/*
 * The JastAdd Extensible Java Compiler (http://jastadd.org) is covered
 * by the modified BSD License. You should have received a copy of the
 * modified BSD license with this compiler.
 * 
 * Copyright (c) 2005-2008, Torbjorn Ekman
 * All rights reserved.
 */

aspect EnhancedForToBytecode {
  // Code generation
  syn lazy int EnhancedForStmt.cond_label() = hostType().constantPool().newLabel();
  syn lazy int EnhancedForStmt.update_label() = hostType().constantPool().newLabel();
  syn lazy int EnhancedForStmt.end_label() = hostType().constantPool().newLabel();

  syn lazy int EnhancedForStmt.extraLocalIndex() = localNum();
  eq EnhancedForStmt.getVariableDeclaration().localNum() = localNum() + (getExpr().type().isArrayDecl() ? 2 : 1);
  eq EnhancedForStmt.getStmt().localNum() = getVariableDeclaration().localNum() + getVariableDeclaration().type().size();

   // EnhancedForStmt can be both break and continue target
  eq EnhancedForStmt.break_label() = end_label();
  eq EnhancedForStmt.continue_label() = update_label();

  public void EnhancedForStmt.createBCode(CodeGeneration gen) {
    if(getExpr().type().isArrayDecl()) {
      getExpr().createBCode(gen);
      gen.emitStoreReference(extraLocalIndex());
      IntegerLiteral.push(gen, 0);
      gen.emit(Bytecode.ISTORE).add(extraLocalIndex()+1);
      gen.addLabel(cond_label());
      gen.emit(Bytecode.ILOAD).add(extraLocalIndex()+1);
      gen.emitLoadReference(extraLocalIndex());
      gen.emit(Bytecode.ARRAYLENGTH);
      gen.emitCompare(Bytecode.IF_ICMPGE, end_label());
      gen.emitLoadReference(extraLocalIndex());
      gen.emit(Bytecode.ILOAD).add(extraLocalIndex()+1);
      gen.emit(getExpr().type().componentType().arrayLoad());
      getExpr().type().componentType().emitCastTo(gen, getVariableDeclaration().type());
      getVariableDeclaration().type().emitStoreLocal(gen, getVariableDeclaration().localNum());
      getStmt().createBCode(gen);
      gen.addLabel(update_label());
      gen.emit(Bytecode.IINC).add(extraLocalIndex()+1).add(1);
      gen.emitGoto(cond_label());
      gen.addLabel(end_label());
    }
    else {
      getExpr().createBCode(gen);
      iteratorMethod().emitInvokeMethod(gen, lookupType("java.lang", "Iterable"));
      gen.emitStoreReference(extraLocalIndex());
      gen.addLabel(cond_label());
      gen.emitLoadReference(extraLocalIndex());
      hasNextMethod().emitInvokeMethod(gen, lookupType("java.util", "Iterator"));
      gen.emitCompare(Bytecode.IFEQ, end_label());
      gen.emitLoadReference(extraLocalIndex());
      nextMethod().emitInvokeMethod(gen, lookupType("java.util", "Iterator"));
      VariableDeclaration obj = getVariableDeclaration();
      if (obj.type().isPrimitive()) {
        gen.emitCheckCast(obj.type().boxed());
        obj.type().boxed().emitCastTo(gen, obj.type());
        obj.type().emitStoreLocal(gen, obj.localNum());
      } else {
        gen.emitCheckCast(obj.type());
        gen.emitStoreReference(obj.localNum());
      }
      getStmt().createBCode(gen);
      gen.addLabel(update_label());	
      gen.emitGoto(cond_label());
      gen.addLabel(end_label());
    }
  }

  private MethodDecl EnhancedForStmt.iteratorMethod() {
    TypeDecl typeDecl = lookupType("java.lang", "Iterable");
		for (Iterator iter = typeDecl.memberMethods("iterator").iterator(); iter.hasNext();) {
			MethodDecl m = (MethodDecl)iter.next();
			if (m.getNumParameter() == 0) {
				return m;
      }
    }
    throw new Error("Could not find java.lang.Iterable.iterator()");
  }
  private MethodDecl EnhancedForStmt.hasNextMethod() {
    TypeDecl typeDecl = lookupType("java.util", "Iterator");
		for (Iterator iter = typeDecl.memberMethods("hasNext").iterator(); iter.hasNext();) {
			MethodDecl m = (MethodDecl)iter.next();
			if (m.getNumParameter() == 0) {
				return m;
      }
    }
    throw new Error("Could not find java.util.Collection.hasNext()");
  }
  private MethodDecl EnhancedForStmt.nextMethod() {
    TypeDecl typeDecl = lookupType("java.util", "Iterator");
		for (Iterator iter = typeDecl.memberMethods("next").iterator(); iter.hasNext();) {
			MethodDecl m = (MethodDecl)iter.next();
			if (m.getNumParameter() == 0) {
				return m;
      }
    }
    throw new Error("Could not find java.util.Collection.next()");
  }
}