[GitHub] [arrow] cyb70289 commented on a change in pull request #10823: ARROW-9948: [C++] Fix scale handling in Decimal{128, 256}::FromString

[GitBox <gi...@apache.org>]

cyb70289 commented on a change in pull request #10823:
URL: https://github.com/apache/arrow/pull/10823#discussion_r679593402



##########
File path: cpp/src/arrow/util/decimal.cc
##########
@@ -528,29 +527,33 @@ Status Decimal128::FromString(const util::string_view& s, Decimal128* out,
   int32_t parsed_scale = 0;
   if (dec.has_exponent) {
     auto adjusted_exponent = dec.exponent;
-    auto len = static_cast<int32_t>(significant_digits);
-    parsed_scale = -adjusted_exponent + len - 1;
+    parsed_scale =
+        -adjusted_exponent + static_cast<int32_t>(dec.fractional_digits.size());
   } else {
     parsed_scale = static_cast<int32_t>(dec.fractional_digits.size());
   }
 
   if (out != nullptr) {
-    std::array<uint64_t, 2> little_endian_array = {0, 0};
+    static_assert(Decimal::kBitWidth % 64 == 0, "decimal bit-width not a multiple of 64");
+    std::array<uint64_t, Decimal::kBitWidth / 64> little_endian_array = {0, 0};

Review comment:
       Maybe an empty `{}` is okay?
   I never understand how c++ zero-initialization really works.




-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: github-unsubscribe@arrow.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org