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 #if defined(LUA_NUMBER_DOUBLE) || defined(LUA_FLOAT_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) || defined(LUA_FLOAT_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_INT_INT) || \
74 defined(LUA_NUMBER_LONG) || defined(LUA_INT_LONG) || \
75 defined(LUA_NUMBER_LONGLONG) || defined(LUA_INT_LONGLONG) || \
76 defined(LUA_NUMBER_LONG_LONG) || defined(LUA_NUMBER_LLONG)
77 if (sizeof(UBits) == sizeof(lua_Number))
78 b = bn.b;
79 else
80 b = (UBits)(SBits)bn.n;
81 #elif defined(LUA_NUMBER_FLOAT) || defined(LUA_FLOAT_FLOAT)
82 #error "A 'float' lua_Number type is incompatible with this library"
83 #else
84 #error "Unknown number type, check LUA_NUMBER_*, LUA_FLOAT_*, LUA_INT_* in luaconf.h"
85 #endif
86 #if LUA_VERSION_NUM < 502
87 if (b == 0 && !lua_isnumber(L, idx)) {
88 luaL_typerror(L, idx, "number");
89 }
90 #endif
91 return b;
92 }
93
94 /* Return bit type. */
95 #if LUA_VERSION_NUM < 503
96 #define BRET(b) lua_pushnumber(L, (lua_Number)(SBits)(b)); return 1;
97 #else
98 #define BRET(b) lua_pushinteger(L, (lua_Integer)(SBits)(b)); return 1;
99 #endif
100
bit_tobit(lua_State * L)101 static int bit_tobit(lua_State *L) { BRET(barg(L, 1)) }
bit_bnot(lua_State * L)102 static int bit_bnot(lua_State *L) { BRET(~barg(L, 1)) }
103
104 #define BIT_OP(func, opr) \
105 static int func(lua_State *L) { int i; UBits b = barg(L, 1); \
106 for (i = lua_gettop(L); i > 1; i--) b opr barg(L, i); BRET(b) }
107 BIT_OP(bit_band, &=)
108 BIT_OP(bit_bor, |=)
109 BIT_OP(bit_bxor, ^=)
110
111 #define bshl(b, n) (b << n)
112 #define bshr(b, n) (b >> n)
113 #define bsar(b, n) ((SBits)b >> n)
114 #define brol(b, n) ((b << n) | (b >> (32-n)))
115 #define bror(b, n) ((b << (32-n)) | (b >> n))
116 #define BIT_SH(func, fn) \
117 static int func(lua_State *L) { \
118 UBits b = barg(L, 1); UBits n = barg(L, 2) & 31; BRET(fn(b, n)) }
BIT_SH(bit_lshift,bshl)119 BIT_SH(bit_lshift, bshl)
120 BIT_SH(bit_rshift, bshr)
121 BIT_SH(bit_arshift, bsar)
122 BIT_SH(bit_rol, brol)
123 BIT_SH(bit_ror, bror)
124
125 static int bit_bswap(lua_State *L)
126 {
127 UBits b = barg(L, 1);
128 b = (b >> 24) | ((b >> 8) & 0xff00) | ((b & 0xff00) << 8) | (b << 24);
129 BRET(b)
130 }
131
bit_tohex(lua_State * L)132 static int bit_tohex(lua_State *L)
133 {
134 UBits b = barg(L, 1);
135 SBits n = lua_isnone(L, 2) ? 8 : (SBits)barg(L, 2);
136 const char *hexdigits = "0123456789abcdef";
137 char buf[8];
138 int i;
139 if (n < 0) { n = -n; hexdigits = "0123456789ABCDEF"; }
140 if (n > 8) n = 8;
141 for (i = (int)n; --i >= 0; ) { buf[i] = hexdigits[b & 15]; b >>= 4; }
142 lua_pushlstring(L, buf, (size_t)n);
143 return 1;
144 }
145
146 static const struct luaL_Reg bit_funcs[] = {
147 { "tobit", bit_tobit },
148 { "bnot", bit_bnot },
149 { "band", bit_band },
150 { "bor", bit_bor },
151 { "bxor", bit_bxor },
152 { "lshift", bit_lshift },
153 { "rshift", bit_rshift },
154 { "arshift", bit_arshift },
155 { "rol", bit_rol },
156 { "ror", bit_ror },
157 { "bswap", bit_bswap },
158 { "tohex", bit_tohex },
159 { NULL, NULL }
160 };
161
162 /* Signed right-shifts are implementation-defined per C89/C99.
163 ** But the de facto standard are arithmetic right-shifts on two's
164 ** complement CPUs. This behaviour is required here, so test for it.
165 */
166 #define BAD_SAR (bsar(-8, 2) != (SBits)-2)
167
luaopen_bit(lua_State * L)168 LUALIB_API int luaopen_bit(lua_State *L)
169 {
170 UBits b;
171 #if LUA_VERSION_NUM < 503
172 lua_pushnumber(L, (lua_Number)1437217655L);
173 #else
174 lua_pushinteger(L, (lua_Integer)1437217655L);
175 #endif
176 b = barg(L, -1);
177 if (b != (UBits)1437217655L || BAD_SAR) { /* Perform a simple self-test. */
178 const char *msg = "compiled with incompatible luaconf.h";
179 #if defined(LUA_NUMBER_DOUBLE) || defined(LUA_FLOAT_DOUBLE)
180 #ifdef _WIN32
181 if (b == (UBits)1610612736L)
182 msg = "use D3DCREATE_FPU_PRESERVE with DirectX";
183 #endif
184 if (b == (UBits)1127743488L)
185 msg = "not compiled with SWAPPED_DOUBLE";
186 #endif
187 if (BAD_SAR)
188 msg = "arithmetic right-shift broken";
189 luaL_error(L, "bit library self-test failed (%s)", msg);
190 }
191 #if LUA_VERSION_NUM < 502
192 luaL_register(L, "bit", bit_funcs);
193 #else
194 luaL_newlib(L, bit_funcs);
195 #endif
196 return 1;
197 }
198
199