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tzdb.cpp: Fall back to numeric offset when the current code page cannot represent the time zone short ID #5558

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Merged
merged 3 commits into from
Jun 14, 2025
Merged

tzdb.cpp: Fall back to numeric offset when the current code page cannot represent the time zone short ID #5558

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ed5992c
`tzdb.cpp`: Fall back to numeric offset when time zone short ID isn't…
cpplearner May 31, 2025
751f4b7
Use `unique_ptr` to hold `_Fallback_abbrev`.
StephanTLavavej Jun 3, 2025
98ecee3
Allocate exactly 4 or 6 chars.
StephanTLavavej Jun 3, 2025
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26 changes: 25 additions & 1 deletion stl/src/tzdb.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -567,7 +567,31 @@ void __stdcall __std_tzdb_delete_current_zone(__std_tzdb_current_zone_info* cons

_Info->_Abbrev = _Allocate_wide_to_narrow(_Abbrev.get(), _Abbrev_len, _Info->_Err);
if (_Info->_Abbrev == nullptr) {
return _Propagate_error(_Info);
const auto _Abs_offset = _Info->_Offset < 0 ? -_Info->_Offset : _Info->_Offset;
const auto _Offset_in_minutes = _Abs_offset / (60 * 1000);
const auto _Hours = _Offset_in_minutes / 60;
const auto _Mins = _Offset_in_minutes % 60;

_STD unique_ptr<char[]> _Fallback_abbrev{new (_STD nothrow) char[_Mins == 0 ? 4 : 6]};

if (_Fallback_abbrev == nullptr) {
return nullptr;
}

_Fallback_abbrev[0] = _Info->_Offset < 0 ? '-' : '+';
_Fallback_abbrev[1] = static_cast<char>('0' + _Hours / 10);
_Fallback_abbrev[2] = static_cast<char>('0' + _Hours % 10);

if (_Mins == 0) {
_Fallback_abbrev[3] = '\0';
} else {
_Fallback_abbrev[3] = static_cast<char>('0' + _Mins / 10);
_Fallback_abbrev[4] = static_cast<char>('0' + _Mins % 10);
_Fallback_abbrev[5] = '\0';
}

_Info->_Err = __std_tzdb_error::_Success;
_Info->_Abbrev = _Fallback_abbrev.release();
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Sorry for commenting after a merge, but does this release() call means we are leaking memory?

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We aren't leaking memory. The returned __std_tzdb_sys_info* will be stored in a unique_ptr<__std_tzdb_sys_info, _Tzdb_deleter<__std_tzdb_sys_info>>, which will call __std_tzdb_delete_sys_info in its destructor, which will perform delete[] _Info->_Abbrev;

}

return _Info.release();
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