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1 | bitlib | |
2 | ------ | |
3 | ||
4 | by Reuben Thomas <rrt@sc3d.org> | |
5 | http://luaforge.net/projects/bitlib | |
6 | ||
7 | ||
8 | bitlib is a C library for Lua 5.1 that provides bitwise operations. It | |
9 | is copyright Reuben Thomas 2000-2009, and is released under the MIT | |
10 | license, like Lua (see http://www.lua.org/copyright.html; it's | |
11 | basically the same as the BSD license). There is no warranty. | |
12 | ||
13 | Please report bugs and make suggestions to the email address above, or | |
14 | use the LuaForge trackers. | |
15 | ||
16 | Thanks to John Passaniti for his bitwise operations library, some of | |
17 | whose ideas I used, to Shmuel Zeigerman for the test suite, to | |
18 | Thatcher Ulrich for portability fixes, and to Enrico Tassi, John | |
19 | Stiles and Eduardo Ochs for bug reports. | |
20 | ||
21 | ||
22 | Installation | |
23 | ------------ | |
24 | ||
25 | As normal: | |
26 | ||
27 | ./configure && make [&& make check] [&& make install] | |
28 | ||
29 | If you get warnings about integer constants being too large, don't | |
30 | worry. They won't be used. | |
31 | ||
32 | The following options may be of interest if you have Lua installed on | |
33 | non-default paths (as you are likely to on any system supporting more | |
34 | than one version of Lua): | |
35 | ||
36 | --libdir=DIR Install shared library in this directory | |
37 | --with-lua-prefix=DIR Lua files are in DIR | |
38 | --with-lua-includes=DIR Lua include files are in DIR | |
39 | --with-lua-libraries=DIR | |
40 | Lua library files are in DIR, or "no" if not used | |
41 | --with-lua-suffix=ARG Lua binary and library files are suffixed with ARG | |
42 | ||
43 | For example, on Debian or Ubuntu: | |
44 | ||
45 | ./configure --libdir=/usr/local/lib/lua/5.1 --with-lua-includes=/usr/include/lua5.1 --with-lua-suffix=5.1 --with-lua-libraries=no | |
46 | ||
47 | ||
48 | Use | |
49 | --- | |
50 | ||
51 | Make sure the library is installed on your LUA_CPATH, and require it. | |
52 | ||
53 | The library provides the constant bit.bits that gives the number of | |
54 | bits that can be used in bitwise operations, and the following | |
55 | functions: | |
56 | ||
57 | bit.cast(a) cast a to the internally-used integer type | |
58 | bit.bnot(a) returns the one's complement of a | |
59 | bit.band(w1, ...) returns the bitwise and of the w's | |
60 | bit.bor(w1, ...) returns the bitwise or of the w's | |
61 | bit.bxor(w1, ...) returns the bitwise exclusive or of the w's | |
62 | bit.lshift(a, b) returns a shifted left b places | |
63 | bit.rshift(a, b) returns a shifted logically right b places | |
64 | bit.arshift(a, b) returns a shifted arithmetically right b places | |
65 | ||
66 | All function arguments should be integers that fit into the C type | |
67 | lua_Integer. | |
68 | ||
69 | The logical operations start with "b" for "bit" to avoid clashing with | |
70 | reserved words; although "xor" isn't a reserved word, it seemed better | |
71 | to use "bxor" for consistency. |