/*

 * 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

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 */

#include "memory/universe.hpp"

#include "oops/klass.hpp"

#include "oops/markOop.hpp"

inline void Klass::set_prototype_header(markOop header) {

  assert(!header->has_bias_pattern() || is_instance_klass(), "biased locking currently only supported for Java instances");

  _prototype_header = header;

}

inline bool Klass::is_null(Klass* obj)  { return obj == NULL; }

inline bool Klass::is_null(narrowKlass obj) { return obj == 0; }

// Encoding and decoding for klass field.

inline bool check_klass_alignment(Klass* obj) {

  return (intptr_t)obj % KlassAlignmentInBytes == 0;

}

inline narrowKlass Klass::encode_klass_not_null(Klass* v) {

  assert(!is_null(v), "klass value can never be zero");

  assert(check_klass_alignment(v), "Address not aligned");

  int    shift = Universe::narrow_klass_shift();

  uint64_t pd = (uint64_t)(pointer_delta((void*)v, Universe::narrow_klass_base(), 1));

  assert(KlassEncodingMetaspaceMax > pd, "change encoding max if new encoding");

  uint64_t result = pd >> shift;

  assert((result & CONST64(0xffffffff00000000)) == 0, "narrow klass pointer overflow");

  assert(decode_klass(result) == v, "reversibility");

  return (narrowKlass)result;

}

inline narrowKlass Klass::encode_klass(Klass* v) {

  return is_null(v) ? (narrowKlass)0 : encode_klass_not_null(v);

}

inline Klass* Klass::decode_klass_not_null(narrowKlass v) {

  assert(!is_null(v), "narrow klass value can never be zero");

  int    shift = Universe::narrow_klass_shift();

  Klass* result = (Klass*)(void*)((uintptr_t)Universe::narrow_klass_base() + ((uintptr_t)v << shift));

  assert(check_klass_alignment(result), "address not aligned: " INTPTR_FORMAT, p2i((void*) result));

  return result;

}

inline Klass* Klass::decode_klass(narrowKlass v) {

  return is_null(v) ? (Klass*)NULL : decode_klass_not_null(v);

}