Module:Hash - Revision history

D0sboots: bugfix

2022-02-12T23:03:17Z

bugfix

D0sboots: Add adaptor for proper #invoking

2022-02-12T23:01:57Z

Add adaptor for proper #invoking

D0sboots: Create simple CRC hashing module

2022-02-12T22:52:15Z

Create simple CRC hashing module

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--[[
Simple module for hashing a string.
Generally you won't #invoke this directly, but use templates that do.
]]

-- Disallow global variable read/writes. Copied from Wikipedia's Module:No globals.
local mt = getmetatable(_G) or {}
function mt.__index (t, k)
if k ~= 'arg' then
error('Tried to read nil global ' .. tostring(k), 2)
end
return nil
end
function mt.__newindex(t, k, v)
if k ~= 'arg' then
error('Tried to write global ' .. tostring(k), 2)
end
rawset(t, k, v)
end
setmetatable(_G, mt)

local p = {}

local function BitXOR(a,b)
local p,c=1,0
while a>0 and b>0 do
local ra,rb=a%2,b%2
if ra~=rb then c=c+p end
a,b,p=(a-ra)/2,(b-rb)/2,p*2
end
if a<b then a=b end
while a>0 do
local ra=a%2
if ra>0 then c=c+p end
a,p=(a-ra)/2,p*2
end
return c
end

-- Returns a (stringified) CRC32 of the data
function p.crc(str)
if not str then
return "nil"
end
local byte = string.byte
local floor = math.floor
local crc = 0xFFFFFFFF
for i = 1, #str do
local b = byte(str, i)
crc = BitXOR(crc, b)
for j = 1, 8 do
local mask = 0
if crc % 2 == 1 then
crc = BitXOR(floor(crc / 2), 0xEDB88320)
else
crc = floor(crc / 2)
end
end
end
return string.format("%x", BitXOR(crc, 0xFFFFFFFF))
end

return p

@@ Line 62: / Line 62: @@
 function p.crc(frame)
-	return crc_internal(frame.args[1])
+	return p.crc_internal(frame.args[1])
 end
 return p

@@ Line 39: / Line 39: @@
 -- Returns a (stringified) CRC32 of the data
-function p.crc(str)
+function p.crc_internal(str)
 	if not str then
 		return "nil"
@@ Line 59: / Line 59: @@
      end
 	return string.format("%x", BitXOR(crc, 0xFFFFFFFF))
 end
 return p