Avoid intermediate Vec allocations #295
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Solves part of rust-phf#88 by providing a separate function to customize the hashing function during generation. That way, one can avoid usage of the default SipHash as well as avoid having a `PhfHash` bound on the keys. This custom hash function can be used in combination with `get_index` directly.
Previously, each `try_generate_hash` call would allocate a bunch of new `Vec`s just to throw them away every time. Now, all these `Vec`s are kept around in a stateful `Generator` struct and reused across multiple `try_generate_hash` calls. As generation of the PHF is probabilistic, it may need lots of trials, and reusing allocations across multiple trials may be benefitial.
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JohnTitor
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Oct 28, 2023
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This is on top of #294, but I can also rebase if needed
Previously, each
try_generate_hashcall would allocate a bunch of newVecs justto throw them away every time.
Now, all these
Vecs are kept around in a statefulGeneratorstruct and reused acrossmultiple
try_generate_hashcalls.As generation of the PHF is probabilistic, it may need lots of trials, and reusing allocations
across multiple trials may be benefitial.