Add common hash/checksum functions #900
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- SipHash64, SipHash128 - Crc32 (fast + small variants) - Adler32 - Fnv1a (32, 64 and 128 bit variants)
A need for it: https://github.com/Hejsil/pokemon-randomizer/blob/60365a24e7790b019df4beb68ef85f7749e3d6aa/src/nds/header.zig#L18 Though, it doesn't matter too much, as I'm already using something I wrote my self. |
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Good enough for me. I won't do anything just yet, but I'll keep that on my list of things to do. |
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Rationale behind each inclusion and rough performance metrics using the
throughput_test.ziginstd/cryptowith minor modifications. Using a i5-6500,--release-fast, best time taken.SipHash
We should provide a collision resistant keyed hash function for hash tables which accept data from external users over a network that aids in avoiding hash flood attacks.
SipHash64(2, 4)- 875Mb/sSipHash128(2, 4)- 862 Mb/sI expect this performance is only on par with Fnv since the test program is dealing in large blocks. SipHash would likely get a fair slow down on smaller keys.
Crc32
Very common. Used as the specified checksum in various other algorithms (such as the gzip file format). I've included two variants since if you only need to do a one-off checksum, the 8Kb table may not be that desired.
Crc32- 2366 Mb/sCrc32Small- 217 Mb/sI haven't included a generic CRC abstracted over different sizes (i.e. CRC64, CRC16) since I'd like to first see a need for it.
Adler32
Very fast checksum. Only included since it is the specified checksum function for the zlib file format which will likely be in
stdat some point (side note: working on a INFLATE implementation).Adler32- 2402 Mb/sFnv1a
Non cryptographic generic hash function useful for small keys where a good distribution is wanted and input is from a controlled environment (no hash flood possibility).
Fnv1a-32- 882 Mb/sFnv1a-64- 881 Mb/sFnv1-128- 803 Mb/s