/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2005 INRIA, France Telecom
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.mvel2.asm.util;

import org.mvel2.asm.Attribute;

import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;

/**
 * An abstract visitor.
 *
 * @author Eric Bruneton
 */
public abstract class AbstractVisitor {

  /**
   * The names of the Java Virtual Machine opcodes.
   */
  public final static String[] OPCODES;
  /**
   * Types for <code>operand</code> parameter of the
   * {@link org.objectweb.asm.MethodVisitor#visitIntInsn} method when
   * <code>opcode</code> is <code>NEWARRAY</code>.
   */
  public final static String[] TYPES;

  static {
    String s = "NOP,ACONST_NULL,ICONST_M1,ICONST_0,ICONST_1,ICONST_2,"
        + "ICONST_3,ICONST_4,ICONST_5,LCONST_0,LCONST_1,FCONST_0,"
        + "FCONST_1,FCONST_2,DCONST_0,DCONST_1,BIPUSH,SIPUSH,LDC,,,"
        + "ILOAD,LLOAD,FLOAD,DLOAD,ALOAD,,,,,,,,,,,,,,,,,,,,,IALOAD,"
        + "LALOAD,FALOAD,DALOAD,AALOAD,BALOAD,CALOAD,SALOAD,ISTORE,"
        + "LSTORE,FSTORE,DSTORE,ASTORE,,,,,,,,,,,,,,,,,,,,,IASTORE,"
        + "LASTORE,FASTORE,DASTORE,AASTORE,BASTORE,CASTORE,SASTORE,POP,"
        + "POP2,DUP,DUP_X1,DUP_X2,DUP2,DUP2_X1,DUP2_X2,SWAP,IADD,LADD,"
        + "FADD,DADD,ISUB,LSUB,FSUB,DSUB,IMUL,LMUL,FMUL,DMUL,IDIV,LDIV,"
        + "FDIV,DDIV,IREM,LREM,FREM,DREM,INEG,LNEG,FNEG,DNEG,ISHL,LSHL,"
        + "ISHR,LSHR,IUSHR,LUSHR,IAND,LAND,IOR,LOR,IXOR,LXOR,IINC,I2L,"
        + "I2F,I2D,L2I,L2F,L2D,F2I,F2L,F2D,D2I,D2L,D2F,I2B,I2C,I2S,LCMP,"
        + "FCMPL,FCMPG,DCMPL,DCMPG,IFEQ,IFNE,IFLT,IFGE,IFGT,IFLE,"
        + "IF_ICMPEQ,IF_ICMPNE,IF_ICMPLT,IF_ICMPGE,IF_ICMPGT,IF_ICMPLE,"
        + "IF_ACMPEQ,IF_ACMPNE,GOTO,JSR,RET,TABLESWITCH,LOOKUPSWITCH,"
        + "IRETURN,LRETURN,FRETURN,DRETURN,ARETURN,RETURN,GETSTATIC,"
        + "PUTSTATIC,GETFIELD,PUTFIELD,INVOKEVIRTUAL,INVOKESPECIAL,"
        + "INVOKESTATIC,INVOKEINTERFACE,,NEW,NEWARRAY,ANEWARRAY,"
        + "ARRAYLENGTH,ATHROW,CHECKCAST,INSTANCEOF,MONITORENTER,"
        + "MONITOREXIT,,MULTIANEWARRAY,IFNULL,IFNONNULL,";
    OPCODES = new String[200];
    int i = 0;
    int j = 0;
    int l;
    while ((l = s.indexOf(',', j)) > 0) {
      OPCODES[i++] = j + 1 == l ? null : s.substring(j, l);
      j = l + 1;
    }

    s = "T_BOOLEAN,T_CHAR,T_FLOAT,T_DOUBLE,T_BYTE,T_SHORT,T_INT,T_LONG,";
    TYPES = new String[12];
    j = 0;
    i = 4;
    while ((l = s.indexOf(',', j)) > 0) {
      TYPES[i++] = s.substring(j, l);
      j = l + 1;
    }
  }

  /**
   * The text to be printed. Since the code of methods is not necessarily
   * visited in sequential order, one method after the other, but can be
   * interlaced (some instructions from method one, then some instructions
   * from method two, then some instructions from method one again...), it is
   * not possible to print the visited instructions directly to a sequential
   * stream. A class is therefore printed in a two steps process: a string
   * tree is constructed during the visit, and printed to a sequential stream
   * at the end of the visit. This string tree is stored in this field, as a
   * string list that can contain other string lists, which can themselves
   * contain other string lists, and so on.
   */
  public final List text;

  /**
   * A buffer that can be used to create strings.
   */
  protected final StringBuffer buf;

  /**
   * Constructs a new {@link AbstractVisitor}.
   */
  protected AbstractVisitor() {
    this.text = new ArrayList();
    this.buf = new StringBuffer();
  }

  /**
   * Returns the text constructed by this visitor.
   *
   * @return the text constructed by this visitor.
   */
  public List getText() {
    return text;
  }

  /**
   * Prints the text constructed by this visitor.
   *
   * @param pw the print writer to be used.
   */
  public void print(final PrintWriter pw) {
    printList(pw, text);
  }

  /**
   * Appends a quoted string to a given buffer.
   *
   * @param buf the buffer where the string must be added.
   * @param s   the string to be added.
   */
  public static void appendString(final StringBuffer buf, final String s) {
    buf.append('\"');
    for (int i = 0; i < s.length(); ++i) {
      char c = s.charAt(i);
      if (c == '\n') {
        buf.append("\\n");
      }
      else if (c == '\r') {
        buf.append("\\r");
      }
      else if (c == '\\') {
        buf.append("\\\\");
      }
      else if (c == '"') {
        buf.append("\\\"");
      }
      else if (c < 0x20 || c > 0x7f) {
        buf.append("\\u");
        if (c < 0x10) {
          buf.append("000");
        }
        else if (c < 0x100) {
          buf.append("00");
        }
        else if (c < 0x1000) {
          buf.append('0');
        }
        buf.append(Integer.toString(c, 16));
      }
      else {
        buf.append(c);
      }
    }
    buf.append('\"');
  }

  /**
   * Prints the given string tree.
   *
   * @param pw the writer to be used to print the tree.
   * @param l  a string tree, i.e., a string list that can contain other string
   *           lists, and so on recursively.
   */
  void printList(final PrintWriter pw, final List l) {
    for (int i = 0; i < l.size(); ++i) {
      Object o = l.get(i);
      if (o instanceof List) {
        printList(pw, (List) o);
      }
      else {
        pw.print(o.toString());
      }
    }
  }

  /**
   * Returns the default {@link ASMifiable} prototypes.
   *
   * @return the default {@link ASMifiable} prototypes.
   */
  public static Attribute[] getDefaultAttributes() {
    return new Attribute[0];
  }
}
