[C++] Improve whitespace escaping #3413
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mike-lischke
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@parrt A C++ patch ready for merge. |
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replaceAllis the only function left and its usage is inefficient as its only use case is escaping whitespace. The current usage involves scanning the string 3 times. If any whitespace is actually encountered it updates the string in place, which is terribly slow as std::string is effectively just std::vector with an additional bookkeeping for the null terminator. So updating in place can involve may may memory moves and re-allocations. If there its lots of whitespace to escape, its performance is unacceptable.Instead an optimal implementation which has a bounded worse case is written inline at its 3 call locations and StringUtils has been removed.