content: /***
   * ASM: a very small and fast Java bytecode manipulation framework
   * Copyright (c) 2000-2007 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 com.alibaba.fastjson.asm;
  
  /**
   * 
   * @author Eric Bruneton
   */
  public class ClassWriter {
      /**
       * Minor and major version numbers of the class to be generated.
       */
      int                     version;
  
      /**
       * Index of the next item to be added in the constant pool.
       */
      int                     index;
  
      /**
       * The constant pool of this class.
       */
      final ByteVector        pool;
  
      /**
       * The constant pool's hash table data.
       */
      Item[]                  items;
  
      /**
       * The threshold of the constant pool's hash table.
       */
      int                     threshold;
  
      /**
       * A reusable key used to look for items in the {@link #items} hash table.
       */
      final Item              key;
  
      /**
       * A reusable key used to look for items in the {@link #items} hash table.
       */
      final Item              key2;
  
      /**
       * A reusable key used to look for items in the {@link #items} hash table.
       */
      final Item              key3;
  
      /**
       * A type table used to temporarily store internal names that will not necessarily be stored in the constant pool.
       * This type table is used by the control flow and data flow analysis algorithm used to compute stack map frames
       * from scratch. This array associates to each index <tt>i</tt> the Item whose index is <tt>i</tt>. All Item objects
       * stored in this array are also stored in the {@link #items} hash table. These two arrays allow to retrieve an Item
       * from its index or, conversely, to get the index of an Item from its value. Each Item stores an internal name in
       * its {@link Item#strVal1} field.
       */
      Item[]                  typeTable;
  
      /**
       * The access flags of this class.
       */
      private int             access;
  
      /**
       * The constant pool item that contains the internal name of this class.
       */
      private int             name;
  
      /**
       * The internal name of this class.
       */
      String                  thisName;
  
      /**
       * The constant pool item that contains the internal name of the super class of this class.
       */
      private int             superName;
  
      /**
       * Number of interfaces implemented or extended by this class or interface.
       */
      private int             interfaceCount;
  
      /**
       * The interfaces implemented or extended by this class or interface. More precisely, this array contains the
       * indexes of the constant pool items that contain the internal names of these interfaces.
       */
      private int[]           interfaces;
  
      /**
       * The fields of this class. These fields are stored in a linked list of {@link FieldWriter} objects, linked to each
       * other by their {@link FieldWriter#next} field. This field stores the first element of this list.
       */
      FieldWriter             firstField;
  
      /**
       * The fields of this class. These fields are stored in a linked list of {@link FieldWriter} objects, linked to each
       * other by their {@link FieldWriter#next} field. This field stores the last element of this list.
       */
      FieldWriter             lastField;
  
      /**
       * The methods of this class. These methods are stored in a linked list of {@link MethodWriter} objects, linked to
       * each other by their {@link MethodWriter#next} field. This field stores the first element of this list.
       */
      MethodWriter            firstMethod;
  
      /**
       * The methods of this class. These methods are stored in a linked list of {@link MethodWriter} objects, linked to
       * each other by their {@link MethodWriter#next} field. This field stores the last element of this list.
       */
      MethodWriter            lastMethod;
  
      // ------------------------------------------------------------------------
      // Constructor
      // ------------------------------------------------------------------------
  
      public ClassWriter(){
          this(0);
      }
  
      private ClassWriter(final int flags){
          index = 1;
          pool = new ByteVector();
          items = new Item[256];
          threshold = (int) (0.75d * items.length);
          key = new Item();
          key2 = new Item();
          key3 = new Item();
      }
  
      // ------------------------------------------------------------------------
      // Implementation of the ClassVisitor interface
      // ------------------------------------------------------------------------
  
      public void visit(final int version, final int access, final String name, final String superName, final String[] interfaces) {
          this.version = version;
          this.access = access;
          this.name = newClassItem(name).index;
          thisName = name;
          this.superName = superName == null ? 0 : newClassItem(superName).index;
          if (interfaces != null && interfaces.length > 0) {
              interfaceCount = interfaces.length;
              this.interfaces = new int[interfaceCount];
              for (int i = 0; i < interfaceCount; ++i) {
                  this.interfaces[i] = newClassItem(interfaces[i]).index;
              }
          }
      }
  
      // ------------------------------------------------------------------------
      // Other public methods
      // ------------------------------------------------------------------------
  
      /**
       * Returns the bytecode of the class that was build with this class writer.
       * 
       * @return the bytecode of the class that was build with this class writer.
       */
      public byte[] toByteArray() {
          // computes the real size of the bytecode of this class
          int size = 24 + 2 * interfaceCount;
          int nbFields = 0;
          FieldWriter fb = firstField;
          while (fb != null) {
              ++nbFields;
              size += fb.getSize();
              fb = fb.next;
          }
          int nbMethods = 0;
          MethodWriter mb = firstMethod;
          while (mb != null) {
              ++nbMethods;
              size += mb.getSize();
              mb = mb.next;
          }
          int attributeCount = 0;
          size += pool.length;
          // allocates a byte vector of this size, in order to avoid unnecessary
          // arraycopy operations in the ByteVector.enlarge() method
          ByteVector out = new ByteVector(size);
          out.putInt(0xCAFEBABE).putInt(version);
          out.putShort(index).putByteArray(pool.data, 0, pool.length);
          int mask = 393216; // Opcodes.ACC_DEPRECATED | ClassWriter.ACC_SYNTHETIC_ATTRIBUTE | ((access & ClassWriter.ACC_SYNTHETIC_ATTRIBUTE) / (ClassWriter.ACC_SYNTHETIC_ATTRIBUTE / Opcodes.ACC_SYNTHETIC));
          out.putShort(access & ~mask).putShort(name).putShort(superName);
          out.putShort(interfaceCount);
          for (int i = 0; i < interfaceCount; ++i) {
              out.putShort(interfaces[i]);
          }
          out.putShort(nbFields);
          fb = firstField;
          while (fb != null) {
              fb.put(out);
              fb = fb.next;
          }
          out.putShort(nbMethods);
          mb = firstMethod;
          while (mb != null) {
              mb.put(out);
              mb = mb.next;
          }
          out.putShort(attributeCount);
          return out.data;
      }
  
      // ------------------------------------------------------------------------
      // Utility methods: constant pool management
      // ------------------------------------------------------------------------
  
      /**
       * Adds a number or string constant to the constant pool of the class being build. Does nothing if the constant pool
       * already contains a similar item.
       * 
       * @param cst the value of the constant to be added to the constant pool. This parameter must be an {@link Integer},
       * a {@link Float}, a {@link Long}, a {@link Double}, a {@link String} or a {@link Type}.
       * @return a new or already existing constant item with the given value.
       */
      Item newConstItem(final Object cst) {
          if (cst instanceof Integer) {
              int val = ((Integer) cst).intValue();
              // return newInteger(val);
              key.set(val);
              Item result = get(key);
              if (result == null) {
                  pool.putByte(3 /* INT */ ).putInt(val);
                  result = new Item(index++, key);
                  put(result);
              }
              return result;
          } else if (cst instanceof String) {
              return newString((String) cst);
          } else if (cst instanceof Type) {
              Type t = (Type) cst;
              return newClassItem(t.sort == 10 /*Type.OBJECT*/ ? t.getInternalName() : t.getDescriptor());
          } else {
              throw new IllegalArgumentException("value " + cst);
          }
      }
  
      public int newUTF8(final String value) {
          key.set(1 /* UTF8 */, value, null, null);
          Item result = get(key);
          if (result == null) {
              pool.putByte(1 /* UTF8 */).putUTF8(value);
              result = new Item(index++, key);
              put(result);
          }
          return result.index;
      }
  
      public Item newClassItem(final String value) {
          key2.set(7 /* CLASS */, value, null, null);
          Item result = get(key2);
          if (result == null) {
              pool.put12(7 /* CLASS */, newUTF8(value));
              result = new Item(index++, key2);
              put(result);
          }
          return result;
      }
  
      /**
       * Adds a field reference to the constant pool of the class being build. Does nothing if the constant pool already
       * contains a similar item.
       * 
       * @param owner the internal name of the field's owner class.
       * @param name the field's name.
       * @param desc the field's descriptor.
       * @return a new or already existing field reference item.
       */
      Item newFieldItem(final String owner, final String name, final String desc) {
          key3.set(9 /* FIELD */, owner, name, desc);
          Item result = get(key3);
          if (result == null) {
              // put122(9 /* FIELD */, newClassItem(owner).index, newNameTypeItem(name, desc).index);
              int s1 = newClassItem(owner).index, s2 = newNameTypeItem(name, desc).index;
              pool.put12(9 /* FIELD */, s1).putShort(s2);
              result = new Item(index++, key3);
              put(result);
          }
          return result;
      }
  
      /**
       * Adds a method reference to the constant pool of the class being build. Does nothing if the constant pool already
       * contains a similar item.
       * 
       * @param owner the internal name of the method's owner class.
       * @param name the method's name.
       * @param desc the method's descriptor.
       * @param itf <tt>true</tt> if <tt>owner</tt> is an interface.
       * @return a new or already existing method reference item.
       */
      Item newMethodItem(final String owner, final String name, final String desc, final boolean itf) {
          int type = itf ? 11 /* IMETH */ : 10 /* METH */;
          key3.set(type, owner, name, desc);
          Item result = get(key3);
          if (result == null) {
              // put122(type, newClassItem(owner).index, newNameTypeItem(name, desc).index);
              int s1 = newClassItem(owner).index, s2 = newNameTypeItem(name, desc).index;
              pool.put12(type, s1).putShort(s2);
              result = new Item(index++, key3);
              put(result);
          }
          return result;
      }
  
      private Item newString(final String value) {
          key2.set(8 /* STR */, value, null, null);
          Item result = get(key2);
          if (result == null) {
              pool.put12(8 /*STR*/, newUTF8(value));
              result = new Item(index++, key2);
              put(result);
          }
          return result;
      }
  
      public Item newNameTypeItem(final String name, final String desc) {
          key2.set(12 /* NAME_TYPE */, name, desc, null);
          Item result = get(key2);
          if (result == null) {
              //put122(12 /* NAME_TYPE */, newUTF8(name), newUTF8(desc));
              int s1 = newUTF8(name), s2 = newUTF8(desc);
              pool.put12(12 /* NAME_TYPE */, s1).putShort(s2);
              result = new Item(index++, key2);
              put(result);
          }
          return result;
      }
  
  
      private Item get(final Item key) {
          Item i = items[key.hashCode % items.length];
          while (i != null && (i.type != key.type || !key.isEqualTo(i))) {
              i = i.next;
          }
          return i;
      }
  
      private void put(final Item i) {
          if (index > threshold) {
              int ll = items.length;
              int nl = ll * 2 + 1;
              Item[] newItems = new Item[nl];
              for (int l = ll - 1; l >= 0; --l) {
                  Item j = items[l];
                  while (j != null) {
                      int index = j.hashCode % newItems.length;
                      Item k = j.next;
                      j.next = newItems[index];
                      newItems[index] = j;
                      j = k;
                  }
              }
              items = newItems;
              threshold = (int) (nl * 0.75);
          }
          int index = i.hashCode % items.length;
          i.next = items[index];
          items[index] = i;
      }
  }
  