/*

 * Copyright (c) 2005, 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

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 */

#ifndef SHARE_UTILITIES_BITMAP_INLINE_HPP

#define SHARE_UTILITIES_BITMAP_INLINE_HPP

#include "runtime/atomic.hpp"

#include "runtime/orderAccess.hpp"

#include "utilities/bitMap.hpp"

#include "utilities/count_trailing_zeros.hpp"

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 const BitMap::bm_word_t BitMap::load_word_ordered(const volatile bm_word_t* const addr, atomic_memory_order memory_order) {

  if (memory_order == memory_order_relaxed || memory_order == memory_order_release) {

    return Atomic::load(addr);

  } else {

    assert(memory_order == memory_order_acq_rel ||

           memory_order == memory_order_acquire ||

           memory_order == memory_order_conservative,

           "unexpected memory ordering");

  }

}

inline bool BitMap::par_at(idx_t index, atomic_memory_order memory_order) const {

  verify_index(index);

  assert(memory_order == memory_order_acquire ||

         memory_order == memory_order_relaxed,

         "unexpected memory ordering");

  const volatile bm_word_t* const addr = word_addr(index);

  return (load_word_ordered(addr, memory_order) & bit_mask(index)) != 0;

}

inline bool BitMap::par_set_bit(idx_t bit, atomic_memory_order memory_order) {

  verify_index(bit);

  volatile bm_word_t* const addr = word_addr(bit);

  const bm_word_t mask = bit_mask(bit);

  bm_word_t old_val = load_word_ordered(addr, memory_order);

  do {

    const bm_word_t new_val = old_val | mask;

    if (new_val == old_val) {

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

    }

    const bm_word_t cur_val = Atomic::cmpxchg(new_val, addr, old_val, memory_order);

    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, atomic_memory_order memory_order) {

  verify_index(bit);

  volatile bm_word_t* const addr = word_addr(bit);

  const bm_word_t mask = ~bit_mask(bit);

  bm_word_t old_val = load_word_ordered(addr, memory_order);

  do {

    const bm_word_t new_val = old_val & mask;

    if (new_val == old_val) {

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

    }

    const bm_word_t cur_val = Atomic::cmpxchg(new_val, addr, old_val, memory_order);

    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 (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] = ~(bm_word_t)0;

}

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

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

}

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

  clear_range_of_words(_map, beg, end);

}

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);

    }

  }

}

template<BitMap::bm_word_t flip, bool aligned_right>

inline BitMap::idx_t BitMap::get_next_bit_impl(idx_t l_index, idx_t r_index) const {

  STATIC_ASSERT(flip == find_ones_flip || flip == find_zeros_flip);

  verify_range(l_index, r_index);

  assert(!aligned_right || is_word_aligned(r_index), "r_index not aligned");

  // The first word often contains an interesting bit, either due to

  // density or because of features of the calling algorithm.  So it's

  // important to examine that first word with a minimum of fuss,

  // minimizing setup time for later words that will be wasted if the

  // first word is indeed interesting.

  // The benefit from aligned_right being true is relatively small.

  // It saves a couple instructions in the setup for the word search

  // loop.  It also eliminates the range check on the final result.

  // However, callers often have a comparison with r_index, and

  // inlining often allows the two comparisons to be combined; it is

  // important when !aligned_right that return paths either return

  // r_index or a value dominated by a comparison with r_index.

  // aligned_right is still helpful when the caller doesn't have a

  // range check because features of the calling algorithm guarantee

  // an interesting bit will be present.

  if (l_index < r_index) {

    // Get the word containing l_index, and shift out low bits.

    idx_t index = word_index(l_index);

    bm_word_t cword = (map(index) ^ flip) >> bit_in_word(l_index);

    if ((cword & 1) != 0) {

      // The first bit is similarly often interesting. When it matters

      // (density or features of the calling algorithm make it likely

      // the first bit is set), going straight to the next clause compares

      // poorly with doing this check first; count_trailing_zeros can be

      // relatively expensive, plus there is the additional range check.

      // But when the first bit isn't set, the cost of having tested for

      // it is relatively small compared to the rest of the search.

      return l_index;

    } else if (cword != 0) {

      // Flipped and shifted first word is non-zero.

      idx_t result = l_index + count_trailing_zeros(cword);

      if (aligned_right || (result < r_index)) return result;

      // Result is beyond range bound; return r_index.

    } else {

      // Flipped and shifted first word is zero.  Word search through

      // aligned up r_index for a non-zero flipped word.

      idx_t limit = aligned_right

        ? word_index(r_index)

        : (word_index(r_index - 1) + 1); // Align up, knowing r_index > 0.

      while (++index < limit) {

        cword = map(index) ^ flip;

        if (cword != 0) {

          idx_t result = bit_index(index) + count_trailing_zeros(cword);

          if (aligned_right || (result < r_index)) return result;

          // Result is beyond range bound; return r_index.

          assert((index + 1) == limit, "invariant");

          break;

        }

      }

      // No bits in range; return r_index.

    }

  }

  return r_index;

}

inline BitMap::idx_t

BitMap::get_next_one_offset(idx_t l_offset, idx_t r_offset) const {

  return get_next_bit_impl<find_ones_flip, false>(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_bit_impl<find_zeros_flip, false>(l_offset, r_offset);

}

inline BitMap::idx_t

BitMap::get_next_one_offset_aligned_right(idx_t l_offset, idx_t r_offset) const {

  return get_next_bit_impl<find_ones_flip, true>(l_offset, 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) {

  assert(beg <= end, "underflow");

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

}

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

  assert(beg <= end, "underflow");

  memset(_map + beg, 0, (end - beg) * sizeof(bm_word_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 bool BitMap2D::is_valid_index(idx_t slot_index, idx_t bit_within_slot_index) {

  verify_bit_within_slot_index(bit_within_slot_index);

  return (bit_index(slot_index, bit_within_slot_index) < size_in_bits());

}

inline bool BitMap2D::at(idx_t slot_index, idx_t bit_within_slot_index) const {

  verify_bit_within_slot_index(bit_within_slot_index);

  return _map.at(bit_index(slot_index, bit_within_slot_index));

}

inline void BitMap2D::set_bit(idx_t slot_index, idx_t bit_within_slot_index) {

  verify_bit_within_slot_index(bit_within_slot_index);

  _map.set_bit(bit_index(slot_index, bit_within_slot_index));

}

inline void BitMap2D::clear_bit(idx_t slot_index, idx_t bit_within_slot_index) {

  verify_bit_within_slot_index(bit_within_slot_index);

  _map.clear_bit(bit_index(slot_index, bit_within_slot_index));

}

inline void BitMap2D::at_put(idx_t slot_index, idx_t bit_within_slot_index, bool value) {

  verify_bit_within_slot_index(bit_within_slot_index);

  _map.at_put(bit_index(slot_index, bit_within_slot_index), value);

}

inline void BitMap2D::at_put_grow(idx_t slot_index, idx_t bit_within_slot_index, bool value) {

  verify_bit_within_slot_index(bit_within_slot_index);

  idx_t bit = bit_index(slot_index, bit_within_slot_index);

  if (bit >= _map.size()) {

    _map.resize(2 * MAX2(_map.size(), bit));

  }

  _map.at_put(bit, value);

}

#endif // SHARE_UTILITIES_BITMAP_INLINE_HPP