Pure Lua xxHash64
local xxh64 = require("xxh64")
-- xxh64.sum(input:string[, seed:integer]):integer
xxh64.sum("qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM") -- -6187071714215514155
-- xxh64.state([seed:integer]):table
local state = xxh64.state()
-- state:digest([input:string]):integer
state:digest("qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM") -- -6187071714215514155
-- state:reset([seed:integer])
state:reset(0xdeadbeef)
-- state:update(input:string)
state:update("qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM")
state:digest() -- 7051555553238361330