nodemcu-firmware/app/modules/bit.c

139 lines
4.2 KiB
C

/* Bitwise operations library */
/* (c) Reuben Thomas 2000-2008 */
/* See README for license */
// Modified by BogdanM for eLua
#include "module.h"
#include <limits.h>
#include "lauxlib.h"
/* FIXME: Assume size_t is an unsigned lua_Integer */
typedef size_t lua_UInteger;
#define LUA_UINTEGER_MAX SIZE_MAX
/* Define TOBIT to get a bit value */
#define TOBIT(L, n) \
(luaL_checkinteger((L), (n)))
/* 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_pushinteger(L, op TOBIT(L, 1)); \
return 1; \
}
#define VARIADIC(name, op) \
static int bit_ ## name(lua_State *L) { \
int n = lua_gettop(L), i; \
lua_Integer w = TOBIT(L, 1); \
for (i = 2; i <= n; i++) \
w op TOBIT(L, i); \
lua_pushinteger(L, w); \
return 1; \
}
#define LOGICAL_SHIFT(name, op) \
static int bit_ ## name(lua_State *L) { \
lua_pushinteger(L, (lua_UInteger)TOBIT(L, 1) op \
(unsigned)luaL_checknumber(L, 2)); \
return 1; \
}
#define ARITHMETIC_SHIFT(name, op) \
static int bit_ ## name(lua_State *L) { \
lua_pushinteger(L, (lua_Integer)TOBIT(L, 1) op \
(unsigned)luaL_checknumber(L, 2)); \
return 1; \
}
MONADIC(bnot, ~)
VARIADIC(band, &=)
VARIADIC(bor, |=)
VARIADIC(bxor, ^=)
ARITHMETIC_SHIFT(lshift, <<)
LOGICAL_SHIFT(rshift, >>)
ARITHMETIC_SHIFT(arshift, >>)
// Lua: res = bit( position )
static int bit_bit( lua_State* L )
{
lua_pushinteger( L, ( lua_Integer )( 1 << luaL_checkinteger( L, 1 ) ) );
return 1;
}
// Lua: res = isset( value, position )
static int bit_isset( lua_State* L )
{
lua_UInteger val = ( lua_UInteger )luaL_checkinteger( L, 1 );
unsigned pos = ( unsigned )luaL_checkinteger( L, 2 );
lua_pushboolean( L, val & ( 1 << pos ) ? 1 : 0 );
return 1;
}
// Lua: res = isclear( value, position )
static int bit_isclear( lua_State* L )
{
lua_UInteger val = ( lua_UInteger )luaL_checkinteger( L, 1 );
unsigned pos = ( unsigned )luaL_checkinteger( L, 2 );
lua_pushboolean( L, val & ( 1 << pos ) ? 0 : 1 );
return 1;
}
// Lua: res = set( value, pos1, pos2, ... )
static int bit_set( lua_State* L )
{
lua_UInteger val = ( lua_UInteger )luaL_checkinteger( L, 1 );
unsigned total = lua_gettop( L ), i;
for( i = 2; i <= total; i ++ )
val |= 1 << ( unsigned )luaL_checkinteger( L, i );
lua_pushinteger( L, ( lua_Integer )val );
return 1;
}
// Lua: res = clear( value, pos1, pos2, ... )
static int bit_clear( lua_State* L )
{
lua_UInteger val = ( lua_UInteger )luaL_checkinteger( L, 1 );
unsigned total = lua_gettop( L ), i;
for( i = 2; i <= total; i ++ )
val &= ~( 1 << ( unsigned )luaL_checkinteger( L, i ) );
lua_pushinteger( L, ( lua_Integer )val );
return 1;
}
LROT_BEGIN(bit, NULL, 0)
LROT_FUNCENTRY( bnot, bit_bnot )
LROT_FUNCENTRY( band, bit_band )
LROT_FUNCENTRY( bor, bit_bor )
LROT_FUNCENTRY( bxor, bit_bxor )
LROT_FUNCENTRY( lshift, bit_lshift )
LROT_FUNCENTRY( rshift, bit_rshift )
LROT_FUNCENTRY( arshift, bit_arshift )
LROT_FUNCENTRY( bit, bit_bit )
LROT_FUNCENTRY( set, bit_set )
LROT_FUNCENTRY( clear, bit_clear )
LROT_FUNCENTRY( isset, bit_isset )
LROT_FUNCENTRY( isclear, bit_isclear )
LROT_END(bit, NULL, 0)
NODEMCU_MODULE(BIT, "bit", bit, NULL);