SSE hashing of parallel streams. Right now, only MD5 is supported with 4 parallel streams using SSE2. Maybe I'll add more hash functions in the future if I feel like it.
You should be able to compile this code using any modern compiler that supports SSE intrinsics. You'll require SSE2 however. For example, using gcc:
$ gcc -O2 -fno-strict-aliasing -msse2 -DPMD5_TEST -o test-pmd5 md5-sse.c
The code will make use of pointer aliasing by default (as the example
command-line suggests). You can disable that behavior for a (slightly slower
but safer) version by defining NO_PTR_ALIASING.
For the API of the MD5 version, check the file md5-sse2.h. You can have up to 4 streams being hashed in parallel.
Note that the code is about 2 times as slow as the normal C version (which is provided). So hashing less than two streams in parallel is useless. Be smart and flip between the SSE and the C version depending on how many streams you are processing.
Booze may have been involved. I found that code on my harddrive, and I have some memories of me writing it. If I get drunk again at some point in the future, I might add a SHA1 version.
Also, this code should only be useful if you're using MD5 for checking a lot of files, and you are able to saturate your CPU bandwidth with your network and/or disk operations, which sounds unlikely. Then again, I might be proven wrong. Let me know if this is useful to you.
This code is officially released into public domain, or if not applicable in your contry or for your case, it is then covered under the terms of the MIT license, copyrighted by myself, Nicolas Noble, in 2017.