fix: correct fractional seconds normalization in RFC3339 parser - #242
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vlastahajek merged 1 commit intoJun 9, 2026
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In convertRfc3339(), the intent was to normalize a sub-6-digit fractional seconds value to microseconds by multiplying by a power of 10. The code used the ^ operator for this, which in C++ is bitwise XOR - not exponentiation. There is no exponentiation operator in C++. This caused incorrect microsecond values for any RFC3339 timestamp with fewer than 6 fractional digits. The most common real-world case is 3-digit millisecond precision (e.g. '2020-02-18T10:34:08.135Z'), where the multiplier becomes 10 XOR 3 = 9 instead of 1000, producing a result roughly 111x too small. Timestamps with 6 digits (microseconds) or 7-9 digits (nanoseconds, truncated to 6 before this branch) are not affected. The struct tm fields (year, month, day, hour, minute, second) are parsed separately by sscanf and are always correct. Only the sub-second microseconds field is affected. Fix: replace the single XOR expression with an explicit multiply loop, which avoids pulling in <math.h> for pow() and keeps the arithmetic integer throughout.
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In convertRfc3339(), the intent was to normalize a sub-6-digit fractional seconds value to microseconds by multiplying by a power of 10. The code used the ^ operator for this, which in C++ is bitwise XOR - not exponentiation. There is no exponentiation operator in C++.
This caused incorrect microsecond values for any RFC3339 timestamp with fewer than 6 fractional digits. The most common real-world case is 3-digit millisecond precision (e.g. '2020-02-18T10:34:08.135Z'), where the multiplier becomes 10 XOR 3 = 9 instead of 1000, producing a result roughly 111x too small.
Timestamps with 6 digits (microseconds) or 7-9 digits (nanoseconds, truncated to 6 before this branch) are not affected.
The struct tm fields (year, month, day, hour, minute, second) are parsed separately by sscanf and are always correct. Only the sub-second microseconds field is affected.
Proposed Changes
replace the single XOR expression with an explicit multiply loop, which avoids pulling in <math.h> for pow() and keeps the arithmetic integer throughout.
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