Fix negative modulo for C89 #45
Merged
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
In C89, negative integer division and modulo is implementation defined. There were cases of this in deque.c which have been fixed.
Have the C89 and non-C89 version of block calculations in the trim function of deque follow the same logic. This will be slightly slower, but it makes the code much cleaner and easier to maintain.
bkthomps
added
the
compliance
Codecov Report
@@ Coverage Diff @@
## master #45 +/- ##
=====================================
Coverage 100% 100%
=====================================
Files 16 16
Lines 2702 2704 +2
=====================================
+ Hits 2702 2704 +2
Continue to review full report at Codecov.
|
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Outdated suggestions cannot be applied.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.
In C89, negative integer division and modulo is implementation-defined.
Case 1: division rounds to 0 (C89/90, C99, C11, C18)
-9 / 7 -> -1
-9 % 7 -> -2
Case 2: division rounds to negative infinity (C89/90)
-9 / 7 -> -2
-9 % 7 -> 5
This change fixes the deque data structure from having negative division and modulo to prevent this implementation-defined behavior.
Related to issue #44