[libcxx-commits] [libcxx] [libc++][TZDB] Fixes parsing interleaved rules. (PR #84808)
Mark de Wever via libcxx-commits
libcxx-commits at lists.llvm.org
Mon Mar 11 11:19:14 PDT 2024
https://github.com/mordante created https://github.com/llvm/llvm-project/pull/84808
Typically the rules in the database are contiguous, but that is not a requirement. This fixes the case when they are not.
>From 557788da3adf697a0162c1ae2e7cc186a3d6eb23 Mon Sep 17 00:00:00 2001
From: Mark de Wever <koraq at xs4all.nl>
Date: Mon, 11 Mar 2024 19:15:30 +0100
Subject: [PATCH] [libc++][TZDB] Fixes parsing interleaved rules.
Typically the rules in the database are contiguous, but that is not a
requirement. This fixes the case when they are not.
---
libcxx/src/tzdb.cpp | 27 ++++++++++++++++---
.../time.zone/time.zone.db/rules.pass.cpp | 24 +++++++++++++++++
2 files changed, 47 insertions(+), 4 deletions(-)
diff --git a/libcxx/src/tzdb.cpp b/libcxx/src/tzdb.cpp
index 2bb801e48694ee..49985b870d8525 100644
--- a/libcxx/src/tzdb.cpp
+++ b/libcxx/src/tzdb.cpp
@@ -511,14 +511,33 @@ static string __parse_version(istream& __input) {
return chrono::__parse_string(__input);
}
+[[nodiscard]]
+static __tz::__rule& __create_entry(__tz::__rules_storage_type& __rules, const string& __name) {
+ auto __result = [&]() -> __tz::__rule& {
+ auto& __rule = __rules.emplace_back(__name, vector<__tz::__rule>{});
+ return __rule.second.emplace_back();
+ };
+
+ if (__rules.empty())
+ return __result();
+
+ // Typically rules are in contiguous order in the database.
+ // But there are exceptions. For example, NZ and Chatham are interleaved.
+ if (__rules.back().first == __name)
+ return __rules.back().second.emplace_back();
+
+ if (auto __it = ranges::find(__rules, __name, [](const auto& __r) { return __r.first; });
+ __it != ranges::end(__rules))
+ return __it->second.emplace_back();
+
+ return __result();
+}
+
static void __parse_rule(tzdb& __tzdb, __tz::__rules_storage_type& __rules, istream& __input) {
chrono::__skip_mandatory_whitespace(__input);
string __name = chrono::__parse_string(__input);
- if (__rules.empty() || __rules.back().first != __name)
- __rules.emplace_back(__name, vector<__tz::__rule>{});
-
- __tz::__rule& __rule = __rules.back().second.emplace_back();
+ __tz::__rule& __rule = __create_entry(__rules, __name);
chrono::__skip_mandatory_whitespace(__input);
__rule.__from = chrono::__parse_year(__input);
diff --git a/libcxx/test/libcxx/time/time.zone/time.zone.db/rules.pass.cpp b/libcxx/test/libcxx/time/time.zone/time.zone.db/rules.pass.cpp
index 5ae2ed1e91ebe5..4814f4aad87fbc 100644
--- a/libcxx/test/libcxx/time/time.zone/time.zone.db/rules.pass.cpp
+++ b/libcxx/test/libcxx/time/time.zone/time.zone.db/rules.pass.cpp
@@ -550,6 +550,29 @@ R a 0 1 - Ja Su>=31 1w 2s abc
assert(result.rules[0].second[2].__letters == "abc");
}
+static void test_mixed_order() {
+ // This is a part of the real database. The interesting part is that the
+ // rules NZ and Chatham are interleaved. Make sure the parse algorithm
+ // handles this correctly.
+ parse_result result{
+ R"(
+# Since 1957 Chatham has been 45 minutes ahead of NZ, but until 2018a
+# there was no documented single notation for the date and time of this
+# transition. Duplicate the Rule lines for now, to give the 2018a change
+# time to percolate out.
+Rule NZ 1974 only - Nov Sun>=1 2:00s 1:00 D
+Rule Chatham 1974 only - Nov Sun>=1 2:45s 1:00 -
+Rule NZ 1975 only - Feb lastSun 2:00s 0 S
+Rule Chatham 1975 only - Feb lastSun 2:45s 0 -
+Rule NZ 1975 1988 - Oct lastSun 2:00s 1:00 D
+Rule Chatham 1975 1988 - Oct lastSun 2:45s 1:00 -
+)"};
+
+ assert(result.rules.size() == 2);
+ assert(result.rules[0].second.size() == 3);
+ assert(result.rules[1].second.size() == 3);
+}
+
int main(int, const char**) {
test_invalid();
test_name();
@@ -560,6 +583,7 @@ int main(int, const char**) {
test_at();
test_save();
test_letter();
+ test_mixed_order();
return 0;
}
More information about the libcxx-commits
mailing list