/*

 * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.

 * 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#ifndef SHARE_VM_OOPS_FIELDINFO_HPP

#define SHARE_VM_OOPS_FIELDINFO_HPP

#include "oops/typeArrayOop.hpp"

#include "classfile/vmSymbols.hpp"

// This class represents the field information contained in the fields

// array of an instanceKlass.  Currently it's laid on top an array of

// Java shorts but in the future it could simply be used as a real

// array type.  FieldInfo generally shouldn't be used directly.

// Fields should be queried either through instanceKlass or through

// the various FieldStreams.

class FieldInfo VALUE_OBJ_CLASS_SPEC {

  friend class fieldDescriptor;

  friend class JavaFieldStream;

  friend class ClassFileParser;

 public:

  // fields

  // Field info extracted from the class file and stored

  // as an array of 7 shorts

  enum FieldOffset {

    access_flags_offset      = 0,

    name_index_offset        = 1,

    signature_index_offset   = 2,

    initval_index_offset     = 3,

    low_offset               = 4,

    high_offset              = 5,

    generic_signature_offset = 6,

    field_slots              = 7

  };

 private:

  u2 _shorts[field_slots];

  void set_name_index(u2 val)                    { _shorts[name_index_offset] = val;         }

  void set_signature_index(u2 val)               { _shorts[signature_index_offset] = val;    }

  void set_initval_index(u2 val)                 { _shorts[initval_index_offset] = val;      }

  void set_generic_signature_index(u2 val)       { _shorts[generic_signature_offset] = val;  }

  u2 name_index() const                          { return _shorts[name_index_offset];        }

  u2 signature_index() const                     { return _shorts[signature_index_offset];   }

  u2 initval_index() const                       { return _shorts[initval_index_offset];     }

  u2 generic_signature_index() const             { return _shorts[generic_signature_offset]; }

 public:

  static FieldInfo* from_field_array(typeArrayOop fields, int index) {

    return ((FieldInfo*)fields->short_at_addr(index * field_slots));

  }

  void initialize(u2 access_flags,

                  u2 name_index,

                  u2 signature_index,

                  u2 initval_index,

                  u2 generic_signature_index,

                  u4 offset) {

    _shorts[access_flags_offset] = access_flags;

    _shorts[name_index_offset] = name_index;

    _shorts[signature_index_offset] = signature_index;

    _shorts[initval_index_offset] = initval_index;

    _shorts[generic_signature_offset] = generic_signature_index;

    set_offset(offset);

  }

  u2 access_flags() const                        { return _shorts[access_flags_offset];            }

  u4 offset() const                              { return build_int_from_shorts(_shorts[low_offset], _shorts[high_offset]); }

  Symbol* name(constantPoolHandle cp) const {

    int index = name_index();

    if (is_internal()) {

      return lookup_symbol(index);

    }

    return cp->symbol_at(index);

  }

  Symbol* signature(constantPoolHandle cp) const {

    int index = signature_index();

    if (is_internal()) {

      return lookup_symbol(index);

    }

    return cp->symbol_at(index);

  }

  Symbol* generic_signature(constantPoolHandle cp) const {

    int index = generic_signature_index();

    if (index == 0) {

      return NULL;

    }

    return cp->symbol_at(index);

  }

  void set_access_flags(u2 val)                  { _shorts[access_flags_offset] = val;             }

  void set_offset(u4 val)                        {

    _shorts[low_offset] = extract_low_short_from_int(val);

    _shorts[high_offset] = extract_high_short_from_int(val);

  }

  bool is_internal() const {

    return (access_flags() & JVM_ACC_FIELD_INTERNAL) != 0;

  }

  Symbol* lookup_symbol(int symbol_index) const {

    assert(is_internal(), "only internal fields");

    return vmSymbols::symbol_at((vmSymbols::SID)symbol_index);

  }

};

#endif // SHARE_VM_OOPS_FIELDINFO_HPP