pitrou commented on code in PR #50616:
URL: https://github.com/apache/arrow/pull/50616#discussion_r3655550514
##########
cpp/src/arrow/compute/kernels/scalar_string_ascii.cc:
##########
@@ -1500,27 +1495,59 @@ std::string MakeLikeRegex(const MatchSubstringOptions&
options) {
return like_pattern;
}
+struct MatchLikeConstants {
+ // NOTE: avoid making those constants global to avoid compiling regexes at
startup
+ RE2::Options regex_options;
+ // A LIKE pattern matching this regex can be translated into a substring
search.
+ RE2 like_pattern_is_substring_match;
+ // A LIKE pattern matching this regex can be translated into a prefix search.
+ RE2 like_pattern_is_starts_with;
+ // A LIKE pattern matching this regex can be translated into a suffix search.
+ RE2 like_pattern_is_ends_with;
+ Status init_status;
+
+ static Result<const MatchLikeConstants*> Instance(bool is_utf8) {
+ static const auto constants = MakeAll();
+ return constants[is_utf8].Map([](const auto& ptr) { return ptr.get(); });
+ }
+
+ private:
+ static Result<std::unique_ptr<MatchLikeConstants>> Make(bool is_utf8) {
+ auto constants = std::unique_ptr<MatchLikeConstants>(new
MatchLikeConstants(is_utf8));
+ if (constants->init_status.ok()) {
+ return constants;
+ } else {
+ return constants->init_status;
+ }
+ }
+
+ static std::array<Result<std::unique_ptr<MatchLikeConstants>>, 2> MakeAll() {
+ return {Make(false), Make(true)};
+ }
+
+ explicit MatchLikeConstants(bool is_utf8)
+ : regex_options(MakeRE2Options(is_utf8)),
+ like_pattern_is_substring_match(R"(%+([^%_]*[^\\%_])?%+)",
regex_options),
Review Comment:
Done.
##########
cpp/src/arrow/compute/kernels/scalar_string_ascii.cc:
##########
@@ -1500,27 +1495,59 @@ std::string MakeLikeRegex(const MatchSubstringOptions&
options) {
return like_pattern;
}
+struct MatchLikeConstants {
+ // NOTE: avoid making those constants global to avoid compiling regexes at
startup
+ RE2::Options regex_options;
+ // A LIKE pattern matching this regex can be translated into a substring
search.
+ RE2 like_pattern_is_substring_match;
+ // A LIKE pattern matching this regex can be translated into a prefix search.
+ RE2 like_pattern_is_starts_with;
+ // A LIKE pattern matching this regex can be translated into a suffix search.
+ RE2 like_pattern_is_ends_with;
+ Status init_status;
Review Comment:
Done.
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