/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 *

 */

package sun.jvm.hotspot.oops;

import java.io.*;

import java.util.*;

import sun.jvm.hotspot.debugger.*;

import sun.jvm.hotspot.runtime.*;

import sun.jvm.hotspot.types.*;

import sun.jvm.hotspot.utilities.*;

// A ConstantPool is an oop containing class constants

// as described in the class file

public class ConstantPool extends Oop implements ClassConstants {

  // Used for debugging this code

  private static final boolean DEBUG = false;

  protected void debugMessage(String message) {

    System.out.println(message);

  }

  static {

    VM.registerVMInitializedObserver(new Observer() {

        public void update(Observable o, Object data) {

          initialize(VM.getVM().getTypeDataBase());

        }

      });

  }

  private static synchronized void initialize(TypeDataBase db) throws WrongTypeException {

    Type type   = db.lookupType("constantPoolOopDesc");

    tags        = new OopField(type.getOopField("_tags"), 0);

    cache       = new OopField(type.getOopField("_cache"), 0);

    poolHolder  = new OopField(type.getOopField("_pool_holder"), 0);

    length      = new CIntField(type.getCIntegerField("_length"), 0);

    headerSize  = type.getSize();

    elementSize = 0;

  }

  ConstantPool(OopHandle handle, ObjectHeap heap) {

    super(handle, heap);

  }

  public boolean isConstantPool()      { return true; }

  private static OopField tags;

  private static OopField cache;

  private static OopField poolHolder;

  private static CIntField length; // number of elements in oop

  private static long headerSize;

  private static long elementSize;

  public TypeArray         getTags()       { return (TypeArray)         tags.getValue(this); }

  public ConstantPoolCache getCache()      { return (ConstantPoolCache) cache.getValue(this); }

  public Klass             getPoolHolder() { return (Klass)             poolHolder.getValue(this); }

  public int               getLength()     { return (int)length.getValue(this); }

  private long getElementSize() {

    if (elementSize !=0 ) {

      return elementSize;

    } else {

      elementSize = VM.getVM().getOopSize();

    }

    return elementSize;

  }

  private long indexOffset(long index) {

    if (Assert.ASSERTS_ENABLED) {

      Assert.that(index > 0 && index < getLength(),  "invalid cp index " + index + " " + getLength());

    }

    return (index * getElementSize()) + headerSize;

  }

  public ConstantTag getTagAt(long index) {

    return new ConstantTag(getTags().getByteAt((int) index));

  }

  public Oop getObjAt(long index){

    return getHeap().newOop(getHandle().getOopHandleAt(indexOffset(index)));

  }

  public Symbol getSymbolAt(long index) {

    return (Symbol) getObjAt(index);

  }

  public int getIntAt(long index){

    return getHandle().getJIntAt(indexOffset(index));

  }

  public float getFloatAt(long index){

    return getHandle().getJFloatAt(indexOffset(index));

  }

  public long getLongAt(long index) {

    int oneHalf = getHandle().getJIntAt(indexOffset(index + 1));

    int otherHalf   = getHandle().getJIntAt(indexOffset(index));

    // buildLongFromIntsPD accepts higher address value, lower address value

    // in that order.

    return VM.getVM().buildLongFromIntsPD(oneHalf, otherHalf);

  }

  public double getDoubleAt(long index) {

    return Double.longBitsToDouble(getLongAt(index));

  }

  public int getFieldOrMethodAt(int which) {

    if (DEBUG) {

      System.err.print("ConstantPool.getFieldOrMethodAt(" + which + "): new index = ");

    }

    int i = -1;

    ConstantPoolCache cache = getCache();

    if (cache == null) {

      i = which;

    } else {

      // change byte-ordering and go via cache

      i = cache.getEntryAt(0xFFFF & VM.getVM().getBytes().swapShort((short) which)).getConstantPoolIndex();

    }

    if (Assert.ASSERTS_ENABLED) {

      Assert.that(getTagAt(i).isFieldOrMethod(), "Corrupted constant pool");

    }

    if (DEBUG) {

      System.err.println(i);

    }

    int res = getIntAt(i);

    if (DEBUG) {

      System.err.println("ConstantPool.getFieldOrMethodAt(" + i + "): result = " + res);

    }

    return res;

  }

  public int getNameAndTypeAt(int which) {

    if (Assert.ASSERTS_ENABLED) {

      Assert.that(getTagAt(which).isNameAndType(), "Corrupted constant pool");

    }

    int i = getIntAt(which);

    if (DEBUG) {

      System.err.println("ConstantPool.getNameAndTypeAt(" + which + "): result = " + i);

    }

    return i;

  }

  public Symbol getNameRefAt(int which) {

    int refIndex = getNameAndTypeAt(getNameAndTypeRefIndexAt(which));

    int nameIndex = extractLowShortFromInt(refIndex);

    return getSymbolAt(nameIndex);

  }

  public Symbol getSignatureRefAt(int which) {

    int refIndex = getNameAndTypeAt(getNameAndTypeRefIndexAt(which));

    int sigIndex = extractHighShortFromInt(refIndex);

    return getSymbolAt(sigIndex);

  }

  // returns null, if not resolved.

  public Klass getKlassRefAt(int which) {

    if( ! getTagAt(which).isKlass()) return null;

    return (Klass) getObjAt(which);

  }

  // returns null, if not resolved.

  public InstanceKlass getFieldOrMethodKlassRefAt(int which) {

    int refIndex = getFieldOrMethodAt(which);

    int klassIndex = extractLowShortFromInt(refIndex);

    return (InstanceKlass) getKlassRefAt(klassIndex);

  }

  // returns null, if not resolved.

  public Method getMethodRefAt(int which) {

    InstanceKlass klass = getFieldOrMethodKlassRefAt(which);

    if (klass == null) return null;

    Symbol name = getNameRefAt(which);

    Symbol sig  = getSignatureRefAt(which);

    return klass.findMethod(name, sig);

  }

  // returns null, if not resolved.

  public Field getFieldRefAt(int which) {

    InstanceKlass klass = getFieldOrMethodKlassRefAt(which);

    if (klass == null) return null;

    Symbol name = getNameRefAt(which);

    Symbol sig  = getSignatureRefAt(which);

    return klass.findField(name, sig);

  }

  public int getNameAndTypeRefIndexAt(int index) {

    int refIndex = getFieldOrMethodAt(index);

    if (DEBUG) {

      System.err.println("ConstantPool.getNameAndTypeRefIndexAt(" + index + "): refIndex = " + refIndex);

    }

    int i = extractHighShortFromInt(refIndex);

    if (DEBUG) {

      System.err.println("ConstantPool.getNameAndTypeRefIndexAt(" + index + "): result = " + i);

    }

    return i;

  }

  /** Lookup for entries consisting of (name_index, signature_index) */

  public int getNameRefIndexAt(int index) {

    int refIndex = getNameAndTypeAt(index);

    if (DEBUG) {

      System.err.println("ConstantPool.getNameRefIndexAt(" + index + "): refIndex = " + refIndex);

    }

    int i = extractLowShortFromInt(refIndex);

    if (DEBUG) {

      System.err.println("ConstantPool.getNameRefIndexAt(" + index + "): result = " + i);

    }

    return i;

  }

  /** Lookup for entries consisting of (name_index, signature_index) */

  public int getSignatureRefIndexAt(int index) {

    int refIndex = getNameAndTypeAt(index);

    if (DEBUG) {

      System.err.println("ConstantPool.getSignatureRefIndexAt(" + index + "): refIndex = " + refIndex);

    }

    int i = extractHighShortFromInt(refIndex);

    if (DEBUG) {

      System.err.println("ConstantPool.getSignatureRefIndexAt(" + index + "): result = " + i);

    }

    return i;

  }

  final private static String[] nameForTag = new String[] {

  };

  private String nameForTag(int tag) {

    switch (tag) {

    case JVM_CONSTANT_Utf8:               return "JVM_CONSTANT_Utf8";

    case JVM_CONSTANT_Unicode:            return "JVM_CONSTANT_Unicode";

    case JVM_CONSTANT_Integer:            return "JVM_CONSTANT_Integer";

    case JVM_CONSTANT_Float:              return "JVM_CONSTANT_Float";

    case JVM_CONSTANT_Long:               return "JVM_CONSTANT_Long";

    case JVM_CONSTANT_Double:             return "JVM_CONSTANT_Double";

    case JVM_CONSTANT_Class:              return "JVM_CONSTANT_Class";

    case JVM_CONSTANT_String:             return "JVM_CONSTANT_String";

    case JVM_CONSTANT_Fieldref:           return "JVM_CONSTANT_Fieldref";

    case JVM_CONSTANT_Methodref:          return "JVM_CONSTANT_Methodref";

    case JVM_CONSTANT_InterfaceMethodref: return "JVM_CONSTANT_InterfaceMethodref";

    case JVM_CONSTANT_NameAndType:        return "JVM_CONSTANT_NameAndType";

    case JVM_CONSTANT_Invalid:            return "JVM_CONSTANT_Invalid";

    case JVM_CONSTANT_UnresolvedClass:    return "JVM_CONSTANT_UnresolvedClass";

    case JVM_CONSTANT_ClassIndex:         return "JVM_CONSTANT_ClassIndex";

    case JVM_CONSTANT_UnresolvedString:   return "JVM_CONSTANT_UnresolvedString";

    case JVM_CONSTANT_StringIndex:        return "JVM_CONSTANT_StringIndex";

    }

    throw new InternalError("unknown tag");

  }

  public void iterateFields(OopVisitor visitor, boolean doVMFields) {

    super.iterateFields(visitor, doVMFields);

    if (doVMFields) {

      visitor.doOop(tags, true);

      visitor.doOop(cache, true);

      visitor.doOop(poolHolder, true);

      final int length = (int) getLength();

      // zero'th pool entry is always invalid. ignore it.

      for (int index = 1; index < length; index++) {

        int ctag = (int) getTags().getByteAt((int) index);

        switch (ctag) {

        case JVM_CONSTANT_ClassIndex:

        case JVM_CONSTANT_StringIndex:

        case JVM_CONSTANT_Integer:

          visitor.doInt(new IntField(new NamedFieldIdentifier(nameForTag(ctag)), indexOffset(index), true), true);

          break;

        case JVM_CONSTANT_Float:

          visitor.doFloat(new FloatField(new NamedFieldIdentifier(nameForTag(ctag)), indexOffset(index), true), true);

          break;

        case JVM_CONSTANT_Long:

          visitor.doLong(new LongField(new NamedFieldIdentifier(nameForTag(ctag)), indexOffset(index), true), true);

          // long entries occupy two slots

          index++;

          break;

        case JVM_CONSTANT_Double:

          visitor.doDouble(new DoubleField(new NamedFieldIdentifier(nameForTag(ctag)), indexOffset(index), true), true);

          // double entries occupy two slots

          index++;

          break;

        case JVM_CONSTANT_UnresolvedClass:

        case JVM_CONSTANT_Class:

        case JVM_CONSTANT_UnresolvedString:

        case JVM_CONSTANT_Utf8:

          visitor.doOop(new OopField(new NamedFieldIdentifier(nameForTag(ctag)), indexOffset(index), true), true);

          break;

        case JVM_CONSTANT_Fieldref:

        case JVM_CONSTANT_Methodref:

        case JVM_CONSTANT_InterfaceMethodref:

        case JVM_CONSTANT_NameAndType:

          visitor.doInt(new IntField(new NamedFieldIdentifier(nameForTag(ctag)), indexOffset(index), true), true);

          break;

        }

      }

    }

    /*

    int length = getLength();

    for (int index = 0; index < length; index++) {

      long offset = baseOffset + (index + typeDataBase.getOopSize());

      visitor.doOop(new IndexableField(index, offset, false), getObjAt(index));

    }

    */

  }

  public void writeBytes(OutputStream os) throws IOException {

          // Map between any modified UTF-8 and it's constant pool index.

          Map utf8ToIndex = new HashMap();

      DataOutputStream dos = new DataOutputStream(os);

      TypeArray tags = getTags();

      int len = (int)getLength();

      int ci = 0; // constant pool index

      // collect all modified UTF-8 Strings from Constant Pool

      for (ci = 1; ci < len; ci++) {

          byte cpConstType = tags.getByteAt(ci);

          if(cpConstType == JVM_CONSTANT_Utf8) {

              Symbol sym = getSymbolAt(ci);

              utf8ToIndex.put(sym.asString(), new Short((short) ci));

          }

          else if(cpConstType == JVM_CONSTANT_Long ||

                  cpConstType == JVM_CONSTANT_Double) {

              ci++;

          }

      }

      for(ci = 1; ci < len; ci++) {

          int cpConstType = (int)tags.getByteAt(ci);

          // write cp_info

          // write constant type

          switch(cpConstType) {

              case JVM_CONSTANT_Utf8: {

                  dos.writeByte(cpConstType);

                  Symbol sym = getSymbolAt(ci);

                  dos.writeShort((short)sym.getLength());

                  dos.write(sym.asByteArray());

                  if (DEBUG) debugMessage("CP[" + ci + "] = modified UTF-8 " + sym.asString());

                  break;

              }

              case JVM_CONSTANT_Unicode:

                  throw new IllegalArgumentException("Unicode constant!");

              case JVM_CONSTANT_Integer:

                  dos.writeByte(cpConstType);

                  dos.writeInt(getIntAt(ci));

                  if (DEBUG) debugMessage("CP[" + ci + "] = int " + getIntAt(ci));

                  break;

              case JVM_CONSTANT_Float:

                  dos.writeByte(cpConstType);

                  dos.writeFloat(getFloatAt(ci));

                  if (DEBUG) debugMessage("CP[" + ci + "] = float " + getFloatAt(ci));

                  break;

              case JVM_CONSTANT_Long: {

                  dos.writeByte(cpConstType);

                  long l = getLongAt(ci);

                  // long entries occupy two pool entries

                  ci++;

                  dos.writeLong(l);

                  break;

              }

              case JVM_CONSTANT_Double:

                  dos.writeByte(cpConstType);

                  dos.writeDouble(getDoubleAt(ci));

                  // double entries occupy two pool entries

                  ci++;

                  break;

              case JVM_CONSTANT_Class: {

                  dos.writeByte(cpConstType);

                  // Klass already resolved. ConstantPool constains klassOop.

                  Klass refKls = (Klass) getObjAt(ci);

                  String klassName = refKls.getName().asString();

                  Short s = (Short) utf8ToIndex.get(klassName);

                  dos.writeShort(s.shortValue());

                  if (DEBUG) debugMessage("CP[" + ci  + "] = class " + s);

                  break;

              }

              // case JVM_CONSTANT_ClassIndex:

              case JVM_CONSTANT_UnresolvedClass: {

                  dos.writeByte(JVM_CONSTANT_Class);

                  String klassName = getSymbolAt(ci).asString();

                  Short s = (Short) utf8ToIndex.get(klassName);

                  dos.writeShort(s.shortValue());

                  if (DEBUG) debugMessage("CP[" + ci + "] = class " + s);

                  break;

              }

              case JVM_CONSTANT_String: {

                  dos.writeByte(cpConstType);

                  String str = OopUtilities.stringOopToString(getObjAt(ci));

                  Short s = (Short) utf8ToIndex.get(str);

                  dos.writeShort(s.shortValue());

                  if (DEBUG) debugMessage("CP[" + ci + "] = string " + s);

                  break;

              }

                  // case JVM_CONSTANT_StringIndex:

              case JVM_CONSTANT_UnresolvedString: {

                  dos.writeByte(JVM_CONSTANT_String);

                  String val = getSymbolAt(ci).asString();

                  Short s = (Short) utf8ToIndex.get(val);

                  dos.writeShort(s.shortValue());

                  if (DEBUG) debugMessage("CP[" + ci + "] = string " + s);

                  break;

              }

              // all external, internal method/field references

              case JVM_CONSTANT_Fieldref:

              case JVM_CONSTANT_Methodref:

              case JVM_CONSTANT_InterfaceMethodref: {

                  dos.writeByte(cpConstType);

                  int value = getIntAt(ci);

                  short klassIndex = (short) extractLowShortFromInt(value);

                  short nameAndTypeIndex = (short) extractHighShortFromInt(value);

                  dos.writeShort(klassIndex);

                  dos.writeShort(nameAndTypeIndex);

                  if (DEBUG) debugMessage("CP[" + ci + "] = ref klass = " +

                                          klassIndex + ", N&T = " + nameAndTypeIndex);

                  break;

              }

              case JVM_CONSTANT_NameAndType: {

                  dos.writeByte(cpConstType);

                  int value = getIntAt(ci);

                  short nameIndex = (short) extractLowShortFromInt(value);

                  short signatureIndex = (short) extractHighShortFromInt(value);

                  dos.writeShort(nameIndex);

                  dos.writeShort(signatureIndex);

                  if (DEBUG) debugMessage("CP[" + ci + "] = N&T name = " + nameIndex

                                          + ", type = " + signatureIndex);

                  break;

              }

          } // switch

      }

      dos.flush();

      return;

  }

  public void printValueOn(PrintStream tty) {

    tty.print("ConstantPool for " + getPoolHolder().getName().asString());

  }

  public long getObjectSize() {

    return alignObjectSize(headerSize + (getLength() * getElementSize()));

  }

  //----------------------------------------------------------------------

  // Internals only below this point

  //

  private static int extractHighShortFromInt(int val) {

    return (val >> 16) & 0xFFFF;

  }

  private static int extractLowShortFromInt(int val) {

    return val & 0xFFFF;

  }

}