String conversion perf improvements + minor unrelated changes #54
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Convert to string with one call to snprintf and no string concatenations instead of 5 calls to snprintf and 8 concatenations. Microbenchmarks indicate that this is approximately 17% faster (1.17 times as fast).
On MSDN it is marked as only being able to return S_OK, but in combaseapi.h it is still marked _Check_result_. This will cause a warning if you have them cranked up high enough.
This could theoretically open up some optimizations, but mostly it's just good hygiene.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
The main change here is a rewrite of
Guid::strto make only one call tosnprintfand avoid string concatenation entirely. It just puts the bytes directly into a buffer and then copies that into the string. My microbenchmarks showed a 15-20% improvement in string conversion there. While this isn't the most common Guid operation it's a decent saving. And I would argue that the new code is a little more clear anyway.I also snuck in some minor unrelated changes:
CoCreateGuid. MSDN says this is alwaysS_OKbut it's still marked_Check_result_which can cause a warning if you don't, well, check the result.