/*

 * Copyright (c) 2011, 2017, 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.

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 */

#ifndef SHARE_VM_OOPS_FIELDSTREAMS_HPP

#define SHARE_VM_OOPS_FIELDSTREAMS_HPP

#include "oops/instanceKlass.hpp"

#include "oops/fieldInfo.hpp"

#include "runtime/fieldDescriptor.hpp"

// The is the base class for iteration over the fields array

// describing the declared fields in the class.  Several subclasses

// are provided depending on the kind of iteration required.  The

// JavaFieldStream is for iterating over regular Java fields and it

// generally the preferred iterator.  InternalFieldStream only

// iterates over fields that have been injected by the JVM.

// AllFieldStream exposes all fields and should only be used in rare

// cases.

class FieldStreamBase : public StackObj {

 protected:

  Array<u2>*          _fields;

  constantPoolHandle  _constants;

  int                 _index;

  int                 _limit;

  int                 _generic_signature_slot;

  fieldDescriptor     _fd_buf;

  FieldInfo* field() const { return FieldInfo::from_field_array(_fields, _index); }

  InstanceKlass* field_holder() const { return _constants->pool_holder(); }

  int init_generic_signature_start_slot() {

    int length = _fields->length();

    int num_fields = _index;

    int skipped_generic_signature_slots = 0;

    FieldInfo* fi;

    AccessFlags flags;

    /* Scan from 0 to the current _index. Count the number of generic

       signature slots for field[0] to field[_index - 1]. */

    for (int i = 0; i < _index; i++) {

      fi = FieldInfo::from_field_array(_fields, i);

      flags.set_flags(fi->access_flags());

      if (flags.field_has_generic_signature()) {

        length --;

        skipped_generic_signature_slots ++;

      }

    }

    /* Scan from the current _index. */

    for (int i = _index; i*FieldInfo::field_slots < length; i++) {

      fi = FieldInfo::from_field_array(_fields, i);

      flags.set_flags(fi->access_flags());

      if (flags.field_has_generic_signature()) {

        length --;

      }

      num_fields ++;

    }

    _generic_signature_slot = length + skipped_generic_signature_slots;

    assert(_generic_signature_slot <= _fields->length(), "");

    return num_fields;

  }

  FieldStreamBase(Array<u2>* fields, const constantPoolHandle& constants, int start, int limit) {

    _fields = fields;

    _constants = constants;

    _index = start;

    int num_fields = init_generic_signature_start_slot();

    if (limit < start) {

      _limit = num_fields;

    } else {

      _limit = limit;

    }

  }

  FieldStreamBase(Array<u2>* fields, const constantPoolHandle& constants) {

    _fields = fields;

    _constants = constants;

    _index = 0;

    _limit = init_generic_signature_start_slot();

  }

 public:

  FieldStreamBase(InstanceKlass* klass) {

    _fields = klass->fields();

    _constants = klass->constants();

    _index = 0;

    _limit = klass->java_fields_count();

    init_generic_signature_start_slot();

    assert(klass == field_holder(), "");

  }

  // accessors

  int index() const                 { return _index; }

  void next() {

    if (access_flags().field_has_generic_signature()) {

      _generic_signature_slot ++;

      assert(_generic_signature_slot <= _fields->length(), "");

    }

    _index += 1;

  }

  bool done() const { return _index >= _limit; }

  // Accessors for current field

  AccessFlags access_flags() const {

    AccessFlags flags;

    flags.set_flags(field()->access_flags());

    return flags;

  }

  void set_access_flags(u2 flags) const {

    field()->set_access_flags(flags);

  }

  void set_access_flags(AccessFlags flags) const {

    set_access_flags(flags.as_short());

  }

  Symbol* name() const {

    return field()->name(_constants);

  }

  Symbol* signature() const {

    return field()->signature(_constants);

  }

  Symbol* generic_signature() const {

    if (access_flags().field_has_generic_signature()) {

      assert(_generic_signature_slot < _fields->length(), "out of bounds");

      int index = _fields->at(_generic_signature_slot);

      return _constants->symbol_at(index);

    } else {

      return NULL;

    }

  }

  int offset() const {

    return field()->offset();

  }

  int allocation_type() const {

    return field()->allocation_type();

  }

  void set_offset(int offset) {

    field()->set_offset(offset);

  }

  bool is_offset_set() const {

    return field()->is_offset_set();

  }

  bool is_contended() const {

    return field()->is_contended();

  }

  int contended_group() const {

    return field()->contended_group();

  }

  // bridge to a heavier API:

  fieldDescriptor& field_descriptor() const {

    fieldDescriptor& field = const_cast<fieldDescriptor&>(_fd_buf);

    field.reinitialize(field_holder(), _index);

    return field;

  }

};

// Iterate over only the internal fields

class JavaFieldStream : public FieldStreamBase {

 public:

  JavaFieldStream(const InstanceKlass* k): FieldStreamBase(k->fields(), k->constants(), 0, k->java_fields_count()) {}

  int name_index() const {

    assert(!field()->is_internal(), "regular only");

    return field()->name_index();

  }

  void set_name_index(int index) {

    assert(!field()->is_internal(), "regular only");

    field()->set_name_index(index);

  }

  int signature_index() const {

    assert(!field()->is_internal(), "regular only");

    return field()->signature_index();

  }

  void set_signature_index(int index) {

    assert(!field()->is_internal(), "regular only");

    field()->set_signature_index(index);

  }

  int generic_signature_index() const {

    assert(!field()->is_internal(), "regular only");

    if (access_flags().field_has_generic_signature()) {

      assert(_generic_signature_slot < _fields->length(), "out of bounds");

      return _fields->at(_generic_signature_slot);

    } else {

      return 0;

    }

  }

  void set_generic_signature_index(int index) {

    assert(!field()->is_internal(), "regular only");

    if (access_flags().field_has_generic_signature()) {

      assert(_generic_signature_slot < _fields->length(), "out of bounds");

      _fields->at_put(_generic_signature_slot, index);

    }

  }

  int initval_index() const {

    assert(!field()->is_internal(), "regular only");

    return field()->initval_index();

  }

  void set_initval_index(int index) {

    assert(!field()->is_internal(), "regular only");

    return field()->set_initval_index(index);

  }

};

// Iterate over only the internal fields

class InternalFieldStream : public FieldStreamBase {

 public:

  InternalFieldStream(InstanceKlass* k):      FieldStreamBase(k->fields(), k->constants(), k->java_fields_count(), 0) {}

};

class AllFieldStream : public FieldStreamBase {

 public:

  AllFieldStream(Array<u2>* fields, const constantPoolHandle& constants): FieldStreamBase(fields, constants) {}

  AllFieldStream(InstanceKlass* k):      FieldStreamBase(k->fields(), k->constants()) {}

};

#endif // SHARE_VM_OOPS_FIELDSTREAMS_HPP