Merge pull request #13 from bxparks/develop

0.7 - support DST transitions at 00:01; validate against Hinnant date library; upgrade to TZ 2019b

Author: bxparks

CHANGELOG.md

@@ -1,6 +1,29 @@
 # Changelog
 
 * Unreleased
+* 0.7
+    * Change TimeZoneData to store mStdOffset and mDstOffset in units of
+      one minute (instead of 15-minute increments, "code") in the off chance
+      that the library supports timezones with one-minute shifts in the future.
+    * Implement TimeOffset using 2 bytes (`int16_t`) instead of one byte
+      (`int8_t`) to give it a resolution of one minute instead of 15 minutes.
+    * Generate zoneinfo files containing AT and UNTIL timestamps with
+      one-minute resolution (instead of 15-minute resolution). ZoneInfo files
+      (`zonedb/` and `zonedbx/`) remain identical in size. Flash memory
+      consumption usually increases by 130 to 500 bytes, but sometimes decreases
+      by 50-100 bytes. Timezones whose DST transitions occur at 00:01
+      (America/Goose_Bay, America/Moncton, America/St_Johns, Asia/Gaza,
+      Asia/Hebron) no longer truncate to 00:00.
+    * Rename `TimeOffset::forHour()` to `forHours()` for consistency with
+      `forMinutes()`.
+    * Make `ExtendedZoneProcessor` more memory efficient for 32-bit processors
+      by packing internal fields to 4-byte boundaries.
+    * Integrate C++11/14/17
+      [Hinnant Date](https://github.com/HowardHinnant/date) library by
+      creating additional `tests/validation` tests.
+    * Upgrade `zonedb` and `zonedbx` zoneinfo files to version 2019b,
+      after validating against the Hinnant date library.
+    * Upgrade to `pytz` version 2019.2 to pickup TZ Database 2019b.
 * 0.6.1
     * Create a second Jenkins continuous build pipeline file
       `tests/JenskinfileUnitHost` to use UnitHostDuino to run the unit tests

README.md

@@ -15,8 +15,8 @@ The AceTime classes are organized into roughly 4 bundles, placed in different
 C++ namespaces:
 
 * date and time classes and types
-    * `ace_time::DateStrings`
     * `ace_time::acetime_t`
+    * `ace_time::DateStrings`
     * `ace_time::LocalTime`
     * `ace_time::LocalDate`
     * `ace_time::LocalDateTime`
@@ -116,16 +116,22 @@ The library provides 2 sets of zoneinfo files created from the IANA TZ Database:
   the TZ Database (essentially the entire database) intended to be used with
   the `ExtendedZoneProcessor` class.
 
-These zoneinfo files (and the `ZoneProcessor` classes which calculate the UTC
-offsets and DST transitions) have been validated to match the UTC offsets
-calculated using the Python [pytz](https://pypi.org/project/pytz/) library from
-the year 2000 until 2037 (inclusive), and using the [Java 11
-Time](https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/time/package-summary.html)
-library from year 2000 to 2049 (inclusive). Custom datasets with smaller or
-larger range of years may be generated by developers using scripts provided in
-this library (although this is not documented currently). The target application
-may be compiled against the custom dataset instead of using `zonedb::` and
-`zonedbx::` zone files provided in this library.
+These zoneinfo files and the algorithms in this library have been validated to
+match the UTC offsets calculated using 3 other date/time libraries:
+
+* the Python [pytz](https://pypi.org/project/pytz/) library from
+  the year 2000 until 2037 (inclusive),
+* the Java JDK 11
+  [java.time](https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/time/package-summary.html)
+  library from year 2000 to 2049 (inclusive),
+* the C++11/14/17 [Hinnant date](https://github.com/HowardHinnant/date) libary
+  from year 2000 to 2049 (inclusive).
+
+Custom datasets with smaller or larger range of years may be generated by
+developers using scripts provided in this library (although this is not
+documented currently). The target application may be compiled against the custom
+dataset instead of using `zonedb::` and `zonedbx::` zone files provided in this
+library.
 
 It is expected that most applications using AceTime will use only a small number
 of timezones at the same time (1 to 3 zones have been extensively tested) and
@@ -198,9 +204,11 @@ Conversion from an epochSeconds to date-time components including timezone
 * 2.8 microseconds on an ESP32,
 * 6 microseconds on a Teensy 3.2.
 
-**Version**: 0.6.1 (2019-08-07, TZ DB version 2019a, beta)
+**Version**: 0.7 (2019-08-13, TZ DB version 2019b, beta)
 
-**Status**: Stable, no major refactoring planned. Expected to go to 1.0 soon.
+**Status**: Upgraded to latest TZ DB version 2019b. Validated against 3
+other timezone libraries (Python, Java, C++). See [CHANGELOG.md](CHANGELOG.md)
+for more details. API quite stable now.
 
 ## Examples