root/src/modules/lua_bit.c

Revision e4877df78137b23c4f223a3c99234f053a384b77, 5.2 kB (checked in by Theo Schlossnagle <jesus@omniti.com>, 1 year ago)

port this up to lua 5.2

  • Property mode set to 100644
Line 
1 /*
2 ** Lua BitOp -- a bit operations library for Lua 5.1.
3 ** http://bitop.luajit.org/
4 **
5 ** Copyright (C) 2008-2009 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       "1.0.1"
30
31 #define LUA_LIB
32 #define LUA_COMPAT_MODULE
33 #include "lua.h"
34 #include "lauxlib.h"
35
36 #ifdef _MSC_VER
37 /* MSVC is stuck in the last century and doesn't have C99's stdint.h. */
38 typedef __int32 int32_t;
39 typedef unsigned __int32 uint32_t;
40 typedef unsigned __int64 uint64_t;
41 #else
42 #include <stdint.h>
43 #endif
44
45 typedef int32_t SBits;
46 typedef uint32_t UBits;
47
48 typedef union {
49   lua_Number n;
50 #ifdef LUA_NUMBER_DOUBLE
51   uint64_t b;
52 #else
53   UBits b;
54 #endif
55 } BitNum;
56
57 /* Convert argument to bit type. */
58 static UBits barg(lua_State *L, int idx)
59 {
60   BitNum bn;
61   UBits b;
62   bn.n = lua_tonumber(L, idx);
63 #if defined(LUA_NUMBER_DOUBLE)
64   bn.n += 6755399441055744.0;  /* 2^52+2^51 */
65 #ifdef SWAPPED_DOUBLE
66   b = (UBits)(bn.b >> 32);
67 #else
68   b = (UBits)bn.b;
69 #endif
70 #elif defined(LUA_NUMBER_INT) || defined(LUA_NUMBER_LONG) || \
71       defined(LUA_NUMBER_LONGLONG) || defined(LUA_NUMBER_LONG_LONG) || \
72       defined(LUA_NUMBER_LLONG)
73   if (sizeof(UBits) == sizeof(lua_Number))
74     b = bn.b;
75   else
76     b = (UBits)(SBits)bn.n;
77 #elif defined(LUA_NUMBER_FLOAT)
78 #error "A 'float' lua_Number type is incompatible with this library"
79 #else
80 #error "Unknown number type, check LUA_NUMBER_* in luaconf.h"
81 #endif
82   if (b == 0 && !lua_isnumber(L, idx))
83     luaL_error(L, "number");
84   return b;
85 }
86
87 /* Return bit type. */
88 #define BRET(b)  lua_pushnumber(L, (lua_Number)(SBits)(b)); return 1;
89
90 static int bit_tobit(lua_State *L) { BRET(barg(L, 1)) }
91 static int bit_bnot(lua_State *L) { BRET(~barg(L, 1)) }
92
93 #define BIT_OP(func, opr) \
94   static int func(lua_State *L) { int i; UBits b = barg(L, 1); \
95     for (i = lua_gettop(L); i > 1; i--) b opr barg(L, i); BRET(b) }
96 BIT_OP(bit_band, &=)
97 BIT_OP(bit_bor, |=)
98 BIT_OP(bit_bxor, ^=)
99
100 #define bshl(b, n)  (b << n)
101 #define bshr(b, n)  (b >> n)
102 #define bsar(b, n)  ((SBits)b >> n)
103 #define brol(b, n)  ((b << n) | (b >> (32-n)))
104 #define bror(b, n)  ((b << (32-n)) | (b >> n))
105 #define BIT_SH(func, fn) \
106   static int func(lua_State *L) { \
107     UBits b = barg(L, 1); UBits n = barg(L, 2) & 31; BRET(fn(b, n)) }
108 BIT_SH(bit_lshift, bshl)
109 BIT_SH(bit_rshift, bshr)
110 BIT_SH(bit_arshift, bsar)
111 BIT_SH(bit_rol, brol)
112 BIT_SH(bit_ror, bror)
113
114 static int bit_bswap(lua_State *L)
115 {
116   UBits b = barg(L, 1);
117   b = (b >> 24) | ((b >> 8) & 0xff00) | ((b & 0xff00) << 8) | (b << 24);
118   BRET(b)
119 }
120
121 static int bit_tohex(lua_State *L)
122 {
123   UBits b = barg(L, 1);
124   SBits n = lua_isnone(L, 2) ? 8 : (SBits)barg(L, 2);
125   const char *hexdigits = "0123456789abcdef";
126   char buf[8];
127   int i;
128   if (n < 0) { n = -n; hexdigits = "0123456789ABCDEF"; }
129   if (n > 8) n = 8;
130   for (i = (int)n; --i >= 0; ) { buf[i] = hexdigits[b & 15]; b >>= 4; }
131   lua_pushlstring(L, buf, (size_t)n);
132   return 1;
133 }
134
135 static const struct luaL_Reg bit_funcs[] = {
136   { "tobit",    bit_tobit },
137   { "bnot",     bit_bnot },
138   { "band",     bit_band },
139   { "bor",      bit_bor },
140   { "bxor",     bit_bxor },
141   { "lshift",   bit_lshift },
142   { "rshift",   bit_rshift },
143   { "arshift",  bit_arshift },
144   { "rol",      bit_rol },
145   { "ror",      bit_ror },
146   { "bswap",    bit_bswap },
147   { "tohex",    bit_tohex },
148   { NULL, NULL }
149 };
150
151 /* Signed right-shifts are implementation-defined per C89/C99.
152 ** But the de facto standard are arithmetic right-shifts on two's
153 ** complement CPUs. This behaviour is required here, so test for it.
154 */
155 #define BAD_SAR         (bsar(-8, 2) != (SBits)-2)
156
157 LUALIB_API int luaopen_bit(lua_State *L)
158 {
159   UBits b;
160   lua_pushnumber(L, (lua_Number)1437217655L);
161   b = barg(L, -1);
162   if (b != (UBits)1437217655L || BAD_SAR) {  /* Perform a simple self-test. */
163     const char *msg = "compiled with incompatible luaconf.h";
164 #ifdef LUA_NUMBER_DOUBLE
165 #ifdef _WIN32
166     if (b == (UBits)1610612736L)
167       msg = "use D3DCREATE_FPU_PRESERVE with DirectX";
168 #endif
169     if (b == (UBits)1127743488L)
170       msg = "not compiled with SWAPPED_DOUBLE";
171 #endif
172     if (BAD_SAR)
173       msg = "arithmetic right-shift broken";
174     luaL_error(L, "bit library self-test failed (%s)", msg);
175   }
176   luaL_openlib(L, "bit", bit_funcs, 0);
177   return 1;
178 }
179
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