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util/bitcompat.lua @ 10571:cfeb0077c9e9
net.server_epoll: Avoid concatenating buffer with single item
Saves creating a string that'll be identical to buffer[1] anyways, as
well as a C function call. Depending on Lua version and length of the
string, this could be reusing an interned string, but a longer one would
probably be duplicated for no reason.
Having exactly one item in the buffer seems like it would be fairly
common, but I have not done an extensive study. If opportunistic writes
are enabled then it will be even more likely.
This special case could be optimized like this in table.concat but it
does not look like it is.
author | Kim Alvefur <zash@zash.se> |
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date | Sat, 28 Dec 2019 06:18:58 +0100 |
parent | 10241:48f7cda4174d |
child | 12573:0f4feaf9ca64 |
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-- Compatibility layer for bitwise operations -- First try the bit32 lib -- Lua 5.3 has it with compat enabled -- Lua 5.2 has it by default if _G.bit32 then return _G.bit32; else -- Lua 5.1 may have it as a standalone module that can be installed local ok, bitop = pcall(require, "bit32") if ok then return bitop; end end do -- Lua 5.3 and 5.4 would be able to use native infix operators local ok, bitop = pcall(require, "util.bit53") if ok then return bitop; end end do -- Lastly, try the LuaJIT bitop library local ok, bitop = pcall(require, "bit") if ok then return bitop; end end error "No bit module found. See https://prosody.im/doc/depends#bitop";