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https://issues.apache.org/jira/browse/QUICKSTEP-53?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15469286#comment-15469286
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ASF GitHub Bot commented on QUICKSTEP-53:
-----------------------------------------
Github user hakanmemisoglu commented on a diff in the pull request:
https://github.com/apache/incubator-quickstep/pull/98#discussion_r77751465
--- Diff: types/DatetimeLit.hpp ---
@@ -51,53 +54,70 @@ struct DateLit {
+ 1 // -
+ 2; // Day
+ // Years should be between [-kMaxYear, +kMaxYear] inclusive both end.
+ static constexpr std::int32_t kMaxYear = 99999;
+ static constexpr std::uint8_t kBitsNeededForDay = 5u;
+ static constexpr std::uint8_t kBitsNeededForMonth = 4u;
+
static DateLit Create(const std::int32_t _year,
const std::uint8_t _month,
const std::uint8_t _day) {
DateLit date;
- date.year = _year;
- date.month = _month;
- date.day = _day;
+ // Normalize year by adding kMaxYear value, because we try to
+ // encode signed year value into an unsigned integer.
--- End diff --
**L125** `std::int32_t result_year = lhs.yearField() + (rhs.months / 12);`
**L126** `std::uint8_t result_month =
static_cast<std::uint8_t>(lhs.monthField()) + (rhs.months % 12);`
**L134** `ClampDayOfMonth(result_year, result_month, lhs.dayField()));`
- Access to the struct happens via these methods (yearField(), monthField()
etc...) that decodes from representation (normalized and shifted) to the year
value (which is -2000 in your example).
- After the operation + is done, and the check is applied.
- The result year, month, day is calculated and given to `DateLit::Create()`
- `DateLit::Create()`encodes the real values to the unified representation.
I might be missing something, but does the execution above make sense?
> New representation and faster comparison operators for DateLit
> --------------------------------------------------------------
>
> Key: QUICKSTEP-53
> URL: https://issues.apache.org/jira/browse/QUICKSTEP-53
> Project: Apache Quickstep
> Issue Type: Improvement
> Components: Types
> Reporter: Hakan Memisoglu
> Assignee: Hakan Memisoglu
>
> DateLit structure contains 3 member:
> 32i for year,
> 8u for month,
> 8u for day.
> Instead we can put all year, month, and day information into 32u. It will
> benefit from having a smaller sized representation.
> The new representation also provide faster comparison operator by directly
> using 32u comparison operators that have corresponding assembly primitives
> (instead of using if else branches).
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