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Commit	Line	Data
	1	/* Bitwise operations library */
	2	/* (c) Reuben Thomas 2000-2008 */
	3	/* See README for license */
	4
	5	#include <lua.h>
	6	#include <lauxlib.h>
	7	#include <limits.h>
	8
	9	#include "pm3_bit_limits.h"
	10
	11
	12	/* FIXME: Assumes lua_Integer is ptrdiff_t */
	13	#define LUA_INTEGER_MAX PTRDIFF_MAX
	14	#define LUA_INTEGER_MIN PTRDIFF_MIN
	15
	16	/* FIXME: Assumes size_t is an unsigned lua_Integer */
	17	typedef size_t lua_UInteger;
	18	#define LUA_UINTEGER_MAX SIZE_MAX
	19
	20
	21	/* Bit type size and limits */
	22
	23	#define BIT_BITS \
	24	(CHAR_BIT * sizeof(lua_Integer) > BITLIB_FLOAT_BITS ? \
	25	BITLIB_FLOAT_BITS : (CHAR_BIT * sizeof(lua_Integer)))
	26
	27	/* This code may give warnings if BITLIB_FLOAT_* are too big to fit in
	28	long, but that doesn't matter since in that case they won't be
	29	used. */
	30	#define BIT_MAX \
	31	(CHAR_BIT * sizeof(lua_Integer) > BITLIB_FLOAT_BITS ? BITLIB_FLOAT_MAX : LUA_INTEGER_MAX)
	32
	33	#define BIT_MIN \
	34	(CHAR_BIT * sizeof(lua_Integer) > BITLIB_FLOAT_BITS ? BITLIB_FLOAT_MIN : LUA_INTEGER_MIN)
	35
	36	#define BIT_UMAX \
	37	(CHAR_BIT * sizeof(lua_Integer) > BITLIB_FLOAT_BITS ? BITLIB_FLOAT_UMAX : LUA_UINTEGER_MAX)
	38
	39
	40	/* Define TOBIT to get a bit value */
	41	#ifdef BUILTIN_CAST
	42	#define
	43	#define TOBIT(L, n, res) \
	44	((void)(res), luaL_checkinteger((L), (n)))
	45	#else
	46	#include <stdint.h>
	47	#include <math.h>
	48
	49	/* FIXME: Assumes lua_Number fits in a double (use of fmod). */
	50	#define TOBIT(L, n, res) \
	51	((lua_Integer)(((res) = fmod(luaL_checknumber(L, (n)), (double)BIT_UMAX + 1.0)), \
	52	(res) > BIT_MAX ? ((res) -= (double)BIT_UMAX, (res) -= 1) : \
	53	((res) < BIT_MIN ? ((res) += (double)BIT_UMAX, (res) += 1) : (res))))
	54	#endif
	55
	56
	57	#define BIT_TRUNCATE(i) \
	58	((i) & BIT_UMAX)
	59
	60
	61	/* Operations
	62
	63	The macros MONADIC and VARIADIC only deal with bitwise operations.
	64
	65	LOGICAL_SHIFT truncates its left-hand operand before shifting so
	66	that any extra bits at the most-significant end are not shifted
	67	into the result.
	68
	69	ARITHMETIC_SHIFT does not truncate its left-hand operand, so that
	70	the sign bits are not removed and right shift work properly.
	71	*/
	72
	73	#define MONADIC(name, op) \
	74	static int bit_ ## name(lua_State *L) { \
	75	lua_Number f; \
	76	lua_pushinteger(L, BIT_TRUNCATE(op TOBIT(L, 1, f))); \
	77	return 1; \
	78	}
	79
	80	#define VARIADIC(name, op) \
	81	static int bit_ ## name(lua_State *L) { \
	82	lua_Number f; \
	83	int n = lua_gettop(L), i; \
	84	lua_Integer w = TOBIT(L, 1, f); \
	85	for (i = 2; i <= n; i++) \
	86	w op TOBIT(L, i, f); \
	87	lua_pushinteger(L, BIT_TRUNCATE(w)); \
	88	return 1; \
	89	}
	90
	91	#define LOGICAL_SHIFT(name, op) \
	92	static int bit_ ## name(lua_State *L) { \
	93	lua_Number f; \
	94	lua_pushinteger(L, BIT_TRUNCATE(BIT_TRUNCATE((lua_UInteger)TOBIT(L, 1, f)) op \
	95	(unsigned)luaL_checknumber(L, 2))); \
	96	return 1; \
	97	}
	98
	99	#define ARITHMETIC_SHIFT(name, op) \
	100	static int bit_ ## name(lua_State *L) { \
	101	lua_Number f; \
	102	lua_pushinteger(L, BIT_TRUNCATE((lua_Integer)TOBIT(L, 1, f) op \
	103	(unsigned)luaL_checknumber(L, 2))); \
	104	return 1; \
	105	}
	106
	107	MONADIC(cast, +)
	108	MONADIC(bnot, ~)
	109	VARIADIC(band, &=)
	110	VARIADIC(bor, \|=)
	111	VARIADIC(bxor, ^=)
	112	ARITHMETIC_SHIFT(lshift, <<)
	113	LOGICAL_SHIFT(rshift, >>)
	114	ARITHMETIC_SHIFT(arshift, >>)
	115
	116	static const struct luaL_Reg bitlib[] = {
	117	{"cast", bit_cast},
	118	{"bnot", bit_bnot},
	119	{"band", bit_band},
	120	{"bor", bit_bor},
	121	{"bxor", bit_bxor},
	122	{"lshift", bit_lshift},
	123	{"rshift", bit_rshift},
	124	{"arshift", bit_arshift},
	125	{NULL, NULL}
	126	};
	127
	128	LUALIB_API int luaopen_bit (lua_State *L) {
	129	luaL_newlib(L, bitlib);
	130	//luaL_register(L, "bit", bitlib);
	131	lua_pushnumber(L, BIT_BITS);
	132	lua_setfield(L, -2, "bits");
	133	return 1;
	134	}
	135
	136	/**
	137	LUALIB_API int luaopen_bit (lua_State *L) {
	138	luaL_register(L, "bit", bitlib);
	139	lua_pushnumber(L, BIT_BITS);
	140	lua_setfield(L, -2, "bits");
	141	return 1;
	142	}
	143	**/
	144	/*
	145	** Open bit library
	146	*/
	147	int set_bit_library (lua_State *L) {
	148
	149	luaL_requiref(L, "bit", luaopen_bit, 1);
	150	lua_pop(L, 1);
	151	return 1;
	152	}