+/* Bitwise operations library */
+/* (c) Reuben Thomas 2000-2008 */
+/* See README for license */
+
+#include <lua.h>
+#include <lauxlib.h>
+#include <limits.h>
+
+#include "pm3_bit_limits.h"
+
+
+/* FIXME: Assumes lua_Integer is ptrdiff_t */
+#define LUA_INTEGER_MAX PTRDIFF_MAX
+#define LUA_INTEGER_MIN PTRDIFF_MIN
+
+/* FIXME: Assumes size_t is an unsigned lua_Integer */
+typedef size_t lua_UInteger;
+#define LUA_UINTEGER_MAX SIZE_MAX
+
+
+/* Bit type size and limits */
+
+#define BIT_BITS \
+ (CHAR_BIT * sizeof(lua_Integer) > BITLIB_FLOAT_BITS ? \
+ BITLIB_FLOAT_BITS : (CHAR_BIT * sizeof(lua_Integer)))
+
+/* This code may give warnings if BITLIB_FLOAT_* are too big to fit in
+ long, but that doesn't matter since in that case they won't be
+ used. */
+#define BIT_MAX \
+ (CHAR_BIT * sizeof(lua_Integer) > BITLIB_FLOAT_BITS ? BITLIB_FLOAT_MAX : LUA_INTEGER_MAX)
+
+#define BIT_MIN \
+ (CHAR_BIT * sizeof(lua_Integer) > BITLIB_FLOAT_BITS ? BITLIB_FLOAT_MIN : LUA_INTEGER_MIN)
+
+#define BIT_UMAX \
+ (CHAR_BIT * sizeof(lua_Integer) > BITLIB_FLOAT_BITS ? BITLIB_FLOAT_UMAX : LUA_UINTEGER_MAX)
+
+
+/* Define TOBIT to get a bit value */
+#ifdef BUILTIN_CAST
+#define
+#define TOBIT(L, n, res) \
+ ((void)(res), luaL_checkinteger((L), (n)))
+#else
+#include <stdint.h>
+#include <math.h>
+
+/* FIXME: Assumes lua_Number fits in a double (use of fmod). */
+#define TOBIT(L, n, res) \
+ ((lua_Integer)(((res) = fmod(luaL_checknumber(L, (n)), (double)BIT_UMAX + 1.0)), \
+ (res) > BIT_MAX ? ((res) -= (double)BIT_UMAX, (res) -= 1) : \
+ ((res) < BIT_MIN ? ((res) += (double)BIT_UMAX, (res) += 1) : (res))))
+#endif
+
+
+#define BIT_TRUNCATE(i) \
+ ((i) & BIT_UMAX)
+
+
+/* Operations
+
+ The macros MONADIC and VARIADIC only deal with bitwise operations.
+
+ LOGICAL_SHIFT truncates its left-hand operand before shifting so
+ that any extra bits at the most-significant end are not shifted
+ into the result.
+
+ ARITHMETIC_SHIFT does not truncate its left-hand operand, so that
+ the sign bits are not removed and right shift work properly.
+ */
+
+#define MONADIC(name, op) \
+ static int bit_ ## name(lua_State *L) { \
+ lua_Number f; \
+ lua_pushinteger(L, BIT_TRUNCATE(op TOBIT(L, 1, f))); \
+ return 1; \
+ }
+
+#define VARIADIC(name, op) \
+ static int bit_ ## name(lua_State *L) { \
+ lua_Number f; \
+ int n = lua_gettop(L), i; \
+ lua_Integer w = TOBIT(L, 1, f); \
+ for (i = 2; i <= n; i++) \
+ w op TOBIT(L, i, f); \
+ lua_pushinteger(L, BIT_TRUNCATE(w)); \
+ return 1; \
+ }
+
+#define LOGICAL_SHIFT(name, op) \
+ static int bit_ ## name(lua_State *L) { \
+ lua_Number f; \
+ lua_pushinteger(L, BIT_TRUNCATE(BIT_TRUNCATE((lua_UInteger)TOBIT(L, 1, f)) op \
+ (unsigned)luaL_checknumber(L, 2))); \
+ return 1; \
+ }
+
+#define ARITHMETIC_SHIFT(name, op) \
+ static int bit_ ## name(lua_State *L) { \
+ lua_Number f; \
+ lua_pushinteger(L, BIT_TRUNCATE((lua_Integer)TOBIT(L, 1, f) op \
+ (unsigned)luaL_checknumber(L, 2))); \
+ return 1; \
+ }
+
+MONADIC(cast, +)
+MONADIC(bnot, ~)
+VARIADIC(band, &=)
+VARIADIC(bor, |=)
+VARIADIC(bxor, ^=)
+ARITHMETIC_SHIFT(lshift, <<)
+LOGICAL_SHIFT(rshift, >>)
+ARITHMETIC_SHIFT(arshift, >>)
+
+static const struct luaL_Reg bitlib[] = {
+ {"cast", bit_cast},
+ {"bnot", bit_bnot},
+ {"band", bit_band},
+ {"bor", bit_bor},
+ {"bxor", bit_bxor},
+ {"lshift", bit_lshift},
+ {"rshift", bit_rshift},
+ {"arshift", bit_arshift},
+ {NULL, NULL}
+};
+
+LUALIB_API int luaopen_bit (lua_State *L) {
+ luaL_newlib(L, bitlib);
+ //luaL_register(L, "bit", bitlib);
+ lua_pushnumber(L, BIT_BITS);
+ lua_setfield(L, -2, "bits");
+ return 1;
+}
+
+/**
+LUALIB_API int luaopen_bit (lua_State *L) {
+ luaL_register(L, "bit", bitlib);
+ lua_pushnumber(L, BIT_BITS);
+ lua_setfield(L, -2, "bits");
+ return 1;
+}
+**/
+/*
+** Open bit library
+*/
+int set_bit_library (lua_State *L) {
+
+ luaL_requiref(L, "bit", luaopen_bit, 1);
+ lua_pop(L, 1);
+ return 1;
+}
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