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/*******************************************************************************
* Copyright (c) 2012 Luaj.org. All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
******************************************************************************/
package org.luaj.vm2.lib;
import org.luaj.vm2.LuaTable;
import org.luaj.vm2.LuaValue;
import org.luaj.vm2.Varargs;
/**
* Subclass of LibFunction that implements the Lua standard {@code bit32} library.
*
* Typically, this library is included as part of a call to either
* {@link JsePlatform#standardGlobals()} or {@link JmePlatform#standardGlobals()}
*
{@code
* Globals globals = JsePlatform.standardGlobals();
* System.out.println( globals.get("bit32").get("bnot").call( LuaValue.valueOf(2) ) );
* }
*
* To instantiate and use it directly,
* link it into your globals table via {@link LuaValue#load(LuaValue)} using code such as:
*
{@code
* Globals globals = new Globals();
* globals.load(new JseBaseLib());
* globals.load(new PackageLib());
* globals.load(new Bit32Lib());
* System.out.println( globals.get("bit32").get("bnot").call( LuaValue.valueOf(2) ) );
* }
*
* This has been implemented to match as closely as possible the behavior in the corresponding library in C.
* @see LibFunction
* @see JsePlatform
* @see JmePlatform
* @see Lua 5.2 Bitwise Operation Lib Reference
*/
public class Bit32Lib extends TwoArgFunction {
public Bit32Lib() {
}
public LuaValue call(LuaValue modname, LuaValue env) {
LuaTable t = new LuaTable();
bind(t, Bit32LibV.class, new String[] {
"band", "bnot", "bor", "btest", "bxor", "extract", "replace"
});
bind(t, Bit32Lib2.class, new String[] {
"arshift", "lrotate", "lshift", "rrotate", "rshift"
});
env.set("bit32", t);
env.get("package").get("loaded").set("bit32", t);
return t;
}
static final class Bit32LibV extends VarArgFunction {
public Varargs invoke(Varargs args) {
switch ( opcode ) {
case 0: return Bit32Lib.band( args );
case 1: return Bit32Lib.bnot( args );
case 2: return Bit32Lib.bor( args );
case 3: return Bit32Lib.btest( args );
case 4: return Bit32Lib.bxor( args );
case 5:
return Bit32Lib.extract( args.checkint(1), args.checkint(2), args.optint(3, 1) );
case 6:
return Bit32Lib.replace( args.checkint(1), args.checkint(2),
args.checkint(3), args.optint(4, 1) );
}
return NIL;
}
}
static final class Bit32Lib2 extends TwoArgFunction {
public LuaValue call(LuaValue arg1, LuaValue arg2) {
switch ( opcode ) {
case 0: return Bit32Lib.arshift(arg1.checkint(), arg2.checkint());
case 1: return Bit32Lib.lrotate(arg1.checkint(), arg2.checkint());
case 2: return Bit32Lib.lshift(arg1.checkint(), arg2.checkint());
case 3: return Bit32Lib.rrotate(arg1.checkint(), arg2.checkint());
case 4: return Bit32Lib.rshift(arg1.checkint(), arg2.checkint());
}
return NIL;
}
}
static LuaValue arshift(int x, int disp) {
if (disp >= 0) {
return bitsToValue(x >> disp);
} else {
return bitsToValue(x << -disp);
}
}
static LuaValue rshift(int x, int disp) {
if (disp >= 32 || disp <= -32) {
return ZERO;
} else if (disp >= 0) {
return bitsToValue(x >>> disp);
} else {
return bitsToValue(x << -disp);
}
}
static LuaValue lshift(int x, int disp) {
if (disp >= 32 || disp <= -32) {
return ZERO;
} else if (disp >= 0) {
return bitsToValue(x << disp);
} else {
return bitsToValue(x >>> -disp);
}
}
static Varargs band( Varargs args ) {
int result = -1;
for ( int i = 1; i <= args.narg(); i++ ) {
result &= args.checkint(i);
}
return bitsToValue( result );
}
static Varargs bnot( Varargs args ) {
return bitsToValue( ~args.checkint(1) );
}
static Varargs bor( Varargs args ) {
int result = 0;
for ( int i = 1; i <= args.narg(); i++ ) {
result |= args.checkint(i);
}
return bitsToValue( result );
}
static Varargs btest( Varargs args ) {
int bits = -1;
for ( int i = 1; i <= args.narg(); i++ ) {
bits &= args.checkint(i);
}
return valueOf( bits != 0 );
}
static Varargs bxor( Varargs args ) {
int result = 0;
for ( int i = 1; i <= args.narg(); i++ ) {
result ^= args.checkint(i);
}
return bitsToValue( result );
}
static LuaValue lrotate(int x, int disp) {
if (disp < 0) {
return rrotate(x, -disp);
} else {
disp = disp & 31;
return bitsToValue((x << disp) | (x >>> (32 - disp)));
}
}
static LuaValue rrotate(int x, int disp) {
if (disp < 0) {
return lrotate(x, -disp);
} else {
disp = disp & 31;
return bitsToValue((x >>> disp) | (x << (32 - disp)));
}
}
static LuaValue extract(int n, int field, int width) {
if (field < 0) {
argerror(2, "field cannot be negative");
}
if (width < 0) {
argerror(3, "width must be postive");
}
if (field + width > 32) {
error("trying to access non-existent bits");
}
return bitsToValue((n >>> field) & (-1 >>> (32 - width)));
}
static LuaValue replace(int n, int v, int field, int width) {
if (field < 0) {
argerror(3, "field cannot be negative");
}
if (width < 0) {
argerror(4, "width must be postive");
}
if (field + width > 32) {
error("trying to access non-existent bits");
}
int mask = (-1 >>> (32 - width)) << field;
n = (n & ~mask) | ((v << field) & mask);
return bitsToValue(n);
}
private static LuaValue bitsToValue( int x ) {
return ( x < 0 ) ? valueOf((double) ((long) x & 0xFFFFFFFFL)) : valueOf(x);
}
}