/*

 * Copyright (c) 1997, 2016, 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.inline.hpp"

#include "utilities/bitMap.inline.hpp"

#include "utilities/copy.hpp"

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

}

#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) {

    intptr_t* pw  = (intptr_t*)word_addr(beg);

    intptr_t  w   = *pw;

    intptr_t  mr  = (intptr_t)inverted_bit_mask_for_range(beg, end);

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

    while (true) {

      intptr_t res = Atomic::cmpxchg_ptr(nw, pw, w);

      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);

  }

}

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);

  assert(end_full_word - beg_full_word >= 32,

         "the range must include at least 32 bytes");

  // 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 (end_full_word - beg_full_word < 32) {

    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);

  assert(end_full_word - beg_full_word >= 32,

         "the range must include at least 32 bytes");

  // 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);

}

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 size = size_in_words();

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

    bm_word_t word_union = dest_map[index] | other_map[index];

    // If this has more bits set than dest_map[index], then other is not a

    // subset.

    if (word_union != dest_map[index]) return false;

  }

  return true;

}

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 size = size_in_words();

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

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

  }

  // Otherwise, no intersection.

  return false;

}

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 size = size_in_words();

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

    dest_map[index] = dest_map[index] | other_map[index];

  }

}

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 size = size_in_words();

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

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

  }

}

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 size = size_in_words();

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

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

  }

}

void BitMap::set_intersection_at_offset(const BitMap& other, idx_t offset) {

  assert(other.size() >= offset, "offset not in range");

  assert(other.size() - offset >= size(), "other not large enough");

  // XXX Ideally, we would remove this restriction.

  guarantee((offset % (sizeof(bm_word_t) * BitsPerByte)) == 0,

            "Only handle aligned cases so far.");

  bm_word_t* dest_map = map();

  const bm_word_t* other_map = other.map();

  idx_t offset_word_ind = word_index(offset);

  idx_t size = size_in_words();

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

    dest_map[index] = dest_map[index] & other_map[offset_word_ind + index];

  }

}

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 size = size_in_words();

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

    idx_t temp = dest_map[index] | other_map[index];

    changed = changed || (temp != dest_map[index]);

    dest_map[index] = temp;

  }

  return changed;

}

bool BitMap::set_difference_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 size = size_in_words();

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

    bm_word_t temp = dest_map[index] & ~(other_map[index]);

    changed = changed || (temp != dest_map[index]);

    dest_map[index] = temp;

  }

  return changed;

}

bool BitMap::set_intersection_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 size = size_in_words();

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

    bm_word_t orig = dest_map[index];

    bm_word_t temp = orig & other_map[index];

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

    dest_map[index]  = temp;

  }

  return changed;

}

void BitMap::set_from(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 size = size_in_words();

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

    dest_map[index] = other_map[index];

  }

}