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. */
barg(lua_State * L,int idx)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
bit_tobit(lua_State * L)96 static int bit_tobit(lua_State *L) { BRET(barg(L, 1)) }
bit_bnot(lua_State * L)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)) }
BIT_SH(bit_lshift,bshl)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
bit_tohex(lua_State * L)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
luaopen_bit(lua_State * L)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