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131 lines
4.0 KiB
131 lines
4.0 KiB
/*
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** Lua BitOp -- a bit operations library for Lua 5.1/5.2.
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** http://bitop.luajit.org/
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**
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** Copyright (C) 2008-2012 Mike Pall. All rights reserved.
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**
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** Permission is hereby granted, free of charge, to any person obtaining
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** a copy of this software and associated documentation files (the
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** "Software"), to deal in the Software without restriction, including
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** without limitation the rights to use, copy, modify, merge, publish,
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** distribute, sublicense, and/or sell copies of the Software, and to
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** permit persons to whom the Software is furnished to do so, subject to
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** the following conditions:
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**
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** The above copyright notice and this permission notice shall be
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** included in all copies or substantial portions of the Software.
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**
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** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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** EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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** MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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** IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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** CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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** TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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** SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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**
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** [ MIT license: http://www.opensource.org/licenses/mit-license.php ]
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*/
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#define LUA_BITOP_VERSION "1.0.2"
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#define LUA_LIB
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#include "lua.h"
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#include "lauxlib.h"
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#include <stdint.h>
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typedef int32_t SBits;
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typedef uint32_t UBits;
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/* Convert argument to bit type. */
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static inline UBits barg(lua_State *L, int idx)
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{
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return (UBits)luaL_checkinteger(L, idx);
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}
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/* Return bit type. */
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#define BRET(b) lua_pushinteger(L, (lua_Integer)(SBits)(b)); return 1;
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static int bit_tobit(lua_State *L) { BRET(barg(L, 1)) }
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static int bit_bnot(lua_State *L) { BRET(~barg(L, 1)) }
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#define BIT_OP(func, opr) \
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static int func(lua_State *L) { int i; UBits b = barg(L, 1); \
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for (i = lua_gettop(L); i > 1; i--) b opr barg(L, i); BRET(b) }
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BIT_OP(bit_band, &=)
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BIT_OP(bit_bor, |=)
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BIT_OP(bit_bxor, ^=)
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#define bshl(b, n) (b << n)
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#define bshr(b, n) (b >> n)
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#define bsar(b, n) ((SBits)b >> n)
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#define brol(b, n) ((b << n) | (b >> (32-n)))
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#define bror(b, n) ((b << (32-n)) | (b >> n))
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#define BIT_SH(func, fn) \
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static int func(lua_State *L) { \
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UBits b = barg(L, 1); UBits n = barg(L, 2) & 31; BRET(fn(b, n)) }
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BIT_SH(bit_lshift, bshl)
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BIT_SH(bit_rshift, bshr)
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BIT_SH(bit_arshift, bsar)
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BIT_SH(bit_rol, brol)
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BIT_SH(bit_ror, bror)
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static int bit_bswap(lua_State *L)
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{
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UBits b = barg(L, 1);
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b = (b >> 24) | ((b >> 8) & 0xff00) | ((b & 0xff00) << 8) | (b << 24);
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BRET(b)
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}
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static int bit_tohex(lua_State *L)
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{
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UBits b = barg(L, 1);
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SBits n = lua_isnone(L, 2) ? 8 : (SBits)barg(L, 2);
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const char *hexdigits = "0123456789abcdef";
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char buf[8];
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int i;
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if (n < 0) { n = -n; hexdigits = "0123456789ABCDEF"; }
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if (n > 8) n = 8;
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for (i = (int)n; --i >= 0; ) { buf[i] = hexdigits[b & 15]; b >>= 4; }
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lua_pushlstring(L, buf, (size_t)n);
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return 1;
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}
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static const struct luaL_Reg bit_funcs[] = {
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{ "tobit", bit_tobit },
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{ "bnot", bit_bnot },
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{ "band", bit_band },
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{ "bor", bit_bor },
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{ "bxor", bit_bxor },
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{ "lshift", bit_lshift },
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{ "rshift", bit_rshift },
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{ "arshift", bit_arshift },
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{ "rol", bit_rol },
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{ "ror", bit_ror },
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{ "bswap", bit_bswap },
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{ "tohex", bit_tohex },
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{ NULL, NULL }
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};
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/* Signed right-shifts are implementation-defined per C89/C99.
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** But the de facto standard are arithmetic right-shifts on two's
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** complement CPUs. This behaviour is required here, so test for it.
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*/
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#define BAD_SAR (bsar(-8, 2) != (SBits)-2)
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LUALIB_API int luaopen_bit(lua_State *L)
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{
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UBits b;
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lua_pushnumber(L, (lua_Number)1437217655L);
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b = barg(L, -1);
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if (b != (UBits)1437217655L || BAD_SAR) { /* Perform a simple self-test. */
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const char *msg = "compiled with incompatible luaconf.h";
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if (BAD_SAR)
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msg = "arithmetic right-shift broken";
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luaL_error(L, "bit library self-test failed (%s)", msg);
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}
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luaL_newlib(L, bit_funcs);
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return 1;
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}
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