/*

 * Copyright (c) 2017, 2018, Red Hat, Inc. All rights reserved.

 *

 * 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_GC_SHENANDOAH_SHENANDOAHSHAREDVARIABLES_HPP

#define SHARE_GC_SHENANDOAH_SHENANDOAHSHAREDVARIABLES_HPP

#include "memory/allocation.hpp"

typedef jbyte ShenandoahSharedValue;

// Needed for cooperation with generated code.

STATIC_ASSERT(sizeof(ShenandoahSharedValue) == 1);

typedef struct ShenandoahSharedFlag {

  enum {

    UNSET = 0,

    SET = 1

  };

  DEFINE_PAD_MINUS_SIZE(0, DEFAULT_CACHE_LINE_SIZE, sizeof(volatile ShenandoahSharedValue));

  volatile ShenandoahSharedValue value;

  DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, 0);

  ShenandoahSharedFlag() {

    unset();

  }

  void set() {

    Atomic::release_store_fence(&value, (ShenandoahSharedValue)SET);

  }

  void unset() {

    Atomic::release_store_fence(&value, (ShenandoahSharedValue)UNSET);

  }

  bool is_set() const {

    return Atomic::load_acquire(&value) == SET;

  }

  bool is_unset() const {

    return Atomic::load_acquire(&value) == UNSET;

  }

  void set_cond(bool val) {

    if (val) {

      set();

    } else {

      unset();

    }

  }

  bool try_set() {

    if (is_set()) {

      return false;

    }

    ShenandoahSharedValue old = Atomic::cmpxchg(&value, (ShenandoahSharedValue)UNSET, (ShenandoahSharedValue)SET);

    return old == UNSET; // success

  }

  bool try_unset() {

    if (!is_set()) {

      return false;

    }

    ShenandoahSharedValue old = Atomic::cmpxchg(&value, (ShenandoahSharedValue)SET, (ShenandoahSharedValue)UNSET);

    return old == SET; // success

  }

  volatile ShenandoahSharedValue* addr_of() {

    return &value;

  }

private:

  volatile ShenandoahSharedValue* operator&() {

    fatal("Use addr_of() instead");

    return NULL;

  }

  bool operator==(ShenandoahSharedFlag& other) { fatal("Use is_set() instead"); return false; }

  bool operator!=(ShenandoahSharedFlag& other) { fatal("Use is_set() instead"); return false; }

  bool operator> (ShenandoahSharedFlag& other) { fatal("Use is_set() instead"); return false; }

  bool operator>=(ShenandoahSharedFlag& other) { fatal("Use is_set() instead"); return false; }

  bool operator< (ShenandoahSharedFlag& other) { fatal("Use is_set() instead"); return false; }

  bool operator<=(ShenandoahSharedFlag& other) { fatal("Use is_set() instead"); return false; }

} ShenandoahSharedFlag;

typedef struct ShenandoahSharedBitmap {

  DEFINE_PAD_MINUS_SIZE(0, DEFAULT_CACHE_LINE_SIZE, sizeof(volatile ShenandoahSharedValue));

  volatile ShenandoahSharedValue value;

  DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, 0);

  ShenandoahSharedBitmap() {

    clear();

  }

  void set(uint mask) {

    assert (mask < (sizeof(ShenandoahSharedValue) * CHAR_MAX), "sanity");

    ShenandoahSharedValue mask_val = (ShenandoahSharedValue) mask;

    while (true) {

      ShenandoahSharedValue ov = Atomic::load_acquire(&value);

      if ((ov & mask_val) != 0) {

        // already set

        return;

      }

      ShenandoahSharedValue nv = ov | mask_val;

      if (Atomic::cmpxchg(&value, ov, nv) == ov) {

        // successfully set

        return;

      }

    }

  }

  void unset(uint mask) {

    assert (mask < (sizeof(ShenandoahSharedValue) * CHAR_MAX), "sanity");

    ShenandoahSharedValue mask_val = (ShenandoahSharedValue) mask;

    while (true) {

      ShenandoahSharedValue ov = Atomic::load_acquire(&value);

      if ((ov & mask_val) == 0) {

        // already unset

        return;

      }

      ShenandoahSharedValue nv = ov & ~mask_val;

      if (Atomic::cmpxchg(&value, ov, nv) == ov) {

        // successfully unset

        return;

      }

    }

  }

  void clear() {

    Atomic::release_store_fence(&value, (ShenandoahSharedValue)0);

  }

  bool is_set(uint mask) const {

    return !is_unset(mask);

  }

  bool is_unset(uint mask) const {

    assert (mask < (sizeof(ShenandoahSharedValue) * CHAR_MAX), "sanity");

    return (Atomic::load_acquire(&value) & (ShenandoahSharedValue) mask) == 0;

  }

  bool is_clear() const {

    return (Atomic::load_acquire(&value)) == 0;

  }

  void set_cond(uint mask, bool val) {

    if (val) {

      set(mask);

    } else {

      unset(mask);

    }

  }

  volatile ShenandoahSharedValue* addr_of() {

    return &value;

  }

  ShenandoahSharedValue raw_value() const {

    return value;

  }

private:

  volatile ShenandoahSharedValue* operator&() {

    fatal("Use addr_of() instead");

    return NULL;

  }

  bool operator==(ShenandoahSharedFlag& other) { fatal("Use is_set() instead"); return false; }

  bool operator!=(ShenandoahSharedFlag& other) { fatal("Use is_set() instead"); return false; }

  bool operator> (ShenandoahSharedFlag& other) { fatal("Use is_set() instead"); return false; }

  bool operator>=(ShenandoahSharedFlag& other) { fatal("Use is_set() instead"); return false; }

  bool operator< (ShenandoahSharedFlag& other) { fatal("Use is_set() instead"); return false; }

  bool operator<=(ShenandoahSharedFlag& other) { fatal("Use is_set() instead"); return false; }

} ShenandoahSharedBitmap;

template<class T>

struct ShenandoahSharedEnumFlag {

  DEFINE_PAD_MINUS_SIZE(0, DEFAULT_CACHE_LINE_SIZE, sizeof(volatile ShenandoahSharedValue));

  volatile ShenandoahSharedValue value;

  DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, 0);

  ShenandoahSharedEnumFlag() {

    value = 0;

  }

  void set(T v) {

    assert (v >= 0, "sanity");

    assert (v < (sizeof(ShenandoahSharedValue) * CHAR_MAX), "sanity");

    Atomic::release_store_fence(&value, (ShenandoahSharedValue)v);

  }

  T get() const {

    return (T)Atomic::load_acquire(&value);

  }

  T cmpxchg(T new_value, T expected) {

    assert (new_value >= 0, "sanity");

    assert (new_value < (sizeof(ShenandoahSharedValue) * CHAR_MAX), "sanity");

    return (T)Atomic::cmpxchg(&value, (ShenandoahSharedValue)expected, (ShenandoahSharedValue)new_value);

  }

  volatile ShenandoahSharedValue* addr_of() {

    return &value;

  }

private:

  volatile T* operator&() {

    fatal("Use addr_of() instead");

    return NULL;

  }

  bool operator==(ShenandoahSharedEnumFlag& other) { fatal("Use get() instead"); return false; }

  bool operator!=(ShenandoahSharedEnumFlag& other) { fatal("Use get() instead"); return false; }

  bool operator> (ShenandoahSharedEnumFlag& other) { fatal("Use get() instead"); return false; }

  bool operator>=(ShenandoahSharedEnumFlag& other) { fatal("Use get() instead"); return false; }

  bool operator< (ShenandoahSharedEnumFlag& other) { fatal("Use get() instead"); return false; }

  bool operator<=(ShenandoahSharedEnumFlag& other) { fatal("Use get() instead"); return false; }

};

#endif // SHARE_GC_SHENANDOAH_SHENANDOAHSHAREDVARIABLES_HPP