1. package com.sun.org.apache.bcel.internal.generic;
  2. /* ====================================================================
  3. * The Apache Software License, Version 1.1
  4. *
  5. * Copyright (c) 2001 The Apache Software Foundation. All rights
  6. * reserved.
  7. *
  8. * Redistribution and use in source and binary forms, with or without
  9. * modification, are permitted provided that the following conditions
  10. * are met:
  11. *
  12. * 1. Redistributions of source code must retain the above copyright
  13. * notice, this list of conditions and the following disclaimer.
  14. *
  15. * 2. Redistributions in binary form must reproduce the above copyright
  16. * notice, this list of conditions and the following disclaimer in
  17. * the documentation and/or other materials provided with the
  18. * distribution.
  19. *
  20. * 3. The end-user documentation included with the redistribution,
  21. * if any, must include the following acknowledgment:
  22. * "This product includes software developed by the
  23. * Apache Software Foundation (http://www.apache.org/)."
  24. * Alternately, this acknowledgment may appear in the software itself,
  25. * if and wherever such third-party acknowledgments normally appear.
  26. *
  27. * 4. The names "Apache" and "Apache Software Foundation" and
  28. * "Apache BCEL" must not be used to endorse or promote products
  29. * derived from this software without prior written permission. For
  30. * written permission, please contact apache@apache.org.
  31. *
  32. * 5. Products derived from this software may not be called "Apache",
  33. * "Apache BCEL", nor may "Apache" appear in their name, without
  34. * prior written permission of the Apache Software Foundation.
  35. *
  36. * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
  37. * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  38. * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  39. * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
  40. * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  41. * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  42. * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  43. * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  44. * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  45. * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  46. * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  47. * SUCH DAMAGE.
  48. * ====================================================================
  49. *
  50. * This software consists of voluntary contributions made by many
  51. * individuals on behalf of the Apache Software Foundation. For more
  52. * information on the Apache Software Foundation, please see
  53. * <http://www.apache.org/>.
  54. */
  55. import java.io.*;
  56. import com.sun.org.apache.bcel.internal.util.ByteSequence;
  57. /**
  58. * RET - Return from subroutine
  59. *
  60. * <PRE>Stack: ..., -> ..., address</PRE>
  61. *
  62. * @version $Id: RET.java,v 1.1.1.1 2001/10/29 20:00:25 jvanzyl Exp $
  63. * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
  64. */
  65. public class RET extends Instruction implements IndexedInstruction, TypedInstruction {
  66. private boolean wide;
  67. private int index; // index to local variable containg the return address
  68. /**
  69. * Empty constructor needed for the Class.newInstance() statement in
  70. * Instruction.readInstruction(). Not to be used otherwise.
  71. */
  72. RET() {}
  73. public RET(int index) {
  74. super(com.sun.org.apache.bcel.internal.Constants.RET, (short)2);
  75. setIndex(index); // May set wide as side effect
  76. }
  77. /**
  78. * Dump instruction as byte code to stream out.
  79. * @param out Output stream
  80. */
  81. public void dump(DataOutputStream out) throws IOException {
  82. if(wide)
  83. out.writeByte(com.sun.org.apache.bcel.internal.Constants.WIDE);
  84. out.writeByte(opcode);
  85. if(wide)
  86. out.writeShort(index);
  87. else
  88. out.writeByte(index);
  89. }
  90. private final void setWide() {
  91. if(wide = index > com.sun.org.apache.bcel.internal.Constants.MAX_BYTE)
  92. length = 4; // Including the wide byte
  93. else
  94. length = 2;
  95. }
  96. /**
  97. * Read needed data (e.g. index) from file.
  98. */
  99. protected void initFromFile(ByteSequence bytes, boolean wide) throws IOException
  100. {
  101. this.wide = wide;
  102. if(wide) {
  103. index = bytes.readUnsignedShort();
  104. length = 4;
  105. } else {
  106. index = bytes.readUnsignedByte();
  107. length = 2;
  108. }
  109. }
  110. /**
  111. * @return index of local variable containg the return address
  112. */
  113. public final int getIndex() { return index; }
  114. /**
  115. * Set index of local variable containg the return address
  116. */
  117. public final void setIndex(int n) {
  118. if(n < 0)
  119. throw new ClassGenException("Negative index value: " + n);
  120. index = n;
  121. setWide();
  122. }
  123. /**
  124. * @return mnemonic for instruction
  125. */
  126. public String toString(boolean verbose) {
  127. return super.toString(verbose) + " " + index;
  128. }
  129. /** @return return address type
  130. */
  131. public Type getType(ConstantPoolGen cp) {
  132. return ReturnaddressType.NO_TARGET;
  133. }
  134. /**
  135. * Call corresponding visitor method(s). The order is:
  136. * Call visitor methods of implemented interfaces first, then
  137. * call methods according to the class hierarchy in descending order,
  138. * i.e., the most specific visitXXX() call comes last.
  139. *
  140. * @param v Visitor object
  141. */
  142. public void accept(Visitor v) {
  143. v.visitRET(this);
  144. }
  145. }