1 /* 2 ** Lua BitOp -- a bit operations library for Lua 5.1/5.2. 3 ** http://bitop.luajit.org/ 4 ** 5 ** Copyright (C) 2008-2012 Mike Pall. All rights reserved. 6 ** 7 ** Permission is hereby granted, free of charge, to any person obtaining 8 ** a copy of this software and associated documentation files (the 9 ** "Software"), to deal in the Software without restriction, including 10 ** without limitation the rights to use, copy, modify, merge, publish, 11 ** distribute, sublicense, and/or sell copies of the Software, and to 12 ** permit persons to whom the Software is furnished to do so, subject to 13 ** the following conditions: 14 ** 15 ** The above copyright notice and this permission notice shall be 16 ** included in all copies or substantial portions of the Software. 17 ** 18 ** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 19 ** EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 20 ** MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 21 ** IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY 22 ** CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 23 ** TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE 24 ** SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 25 ** 26 ** [ MIT license: http://www.opensource.org/licenses/mit-license.php ] 27 */ 28 29 #define LUA_BITOP_VERSION "1.0.2" 30 31 #define LUA_LIB 32 #include "lua.h" 33 #include "lauxlib.h" 34 35 #ifdef _MSC_VER 36 /* MSVC is stuck in the last century and doesn't have C99's stdint.h. */ 37 typedef __int32 int32_t; 38 typedef unsigned __int32 uint32_t; 39 typedef unsigned __int64 uint64_t; 40 #else 41 #include <stdint.h> 42 #endif 43 44 typedef int32_t SBits; 45 typedef uint32_t UBits; 46 47 typedef union { 48 lua_Number n; 49 #ifdef LUA_NUMBER_DOUBLE 50 uint64_t b; 51 #else 52 UBits b; 53 #endif 54 } BitNum; 55 56 /* Convert argument to bit type. */ 57 static UBits barg(lua_State *L, int idx) 58 { 59 BitNum bn; 60 UBits b; 61 #if LUA_VERSION_NUM < 502 62 bn.n = lua_tonumber(L, idx); 63 #else 64 bn.n = luaL_checknumber(L, idx); 65 #endif 66 #if defined(LUA_NUMBER_DOUBLE) 67 bn.n += 6755399441055744.0; /* 2^52+2^51 */ 68 #ifdef SWAPPED_DOUBLE 69 b = (UBits)(bn.b >> 32); 70 #else 71 b = (UBits)bn.b; 72 #endif 73 #elif defined(LUA_NUMBER_INT) || defined(LUA_NUMBER_LONG) || \ 74 defined(LUA_NUMBER_LONGLONG) || defined(LUA_NUMBER_LONG_LONG) || \ 75 defined(LUA_NUMBER_LLONG) 76 if (sizeof(UBits) == sizeof(lua_Number)) 77 b = bn.b; 78 else 79 b = (UBits)(SBits)bn.n; 80 #elif defined(LUA_NUMBER_FLOAT) 81 #error "A 'float' lua_Number type is incompatible with this library" 82 #else 83 #error "Unknown number type, check LUA_NUMBER_* in luaconf.h" 84 #endif 85 #if LUA_VERSION_NUM < 502 86 if (b == 0 && !lua_isnumber(L, idx)) { 87 luaL_typerror(L, idx, "number"); 88 } 89 #endif 90 return b; 91 } 92 93 /* Return bit type. */ 94 #define BRET(b) lua_pushnumber(L, (lua_Number)(SBits)(b)); return 1; 95 96 static int bit_tobit(lua_State *L) { BRET(barg(L, 1)) } 97 static int bit_bnot(lua_State *L) { BRET(~barg(L, 1)) } 98 99 #define BIT_OP(func, opr) \ 100 static int func(lua_State *L) { int i; UBits b = barg(L, 1); \ 101 for (i = lua_gettop(L); i > 1; i--) b opr barg(L, i); BRET(b) } 102 BIT_OP(bit_band, &=) 103 BIT_OP(bit_bor, |=) 104 BIT_OP(bit_bxor, ^=) 105 106 #define bshl(b, n) (b << n) 107 #define bshr(b, n) (b >> n) 108 #define bsar(b, n) ((SBits)b >> n) 109 #define brol(b, n) ((b << n) | (b >> (32-n))) 110 #define bror(b, n) ((b << (32-n)) | (b >> n)) 111 #define BIT_SH(func, fn) \ 112 static int func(lua_State *L) { \ 113 UBits b = barg(L, 1); UBits n = barg(L, 2) & 31; BRET(fn(b, n)) } 114 BIT_SH(bit_lshift, bshl) 115 BIT_SH(bit_rshift, bshr) 116 BIT_SH(bit_arshift, bsar) 117 BIT_SH(bit_rol, brol) 118 BIT_SH(bit_ror, bror) 119 120 static int bit_bswap(lua_State *L) 121 { 122 UBits b = barg(L, 1); 123 b = (b >> 24) | ((b >> 8) & 0xff00) | ((b & 0xff00) << 8) | (b << 24); 124 BRET(b) 125 } 126 127 static int bit_tohex(lua_State *L) 128 { 129 UBits b = barg(L, 1); 130 SBits n = lua_isnone(L, 2) ? 8 : (SBits)barg(L, 2); 131 const char *hexdigits = "0123456789abcdef"; 132 char buf[8]; 133 int i; 134 if (n < 0) { n = -n; hexdigits = "0123456789ABCDEF"; } 135 if (n > 8) n = 8; 136 for (i = (int)n; --i >= 0; ) { buf[i] = hexdigits[b & 15]; b >>= 4; } 137 lua_pushlstring(L, buf, (size_t)n); 138 return 1; 139 } 140 141 static const struct luaL_Reg bit_funcs[] = { 142 { "tobit", bit_tobit }, 143 { "bnot", bit_bnot }, 144 { "band", bit_band }, 145 { "bor", bit_bor }, 146 { "bxor", bit_bxor }, 147 { "lshift", bit_lshift }, 148 { "rshift", bit_rshift }, 149 { "arshift", bit_arshift }, 150 { "rol", bit_rol }, 151 { "ror", bit_ror }, 152 { "bswap", bit_bswap }, 153 { "tohex", bit_tohex }, 154 { NULL, NULL } 155 }; 156 157 /* Signed right-shifts are implementation-defined per C89/C99. 158 ** But the de facto standard are arithmetic right-shifts on two's 159 ** complement CPUs. This behaviour is required here, so test for it. 160 */ 161 #define BAD_SAR (bsar(-8, 2) != (SBits)-2) 162 163 LUALIB_API int luaopen_bit(lua_State *L) 164 { 165 UBits b; 166 lua_pushnumber(L, (lua_Number)1437217655L); 167 b = barg(L, -1); 168 if (b != (UBits)1437217655L || BAD_SAR) { /* Perform a simple self-test. */ 169 const char *msg = "compiled with incompatible luaconf.h"; 170 #ifdef LUA_NUMBER_DOUBLE 171 #ifdef _WIN32 172 if (b == (UBits)1610612736L) 173 msg = "use D3DCREATE_FPU_PRESERVE with DirectX"; 174 #endif 175 if (b == (UBits)1127743488L) 176 msg = "not compiled with SWAPPED_DOUBLE"; 177 #endif 178 if (BAD_SAR) 179 msg = "arithmetic right-shift broken"; 180 luaL_error(L, "bit library self-test failed (%s)", msg); 181 } 182 #if LUA_VERSION_NUM < 502 183 luaL_register(L, "bit", bit_funcs); 184 #else 185 luaL_newlib(L, bit_funcs); 186 #endif 187 return 1; 188 } 189 190