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. */
37typedef __int32 int32_t;
38typedef unsigned __int32 uint32_t;
39typedef unsigned __int64 uint64_t;
40#else
41#include <stdint.h>
42#endif
43
44typedef int32_t SBits;
45typedef uint32_t UBits;
46
47typedef 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. */
57static 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
96static int bit_tobit(lua_State *L) { BRET(barg(L, 1)) }
97static 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); \
102 BRET(b) }
103BIT_OP(bit_band, &=)
104BIT_OP(bit_bor, |=)
105BIT_OP(bit_bxor, ^=)
106
107#define bshl(b, n) (b << n)
108#define bshr(b, n) (b >> n)
109#define bsar(b, n) ((SBits)b >> n)
110#define brol(b, n) ((b << n) | (b >> (32-n)))
111#define bror(b, n) ((b << (32-n)) | (b >> n))
112#define BIT_SH(func, fn) \
113 static int func(lua_State *L) { \
114 UBits b = barg(L, 1); UBits n = barg(L, 2) & 31; BRET(fn(b, n)) }
115BIT_SH(bit_lshift, bshl)
116BIT_SH(bit_rshift, bshr)
117BIT_SH(bit_arshift, bsar)
118BIT_SH(bit_rol, brol)
119BIT_SH(bit_ror, bror)
120
121static int bit_bswap(lua_State *L)
122{
123 UBits b = barg(L, 1);
124 b = (b >> 24) | ((b >> 8) & 0xff00) | ((b & 0xff00) << 8) | (b << 24);
125 BRET(b)
126}
127
128static int bit_tohex(lua_State *L)
129{
130 UBits b = barg(L, 1);
131 SBits n = lua_isnone(L, 2) ? 8 : (SBits)barg(L, 2);
132 const char *hexdigits = "0123456789abcdef";
133 char buf[8];
134 int i;
135 if (n < 0) { n = -n; hexdigits = "0123456789ABCDEF"; }
136 if (n > 8) n = 8;
137 for (i = (int)n; --i >= 0; ) { buf[i] = hexdigits[b & 15]; b >>= 4; }
138 lua_pushlstring(L, buf, (size_t)n);
139 return 1;
140}
141
142static const struct luaL_Reg bit_funcs[] = {
143 { "tobit", bit_tobit },
144 { "bnot", bit_bnot },
145 { "band", bit_band },
146 { "bor", bit_bor },
147 { "bxor", bit_bxor },
148 { "lshift", bit_lshift },
149 { "rshift", bit_rshift },
150 { "arshift", bit_arshift },
151 { "rol", bit_rol },
152 { "ror", bit_ror },
153 { "bswap", bit_bswap },
154 { "tohex", bit_tohex },
155 { NULL, NULL }
156};
157
158/* Signed right-shifts are implementation-defined per C89/C99.
159** But the de facto standard are arithmetic right-shifts on two's
160** complement CPUs. This behaviour is required here, so test for it.
161*/
162#define BAD_SAR (bsar(-8, 2) != (SBits)-2)
163
164LUALIB_API int luaopen_bit(lua_State *L)
165{
166 UBits b;
167 lua_pushnumber(L, (lua_Number)1437217655L);
168 b = barg(L, -1);
169 if (b != (UBits)1437217655L || BAD_SAR) { /* Perform a simple self-test. */
170 const char *msg = "compiled with incompatible luaconf.h";
171#ifdef LUA_NUMBER_DOUBLE
172#ifdef _WIN32
173 if (b == (UBits)1610612736L)
174 msg = "use D3DCREATE_FPU_PRESERVE with DirectX";
175#endif
176 if (b == (UBits)1127743488L)
177 msg = "not compiled with SWAPPED_DOUBLE";
178#endif
179 if (BAD_SAR)
180 msg = "arithmetic right-shift broken";
181 luaL_error(L, "bit library self-test failed (%s)", msg);
182 }
183#if LUA_VERSION_NUM < 502
184 luaL_register(L, "bit", bit_funcs);
185#else
186 luaL_newlib(L, bit_funcs);
187#endif
188 return 1;
189}
190
191