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Niels Lohmann
447df43650
The previous commit made get_unchecked strongly exception safe but slower with GCC 16 when it creates values (up to +6 % instructions for appending with "-"). This restructures it so that no benchmark row is slower than before the strong guarantee, with GCC 16, Clang 22 and Apple Clang. - get_unchecked walks existing values in one loop that inserts nothing. The last reference token is resolved in that walk: "-" appends with emplace_back(), an index grows the array with operator[], and a missing key is inserted with emplace_hint() at the position the walk's lower_bound() found, so the key is searched once. - With std::less<string_t> or std::less<> as comparator, the walk checks the key at the lower bound for equality instead of equivalence, which is the same for these comparators and cheaper. - get_unchecked_create (not inlined) handles all other changes. Its guard swaps a null value with a fresh null value instead of copying it and reverts the change in a non-inlined function, so a successful call pays one compare for it. As every null value converted afterwards is a fresh one, it is converted in place instead of assigning a new array or object. - Keys are added to new objects with emplace(), which also replaces the basic_json::operator[] call for ordered_json. Signed-off-by: Niels Lohmann <mail@nlohmann.me>