/*

 * Copyright (c) 1997, 2019, 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.

 *

 */

#include "precompiled.hpp"

#include "memory/allocation.inline.hpp"

#include "memory/resourceArea.hpp"

#include "runtime/atomic.hpp"

#include "utilities/bitMap.inline.hpp"

#include "utilities/copy.hpp"

#include "utilities/debug.hpp"

STATIC_ASSERT(sizeof(BitMap::bm_word_t) == BytesPerWord); // "Implementation assumption."

typedef BitMap::bm_word_t bm_word_t;

typedef BitMap::idx_t     idx_t;

class ResourceBitMapAllocator : StackObj {

 public:

  bm_word_t* allocate(idx_t size_in_words) const {

    return NEW_RESOURCE_ARRAY(bm_word_t, size_in_words);

  }

  void free(bm_word_t* map, idx_t size_in_words) const {

    // Don't free resource allocated arrays.

  }

};

class CHeapBitMapAllocator : StackObj {

  MEMFLAGS _flags;

 public:

  CHeapBitMapAllocator(MEMFLAGS flags) : _flags(flags) {}

  bm_word_t* allocate(size_t size_in_words) const {

    return ArrayAllocator<bm_word_t>::allocate(size_in_words, _flags);

  }

  void free(bm_word_t* map, idx_t size_in_words) const {

    ArrayAllocator<bm_word_t>::free(map, size_in_words);

  }

};

class ArenaBitMapAllocator : StackObj {

  Arena* _arena;

 public:

  ArenaBitMapAllocator(Arena* arena) : _arena(arena) {}

  bm_word_t* allocate(idx_t size_in_words) const {

    return (bm_word_t*)_arena->Amalloc(size_in_words * BytesPerWord);

  }

  void free(bm_word_t* map, idx_t size_in_words) const {

    // ArenaBitMaps currently don't free memory.

  }

};

template <class Allocator>

BitMap::bm_word_t* BitMap::reallocate(const Allocator& allocator, bm_word_t* old_map, idx_t old_size_in_bits, idx_t new_size_in_bits, bool clear) {

  size_t old_size_in_words = calc_size_in_words(old_size_in_bits);

  size_t new_size_in_words = calc_size_in_words(new_size_in_bits);

  bm_word_t* map = NULL;

  if (new_size_in_words > 0) {

    map = allocator.allocate(new_size_in_words);

    if (old_map != NULL) {

      Copy::disjoint_words((HeapWord*)old_map, (HeapWord*) map,

                           MIN2(old_size_in_words, new_size_in_words));

    }

    if (clear && new_size_in_words > old_size_in_words) {

      clear_range_of_words(map, old_size_in_words, new_size_in_words);

    }

  }

  if (old_map != NULL) {

    allocator.free(old_map, old_size_in_words);

  }

  return map;

}

template <class Allocator>

bm_word_t* BitMap::allocate(const Allocator& allocator, idx_t size_in_bits, bool clear) {

  // Reuse reallocate to ensure that the new memory is cleared.

  return reallocate(allocator, NULL, 0, size_in_bits, clear);

}

template <class Allocator>

void BitMap::free(const Allocator& allocator, bm_word_t* map, idx_t  size_in_bits) {

  bm_word_t* ret = reallocate(allocator, map, size_in_bits, 0);

  assert(ret == NULL, "Reallocate shouldn't have allocated");

}

template <class Allocator>

void BitMap::resize(const Allocator& allocator, idx_t new_size_in_bits, bool clear) {

  bm_word_t* new_map = reallocate(allocator, map(), size(), new_size_in_bits, clear);

  update(new_map, new_size_in_bits);

}

template <class Allocator>

void BitMap::initialize(const Allocator& allocator, idx_t size_in_bits, bool clear) {

  assert(map() == NULL, "precondition");

  assert(size() == 0,   "precondition");

  resize(allocator, size_in_bits, clear);

}

template <class Allocator>

void BitMap::reinitialize(const Allocator& allocator, idx_t new_size_in_bits, bool clear) {

  // Remove previous bits - no need to clear

  resize(allocator, 0, false /* clear */);

  initialize(allocator, new_size_in_bits, clear);

}

ResourceBitMap::ResourceBitMap(idx_t size_in_bits, bool clear)

    : BitMap(allocate(ResourceBitMapAllocator(), size_in_bits, clear), size_in_bits) {

}

void ResourceBitMap::resize(idx_t new_size_in_bits) {

  BitMap::resize(ResourceBitMapAllocator(), new_size_in_bits, true /* clear */);

}

void ResourceBitMap::initialize(idx_t size_in_bits) {

  BitMap::initialize(ResourceBitMapAllocator(), size_in_bits, true /* clear */);

}

void ResourceBitMap::reinitialize(idx_t size_in_bits) {

  BitMap::reinitialize(ResourceBitMapAllocator(), size_in_bits, true /* clear */);

}

ArenaBitMap::ArenaBitMap(Arena* arena, idx_t size_in_bits)

    : BitMap(allocate(ArenaBitMapAllocator(arena), size_in_bits), size_in_bits) {

}

CHeapBitMap::CHeapBitMap(idx_t size_in_bits, MEMFLAGS flags, bool clear)

    : BitMap(allocate(CHeapBitMapAllocator(flags), size_in_bits, clear), size_in_bits), _flags(flags) {

}

CHeapBitMap::~CHeapBitMap() {

  free(CHeapBitMapAllocator(_flags), map(), size());

}

void CHeapBitMap::resize(idx_t new_size_in_bits, bool clear) {

  BitMap::resize(CHeapBitMapAllocator(_flags), new_size_in_bits, clear);

}

void CHeapBitMap::initialize(idx_t size_in_bits, bool clear) {

  BitMap::initialize(CHeapBitMapAllocator(_flags), size_in_bits, clear);

}

void CHeapBitMap::reinitialize(idx_t size_in_bits, bool clear) {

  BitMap::reinitialize(CHeapBitMapAllocator(_flags), size_in_bits, clear);

}

#ifdef ASSERT

void BitMap::verify_index(idx_t index) const {

  assert(index < _size, "BitMap index out of bounds");

}

void BitMap::verify_range(idx_t beg_index, idx_t end_index) const {

  assert(beg_index <= end_index, "BitMap range error");

  // Note that [0,0) and [size,size) are both valid ranges.

  if (end_index != _size) verify_index(end_index);

}

#endif // #ifdef ASSERT

void BitMap::pretouch() {

  os::pretouch_memory(word_addr(0), word_addr(size()));

}

void BitMap::set_range_within_word(idx_t beg, idx_t end) {

  // With a valid range (beg <= end), this test ensures that end != 0, as

  // required by inverted_bit_mask_for_range.  Also avoids an unnecessary write.

  if (beg != end) {

    bm_word_t mask = inverted_bit_mask_for_range(beg, end);

    *word_addr(beg) |= ~mask;

  }

}

void BitMap::clear_range_within_word(idx_t beg, idx_t end) {

  // With a valid range (beg <= end), this test ensures that end != 0, as

  // required by inverted_bit_mask_for_range.  Also avoids an unnecessary write.

  if (beg != end) {

    bm_word_t mask = inverted_bit_mask_for_range(beg, end);

    *word_addr(beg) &= mask;

  }

}

void BitMap::par_put_range_within_word(idx_t beg, idx_t end, bool value) {

  assert(value == 0 || value == 1, "0 for clear, 1 for set");

  // With a valid range (beg <= end), this test ensures that end != 0, as

  // required by inverted_bit_mask_for_range.  Also avoids an unnecessary write.

  if (beg != end) {

    bm_word_t* pw = word_addr(beg);

    bm_word_t  w  = *pw;

    bm_word_t  mr = inverted_bit_mask_for_range(beg, end);

    bm_word_t  nw = value ? (w | ~mr) : (w & mr);

    while (true) {

      if (res == w) break;

      w  = res;

      nw = value ? (w | ~mr) : (w & mr);

    }

  }

}

void BitMap::set_range(idx_t beg, idx_t end) {

  verify_range(beg, end);

  idx_t beg_full_word = word_index_round_up(beg);

  idx_t end_full_word = word_index(end);

  if (beg_full_word < end_full_word) {

    // The range includes at least one full word.

    set_range_within_word(beg, bit_index(beg_full_word));

    set_range_of_words(beg_full_word, end_full_word);

    set_range_within_word(bit_index(end_full_word), end);

  } else {

    // The range spans at most 2 partial words.

    idx_t boundary = MIN2(bit_index(beg_full_word), end);

    set_range_within_word(beg, boundary);

    set_range_within_word(boundary, end);

  }

}

void BitMap::clear_range(idx_t beg, idx_t end) {

  verify_range(beg, end);

  idx_t beg_full_word = word_index_round_up(beg);

  idx_t end_full_word = word_index(end);

  if (beg_full_word < end_full_word) {

    // The range includes at least one full word.

    clear_range_within_word(beg, bit_index(beg_full_word));

    clear_range_of_words(beg_full_word, end_full_word);

    clear_range_within_word(bit_index(end_full_word), end);

  } else {

    // The range spans at most 2 partial words.

    idx_t boundary = MIN2(bit_index(beg_full_word), end);

    clear_range_within_word(beg, boundary);

    clear_range_within_word(boundary, end);

  }

}

bool BitMap::is_small_range_of_words(idx_t beg_full_word, idx_t end_full_word) {

  // There is little point to call large version on small ranges.

  // Need to check carefully, keeping potential idx_t underflow in mind.

  // The threshold should be at least one word.

  STATIC_ASSERT(small_range_words >= 1);

  return (beg_full_word + small_range_words >= end_full_word);

}

void BitMap::set_large_range(idx_t beg, idx_t end) {

  verify_range(beg, end);

  idx_t beg_full_word = word_index_round_up(beg);

  idx_t end_full_word = word_index(end);

  if (is_small_range_of_words(beg_full_word, end_full_word)) {

    set_range(beg, end);

    return;

  }

  // The range includes at least one full word.

  set_range_within_word(beg, bit_index(beg_full_word));

  set_large_range_of_words(beg_full_word, end_full_word);

  set_range_within_word(bit_index(end_full_word), end);

}

void BitMap::clear_large_range(idx_t beg, idx_t end) {

  verify_range(beg, end);

  idx_t beg_full_word = word_index_round_up(beg);

  idx_t end_full_word = word_index(end);

  if (is_small_range_of_words(beg_full_word, end_full_word)) {

    clear_range(beg, end);

    return;

  }

  // The range includes at least one full word.

  clear_range_within_word(beg, bit_index(beg_full_word));

  clear_large_range_of_words(beg_full_word, end_full_word);

  clear_range_within_word(bit_index(end_full_word), end);

}

void BitMap::at_put(idx_t offset, bool value) {

  if (value) {

    set_bit(offset);

  } else {

    clear_bit(offset);

  }

}

// Return true to indicate that this thread changed

// the bit, false to indicate that someone else did.

// In either case, the requested bit is in the

// requested state some time during the period that

// this thread is executing this call. More importantly,

// if no other thread is executing an action to

// change the requested bit to a state other than

// the one that this thread is trying to set it to,

// then the the bit is in the expected state

// at exit from this method. However, rather than

// make such a strong assertion here, based on

// assuming such constrained use (which though true

// today, could change in the future to service some

// funky parallel algorithm), we encourage callers

// to do such verification, as and when appropriate.

bool BitMap::par_at_put(idx_t bit, bool value) {

  return value ? par_set_bit(bit) : par_clear_bit(bit);

}

void BitMap::at_put_range(idx_t start_offset, idx_t end_offset, bool value) {

  if (value) {

    set_range(start_offset, end_offset);

  } else {

    clear_range(start_offset, end_offset);

  }

}

void BitMap::par_at_put_range(idx_t beg, idx_t end, bool value) {

  verify_range(beg, end);

  idx_t beg_full_word = word_index_round_up(beg);

  idx_t end_full_word = word_index(end);

  if (beg_full_word < end_full_word) {

    // The range includes at least one full word.

    par_put_range_within_word(beg, bit_index(beg_full_word), value);

    if (value) {

      set_range_of_words(beg_full_word, end_full_word);

    } else {

      clear_range_of_words(beg_full_word, end_full_word);

    }

    par_put_range_within_word(bit_index(end_full_word), end, value);

  } else {

    // The range spans at most 2 partial words.

    idx_t boundary = MIN2(bit_index(beg_full_word), end);

    par_put_range_within_word(beg, boundary, value);

    par_put_range_within_word(boundary, end, value);

  }

}

void BitMap::at_put_large_range(idx_t beg, idx_t end, bool value) {

  if (value) {

    set_large_range(beg, end);

  } else {

    clear_large_range(beg, end);

  }

}

void BitMap::par_at_put_large_range(idx_t beg, idx_t end, bool value) {

  verify_range(beg, end);

  idx_t beg_full_word = word_index_round_up(beg);

  idx_t end_full_word = word_index(end);

  if (is_small_range_of_words(beg_full_word, end_full_word)) {

    par_at_put_range(beg, end, value);

    return;

  }

  // The range includes at least one full word.

  par_put_range_within_word(beg, bit_index(beg_full_word), value);

  if (value) {

    set_large_range_of_words(beg_full_word, end_full_word);

  } else {

    clear_large_range_of_words(beg_full_word, end_full_word);

  }

  par_put_range_within_word(bit_index(end_full_word), end, value);

}

inline bm_word_t tail_mask(idx_t tail_bits) {

  assert(tail_bits != 0, "precondition"); // Works, but shouldn't be called.

  assert(tail_bits < (idx_t)BitsPerWord, "precondition");

  return (bm_word_t(1) << tail_bits) - 1;

}

// Get the low tail_bits of value, which is the last partial word of a map.

inline bm_word_t tail_of_map(bm_word_t value, idx_t tail_bits) {

  return value & tail_mask(tail_bits);

}

// Compute the new last word of a map with a non-aligned length.

// new_value has the new trailing bits of the map in the low tail_bits.

// old_value is the last word of the map, including bits beyond the end.

// Returns old_value with the low tail_bits replaced by the corresponding

// bits in new_value.

inline bm_word_t merge_tail_of_map(bm_word_t new_value,

                                   bm_word_t old_value,

                                   idx_t tail_bits) {

  bm_word_t mask = tail_mask(tail_bits);

  return (new_value & mask) | (old_value & ~mask);

}

bool BitMap::contains(const BitMap& other) const {

  assert(size() == other.size(), "must have same size");

  const bm_word_t* dest_map = map();

  const bm_word_t* other_map = other.map();

  idx_t limit = word_index(size());

  for (idx_t index = 0; index < limit; ++index) {

    // false if other bitmap has bits set which are clear in this bitmap.

    if ((~dest_map[index] & other_map[index]) != 0) return false;

  }

  idx_t rest = bit_in_word(size());

  // true unless there is a partial-word tail in which the other

  // bitmap has bits set which are clear in this bitmap.

  return (rest == 0) || tail_of_map(~dest_map[limit] & other_map[limit], rest) == 0;

}

bool BitMap::intersects(const BitMap& other) const {

  assert(size() == other.size(), "must have same size");

  const bm_word_t* dest_map = map();

  const bm_word_t* other_map = other.map();

  idx_t limit = word_index(size());

  for (idx_t index = 0; index < limit; ++index) {

    if ((dest_map[index] & other_map[index]) != 0) return true;

  }

  idx_t rest = bit_in_word(size());

  // false unless there is a partial-word tail with non-empty intersection.

  return (rest > 0) && tail_of_map(dest_map[limit] & other_map[limit], rest) != 0;

}

void BitMap::set_union(const BitMap& other) {

  assert(size() == other.size(), "must have same size");

  bm_word_t* dest_map = map();

  const bm_word_t* other_map = other.map();

  idx_t limit = word_index(size());

  for (idx_t index = 0; index < limit; ++index) {

    dest_map[index] |= other_map[index];

  }

  idx_t rest = bit_in_word(size());

  if (rest > 0) {

    bm_word_t orig = dest_map[limit];

    dest_map[limit] = merge_tail_of_map(orig | other_map[limit], orig, rest);

  }

}

void BitMap::set_difference(const BitMap& other) {

  assert(size() == other.size(), "must have same size");

  bm_word_t* dest_map = map();

  const bm_word_t* other_map = other.map();

  idx_t limit = word_index(size());

  for (idx_t index = 0; index < limit; ++index) {

    dest_map[index] &= ~other_map[index];

  }

  idx_t rest = bit_in_word(size());

  if (rest > 0) {

    bm_word_t orig = dest_map[limit];

    dest_map[limit] = merge_tail_of_map(orig & ~other_map[limit], orig, rest);

  }

}

void BitMap::set_intersection(const BitMap& other) {

  assert(size() == other.size(), "must have same size");

  bm_word_t* dest_map = map();

  const bm_word_t* other_map = other.map();

  idx_t limit = word_index(size());

  for (idx_t index = 0; index < limit; ++index) {

    dest_map[index] &= other_map[index];

  }

  idx_t rest = bit_in_word(size());

  if (rest > 0) {

    bm_word_t orig = dest_map[limit];

    dest_map[limit] = merge_tail_of_map(orig & other_map[limit], orig, rest);

  }

}

bool BitMap::set_union_with_result(const BitMap& other) {

  assert(size() == other.size(), "must have same size");

  bool changed = false;

  bm_word_t* dest_map = map();

  const bm_word_t* other_map = other.map();

  idx_t limit = word_index(size());

  for (idx_t index = 0; index < limit; ++index) {

    bm_word_t orig = dest_map[index];

    bm_word_t temp = orig | other_map[index];

    changed = changed || (temp != orig);

    dest_map[index] = temp;