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if not modules then modules = { } end modules ['l-bit32'] = {
version = 1.001,
license = "the same as regular Lua",
source = "bitwise.lua, v 1.24 2014/12/26 17:20:53 roberto",
comment = "drop-in for bit32, adapted a bit by Hans Hagen",
}
-- Lua 5.3 has bitwise operators built in but code meant for 5.2 can expect the
-- bit32 library to be present. For the moment (and maybe forever) we will ship
-- the bit32 library as part of LuaTeX bit just in case it is missing, here is a
-- drop-in. The code is an adapted version of code by Roberto. The Luajit variant
-- is a mixture of mapping and magic.
if bit32 then
-- lua 5.2: we're okay
elseif utf8 then
-- lua 5.3: bitwise.lua, v 1.24 2014/12/26 17:20:53 roberto
load ( [[
local select = select -- instead of: arg = { ... }
bit32 = {
bnot = function (a)
return ~a & 0xFFFFFFFF
end,
band = function (x, y, z, ...)
if not z then
return ((x or -1) & (y or -1)) & 0xFFFFFFFF
else
local res = x & y & z
for i=1,select("#",...) do
res = res & select(i,...)
end
return res & 0xFFFFFFFF
end
end,
bor = function (x, y, z, ...)
if not z then
return ((x or 0) | (y or 0)) & 0xFFFFFFFF
else
local res = x | y | z
for i=1,select("#",...) do
res = res | select(i,...)
end
return res & 0xFFFFFFFF
end
end,
bxor = function (x, y, z, ...)
if not z then
return ((x or 0) ~ (y or 0)) & 0xFFFFFFFF
else
local res = x ~ y ~ z
for i=1,select("#",...) do
res = res ~ select(i,...)
end
return res & 0xFFFFFFFF
end
end,
btest = function (x, y, z, ...)
if not z then
return (((x or -1) & (y or -1)) & 0xFFFFFFFF) ~= 0
else
local res = x & y & z
for i=1,select("#",...) do
res = res & select(i,...)
end
return (res & 0xFFFFFFFF) ~= 0
end
end,
lshift = function (a, b)
return ((a & 0xFFFFFFFF) << b) & 0xFFFFFFFF
end,
rshift = function (a, b)
return ((a & 0xFFFFFFFF) >> b) & 0xFFFFFFFF
end,
arshift = function (a, b)
a = a & 0xFFFFFFFF
if b <= 0 or (a & 0x80000000) == 0 then
return (a >> b) & 0xFFFFFFFF
else
return ((a >> b) | ~(0xFFFFFFFF >> b)) & 0xFFFFFFFF
end
end,
lrotate = function (a ,b)
b = b & 31
a = a & 0xFFFFFFFF
a = (a << b) | (a >> (32 - b))
return a & 0xFFFFFFFF
end,
rrotate = function (a, b)
b = -b & 31
a = a & 0xFFFFFFFF
a = (a << b) | (a >> (32 - b))
return a & 0xFFFFFFFF
end,
extract = function (a, f, w)
return (a >> f) & ~(-1 << (w or 1))
end,
replace = function (a, v, f, w)
local mask = ~(-1 << (w or 1))
return ((a & ~(mask << f)) | ((v & mask) << f)) & 0xFFFFFFFF
end,
}
]] ) ()
elseif bit then
-- luajit (for now)
load ( [[
local band, bnot, rshift, lshift = bit.band, bit.bnot, bit.rshift, bit.lshift
bit32 = {
arshift = bit.arshift,
band = band,
bnot = bnot,
bor = bit.bor,
bxor = bit.bxor,
btest = function(...)
return band(...) ~= 0
end,
extract = function(a,f,w)
return band(rshift(a,f),2^(w or 1)-1)
end,
lrotate = bit.rol,
lshift = lshift,
replace = function(a,v,f,w)
local mask = 2^(w or 1)-1
return band(a,bnot(lshift(mask,f)))+lshift(band(v,mask),f)
end,
rrotate = bit.ror,
rshift = rshift,
}
]] ) ()
else
-- hope for the best or fail
-- bit32 = require("bit32")
xpcall(function() local _, t = require("bit32") if t then bit32 = t end return end,function() end)
end
|
