mirror of
https://github.com/ZDoom/raze-gles.git
synced 2024-12-25 11:10:47 +00:00
138 lines
3.3 KiB
Lua
138 lines
3.3 KiB
Lua
|
|
-- "Bit array" module based on LuaJIT's BitOp.
|
|
|
|
local ffi = require "ffi"
|
|
local bit = require "bit"
|
|
|
|
local error = error
|
|
local assert = assert
|
|
local type = type
|
|
|
|
local setmetatable=setmetatable
|
|
|
|
|
|
module(...)
|
|
|
|
|
|
-- Is bit i set in bit array ar?
|
|
function isset(ar, i)
|
|
return bit.band(ar[bit.rshift(i, 5)], bit.lshift(1, i)) ~= 0
|
|
end
|
|
|
|
-- Set bit j in bit array ar.
|
|
function set0(ar, j)
|
|
local jx = bit.rshift(j, 5)
|
|
ar[jx] = bit.band(ar[jx], bit.rol(0xfffffffe, j))
|
|
end
|
|
|
|
-- Clear bit j in bit array ar.
|
|
function set1(ar, j)
|
|
local jx = bit.rshift(j, 5)
|
|
ar[jx] = bit.bor(ar[jx], bit.rol(0x00000001, j))
|
|
end
|
|
|
|
local ops = { isset=isset, set0=set0, set1=set1 }
|
|
local mt
|
|
mt = {
|
|
__index=ops,
|
|
|
|
-- set ops disguised as arithmetic ones...
|
|
|
|
__mul = function(ar1, ar2) -- set intersection
|
|
assert(#ar1 == #ar2)
|
|
local p = {}
|
|
for i=0,#ar1 do
|
|
p[i] = bit.band(ar1[i], ar2[i])
|
|
end
|
|
return setmetatable(p, mt)
|
|
end,
|
|
|
|
__add = function(ar1, ar2) -- set union
|
|
assert(#ar1 == #ar2)
|
|
local p = {}
|
|
for i=0,#ar1 do
|
|
p[i] = bit.bor(ar1[i], ar2[i])
|
|
end
|
|
return setmetatable(p, mt)
|
|
end,
|
|
|
|
__sub = function(ar1, ar2) -- set difference
|
|
assert(#ar1 == #ar2)
|
|
local p = {}
|
|
for i=0,#ar1 do
|
|
p[i] = bit.band(ar1[i], bit.bnot(ar2[i]))
|
|
end
|
|
return setmetatable(p, mt)
|
|
end,
|
|
|
|
-- serialization
|
|
__tostring = function(ar)
|
|
local maxidx=#ar
|
|
local size=maxidx+1
|
|
|
|
local hdr = "bitar.new('"
|
|
local ofs = #hdr
|
|
local totalstrlen = ofs+8*size+2
|
|
local str = ffi.new("char [?]", totalstrlen)
|
|
|
|
ffi.copy(str, hdr, ofs)
|
|
|
|
for i=0,maxidx do
|
|
-- 'a' is ASCII 97
|
|
for nib=0,7 do
|
|
str[ofs + 8*i + nib] = 97 + bit.band(bit.rshift(ar[i], 4*nib), 0x0000000f)
|
|
end
|
|
end
|
|
|
|
ffi.copy(str+totalstrlen-2, "')", 2)
|
|
|
|
return ffi.string(str, totalstrlen)
|
|
end,
|
|
}
|
|
|
|
-- Create new bit array.
|
|
-- Returns a table p in which entries p[0] through p[floor((maxbidx+31)/32)]
|
|
-- are set to an initialization value: 0 if 0 has been passed, -1 if 1
|
|
-- has been passed.
|
|
-- Storage: 4 bits/bit + O(1)? (per 32 bits: 64 bits key, 64 bits value)
|
|
function new(maxbidx, initval)
|
|
local p = {}
|
|
|
|
if (type(maxbidx)=="string") then
|
|
-- string containing hex digits (a..p) given, internal
|
|
local lstr = maxbidx
|
|
|
|
local numnibs = #lstr
|
|
assert(numnibs%8 == 0)
|
|
|
|
local size = numnibs/8
|
|
local maxidx = size-1
|
|
|
|
local str = ffi.new("char [?]", numnibs)
|
|
ffi.copy(str, lstr, numnibs)
|
|
|
|
for i=0,maxidx do
|
|
p[i] = 0
|
|
|
|
for nib=0,7 do
|
|
local hexdig = str[8*i + nib]
|
|
assert(hexdig >= 97 and hexdig < 97+16)
|
|
p[i] = bit.bor(p[i], bit.lshift(hexdig-97, 4*nib))
|
|
end
|
|
end
|
|
else
|
|
if (type(maxbidx) ~= "number" or not (maxbidx >= 0)) then
|
|
error("bad argument #1 to newarray (must be a nonnegative number)", 2)
|
|
end
|
|
|
|
if (initval ~= 0 and initval ~= 1) then
|
|
error("bad argument #2 to newarray (must be either 0 or 1)", 2)
|
|
end
|
|
|
|
for i=0,maxbidx/32 do
|
|
p[i] = -initval
|
|
end
|
|
end
|
|
|
|
return setmetatable(p, mt)
|
|
end
|