| 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. |