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utils: big_decimal: optimize big_decimal::compare()

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before this change in the worst case, the underlying
`number::compare()` gets called twice. as it is used by Boost::multiprecision
to implement the comparing operators of `number`. but since we can
have the result in one go, there is no need to to perform the
comparison multiple times.

so, in this change, we just call `number::compare()` explicitly,
and use it to implement `compare()`. this should save a call of
`number::compare()`. also, the chained ternary expression is
replaced using if-else statement for better readability.

Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
This commit is contained in:
Kefu Chai
2023-04-12 10:59:21 +08:00
parent c501163f95
commit e991e6087e
1 changed files with 1 additions and 1 deletions
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utils/big_decimal.cc
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@@ -141,7 +141,7 @@ std::strong_ordering big_decimal::compare(const big_decimal& other) const
boost::multiprecision::cpp_int rescale(10);
boost::multiprecision::cpp_int x = _unscaled_value * boost::multiprecision::pow(rescale, max_scale - _scale);
boost::multiprecision::cpp_int y = other._unscaled_value * boost::multiprecision::pow(rescale, max_scale - other._scale);
return x == y ? std::strong_ordering::equal : x < y ? std::strong_ordering::less : std::strong_ordering::greater;
return x.compare(y) <=> 0;
}
big_decimal& big_decimal::operator+=(const big_decimal& other)