[jira] [Created] (GEODE-8756) CacheableString objectSize is not correct

["Mario Salazar de Torres (Jira)" <ji...@apache.org>]

Mario Salazar de Torres created GEODE-8756:
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             Summary: CacheableString objectSize is not correct
                 Key: GEODE-8756
                 URL: https://issues.apache.org/jira/browse/GEODE-8756
             Project: Geode
          Issue Type: Sub-task
          Components: native client
    Affects Versions: 1.13.1, 1.13.0, 1.12.0, 1.11.0
            Reporter: Mario Salazar de Torres


CacheableString objectSize function is returning an incorrect value.
This class is based upon STL's string implementation, and most of the compilers implementations apply what's called SSO.

What SSO basically does is if the string occupies less than a certain amount, no extra memory would be allocated in the heap, and the character-sequence would be stored in the object itself. This is typically achieved by using union semantics.
Right now if SSO applies, objectSize calculates the size of std::string as sizeof(std::string) + m_str.capacity(), which is more than it actually occupies.

On the other hand starting C++11 STL's strings needs to allocate an extra character
to keep the null-terminator in the same buffer as the actual string. This is specified in section § 21.4.7.1 within the C++11 standard.
Because of this objectSize should take the null-terminator into account, which was not the case.



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