LuaRocks

Bitarray

A simple bit array (or bit set, bit string, boolean vector, … whatever) data structure for Lua written in pure C.

The data structure Bitarray stores bits (booleans) in an array in a memory-saving manner internally. One can assign value (false or true) to each element as well as extract values from the array.

Array bit access using overloaded [] operators, concatenation with .., as well as &, |, ~ for bit operations (5.3+).
Object-oriented access. Method chaining is available.
Conversion between bitarray and unsigned integers (big-endian).

Install from luarocks

It will install the release version.

luarocks install bitarray

Build the library manually

make all LUA_VERSION=5.3 # or 5.1, 5.2

The generated shared library will reside in out folder. Unfortunately, I understand the difficulty of finding the right install path for libraries for different platforms so it is your responsibility to copy the file there. Typically it can be /usr/local/lib/lua/5.3/.

FreeBSD users will need to use gmake.

Documentation

Requiring ldoc, available by issuing

make doc

It is also available at here.

Basic usage

Array access

local Bitarray = require'bitarray'
local a = Bitarray.new(10)
a[1] = true
for i = 1, #a do print(a[i]) end
-- true false false false false false false false false false

Method chaining

local b = Bitarray.new(10)
b:fill(true):set(1, false):set(#b, false)
print(b)
-- Bitarray[0,1,1,1,1,1,1,1,1,0]

Storing integers

local c1 = Bitarray.new(16):from_uint16(65535)
print(c1)
-- Bitarray[1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1]
local c2 = Bitarray.new(16):from_uint16(4015)
print(c2)
-- Bitarray[0,0,0,0,1,1,1,1,1,0,1,0,1,1,1,1]
local c3 = c1 .. c2
print(c3)
-- Bitarray[1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,1,1,1,1,1,0,1,0,1,1,1,1]
print(c3:at_uint16(1))
-- 65535
print(c3:at_uint16(17))
-- 4015
print(c3:at_uint32(1))
-- 4294905775

License

MIT

bitarray