We had a long discussion of this, so trying to document what seems to be
the conclusion... and also clean up the exceptions that I could find.
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Co-authored-by: Dana Jansens <danakj@orodu.net>
Also makes the style guide explicitly comment on void, but this was the
intent IIRC because it matches Carbon's `-> ()` (and "always" versus
"except for void", which we definitely went back and forth on).
Includes adjusting function pointers, which I definitely forget this
syntax works sometimes.
Excludes utils/tree_sitter/src/scanner.c because it claims to be C, but
really we should probably fix that to be cpp.
This lets copy and move assignment work. While it's a bit suboptimal to
do assignment with these tables, it still seems like an unreasonable
burden to not allow the basics to work. Even the toolchain ended up
doing this in a few places.
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Co-authored-by: Richard Smith <richard@metafoo.co.uk>
This adds two different growth APIs. This is instead of the more
conventional STL `reserve` method. One allows users that aren't trying
to grow in anticipation of an *exact* count of insertions, but generally
trying to size the table to the correct ballpark with a power-of-two
estimate.
The other API allows pre-growing to allow a specific number of
insertions to be performed without further growth. This API takes the
maximum load factor and other implementation details into account.
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Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
While it was convenient once to have an immediate check while inserting,
it is indeed far too quadratic. The test was taking 30-60 seconds for
me. =[ So most of the fix here is just to stop doing the check on every
insertion for all previous elements.
There were a few other somewhat slow steps, and I tried to pull those
back as well. I don't think we lose any utility here. Now everything
runs nice and quickly. =]
The hash table design is heavily based on Abseil's ["Swiss
Tables"][swiss-tables] design. It uses an array of bytes storing
metadata about each entry and an array of entries where each is a pair
of key and value. The metadata byte consists of 7-bits of hash of the
key (distinct from the bits used to index the table), and one bit
indicating the presence of a special entry -- either empty or deleted.
[swiss-tables]: https://abseil.io/about/design/swisstables
There are a large range of optimizations and other nuanced aspects of
this hash table design and implementation, a good point to understand
that context is `raw_hashtable.h` which has an overview of the design
and references to various other files for relevant details.
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Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
Dana Jansens
Jon Ross-PerkinsandDana Jansens
Chandler CarruthandRichard Smith
