content: /*******************************************************************************
   * Copyright (c) 2009, 2019 Mountainminds GmbH & Co. KG and Contributors
   * All rights reserved. This program and the accompanying materials
   * are made available under the terms of the Eclipse Public License v1.0
   * which accompanies this distribution, and is available at
   * http://www.eclipse.org/legal/epl-v10.html
   *
   * Contributors:
   *    Evgeny Mandrikov - initial API and implementation
   *
   *******************************************************************************/
  package org.jacoco.core.internal.analysis.filter;
  
  import java.util.HashSet;
  import java.util.Set;
  
  import org.objectweb.asm.Opcodes;
  import org.objectweb.asm.tree.AbstractInsnNode;
  import org.objectweb.asm.tree.JumpInsnNode;
  import org.objectweb.asm.tree.LabelNode;
  import org.objectweb.asm.tree.LookupSwitchInsnNode;
  import org.objectweb.asm.tree.MethodNode;
  import org.objectweb.asm.tree.TableSwitchInsnNode;
  import org.objectweb.asm.tree.VarInsnNode;
  
  /**
   * Filters code that is generated by ECJ for a <code>switch</code> statement
   * with a <code>String</code>.
   */
  public final class StringSwitchEcjFilter implements IFilter {
  
  	public void filter(final MethodNode methodNode,
  			final IFilterContext context, final IFilterOutput output) {
  		final Matcher matcher = new Matcher();
  		for (AbstractInsnNode i = methodNode.instructions
  				.getFirst(); i != null; i = i.getNext()) {
  			matcher.match(i, output);
  		}
  	}
  
  	private static class Matcher extends AbstractMatcher {
  		public void match(final AbstractInsnNode start,
  				final IFilterOutput output) {
  
  			if (Opcodes.ASTORE != start.getOpcode()) {
  				return;
  			}
  			cursor = start;
  			nextIsInvoke(Opcodes.INVOKEVIRTUAL, "java/lang/String", "hashCode",
  					"()I");
  			nextIsSwitch();
  			if (cursor == null) {
  				return;
  			}
  			vars.put("s", (VarInsnNode) start);
  
  			final AbstractInsnNode s = cursor;
  			final int hashCodes;
  			final LabelNode defaultLabel;
  			if (s.getOpcode() == Opcodes.LOOKUPSWITCH) {
  				final LookupSwitchInsnNode lookupSwitch = (LookupSwitchInsnNode) cursor;
  				defaultLabel = lookupSwitch.dflt;
  				hashCodes = lookupSwitch.labels.size();
  			} else {
  				final TableSwitchInsnNode tableSwitch = (TableSwitchInsnNode) cursor;
  				defaultLabel = tableSwitch.dflt;
  				hashCodes = tableSwitch.labels.size();
  			}
  
  			final Set<AbstractInsnNode> replacements = new HashSet<AbstractInsnNode>();
  			replacements.add(skipNonOpcodes(defaultLabel));
  
  			for (int i = 0; i < hashCodes; i++) {
  				while (true) {
  					nextIsVar(Opcodes.ALOAD, "s");
  					nextIs(Opcodes.LDC);
  					nextIsInvoke(Opcodes.INVOKEVIRTUAL, "java/lang/String",
  							"equals", "(Ljava/lang/Object;)Z");
  					// jump to case
  					nextIs(Opcodes.IFNE);
  					if (cursor == null) {
  						return;
  					}
  
  					replacements
  							.add(skipNonOpcodes(((JumpInsnNode) cursor).label));
  
  					if (cursor.getNext().getOpcode() == Opcodes.GOTO) {
  						// end of comparisons for same hashCode
  						// jump to default
  						nextIs(Opcodes.GOTO);
  						break;
  					} else if (cursor.getNext() == defaultLabel) {
  						break;
  					}
  				}
  			}
  
  			output.ignore(s.getNext(), cursor);
  			output.replaceBranches(s, replacements);
  		}
  	}
  
  }
  