ianmcook commented on code in PR #50146:
URL: https://github.com/apache/arrow/pull/50146#discussion_r4201355635
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cpp/src/arrow/csv/converter.cc:
##########
@@ -464,18 +472,93 @@ struct MultipleParsersTimestampValueDecoder : public
ValueDecoder {
}
protected:
- using ParserVector = std::vector<const TimestampParser*>;
+ TimeUnit::type unit_;
+ bool expect_timezone_;
+ std::vector<const TimestampParser*> parsers_;
+};
- static ParserVector GetParsers(const ConvertOptions& options) {
- ParserVector parsers(options.timestamp_parsers.size());
- for (size_t i = 0; i < options.timestamp_parsers.size(); ++i) {
- parsers[i] = options.timestamp_parsers[i].get();
+//
+// Value decoder for dates and times, with fallback to user-defined
+// timestamp parsers
+//
+
+// Tries the ISO-8601 format first, then the user-defined timestamp parsers.
+// A timestamp produced by a user-defined parser is floored to the day
+// boundary for dates, and reduced to the time of day for times (consistent
+// with casting a timestamp to date32/date64/time32/time64).
+template <typename T>
+struct DateTimeWithParsersValueDecoder : public ValueDecoder {
+ using value_type = typename T::c_type;
+
+ DateTimeWithParsersValueDecoder(const std::shared_ptr<DataType>& type,
+ const ConvertOptions& options,
+ const TrieCache* trie_cache)
+ : ValueDecoder(type, options, trie_cache),
+ concrete_type_(checked_cast<const T&>(*type)),
+ parse_unit_(GetParseUnit(concrete_type_)),
+ ticks_per_day_(TicksPerDay(parse_unit_)),
+ parsers_(GetTimestampParsers(options_)) {}
+
+ Status Decode(const uint8_t* data, uint32_t size, bool quoted, value_type*
out) {
+ TrimWhiteSpace(&data, &size);
+ if (ARROW_PREDICT_TRUE(string_converter_.Convert(
+ concrete_type_, reinterpret_cast<const char*>(data), size, out))) {
+ return Status::OK();
+ }
+ for (const auto& parser : parsers_) {
+ int64_t timestamp = 0;
+ bool zone_offset_present = false;
+ if (parser->operator()(reinterpret_cast<const char*>(data), size,
parse_unit_,
+ ×tamp, &zone_offset_present) &&
+ !zone_offset_present) {
+ // Floor division, to handle values before the epoch
+ int64_t days = timestamp / ticks_per_day_;
+ days -= (timestamp % ticks_per_day_) < 0;
+ if constexpr (std::is_same_v<T, Date32Type>) {
+ *out = static_cast<value_type>(days);
+ } else if constexpr (std::is_same_v<T, Date64Type>) {
+ *out = days * kMillisPerDay;
+ } else {
+ static_assert(is_time_type<T>::value);
+ *out = static_cast<value_type>(timestamp - days * ticks_per_day_);
Review Comment:
The date branches in this block need bounds checks too. With a custom C++
`TimestampParser` that reads integer epoch seconds, I reproduced two additional
cases:
- For `date32`, `185542587187200` seconds corresponds to `2147483648` days.
The unchecked cast silently wraps this to `-2147483648`.
- For `date64`, `INT64_MAX` seconds triggers a UBSan signed-overflow error
in `days * kMillisPerDay`.
Both should return a conversion error because the result is outside the
target type’s range.
Could we also check `days` against the `int32_t` bounds before narrowing to
`date32`, and use checked multiplication for `date64`? The normalized-remainder
change suggested above addresses the time branch, but these date branches need
separate checks.
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