LuaJIT SHA1
- From: William Adams <william_a_adams@xxxxxxx>
- To: <luajit@xxxxxxxxxxxxx>
- Date: Mon, 18 Jun 2012 14:28:49 +0000
Looking at the sha1 code briefly, I'm sure you could speed things up
significantly with a few small changes. Probably the biggest thing you could do
is implement based on a straight buffer instead of relying on Lua strings in
any way. For example, in your test case: repeat
rsize = ffi.C.read(0, buf, bufsize)
sha1.update(hash, ffi.string(buf, rsize))
until rsize < 1
At the very least, ffi.string is going to do some hashing, andcomparing as it
tries to intern your buffer into a lua string.At the very worst, it's going to
do a memcpy on your buffer,which I'm sure you don't want in this case. Then,
within your implementation, you do some string concatstuff: function
update(hash, data)
if not data then return end hash[6] = hash[6] + #data
data = hash[7]..data ... if pad == 64 then pad = 0 end
data = data.."\128"..string.rep("\0", pad)..len
Again, in each of these cases, any time you use '..', you'regoing to create a
new string, with the attendant copyingof buffers. I did the same thing with my
initial implementation. Ifyou can eliminate these cases, you'll probably get
much closer to the speed of a typical 'C' implementation. -- William
===============================
- Shaping clay is easier than digging it out of the ground.
> Date: Mon, 18 Jun 2012 08:29:55 -0400
> From: chris@xxxxxxxxxx
> To: luajit@xxxxxxxxxxxxx
> Subject: Re: Projects using LuaJIT ?
>
> On 06/18/2012 07:38 AM, Patrick Masotta wrote:
> > I’ve been there, there are 3 projects??That’s all the available LuaJIT
> > codebase??
>
> The ufo project has a bunch of FFI bindings. Specifically check out the
> "ffi" directory.
>
> https://github.com/malkia/ufo
>
> My sha1 library uses LuaJIT but it's not really tuned directly for
> LuaJIT. In fact I would appreciate any help increasing the performance
> if anyone knows of LuaJIT specific tweaks.
>
> http://luadev.com
>
> --
> Chris
>
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