// Invalid date/time format
-REQUIRE_THROWS(mgutility::chrono::parse("{:%FT%T}", "not-a-date"));
+TEST_CASE("Error Handling") {
+  REQUIRE_THROWS(mgutility::chrono::parse("{:%FT%T", "2023-04-30T16:22:18")); // Malformed format
+  REQUIRE_THROWS(mgutility::chrono::parse("%FT%T}", "2023-04-30T16:22:18")); // Malformed format
+  REQUIRE_THROWS(mgutility::chrono::parse("{%F %T}", "2023-04-30T16:22:18")); // Malformed format
+  REQUIRE_THROWS(mgutility::chrono::parse("{:%F %T}", "2023-04-30T16:22:18")); // Format mismatch
+  REQUIRE_THROWS(mgutility::chrono::parse("{:%FT%T}", "2021-02-29T12:00:00")); // Invalid date (non-leap year)
+  REQUIRE_THROWS(mgutility::chrono::parse("{:%FT%T}", "2023-04-31T12:00:00")); // Invalid date (April 31)
+  REQUIRE_THROWS(mgutility::chrono::parse("{:%FT%T}", "not-a-date")); // Invalid format
+  REQUIRE_THROWS(mgutility::chrono::parse("{:%FT%H:%M:%S %p}", "2023-04-30T13:00:00 AM")); // Hour > 12
+  REQUIRE_THROWS(mgutility::chrono::parse("{:%FT%H:%M:%S %p}", "2023-04-30T12:00:00 XM")); // Invalid AM/PM
+  REQUIRE_THROWS(mgutility::chrono::parse("{:%FT%H:%M:%S %p}", "2023-04-30T12:00:00")); // Missing AM/PM
+  REQUIRE_THROWS(mgutility::chrono::parse("{:%FT%T.%f}", "2023-04-30T16:22:18.")); // No digits after decimal
+  REQUIRE_THROWS(mgutility::chrono::parse("{:%FT%T.%f}", "2023-04-30T16:22:18.A")); // Invalid fraction
 }