TIFF extraction makes fewer, larger reads #408
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
Previously we would read values one-at-a-time through IFD tables of TIFF data. There's a fair amount of indirection here. With this code, we load the entire IFD table into a span (ideally on the stack) and read through it from there. As part of this work, constants were added to indicate the sizes involved, and some variable names were made clearer. Also, the size restriction placed on IFDs was improved, so that they aren't required to have space at the end for the optional follower IFD pointer, fixing some cases in the regression suite.
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Outdated suggestions cannot be applied.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.
Previously we would read values one-at-a-time through IFD tables of TIFF data. There's a fair amount of indirection here.
With this code, we load the entire IFD table into a span (ideally on the stack) and read through it from there. This was identified in traces as a nice perf win.
As part of this work, constants were added to indicate the sizes involved, and some variable names were made clearer.
Also, the size restriction placed on IFDs was improved, so that they aren't required to have space at the end for the optional follower IFD pointer, fixing some cases in the regression suite.