zinovy.nis added inline comments.
================ Comment at: clang-tidy/modernize/RawStringLiteralCheck.cpp:71 + // supported by specific code pages only. + if (Bytes.find_if_not(isASCII) != StringRef::npos) + return false; ---------------- aaron.ballman wrote: > zinovy.nis wrote: > > aaron.ballman wrote: > > > I am starting to think that this functionality should be refactored > > > because the check is now O(N^2) in the worst case because all of the > > > bytes of the string need to be touched twice. It would be nice for > > > performance reasons to combine this so that there's only a single pass > > > over all of the characters. > > > > > > What do you think? > > Sorry, but why O(N^2)? `isASCII` is O(1), it's just `return C<=127`. > > `find_if_not` is O(N). > The `find_if_not()` call you add touches every character in the string to see > if it's ASCII and it all characters are ASCII, then `containsEscape()` calls > `find()` which touches every character again (assuming the searched character > is never encountered). > > Looking a bit deeper, `isRawStringLiteral()` also calls `find()`, but it > asserts that the character is found, so not every character is touched in the > string and it should find a the searched character quite quickly. OK, I'll see how to combine theses checks into a single one. But anyway I see only 2*O(N), not O(N^2) here. https://reviews.llvm.org/D45932 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
