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-rw-r--r--absl/time/internal/cctz/include/cctz/civil_time_detail.h38
1 files changed, 34 insertions, 4 deletions
diff --git a/absl/time/internal/cctz/include/cctz/civil_time_detail.h b/absl/time/internal/cctz/include/cctz/civil_time_detail.h
index bb191b3f..3e243403 100644
--- a/absl/time/internal/cctz/include/cctz/civil_time_detail.h
+++ b/absl/time/internal/cctz/include/cctz/civil_time_detail.h
@@ -555,13 +555,43 @@ CONSTEXPR_F weekday get_weekday(const civil_day& cd) noexcept {
////////////////////////////////////////////////////////////////////////
CONSTEXPR_F civil_day next_weekday(civil_day cd, weekday wd) noexcept {
- do { cd += 1; } while (get_weekday(cd) != wd);
- return cd;
+ CONSTEXPR_D weekday k_weekdays_forw[14] = {
+ weekday::monday, weekday::tuesday, weekday::wednesday,
+ weekday::thursday, weekday::friday, weekday::saturday,
+ weekday::sunday, weekday::monday, weekday::tuesday,
+ weekday::wednesday, weekday::thursday, weekday::friday,
+ weekday::saturday, weekday::sunday,
+ };
+ weekday base = get_weekday(cd);
+ for (int i = 0;; ++i) {
+ if (base == k_weekdays_forw[i]) {
+ for (int j = i + 1;; ++j) {
+ if (wd == k_weekdays_forw[j]) {
+ return cd + (j - i);
+ }
+ }
+ }
+ }
}
CONSTEXPR_F civil_day prev_weekday(civil_day cd, weekday wd) noexcept {
- do { cd -= 1; } while (get_weekday(cd) != wd);
- return cd;
+ CONSTEXPR_D weekday k_weekdays_back[14] = {
+ weekday::sunday, weekday::saturday, weekday::friday,
+ weekday::thursday, weekday::wednesday, weekday::tuesday,
+ weekday::monday, weekday::sunday, weekday::saturday,
+ weekday::friday, weekday::thursday, weekday::wednesday,
+ weekday::tuesday, weekday::monday,
+ };
+ weekday base = get_weekday(cd);
+ for (int i = 0;; ++i) {
+ if (base == k_weekdays_back[i]) {
+ for (int j = i + 1;; ++j) {
+ if (wd == k_weekdays_back[j]) {
+ return cd - (j - i);
+ }
+ }
+ }
+ }
}
CONSTEXPR_F int get_yearday(const civil_day& cd) noexcept {