/*
* @(#)AndExpression.java 1.13 95/11/12 Arthur van Hoff
*
* Copyright (c) 1994 Sun Microsystems, Inc. All Rights Reserved.
*
* Permission to use, copy, modify, and distribute this software
* and its documentation for NON-COMMERCIAL purposes and without
* fee is hereby granted provided that this copyright notice
* appears in all copies. Please refer to the file "copyright.html"
* for further important copyright and licensing information.
*
* SUN MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
* THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
* TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
* PARTICULAR PURPOSE, OR NON-INFRINGEMENT. SUN SHALL NOT BE LIABLE FOR
* ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
* DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
*/
package sun.tools.tree;
import sun.tools.java.*;
import sun.tools.asm.Assembler;
import sun.tools.asm.Label;
import java.util.Hashtable;
public
class AndExpression extends BinaryLogicalExpression {
/**
* constructor
*/
public AndExpression(int where, Expression left, Expression right) {
super(AND, where, left, right);
}
/*
* Check an "and" expression.
*
* cvars is modified so that
* cvar.vsTrue indicates variables with a known value if
* both the left and right hand side are true
* cvars.vsFalse indicates variables with a known value
* either the left or right hand side is false
*/
public void checkCondition(Environment env, Context ctx, long vset,
Hashtable exp, ConditionVars cvars) {
// Find out when the left side is true/false
left.checkCondition(env, ctx, vset, exp, cvars);
left = convert(env, ctx, Type.tBoolean, left);
long vsTrue = cvars.vsTrue;
long vsFalse = cvars.vsFalse;
// Only look at the right side if the left side is true
right.checkCondition(env, ctx, vsTrue, exp, cvars);
right = convert(env, ctx, Type.tBoolean, right);
// cvars.vsTrue already reports when both returned true
// cvars.vsFalse must be set to either the left or right side
// returning false
cvars.vsFalse &= vsFalse;
}
/**
* Evaluate
*/
Expression eval(boolean a, boolean b) {
return new BooleanExpression(where, a && b);
}
/**
* Simplify
*/
Expression simplify() {
if (left.equals(true) || right.equals(false)) {
return right;
}
if (left.equals(false) || right.equals(true)) {
return left;
}
return this;
}
/**
* Code
*/
void codeBranch(Environment env, Context ctx, Assembler asm, Label lbl, boolean whenTrue) {
if (whenTrue) {
Label lbl2 = new Label();
left.codeBranch(env, ctx, asm, lbl2, false);
right.codeBranch(env, ctx, asm, lbl, true);
asm.add(lbl2);
} else {
left.codeBranch(env, ctx, asm, lbl, false);
right.codeBranch(env, ctx, asm, lbl, false);
}
}
}