first scanner /parser copied from the jdt java version
[phpeclipse.git] / net.sourceforge.phpeclipse / src / net / sourceforge / phpdt / internal / compiler / ast / SwitchStatement.java
diff --git a/net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/compiler/ast/SwitchStatement.java b/net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/compiler/ast/SwitchStatement.java
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+/*******************************************************************************
+ * Copyright (c) 2000, 2001, 2002 International Business Machines Corp. and others.
+ * All rights reserved. This program and the accompanying materials 
+ * are made available under the terms of the Common Public License v0.5 
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/cpl-v05.html
+ * 
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ ******************************************************************************/
+package net.sourceforge.phpdt.internal.compiler.ast;
+
+import net.sourceforge.phpdt.internal.compiler.IAbstractSyntaxTreeVisitor;
+import net.sourceforge.phpdt.internal.compiler.impl.*;
+import net.sourceforge.phpdt.internal.compiler.codegen.*;
+import net.sourceforge.phpdt.internal.compiler.flow.*;
+import net.sourceforge.phpdt.internal.compiler.lookup.*;
+
+public class SwitchStatement extends Statement {
+       public Expression testExpression;
+       public Statement[] statements;
+       public BlockScope scope;
+       public int explicitDeclarations;
+       public Label breakLabel;
+       public Case[] cases;
+       public DefaultCase defaultCase;
+       public int caseCount = 0;
+
+       // for local variables table attributes
+       int preSwitchInitStateIndex = -1;
+       int mergedInitStateIndex = -1;
+       /**
+        * SwitchStatement constructor comment.
+        */
+       public SwitchStatement() {
+               super();
+       }
+       public FlowInfo analyseCode(
+               BlockScope currentScope,
+               FlowContext flowContext,
+               FlowInfo flowInfo) {
+               flowInfo = testExpression.analyseCode(currentScope, flowContext, flowInfo);
+               SwitchFlowContext switchContext =
+                       new SwitchFlowContext(flowContext, this, (breakLabel = new Label()));
+
+               // analyse the block by considering specially the case/default statements (need to bind them 
+               // to the entry point)
+               FlowInfo caseInits = FlowInfo.DeadEnd;
+               // in case of statements before the first case
+               preSwitchInitStateIndex =
+                       currentScope.methodScope().recordInitializationStates(flowInfo);
+               int caseIndex = 0;
+               if (statements != null) {
+                       for (int i = 0, max = statements.length; i < max; i++) {
+                               Statement statement = statements[i];
+                               if ((caseIndex < caseCount)
+                                       && (statement == cases[caseIndex])) { // statements[i] is a case or a default case
+                                       caseIndex++;
+                                       caseInits = caseInits.mergedWith(flowInfo.copy().unconditionalInits());
+                               } else {
+                                       if (statement == defaultCase) {
+                                               caseInits = caseInits.mergedWith(flowInfo.copy().unconditionalInits());
+                                       }
+                               }
+                               if (!caseInits.complainIfUnreachable(statement, scope)) {
+                                       caseInits = statement.analyseCode(scope, switchContext, caseInits);
+                               }
+                       }
+               }
+
+               // if no default case, then record it may jump over the block directly to the end
+               if (defaultCase == null) {
+                       // only retain the potential initializations
+                       flowInfo.addPotentialInitializationsFrom(
+                               caseInits.mergedWith(switchContext.initsOnBreak));
+                       mergedInitStateIndex =
+                               currentScope.methodScope().recordInitializationStates(flowInfo);
+                       return flowInfo;
+               }
+
+               // merge all branches inits
+               FlowInfo mergedInfo = caseInits.mergedWith(switchContext.initsOnBreak);
+               mergedInitStateIndex =
+                       currentScope.methodScope().recordInitializationStates(mergedInfo);
+               return mergedInfo;
+       }
+       /**
+        * Switch code generation
+        *
+        * @param currentScope org.eclipse.jdt.internal.compiler.lookup.BlockScope
+        * @param codeStream org.eclipse.jdt.internal.compiler.codegen.CodeStream
+        */
+       public void generateCode(BlockScope currentScope, CodeStream codeStream) {
+               int[] sortedIndexes = new int[caseCount];
+               int[] localKeysCopy;
+               if ((bits & IsReachableMASK) == 0) {
+                       return;
+               }
+               int pc = codeStream.position;
+
+               // prepare the labels and constants
+               breakLabel.codeStream = codeStream;
+               CaseLabel[] caseLabels = new CaseLabel[caseCount];
+               int[] constants = new int[caseCount];
+               boolean needSwitch = caseCount != 0;
+               for (int i = 0; i < caseCount; i++) {
+                       constants[i] = cases[i].constantExpression.constant.intValue();
+                       cases[i].targetLabel = (caseLabels[i] = new CaseLabel(codeStream));
+               }
+
+               // we sort the keys to be able to generate the code for tableswitch or lookupswitch
+               for (int i = 0; i < caseCount; i++) {
+                       sortedIndexes[i] = i;
+               }
+               System.arraycopy(
+                       constants,
+                       0,
+                       (localKeysCopy = new int[caseCount]),
+                       0,
+                       caseCount);
+               CodeStream.sort(localKeysCopy, 0, caseCount - 1, sortedIndexes);
+               CaseLabel defaultLabel = new CaseLabel(codeStream);
+               if (defaultCase != null) {
+                       defaultCase.targetLabel = defaultLabel;
+               }
+               // generate expression testes
+               testExpression.generateCode(currentScope, codeStream, needSwitch);
+
+               // generate the appropriate switch table
+               if (needSwitch) {
+                       int max = localKeysCopy[caseCount - 1];
+                       int min = localKeysCopy[0];
+                       if ((long) (caseCount * 2.5) > ((long) max - (long) min)) {
+                               codeStream.tableswitch(
+                                       defaultLabel,
+                                       min,
+                                       max,
+                                       constants,
+                                       sortedIndexes,
+                                       caseLabels);
+                       } else {
+                               codeStream.lookupswitch(defaultLabel, constants, sortedIndexes, caseLabels);
+                       }
+                       codeStream.updateLastRecordedEndPC(codeStream.position);
+               }
+               // generate the switch block statements
+               int caseIndex = 0;
+               if (statements != null) {
+                       for (int i = 0, maxCases = statements.length; i < maxCases; i++) {
+                               Statement statement = statements[i];
+                               if ((caseIndex < caseCount)
+                                       && (statement == cases[caseIndex])) { // statements[i] is a case
+                                       if (preSwitchInitStateIndex != -1) {
+                                               codeStream.removeNotDefinitelyAssignedVariables(
+                                                       currentScope,
+                                                       preSwitchInitStateIndex);
+                                               caseIndex++;
+                                       }
+                               } else {
+                                       if (statement == defaultCase) { // statements[i] is a case or a default case
+                                               if (preSwitchInitStateIndex != -1) {
+                                                       codeStream.removeNotDefinitelyAssignedVariables(
+                                                               currentScope,
+                                                               preSwitchInitStateIndex);
+                                               }
+                                       }
+                               }
+                               statement.generateCode(scope, codeStream);
+                       }
+               }
+               // place the trailing labels (for break and default case)
+               breakLabel.place();
+               if (defaultCase == null) {
+                       defaultLabel.place();
+               }
+               // May loose some local variable initializations : affecting the local variable attributes
+               if (mergedInitStateIndex != -1) {
+                       codeStream.removeNotDefinitelyAssignedVariables(
+                               currentScope,
+                               mergedInitStateIndex);
+                       codeStream.addDefinitelyAssignedVariables(currentScope, mergedInitStateIndex);
+               }
+               if (scope != currentScope) {
+                       codeStream.exitUserScope(scope);
+               }
+               codeStream.recordPositionsFrom(pc, this.sourceStart);
+       }
+
+
+       public void resetStateForCodeGeneration() {
+
+               this.breakLabel.resetStateForCodeGeneration();
+       }
+
+       public void resolve(BlockScope upperScope) {
+
+               TypeBinding testType = testExpression.resolveType(upperScope);
+               if (testType == null)
+                       return;
+               testExpression.implicitWidening(testType, testType);
+               if (!(testExpression
+                       .isConstantValueOfTypeAssignableToType(testType, IntBinding))) {
+                       if (!upperScope.areTypesCompatible(testType, IntBinding)) {
+                               upperScope.problemReporter().incorrectSwitchType(testExpression, testType);
+                               return;
+                       }
+               }
+               if (statements != null) {
+                       scope = explicitDeclarations == 0 ? upperScope : new BlockScope(upperScope);
+                       int length;
+                       // collection of cases is too big but we will only iterate until caseCount
+                       cases = new Case[length = statements.length];
+                       int[] casesValues = new int[length];
+                       int counter = 0;
+                       for (int i = 0; i < length; i++) {
+                               Constant cst;
+                               if ((cst = statements[i].resolveCase(scope, testType, this)) != null) {
+                                       //----check for duplicate case statement------------
+                                       if (cst != NotAConstant) {
+                                               int key = cst.intValue();
+                                               for (int j = 0; j < counter; j++) {
+                                                       if (casesValues[j] == key) {
+                                                               scope.problemReporter().duplicateCase((Case) statements[i], cst);
+                                                       }
+                                               }
+                                               casesValues[counter++] = key;
+                                       }
+                               }
+                       }
+               }
+       }
+       public String toString(int tab) {
+
+               String inFront, s = tabString(tab);
+               inFront = s;
+               s = s + "switch (" + testExpression.toStringExpression() + ") "; //$NON-NLS-1$ //$NON-NLS-2$
+               if (statements == null) {
+                       s = s + "{}"; //$NON-NLS-1$
+                       return s;
+               } else
+                       s = s + "{"; //$NON-NLS-1$
+                       s = s
+                                       + (explicitDeclarations != 0
+                                               ? "// ---scope needed for " //$NON-NLS-1$
+                                                       + String.valueOf(explicitDeclarations)
+                                                       + " locals------------ \n"//$NON-NLS-1$
+                                               : "// ---NO scope needed------ \n"); //$NON-NLS-1$
+
+               int i = 0;
+               String tabulation = "  "; //$NON-NLS-1$
+               try {
+                       while (true) {
+                               //use instanceof in order not to polluate classes with behavior only needed for printing purpose.
+                               if (statements[i] instanceof Expression)
+                                       s = s + "\n" + inFront + tabulation; //$NON-NLS-1$
+                               if (statements[i] instanceof Break)
+                                       s = s + statements[i].toString(0);
+                               else
+                                       s = s + "\n" + statements[i].toString(tab + 2); //$NON-NLS-1$
+                               //============= 
+                               if ((statements[i] instanceof Case)
+                                       || (statements[i] instanceof DefaultCase)) {
+                                       i++;
+                                       while (!((statements[i] instanceof Case)
+                                               || (statements[i] instanceof DefaultCase))) {
+                                               if ((statements[i] instanceof Expression) || (statements[i] instanceof Break))
+                                                       s = s + statements[i].toString(0) + " ; "; //$NON-NLS-1$
+                                               else
+                                                       s = s + "\n" + statements[i].toString(tab + 6) + " ; "; //$NON-NLS-1$ //$NON-NLS-2$
+                                               i++;
+                                       }
+                               } else {
+                                       s = s + " ;"; //$NON-NLS-1$
+                                       i++;
+                               }
+                       }
+               } catch (IndexOutOfBoundsException e) {
+               };
+               s = s + "}"; //$NON-NLS-1$
+               return s;
+       }
+
+       public void traverse(
+               IAbstractSyntaxTreeVisitor visitor,
+               BlockScope blockScope) {
+
+               if (visitor.visit(this, blockScope)) {
+                       testExpression.traverse(visitor, scope);
+                       if (statements != null) {
+                               int statementsLength = statements.length;
+                               for (int i = 0; i < statementsLength; i++)
+                                       statements[i].traverse(visitor, scope);
+                       }
+               }
+               visitor.endVisit(this, blockScope);
+       }
+       
+       /**
+        * Dispatch the call on its last statement.
+        */
+       public void branchChainTo(Label label) {
+               
+               // in order to improve debug attributes for stepping (11431)
+               // we want to inline the jumps to #breakLabel which already got
+               // generated (if any), and have them directly branch to a better
+               // location (the argument label).
+               // we know at this point that the breakLabel already got placed
+               if (this.breakLabel.hasForwardReferences()) {
+                       label.appendForwardReferencesFrom(this.breakLabel);
+               }
+       }
+}
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