/*

 * Copyright (c) 2016, 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.

 */

#ifndef SHARE_GC_Z_ZMARKSTACK_INLINE_HPP

#define SHARE_GC_Z_ZMARKSTACK_INLINE_HPP

#include "gc/z/zMarkStack.hpp"

#include "utilities/debug.hpp"

#include "runtime/atomic.hpp"

template <typename T, size_t S>

inline ZStack<T, S>::ZStack() :

    _top(0),

    _next(NULL) {}

template <typename T, size_t S>

inline bool ZStack<T, S>::is_empty() const {

  return _top == 0;

}

template <typename T, size_t S>

inline bool ZStack<T, S>::is_full() const {

  return _top == S;

}

template <typename T, size_t S>

inline bool ZStack<T, S>::push(T value) {

  if (is_full()) {

    return false;

  }

  _slots[_top++] = value;

  return true;

}

template <typename T, size_t S>

inline bool ZStack<T, S>::pop(T& value) {

  if (is_empty()) {

    return false;

  }

  value = _slots[--_top];

  return true;

}

template <typename T, size_t S>

inline ZStack<T, S>* ZStack<T, S>::next() const {

  return _next;

}

template <typename T, size_t S>

inline ZStack<T, S>** ZStack<T, S>::next_addr() {

  return &_next;

}

template <typename T>

inline ZStackList<T>::ZStackList() :

    _head(encode_versioned_pointer(NULL, 0)) {}

template <typename T>

inline T* ZStackList<T>::encode_versioned_pointer(const T* stack, uint32_t version) const {

  uint64_t addr;

  if (stack == NULL) {

    addr = (uint32_t)-1;

  } else {

    addr = ((uint64_t)stack - ZMarkStackSpaceStart) >> ZMarkStackSizeShift;

  }

  return (T*)((addr << 32) | (uint64_t)version);

}

template <typename T>

inline void ZStackList<T>::decode_versioned_pointer(const T* vstack, T** stack, uint32_t* version) const {

  const uint64_t addr = (uint64_t)vstack >> 32;

  if (addr == (uint32_t)-1) {

    *stack = NULL;

  } else {

    *stack = (T*)((addr << ZMarkStackSizeShift) + ZMarkStackSpaceStart);

  }

  *version = (uint32_t)(uint64_t)vstack;

}

template <typename T>

inline bool ZStackList<T>::is_empty() const {

  const T* vstack = _head;

  T* stack = NULL;

  uint32_t version = 0;

  decode_versioned_pointer(vstack, &stack, &version);

  return stack == NULL;

}

template <typename T>

  T* vstack = _head;

  uint32_t version = 0;

  for (;;) {

    decode_versioned_pointer(vstack, stack->next_addr(), &version);

    T* const new_vstack = encode_versioned_pointer(stack, version + 1);

    T* const prev_vstack = Atomic::cmpxchg(new_vstack, &_head, vstack);

    if (prev_vstack == vstack) {

      // Success

      break;

    }

    // Retry

    vstack = prev_vstack;

  }

}

template <typename T>

  T* vstack = _head;

  T* stack = NULL;

  uint32_t version = 0;

  for (;;) {

    decode_versioned_pointer(vstack, &stack, &version);

    if (stack == NULL) {

      return NULL;

    }

    T* const new_vstack = encode_versioned_pointer(stack->next(), version + 1);

    T* const prev_vstack = Atomic::cmpxchg(new_vstack, &_head, vstack);

    if (prev_vstack == vstack) {

      // Success

      return stack;

    }

    // Retry

    vstack = prev_vstack;

  }

}

inline bool ZMarkStripe::is_empty() const {

  return _published.is_empty() && _overflowed.is_empty();

}

inline void ZMarkStripe::publish_stack(ZMarkStack* stack, bool publish) {

  // A stack is published either on the published list or the overflowed

  // list. The published list is used by mutators publishing stacks for GC

  // workers to work on, while the overflowed list is used by GC workers

  // to publish stacks that overflowed. The intention here is to avoid

  // contention between mutators and GC workers as much as possible, while

  // still allowing GC workers to help out and steal work from each other.

  if (publish) {

  } else {

  }

}

inline ZMarkStack* ZMarkStripe::steal_stack() {

  // Steal overflowed stacks first, then published stacks

  if (stack != NULL) {

    return stack;

  }

}

inline size_t ZMarkStripeSet::nstripes() const {

  return _nstripes;

}

inline size_t ZMarkStripeSet::stripe_id(const ZMarkStripe* stripe) const {

  const size_t index = ((uintptr_t)stripe - (uintptr_t)_stripes) / sizeof(ZMarkStripe);

  assert(index < _nstripes, "Invalid index");

  return index;

}

inline ZMarkStripe* ZMarkStripeSet::stripe_at(size_t index) {

  assert(index < _nstripes, "Invalid index");

  return &_stripes[index];

}

inline ZMarkStripe* ZMarkStripeSet::stripe_next(ZMarkStripe* stripe) {

  const size_t index = (stripe_id(stripe) + 1) & _nstripes_mask;

  assert(index < _nstripes, "Invalid index");

  return &_stripes[index];

}

inline ZMarkStripe* ZMarkStripeSet::stripe_for_addr(uintptr_t addr) {

  const size_t index = (addr >> ZMarkStripeShift) & _nstripes_mask;

  assert(index < _nstripes, "Invalid index");

  return &_stripes[index];

}

inline void ZMarkThreadLocalStacks::install(ZMarkStripeSet* stripes,

                                            ZMarkStripe* stripe,

                                            ZMarkStack* stack) {

  ZMarkStack** const stackp = &_stacks[stripes->stripe_id(stripe)];

  assert(*stackp == NULL, "Should be empty");

  *stackp = stack;

}

inline bool ZMarkThreadLocalStacks::push(ZMarkStackAllocator* allocator,

                                         ZMarkStripeSet* stripes,

                                         ZMarkStripe* stripe,

                                         ZMarkStackEntry entry,

                                         bool publish) {

  ZMarkStack** const stackp = &_stacks[stripes->stripe_id(stripe)];

  ZMarkStack* const stack = *stackp;

  if (stack != NULL && stack->push(entry)) {

    return true;

  }

  return push_slow(allocator, stripe, stackp, entry, publish);

}

inline bool ZMarkThreadLocalStacks::pop(ZMarkStackAllocator* allocator,

                                        ZMarkStripeSet* stripes,

                                        ZMarkStripe* stripe,

                                        ZMarkStackEntry& entry) {

  ZMarkStack** const stackp = &_stacks[stripes->stripe_id(stripe)];

  ZMarkStack* const stack = *stackp;

  if (stack != NULL && stack->pop(entry)) {

    return true;

  }

  return pop_slow(allocator, stripe, stackp, entry);

}

#endif // SHARE_GC_Z_ZMARKSTACK_INLINE_HPP