/*

 * Copyright 1997-2006 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 *

 */

# include "incls/_precompiled.incl"

# include "incls/_bitMap.cpp.incl"

BitMap::BitMap(idx_t* map, idx_t size_in_bits) {

  assert(size_in_bits >= 0, "just checking");

  _map = map;

  _size = size_in_bits;

}

BitMap::BitMap(idx_t size_in_bits) {

  assert(size_in_bits >= 0, "just checking");

  _size = size_in_bits;

  _map = NEW_RESOURCE_ARRAY(idx_t, size_in_words());

}

void BitMap::resize(idx_t size_in_bits) {

  assert(size_in_bits >= 0, "just checking");

  size_t old_size_in_words = size_in_words();

  uintptr_t* old_map = map();

  _size = size_in_bits;

  size_t new_size_in_words = size_in_words();

  _map = NEW_RESOURCE_ARRAY(idx_t, new_size_in_words);

  Copy::disjoint_words((HeapWord*) old_map, (HeapWord*) _map, MIN2(old_size_in_words, new_size_in_words));

  if (new_size_in_words > old_size_in_words) {

    clear_range_of_words(old_size_in_words, size_in_words());

  }

}

// Returns a bit mask for a range of bits [beg, end) within a single word.  Each

// bit in the mask is 0 if the bit is in the range, 1 if not in the range.  The

// returned mask can be used directly to clear the range, or inverted to set the

// range.  Note:  end must not be 0.

inline BitMap::idx_t

BitMap::inverted_bit_mask_for_range(idx_t beg, idx_t end) const {

  assert(end != 0, "does not work when end == 0");

  assert(beg == end || word_index(beg) == word_index(end - 1),

         "must be a single-word range");

  idx_t mask = bit_mask(beg) - 1;       // low (right) bits

  if (bit_in_word(end) != 0) {

    mask |= ~(bit_mask(end) - 1);       // high (left) bits

  }

  return mask;

}

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) {

    idx_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) {

    idx_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  = *pw;

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

    }

  }

}

inline void BitMap::set_large_range_of_words(idx_t beg, idx_t end) {

  memset(_map + beg, ~(unsigned char)0, (end - beg) * sizeof(uintptr_t));

}

inline void BitMap::clear_large_range_of_words(idx_t beg, idx_t end) {

  memset(_map + beg, 0, (end - beg) * sizeof(uintptr_t));

}

inline BitMap::idx_t BitMap::word_index_round_up(idx_t bit) const {

  idx_t bit_rounded_up = bit + (BitsPerWord - 1);

  // Check for integer arithmetic overflow.

  return bit_rounded_up > bit ? word_index(bit_rounded_up) : size_in_words();

}

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);

  assert(end_full_word - beg_full_word >= 32,

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

  // 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_grow(idx_t offset, bool value) {

  if (offset >= size()) {

    resize(2 * MAX2(size(), offset));

  }

  at_put(offset, value);

}

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");

  uintptr_t* dest_map = map();

  uintptr_t* other_map = other.map();

  idx_t size = size_in_words();

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

    uintptr_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");

  uintptr_t* dest_map = map();

  uintptr_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(BitMap other) {

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

  idx_t* dest_map = map();

  idx_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(BitMap other) {

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

  idx_t* dest_map = map();

  idx_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(BitMap other) {

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

  idx_t* dest_map = map();

  idx_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];

  }

}

bool BitMap::set_union_with_result(BitMap other) {

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

  bool changed = false;

  idx_t* dest_map = map();

  idx_t* other_map = other.map();

  idx_t size = size_in_words();

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

    idx_t temp = map(index) | other_map[index];

    changed = changed || (temp != map(index));

    map()[index] = temp;

  }

  return changed;

}

bool BitMap::set_difference_with_result(BitMap other) {

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

  bool changed = false;

  idx_t* dest_map = map();

  idx_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_intersection_with_result(BitMap other) {

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

  bool changed = false;

  idx_t* dest_map = map();

  idx_t* other_map = other.map();

  idx_t size = size_in_words();

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

    idx_t orig = dest_map[index];

    idx_t temp = orig & other_map[index];

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

    dest_map[index]  = temp;

  }

  return changed;

}

void BitMap::set_from(BitMap other) {

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

  idx_t* dest_map = map();

  idx_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];

  }

}

bool BitMap::is_same(BitMap other) {

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

  idx_t* dest_map = map();

  idx_t* other_map = other.map();

  idx_t size = size_in_words();

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

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

  }

  return true;

}

bool BitMap::is_full() const {

  uintptr_t* word = map();

  idx_t rest = size();

  for (; rest >= (idx_t) BitsPerWord; rest -= BitsPerWord) {

    if (*word != (uintptr_t) AllBits) return false;

    word++;

  }

  return rest == 0 || (*word | ~right_n_bits((int)rest)) == (uintptr_t) AllBits;

}

bool BitMap::is_empty() const {

  uintptr_t* word = map();

  idx_t rest = size();

  for (; rest >= (idx_t) BitsPerWord; rest -= BitsPerWord) {

    if (*word != (uintptr_t) NoBits) return false;

    word++;

  }

  return rest == 0 || (*word & right_n_bits((int)rest)) == (uintptr_t) NoBits;

}

void BitMap::clear_large() {

  clear_large_range_of_words(0, size_in_words());

}

// Note that if the closure itself modifies the bitmap

// then modifications in and to the left of the _bit_ being

// currently sampled will not be seen. Note also that the

// interval [leftOffset, rightOffset) is right open.

void BitMap::iterate(BitMapClosure* blk, idx_t leftOffset, idx_t rightOffset) {

  verify_range(leftOffset, rightOffset);

  idx_t startIndex = word_index(leftOffset);

  idx_t endIndex   = MIN2(word_index(rightOffset) + 1, size_in_words());

  for (idx_t index = startIndex, offset = leftOffset;

       offset < rightOffset && index < endIndex;

       offset = (++index) << LogBitsPerWord) {

    idx_t rest = map(index) >> (offset & (BitsPerWord - 1));

    for (; offset < rightOffset && rest != (uintptr_t)NoBits; offset++) {

      if (rest & 1) {

        blk->do_bit(offset);

        //  resample at each closure application

        // (see, for instance, CMS bug 4525989)

        rest = map(index) >> (offset & (BitsPerWord -1));

        // XXX debugging: remove

        // The following assertion assumes that closure application

        // doesn't clear bits (may not be true in general, e.g. G1).

        assert(rest & 1,

               "incorrect shift or closure application can clear bits?");

      }

      rest = rest >> 1;

    }

  }

}

BitMap::idx_t BitMap::get_next_one_offset(idx_t l_offset,

                                          idx_t r_offset) const {

  assert(l_offset <= size(), "BitMap index out of bounds");

  assert(r_offset <= size(), "BitMap index out of bounds");

  assert(l_offset <= r_offset, "l_offset > r_offset ?");

  if (l_offset == r_offset) {

    return l_offset;

  }

  idx_t   index = word_index(l_offset);

  idx_t r_index = word_index(r_offset-1) + 1;

  idx_t res_offset = l_offset;

  // check bits including and to the _left_ of offset's position

  idx_t pos = bit_in_word(res_offset);

  idx_t res = map(index) >> pos;

  if (res != (uintptr_t)NoBits) {

    // find the position of the 1-bit

    for (; !(res & 1); res_offset++) {

      res = res >> 1;

    }

    assert(res_offset >= l_offset, "just checking");

    return MIN2(res_offset, r_offset);

  }

  // skip over all word length 0-bit runs

  for (index++; index < r_index; index++) {

    res = map(index);

    if (res != (uintptr_t)NoBits) {

      // found a 1, return the offset

      for (res_offset = index << LogBitsPerWord; !(res & 1);

           res_offset++) {

        res = res >> 1;

      }

      assert(res & 1, "tautology; see loop condition");

      assert(res_offset >= l_offset, "just checking");

      return MIN2(res_offset, r_offset);

    }

  }

  return r_offset;

}

BitMap::idx_t BitMap::get_next_zero_offset(idx_t l_offset,

                                           idx_t r_offset) const {

  assert(l_offset <= size(), "BitMap index out of bounds");

  assert(r_offset <= size(), "BitMap index out of bounds");

  assert(l_offset <= r_offset, "l_offset > r_offset ?");

  if (l_offset == r_offset) {

    return l_offset;

  }

  idx_t   index = word_index(l_offset);

  idx_t r_index = word_index(r_offset-1) + 1;

  idx_t res_offset = l_offset;

  // check bits including and to the _left_ of offset's position

  idx_t pos = res_offset & (BitsPerWord - 1);

  idx_t res = (map(index) >> pos) | left_n_bits((int)pos);

  if (res != (uintptr_t)AllBits) {

    // find the position of the 0-bit

    for (; res & 1; res_offset++) {

      res = res >> 1;

    }

    assert(res_offset >= l_offset, "just checking");

    return MIN2(res_offset, r_offset);