/*

 * Copyright (c) 2005, 2012, 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

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 * questions.

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 */

#ifndef SHARE_VM_UTILITIES_BITMAP_INLINE_HPP

#define SHARE_VM_UTILITIES_BITMAP_INLINE_HPP

#include "runtime/atomic.hpp"

#include "utilities/bitMap.hpp"

#ifdef ASSERT

inline void BitMap::verify_index(idx_t index) const {

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

}

inline 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

inline void BitMap::set_bit(idx_t bit) {

  verify_index(bit);

  *word_addr(bit) |= bit_mask(bit);

}

inline void BitMap::clear_bit(idx_t bit) {

  verify_index(bit);

  *word_addr(bit) &= ~bit_mask(bit);

}

inline bool BitMap::par_set_bit(idx_t bit) {

  verify_index(bit);

  volatile idx_t* const addr = word_addr(bit);

  const idx_t mask = bit_mask(bit);

  idx_t old_val = *addr;

  do {

    const idx_t new_val = old_val | mask;

    if (new_val == old_val) {

      return false;     // Someone else beat us to it.

    }

    const idx_t cur_val = (idx_t) Atomic::cmpxchg_ptr((void*) new_val,

                                                      (volatile void*) addr,

                                                      (void*) old_val);

    if (cur_val == old_val) {

      return true;      // Success.

    }

    old_val = cur_val;  // The value changed, try again.

  } while (true);

}

inline bool BitMap::par_clear_bit(idx_t bit) {

  verify_index(bit);

  volatile idx_t* const addr = word_addr(bit);

  const idx_t mask = ~bit_mask(bit);

  idx_t old_val = *addr;

  do {

    const idx_t new_val = old_val & mask;

    if (new_val == old_val) {

      return false;     // Someone else beat us to it.

    }

    const idx_t cur_val = (idx_t) Atomic::cmpxchg_ptr((void*) new_val,

                                                      (volatile void*) addr,

                                                      (void*) old_val);

    if (cur_val == old_val) {

      return true;      // Success.

    }

    old_val = cur_val;  // The value changed, try again.

  } while (true);

}

inline void BitMap::set_range(idx_t beg, idx_t end, RangeSizeHint hint) {

  if (hint == small_range && end - beg == 1) {

    set_bit(beg);

  } else {

    if (hint == large_range) {

      set_large_range(beg, end);

    } else {

      set_range(beg, end);

    }

  }

}

inline void BitMap::clear_range(idx_t beg, idx_t end, RangeSizeHint hint) {

  if (hint == small_range && end - beg == 1) {

    clear_bit(beg);

  } else {

    if (hint == large_range) {

      clear_large_range(beg, end);

    } else {

      clear_range(beg, end);

    }

  }

}

inline void BitMap::par_set_range(idx_t beg, idx_t end, RangeSizeHint hint) {

  if (hint == small_range && end - beg == 1) {

    par_at_put(beg, true);

  } else {

    if (hint == large_range) {

      par_at_put_large_range(beg, end, true);

    } else {

      par_at_put_range(beg, end, true);

    }

  }

}

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

  bm_word_t* map = _map;

  for (idx_t i = beg; i < end; ++i) map[i] = ~(uintptr_t)0;

}

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

  bm_word_t* map = _map;

  for (idx_t i = beg; i < end; ++i) map[i] = 0;

}

inline void BitMap::clear() {

  clear_range_of_words(0, size_in_words());

}

inline void BitMap::par_clear_range(idx_t beg, idx_t end, RangeSizeHint hint) {

  if (hint == small_range && end - beg == 1) {

    par_at_put(beg, false);

  } else {

    if (hint == large_range) {

      par_at_put_large_range(beg, end, false);

    } else {

      par_at_put_range(beg, end, false);

    }

  }

}

inline BitMap::idx_t

BitMap::get_next_one_offset_inline(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;

    }

#ifdef ASSERT

    // In the following assert, if r_offset is not bitamp word aligned,

    // checking that res_offset is strictly less than r_offset is too

    // strong and will trip the assert.

    //

    // Consider the case where l_offset is bit 15 and r_offset is bit 17

    // of the same map word, and where bits [15:16:17:18] == [00:00:00:01].

    // All the bits in the range [l_offset:r_offset) are 0.

    // The loop that calculates res_offset, above, would yield the offset

    // of bit 18 because it's in the same map word as l_offset and there

    // is a set bit in that map word above l_offset (i.e. res != NoBits).

    //

    // In this case, however, we can assert is that res_offset is strictly

    // less than size() since we know that there is at least one set bit

    // at an offset above, but in the same map word as, r_offset.

    // Otherwise, if r_offset is word aligned then it will not be in the

    // same map word as l_offset (unless it equals l_offset). So either

    // there won't be a set bit between l_offset and the end of it's map

    // word (i.e. res == NoBits), or res_offset will be less than r_offset.

    idx_t limit = is_word_aligned(r_offset) ? r_offset : size();

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

#endif // ASSERT

    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 = bit_index(index); !(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;

}

inline BitMap::idx_t

BitMap::get_next_zero_offset_inline(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);

  }

  // skip over all word length 1-bit runs

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

    res = map(index);

    if (res != (uintptr_t)AllBits) {

      // found a 0, 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;

}

inline BitMap::idx_t

BitMap::get_next_one_offset_inline_aligned_right(idx_t l_offset,

                                                 idx_t r_offset) const

{

  verify_range(l_offset, r_offset);

  assert(bit_in_word(r_offset) == 0, "r_offset not word-aligned");

  if (l_offset == r_offset) {

    return l_offset;

  }

  idx_t   index = word_index(l_offset);

  idx_t r_index = word_index(r_offset);

  idx_t res_offset = l_offset;

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

  idx_t res = map(index) >> bit_in_word(res_offset);

  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 &&

           res_offset < r_offset, "just checking");

    return res_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 = bit_index(index); !(res & 1); res_offset++) {

        res = res >> 1;

      }

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

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

      return res_offset;

    }

  }

  return r_offset;

}

// 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::bm_word_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");

  bm_word_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;

}

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();

}

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

                                          idx_t r_offset) const {

  return get_next_one_offset_inline(l_offset, r_offset);

}

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

                                           idx_t r_offset) const {

  return get_next_zero_offset_inline(l_offset, r_offset);

}

inline void BitMap2D::clear() {

  _map.clear();

}

#endif // SHARE_VM_UTILITIES_BITMAP_INLINE_HPP