bit.c (5258B)
1 /* 2 ** Lua BitOp -- a bit operations library for Lua 5.1/5.2. 3 ** http://bitop.luajit.org/ 4 ** 5 ** Copyright (C) 2008-2025 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 "1.0.3" 30 31 #define LUA_LIB 32 #include "lua.h" 33 #include "lauxlib.h" 34 35 #include <stdint.h> 36 37 typedef int32_t SBits; 38 typedef uint32_t UBits; 39 40 typedef union { 41 lua_Number n; 42 #ifdef LUA_NUMBER_DOUBLE 43 uint64_t b; 44 #else 45 UBits b; 46 #endif 47 } BitNum; 48 49 /* Convert argument to bit type. */ 50 static UBits barg(lua_State *L, int idx) 51 { 52 BitNum bn; 53 UBits b; 54 #if LUA_VERSION_NUM < 502 55 bn.n = lua_tonumber(L, idx); 56 #else 57 bn.n = luaL_checknumber(L, idx); 58 #endif 59 #if defined(LUA_NUMBER_DOUBLE) 60 bn.n += 6755399441055744.0; /* 2^52+2^51 */ 61 #ifdef SWAPPED_DOUBLE 62 b = (UBits)(bn.b >> 32); 63 #else 64 b = (UBits)bn.b; 65 #endif 66 #elif defined(LUA_NUMBER_INT) || defined(LUA_NUMBER_LONG) || \ 67 defined(LUA_NUMBER_LONGLONG) || defined(LUA_NUMBER_LONG_LONG) || \ 68 defined(LUA_NUMBER_LLONG) 69 if (sizeof(UBits) == sizeof(lua_Number)) 70 b = bn.b; 71 else 72 b = (UBits)(SBits)bn.n; 73 #elif defined(LUA_NUMBER_FLOAT) 74 #error "A 'float' lua_Number type is incompatible with this library" 75 #else 76 #error "Unknown number type, check LUA_NUMBER_* in luaconf.h" 77 #endif 78 #if LUA_VERSION_NUM < 502 79 if (b == 0 && !lua_isnumber(L, idx)) { 80 luaL_typerror(L, idx, "number"); 81 } 82 #endif 83 return b; 84 } 85 86 /* Return bit type. */ 87 #define BRET(b) lua_pushnumber(L, (lua_Number)(SBits)(b)); return 1; 88 89 static int bit_tobit(lua_State *L) { BRET(barg(L, 1)) } 90 static int bit_bnot(lua_State *L) { BRET(~barg(L, 1)) } 91 92 #define BIT_OP(func, opr) \ 93 static int func(lua_State *L) { int i; UBits b = barg(L, 1); \ 94 for (i = lua_gettop(L); i > 1; i--) b opr barg(L, i); BRET(b) } 95 BIT_OP(bit_band, &=) 96 BIT_OP(bit_bor, |=) 97 BIT_OP(bit_bxor, ^=) 98 99 #define bshl(b, n) (b << n) 100 #define bshr(b, n) (b >> n) 101 #define bsar(b, n) ((SBits)b >> n) 102 #define brol(b, n) ((b << n) | (b >> (32-n))) 103 #define bror(b, n) ((b << (32-n)) | (b >> n)) 104 #define BIT_SH(func, fn) \ 105 static int func(lua_State *L) { \ 106 UBits b = barg(L, 1); UBits n = barg(L, 2) & 31; BRET(fn(b, n)) } 107 BIT_SH(bit_lshift, bshl) 108 BIT_SH(bit_rshift, bshr) 109 BIT_SH(bit_arshift, bsar) 110 BIT_SH(bit_rol, brol) 111 BIT_SH(bit_ror, bror) 112 113 static int bit_bswap(lua_State *L) 114 { 115 UBits b = barg(L, 1); 116 b = (b >> 24) | ((b >> 8) & 0xff00) | ((b & 0xff00) << 8) | (b << 24); 117 BRET(b) 118 } 119 120 static int bit_tohex(lua_State *L) 121 { 122 UBits b = barg(L, 1); 123 UBits n = lua_isnone(L, 2) ? 8 : barg(L, 2); 124 const char *hexdigits = "0123456789abcdef"; 125 char buf[8]; 126 int i; 127 if ((SBits)n < 0) { n = ~n+1; hexdigits = "0123456789ABCDEF"; } 128 if (n > 8) n = 8; 129 for (i = (int)n; --i >= 0; ) { buf[i] = hexdigits[b & 15]; b >>= 4; } 130 lua_pushlstring(L, buf, (size_t)n); 131 return 1; 132 } 133 134 static const struct luaL_Reg bit_funcs[] = { 135 { "tobit", bit_tobit }, 136 { "bnot", bit_bnot }, 137 { "band", bit_band }, 138 { "bor", bit_bor }, 139 { "bxor", bit_bxor }, 140 { "lshift", bit_lshift }, 141 { "rshift", bit_rshift }, 142 { "arshift", bit_arshift }, 143 { "rol", bit_rol }, 144 { "ror", bit_ror }, 145 { "bswap", bit_bswap }, 146 { "tohex", bit_tohex }, 147 { NULL, NULL } 148 }; 149 150 /* Signed right-shifts are implementation-defined per C89/C99. 151 ** But the de facto standard are arithmetic right-shifts on two's 152 ** complement CPUs. This behaviour is required here, so test for it. 153 */ 154 #define BAD_SAR (bsar(-8, 2) != (SBits)-2) 155 156 LUALIB_API int luaopen_bit(lua_State *L) 157 { 158 UBits b; 159 lua_pushnumber(L, (lua_Number)1437217655L); 160 b = barg(L, -1); 161 if (b != (UBits)1437217655L || BAD_SAR) { /* Perform a simple self-test. */ 162 const char *msg = "compiled with incompatible luaconf.h"; 163 #ifdef LUA_NUMBER_DOUBLE 164 #ifdef _WIN32 165 if (b == (UBits)1610612736L) 166 msg = "use D3DCREATE_FPU_PRESERVE with DirectX"; 167 #endif 168 if (b == (UBits)1127743488L) 169 msg = "not compiled with SWAPPED_DOUBLE"; 170 #endif 171 if (BAD_SAR) 172 msg = "arithmetic right-shift broken"; 173 luaL_error(L, "bit library self-test failed (%s)", msg); 174 } 175 #if LUA_VERSION_NUM < 502 176 luaL_register(L, "bit", bit_funcs); 177 #else 178 luaL_newlib(L, bit_funcs); 179 #endif 180 return 1; 181 }