innobase/include/page0page.ic

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*****************************************************************************/

/** @file include/page0page.ic
 Index page routines

 Created 2/2/1994 Heikki Tuuri
 *******************************************************/

#include "mach0data.h"
#ifdef UNIV_DEBUG
#include "log0recv.h"
#endif /* !UNIV_DEBUG */
#ifndef UNIV_HOTBACKUP
#include "rem0cmp.h"
#endif /* !UNIV_HOTBACKUP */
#include "mtr0log.h"
#include "page0zip.h"

#ifdef UNIV_MATERIALIZE
#undef UNIV_INLINE
#define UNIV_INLINE
#endif

/** Gets the start of a page.
 @return start of the page */
UNIV_INLINE
page_t *page_align(const void *ptr) /*!< in: pointer to page frame */
{
  return ((page_t *)ut_align_down(ptr, UNIV_PAGE_SIZE));
}
/** Gets the offset within a page.
 @return offset from the start of the page */
UNIV_INLINE
ulint page_offset(const void *ptr) /*!< in: pointer to page frame */
{
  return (ut_align_offset(ptr, UNIV_PAGE_SIZE));
}
/** Returns the max trx id field value. */
UNIV_INLINE
trx_id_t page_get_max_trx_id(const page_t *page) /*!< in: page */
{
  ut_ad(page);

  return (mach_read_from_8(page + PAGE_HEADER + PAGE_MAX_TRX_ID));
}

/** Sets the max trx id field value if trx_id is bigger than the previous
 value. */
UNIV_INLINE
void page_update_max_trx_id(
    buf_block_t *block,       /*!< in/out: page */
    page_zip_des_t *page_zip, /*!< in/out: compressed page whose
                             uncompressed part will be updated, or NULL */
    trx_id_t trx_id,          /*!< in: transaction id */
    mtr_t *mtr)               /*!< in/out: mini-transaction */
{
  ut_ad(block);
#ifndef UNIV_HOTBACKUP
  ut_ad(mtr_memo_contains(mtr, block, MTR_MEMO_PAGE_X_FIX));
#endif /* !UNIV_HOTBACKUP */
  /* During crash recovery, this function may be called on
  something else than a leaf page of a secondary index or the
  insert buffer index tree (dict_index_is_sec_or_ibuf() returns
  TRUE for the dummy indexes constructed during redo log
  application).  In that case, PAGE_MAX_TRX_ID is unused,
  and trx_id is usually zero. */
  ut_ad(trx_id || recv_recovery_is_on());
  ut_ad(page_is_leaf(buf_block_get_frame(block)));

  if (page_get_max_trx_id(buf_block_get_frame(block)) < trx_id) {
    page_set_max_trx_id(block, page_zip, trx_id, mtr);
  }
}

/** Returns the RTREE SPLIT SEQUENCE NUMBER (FIL_RTREE_SPLIT_SEQ_NUM).
@param[in]	page	page
@return SPLIT SEQUENCE NUMBER */
UNIV_INLINE
node_seq_t page_get_ssn_id(const page_t *page) {
  ut_ad(page);

  return (static_cast<node_seq_t>(
      mach_read_from_8(page + FIL_RTREE_SPLIT_SEQ_NUM)));
}

/** Sets the RTREE SPLIT SEQUENCE NUMBER field value
@param[in,out]	block		page
@param[in,out]	page_zip	compressed page whose uncompressed part will
                                be updated, or NULL
@param[in]	ssn_id		transaction id
@param[in,out]	mtr		mini-transaction */
UNIV_INLINE
void page_set_ssn_id(buf_block_t *block, page_zip_des_t *page_zip,
                     node_seq_t ssn_id, mtr_t *mtr) {
  page_t *page = buf_block_get_frame(block);
#ifndef UNIV_HOTBACKUP
  ut_ad(!mtr || mtr_memo_contains(mtr, block, MTR_MEMO_PAGE_SX_FIX) ||
        mtr_memo_contains(mtr, block, MTR_MEMO_PAGE_X_FIX));
#endif /* !UNIV_HOTBACKUP */

  if (page_zip) {
    mach_write_to_8(page + FIL_RTREE_SPLIT_SEQ_NUM, ssn_id);
    page_zip_write_header(page_zip, page + FIL_RTREE_SPLIT_SEQ_NUM, 8, mtr);
#ifndef UNIV_HOTBACKUP
  } else if (mtr) {
    mlog_write_ull(page + FIL_RTREE_SPLIT_SEQ_NUM, ssn_id, mtr);
#endif /* !UNIV_HOTBACKUP */
  } else {
    mach_write_to_8(page + FIL_RTREE_SPLIT_SEQ_NUM, ssn_id);
  }
}

/** Sets the given header field. */
UNIV_INLINE
void page_header_set_field(
    page_t *page,             /*!< in/out: page */
    page_zip_des_t *page_zip, /*!< in/out: compressed page whose
                             uncompressed part will be updated, or NULL */
    ulint field,              /*!< in: PAGE_N_DIR_SLOTS, ... */
    ulint val)                /*!< in: value */
{
  ut_ad(page);
  ut_ad(field <= PAGE_N_RECS);
  ut_ad(field == PAGE_N_HEAP || val < UNIV_PAGE_SIZE);
  ut_ad(field != PAGE_N_HEAP || (val & 0x7fff) < UNIV_PAGE_SIZE);

  mach_write_to_2(page + PAGE_HEADER + field, val);
  if (page_zip) {
    page_zip_write_header(page_zip, page + PAGE_HEADER + field, 2, nullptr);
  }
}

/** Returns the offset stored in the given header field.
 @return offset from the start of the page, or 0 */
UNIV_INLINE
ulint page_header_get_offs(const page_t *page, /*!< in: page */
                           ulint field)        /*!< in: PAGE_FREE, ... */
{
  ulint offs;

  ut_ad(page);
  ut_ad((field == PAGE_FREE) || (field == PAGE_LAST_INSERT) ||
        (field == PAGE_HEAP_TOP));

  offs = page_header_get_field(page, field);

  ut_ad((field != PAGE_HEAP_TOP) || offs);

  return (offs);
}

/** Sets the pointer stored in the given header field. */
UNIV_INLINE
void page_header_set_ptr(
    page_t *page,             /*!< in: page */
    page_zip_des_t *page_zip, /*!< in/out: compressed page whose
                             uncompressed part will be updated, or NULL */
    ulint field,              /*!< in: PAGE_FREE, ... */
    const byte *ptr)          /*!< in: pointer or NULL*/
{
  ulint offs;

  ut_ad(page);
  ut_ad((field == PAGE_FREE) || (field == PAGE_LAST_INSERT) ||
        (field == PAGE_HEAP_TOP));

  if (ptr == nullptr) {
    offs = 0;
  } else {
    offs = ptr - page;
  }

  ut_ad((field != PAGE_HEAP_TOP) || offs);

  page_header_set_field(page, page_zip, field, offs);
}

#ifndef UNIV_HOTBACKUP
/** Resets the last insert info field in the page header. Writes to mlog
 about this operation. */
UNIV_INLINE
void page_header_reset_last_insert(
    page_t *page,             /*!< in/out: page */
    page_zip_des_t *page_zip, /*!< in/out: compressed page whose
                             uncompressed part will be updated, or NULL */
    mtr_t *mtr)               /*!< in: mtr */
{
  ut_ad(page != nullptr);
  ut_ad(mtr != nullptr);

  if (page_zip) {
    mach_write_to_2(page + (PAGE_HEADER + PAGE_LAST_INSERT), 0);
    page_zip_write_header(page_zip, page + (PAGE_HEADER + PAGE_LAST_INSERT), 2,
                          mtr);
  } else {
    mlog_write_ulint(page + (PAGE_HEADER + PAGE_LAST_INSERT), 0, MLOG_2BYTES,
                     mtr);
  }
}
#endif /* !UNIV_HOTBACKUP */

/** Determine whether the page is in new-style compact format.
 @return nonzero if the page is in compact format, zero if it is in
 old-style format */
UNIV_INLINE
ulint page_is_comp(const page_t *page) /*!< in: index page */
{
  return (page_header_get_field(page, PAGE_N_HEAP) & 0x8000);
}

/** TRUE if the record is on a page in compact format.
 @return nonzero if in compact format */
UNIV_INLINE
ulint page_rec_is_comp(const rec_t *rec) /*!< in: record */
{
  return (page_is_comp(page_align(rec)));
}

/** Returns the heap number of a record.
 @return heap number */
UNIV_INLINE
ulint page_rec_get_heap_no(const rec_t *rec) /*!< in: the physical record */
{
  if (page_rec_is_comp(rec)) {
    return (rec_get_heap_no_new(rec));
  } else {
    return (rec_get_heap_no_old(rec));
  }
}

/** Determine whether the page is a B-tree leaf.
 @return true if the page is a B-tree leaf (PAGE_LEVEL = 0) */
UNIV_INLINE
bool page_is_leaf(const page_t *page) /*!< in: page */
{
  return (!*(const uint16 *)(page + (PAGE_HEADER + PAGE_LEVEL)));
}

/** Determine whether the page is empty.
 @return true if the page is empty (PAGE_N_RECS = 0) */
UNIV_INLINE
bool page_is_empty(const page_t *page) /*!< in: page */
{
  return (!*(const uint16 *)(page + (PAGE_HEADER + PAGE_N_RECS)));
}

/** Determine whether a page is an index root page.
@param[in]	page	page frame
@return true if the page is a root page of an index */
UNIV_INLINE
bool page_is_root(const page_t *page) {
#if FIL_PAGE_PREV % 8
#error FIL_PAGE_PREV must be 64-bit aligned
#endif
#if FIL_PAGE_NEXT != FIL_PAGE_PREV + 4
#error FIL_PAGE_NEXT must be adjacent to FIL_PAGE_PREV
#endif

  static_assert(FIL_NULL == 0xffffffff, "FIL_NULL != 0xffffffff");

  /* Check that this is an index page and both the PREV and NEXT
  pointers are FIL_NULL, because the root page does not have any
  siblings. */
  return (fil_page_index_page_check(page) &&
          *reinterpret_cast<const ib_uint64_t *>(page + FIL_PAGE_PREV) ==
              IB_UINT64_MAX);
}

/** Determine whether the page contains garbage.
 @return true if the page contains garbage (PAGE_GARBAGE is not 0) */
UNIV_INLINE
bool page_has_garbage(const page_t *page) /*!< in: page */
{
  return (!!*(const uint16 *)(page + (PAGE_HEADER + PAGE_GARBAGE)));
}

/** Gets the offset of the first record on the page.
 @return offset of the first record in record list, relative from page */
UNIV_INLINE
ulint page_get_infimum_offset(
    const page_t *page) /*!< in: page which must have record(s) */
{
  ut_ad(page);
  ut_ad(!page_offset(page));

  if (page_is_comp(page)) {
    return (PAGE_NEW_INFIMUM);
  } else {
    return (PAGE_OLD_INFIMUM);
  }
}

/** Gets the offset of the last record on the page.
 @return offset of the last record in record list, relative from page */
UNIV_INLINE
ulint page_get_supremum_offset(
    const page_t *page) /*!< in: page which must have record(s) */
{
  ut_ad(page);
  ut_ad(!page_offset(page));

  if (page_is_comp(page)) {
    return (PAGE_NEW_SUPREMUM);
  } else {
    return (PAGE_OLD_SUPREMUM);
  }
}

/** TRUE if the record is a user record on the page.
 @return true if a user record */
UNIV_INLINE
ibool page_rec_is_user_rec_low(ulint offset) /*!< in: record offset on page */
{
  ut_ad(offset >= PAGE_NEW_INFIMUM);

  static_assert(PAGE_OLD_INFIMUM >= PAGE_NEW_INFIMUM,
                "PAGE_OLD_INFIMUM < PAGE_NEW_INFIMUM");

  static_assert(PAGE_OLD_SUPREMUM >= PAGE_NEW_SUPREMUM,
                "PAGE_OLD_SUPREMUM < PAGE_NEW_SUPREMUM");

  static_assert(PAGE_NEW_INFIMUM <= PAGE_OLD_SUPREMUM,
                "PAGE_NEW_INFIMUM > PAGE_OLD_SUPREMUM");

  static_assert(PAGE_OLD_INFIMUM <= PAGE_NEW_SUPREMUM,
                "PAGE_OLD_INFIMUM > PAGE_NEW_SUPREMUM");

  static_assert(PAGE_NEW_SUPREMUM <= PAGE_OLD_SUPREMUM_END,
                "PAGE_NEW_SUPREMUM > PAGE_OLD_SUPREMUM_END");

  static_assert(PAGE_OLD_SUPREMUM <= PAGE_NEW_SUPREMUM_END,
                "PAGE_OLD_SUPREMUM > PAGE_NEW_SUPREMUM_END");

  ut_ad(offset <= UNIV_PAGE_SIZE - PAGE_EMPTY_DIR_START);

  return (offset != PAGE_NEW_SUPREMUM && offset != PAGE_NEW_INFIMUM &&
          offset != PAGE_OLD_INFIMUM && offset != PAGE_OLD_SUPREMUM);
}

/** TRUE if the record is the supremum record on a page.
 @return true if the supremum record */
UNIV_INLINE
ibool page_rec_is_supremum_low(ulint offset) /*!< in: record offset on page */
{
  ut_ad(offset >= PAGE_NEW_INFIMUM);
  ut_ad(offset <= UNIV_PAGE_SIZE - PAGE_EMPTY_DIR_START);

  return (offset == PAGE_NEW_SUPREMUM || offset == PAGE_OLD_SUPREMUM);
}

/** TRUE if the record is the infimum record on a page.
 @return true if the infimum record */
UNIV_INLINE
ibool page_rec_is_infimum_low(ulint offset) /*!< in: record offset on page */
{
  ut_ad(offset >= PAGE_NEW_INFIMUM);
  ut_ad(offset <= UNIV_PAGE_SIZE - PAGE_EMPTY_DIR_START);

  return (offset == PAGE_NEW_INFIMUM || offset == PAGE_OLD_INFIMUM);
}

/** TRUE if the record is a user record on the page.
 @return true if a user record */
UNIV_INLINE
ibool page_rec_is_user_rec(const rec_t *rec) /*!< in: record */
{
  ut_ad(page_rec_check(rec));

  return (page_rec_is_user_rec_low(page_offset(rec)));
}

/** TRUE if the record is the supremum record on a page.
 @return true if the supremum record */
UNIV_INLINE
ibool page_rec_is_supremum(const rec_t *rec) /*!< in: record */
{
  ut_ad(page_rec_check(rec));

  return (page_rec_is_supremum_low(page_offset(rec)));
}

/** TRUE if the record is the infimum record on a page.
 @return true if the infimum record */
UNIV_INLINE
ibool page_rec_is_infimum(const rec_t *rec) /*!< in: record */
{
  ut_ad(page_rec_check(rec));

  return (page_rec_is_infimum_low(page_offset(rec)));
}

/** true if the record is the first user record on a page.
 @return true if the first user record */
UNIV_INLINE
bool page_rec_is_first(const rec_t *rec,   /*!< in: record */
                       const page_t *page) /*!< in: page */
{
  ut_ad(page_get_n_recs(page) > 0);

  return (page_rec_get_next_const(page_get_infimum_rec(page)) == rec);
}

/** true if the record is the second user record on a page.
 @return true if the second user record */
UNIV_INLINE
bool page_rec_is_second(const rec_t *rec,   /*!< in: record */
                        const page_t *page) /*!< in: page */
{
  ut_ad(page_get_n_recs(page) > 1);

  return (page_rec_get_next_const(
              page_rec_get_next_const(page_get_infimum_rec(page))) == rec);
}

/** true if the record is the last user record on a page.
 @return true if the last user record */
UNIV_INLINE
bool page_rec_is_last(const rec_t *rec,   /*!< in: record */
                      const page_t *page) /*!< in: page */
{
  ut_ad(page_get_n_recs(page) > 0);

  return (page_rec_get_next_const(rec) == page_get_supremum_rec(page));
}

UNIV_INLINE
bool page_rec_distance_is_at_most(const rec_t *left_rec, const rec_t *right_rec,
                                  ulint val) {
  for (ulint i = 0; i <= val; i++) {
    if (left_rec == right_rec) {
      return (true);
    }
    left_rec = page_rec_get_next_const(left_rec);
  }
  return (false);
}

/** true if the record is the second last user record on a page.
 @return true if the second last user record */
UNIV_INLINE
bool page_rec_is_second_last(const rec_t *rec,   /*!< in: record */
                             const page_t *page) /*!< in: page */
{
  ut_ad(page_get_n_recs(page) > 1);
  ut_ad(!page_rec_is_last(rec, page));

  return (page_rec_get_next_const(page_rec_get_next_const(rec)) ==
          page_get_supremum_rec(page));
}

/** Returns the nth record of the record list.
 This is the inverse function of page_rec_get_n_recs_before().
 @return nth record */
UNIV_INLINE
rec_t *page_rec_get_nth(page_t *page, /*!< in: page */
                        ulint nth)    /*!< in: nth record */
{
  return ((rec_t *)page_rec_get_nth_const(page, nth));
}

#ifndef UNIV_HOTBACKUP
/** Returns the middle record of the records on the page. If there is an
 even number of records in the list, returns the first record of the
 upper half-list.
 @return middle record */
UNIV_INLINE
rec_t *page_get_middle_rec(page_t *page) /*!< in: page */
{
  ulint middle = (page_get_n_recs(page) + PAGE_HEAP_NO_USER_LOW) / 2;

  return (page_rec_get_nth(page, middle));
}
#endif /* !UNIV_HOTBACKUP */

/** Gets the page number.
 @return page number */
UNIV_INLINE
page_no_t page_get_page_no(const page_t *page) /*!< in: page */
{
  ut_ad(page == page_align((page_t *)page));
  return (mach_read_from_4(page + FIL_PAGE_OFFSET));
}

/** Gets the tablespace identifier.
 @return space id */
UNIV_INLINE
space_id_t page_get_space_id(const page_t *page) /*!< in: page */
{
  ut_ad(page == page_align((page_t *)page));
  return (mach_read_from_4(page + FIL_PAGE_ARCH_LOG_NO_OR_SPACE_ID));
}

UNIV_INLINE
page_id_t page_get_page_id(const page_t *page) {
  return page_id_t{page_get_space_id(page), page_get_page_no(page)};
}

/** Gets the number of user records on page (infimum and supremum records
 are not user records).
 @return number of user records */
UNIV_INLINE
ulint page_get_n_recs(const page_t *page) /*!< in: index page */
{
  return (page_header_get_field(page, PAGE_N_RECS));
}

/** Gets the number of dir slots in directory.
 @return number of slots */
UNIV_INLINE
ulint page_dir_get_n_slots(const page_t *page) /*!< in: index page */
{
  return (page_header_get_field(page, PAGE_N_DIR_SLOTS));
}
/** Sets the number of dir slots in directory. */
UNIV_INLINE
void page_dir_set_n_slots(
    page_t *page,             /*!< in/out: page */
    page_zip_des_t *page_zip, /*!< in/out: compressed page whose
                             uncompressed part will be updated, or NULL */
    ulint n_slots)            /*!< in: number of slots */
{
  page_header_set_field(page, page_zip, PAGE_N_DIR_SLOTS, n_slots);
}

/** Sets the number of records in the heap. */
UNIV_INLINE
void page_dir_set_n_heap(
    page_t *page,             /*!< in/out: index page */
    page_zip_des_t *page_zip, /*!< in/out: compressed page whose
                             uncompressed part will be updated, or NULL.
                             Note that the size of the dense page directory
                             in the compressed page trailer is
                             n_heap * PAGE_ZIP_DIR_SLOT_SIZE. */
    ulint n_heap)             /*!< in: number of records */
{
  ut_ad(n_heap < 0x8000);
  ut_ad(!page_zip ||
        n_heap == (page_header_get_field(page, PAGE_N_HEAP) & 0x7fff) + 1);

  page_header_set_field(
      page, page_zip, PAGE_N_HEAP,
      n_heap | (0x8000 & page_header_get_field(page, PAGE_N_HEAP)));
}

#ifdef UNIV_DEBUG
/** Gets pointer to nth directory slot.
 @return pointer to dir slot */
UNIV_INLINE
page_dir_slot_t *page_dir_get_nth_slot(
    const page_t *page, /*!< in: index page */
    ulint n)            /*!< in: position */
{
  ut_ad(page_dir_get_n_slots(page) > n);

  return ((page_dir_slot_t *)page + UNIV_PAGE_SIZE - PAGE_DIR -
          (n + 1) * PAGE_DIR_SLOT_SIZE);
}
#endif /* UNIV_DEBUG */

/** Used to check the consistency of a record on a page.
 @return true if succeed */
UNIV_INLINE
ibool page_rec_check(const rec_t *rec) /*!< in: record */
{
  const page_t *page = page_align(rec);

  ut_a(rec);

  ut_a(page_offset(rec) <= page_header_get_field(page, PAGE_HEAP_TOP));
  ut_a(page_offset(rec) >= PAGE_DATA);

  return (TRUE);
}

/** Gets the record pointed to by a directory slot.
 @return pointer to record */
UNIV_INLINE
const rec_t *page_dir_slot_get_rec(
    const page_dir_slot_t *slot) /*!< in: directory slot */
{
  return (page_align(slot) + mach_read_from_2(slot));
}

/** This is used to set the record offset in a directory slot. */
UNIV_INLINE
void page_dir_slot_set_rec(page_dir_slot_t *slot, /*!< in: directory slot */
                           rec_t *rec)            /*!< in: record on the page */
{
  ut_ad(page_rec_check(rec));

  mach_write_to_2(slot, page_offset(rec));
}

/** Gets the number of records owned by a directory slot.
 @return number of records */
UNIV_INLINE
ulint page_dir_slot_get_n_owned(
    const page_dir_slot_t *slot) /*!< in: page directory slot */
{
  const rec_t *rec = page_dir_slot_get_rec(slot);
  if (page_rec_is_comp(slot)) {
    return (rec_get_n_owned_new(rec));
  } else {
    return (rec_get_n_owned_old(rec));
  }
}

/** This is used to set the owned records field of a directory slot. */
UNIV_INLINE
void page_dir_slot_set_n_owned(
    page_dir_slot_t *slot,    /*!< in/out: directory slot */
    page_zip_des_t *page_zip, /*!< in/out: compressed page, or NULL */
    ulint n)                  /*!< in: number of records owned by the slot */
{
  rec_t *rec = (rec_t *)page_dir_slot_get_rec(slot);
  if (page_rec_is_comp(slot)) {
    rec_set_n_owned_new(rec, page_zip, n);
  } else {
    ut_ad(!page_zip);
    rec_set_n_owned_old(rec, n);
  }
}

/** Calculates the space reserved for directory slots of a given number of
 records. The exact value is a fraction number n * PAGE_DIR_SLOT_SIZE /
 PAGE_DIR_SLOT_MIN_N_OWNED, and it is rounded upwards to an integer. */
UNIV_INLINE
ulint page_dir_calc_reserved_space(ulint n_recs) /*!< in: number of records */
{
  return ((PAGE_DIR_SLOT_SIZE * n_recs + PAGE_DIR_SLOT_MIN_N_OWNED - 1) /
          PAGE_DIR_SLOT_MIN_N_OWNED);
}

/** Gets the pointer to the next record on the page.
 @return pointer to next record */
UNIV_INLINE
const rec_t *page_rec_get_next_low(
    const rec_t *rec, /*!< in: pointer to record */
    ulint comp)       /*!< in: nonzero=compact page layout */
{
  ulint offs;
  const page_t *page;

  ut_ad(page_rec_check(rec));

  page = page_align(rec);

  offs = rec_get_next_offs(rec, comp);

  if (offs >= UNIV_PAGE_SIZE) {
    fprintf(stderr,
            "InnoDB: Next record offset is nonsensical %lu"
            " in record at offset %lu\n"
            "InnoDB: rec address %p, space id %lu, page %lu\n",
            (ulong)offs, (ulong)page_offset(rec), (void *)rec,
            (ulong)page_get_space_id(page), (ulong)page_get_page_no(page));
    ut_error;
  } else if (offs == 0) {
    return (nullptr);
  }

  return (page + offs);
}

/** Gets the pointer to the next record on the page.
 @return pointer to next record */
UNIV_INLINE
rec_t *page_rec_get_next(rec_t *rec) /*!< in: pointer to record */
{
  return ((rec_t *)page_rec_get_next_low(rec, page_rec_is_comp(rec)));
}

/** Gets the pointer to the next record on the page.
 @return pointer to next record */
UNIV_INLINE
const rec_t *page_rec_get_next_const(
    const rec_t *rec) /*!< in: pointer to record */
{
  return (page_rec_get_next_low(rec, page_rec_is_comp(rec)));
}

/** Gets the pointer to the next non delete-marked record on the page.
 If all subsequent records are delete-marked, then this function
 will return the supremum record.
 @return pointer to next non delete-marked record or pointer to supremum */
UNIV_INLINE
const rec_t *page_rec_get_next_non_del_marked(
    const rec_t *rec) /*!< in: pointer to record */
{
  const rec_t *r;
  ulint page_is_compact = page_rec_is_comp(rec);

  for (r = page_rec_get_next_const(rec);
       !page_rec_is_supremum(r) && rec_get_deleted_flag(r, page_is_compact);
       r = page_rec_get_next_const(r)) {
    /* noop */
  }

  return (r);
}

/** Sets the pointer to the next record on the page. */
UNIV_INLINE
void page_rec_set_next(rec_t *rec,        /*!< in: pointer to record,
                                          must not be page supremum */
                       const rec_t *next) /*!< in: pointer to next record,
                                          must not be page infimum */
{
  ulint offs;

  ut_ad(page_rec_check(rec));
  ut_ad(!page_rec_is_supremum(rec));
  ut_ad(rec != next);

  ut_ad(!next || !page_rec_is_infimum(next));
  ut_ad(!next || page_align(rec) == page_align(next));

  offs = next != nullptr ? page_offset(next) : 0;

  if (page_rec_is_comp(rec)) {
    rec_set_next_offs_new(rec, offs);
  } else {
    rec_set_next_offs_old(rec, offs);
  }
}

/** Gets the pointer to the previous record.
 @return pointer to previous record */
UNIV_INLINE
const rec_t *page_rec_get_prev_const(
    const rec_t *rec) /*!< in: pointer to record, must not be page
                      infimum */
{
  const page_dir_slot_t *slot;
  ulint slot_no;
  const rec_t *rec2;
  const rec_t *prev_rec = nullptr;
  const page_t *page;

  ut_ad(page_rec_check(rec));

  page = page_align(rec);

  ut_ad(!page_rec_is_infimum(rec));

  slot_no = page_dir_find_owner_slot(rec);

  ut_a(slot_no != 0);

  slot = page_dir_get_nth_slot(page, slot_no - 1);

  rec2 = page_dir_slot_get_rec(slot);

  if (page_is_comp(page)) {
    while (rec != rec2) {
      prev_rec = rec2;
      rec2 = page_rec_get_next_low(rec2, TRUE);
    }
  } else {
    while (rec != rec2) {
      prev_rec = rec2;
      rec2 = page_rec_get_next_low(rec2, FALSE);
    }
  }

  ut_a(prev_rec);

  return (prev_rec);
}

/** Gets the pointer to the previous record.
 @return pointer to previous record */
UNIV_INLINE
rec_t *page_rec_get_prev(rec_t *rec) /*!< in: pointer to record, must not be
                                     page infimum */
{
  return ((rec_t *)page_rec_get_prev_const(rec));
}

/** Looks for the record which owns the given record.
 @return the owner record */
UNIV_INLINE
rec_t *page_rec_find_owner_rec(rec_t *rec) /*!< in: the physical record */
{
  ut_ad(page_rec_check(rec));

  if (page_rec_is_comp(rec)) {
    while (rec_get_n_owned_new(rec) == 0) {
      rec = page_rec_get_next(rec);
    }
  } else {
    while (rec_get_n_owned_old(rec) == 0) {
      rec = page_rec_get_next(rec);
    }
  }

  return (rec);
}

/** Returns the base extra size of a physical record.  This is the
 size of the fixed header, independent of the record size.
 @return REC_N_NEW_EXTRA_BYTES or REC_N_OLD_EXTRA_BYTES */
UNIV_INLINE
ulint page_rec_get_base_extra_size(const rec_t *rec) /*!< in: physical record */
{
#if REC_N_NEW_EXTRA_BYTES + 1 != REC_N_OLD_EXTRA_BYTES
#error "REC_N_NEW_EXTRA_BYTES + 1 != REC_N_OLD_EXTRA_BYTES"
#endif
  return (REC_N_NEW_EXTRA_BYTES + (ulint)!page_rec_is_comp(rec));
}

/** Returns the sum of the sizes of the records in the record list, excluding
 the infimum and supremum records.
 @return data in bytes */
UNIV_INLINE
ulint page_get_data_size(const page_t *page) /*!< in: index page */
{
  ulint ret;

  ret = (ulint)(
      page_header_get_field(page, PAGE_HEAP_TOP) -
      (page_is_comp(page) ? PAGE_NEW_SUPREMUM_END : PAGE_OLD_SUPREMUM_END) -
      page_header_get_field(page, PAGE_GARBAGE));

  ut_ad(ret < UNIV_PAGE_SIZE);

  return (ret);
}

/** Allocates a block of memory from the free list of an index page. */
UNIV_INLINE
void page_mem_alloc_free(
    page_t *page,             /*!< in/out: index page */
    page_zip_des_t *page_zip, /*!< in/out: compressed page with enough
                             space available for inserting the record,
                             or NULL */
    rec_t *next_rec,          /*!< in: pointer to the new head of the
                             free record list */
    ulint need)               /*!< in: number of bytes allocated */
{
  ulint garbage;

#ifdef UNIV_DEBUG
  const rec_t *old_rec = page_header_get_ptr(page, PAGE_FREE);
  ulint next_offs;

  ut_ad(old_rec);
  next_offs = rec_get_next_offs(old_rec, page_is_comp(page));
  ut_ad(next_rec == (next_offs ? page + next_offs : nullptr));
#endif

  page_header_set_ptr(page, page_zip, PAGE_FREE, next_rec);

  garbage = page_header_get_field(page, PAGE_GARBAGE);
  ut_ad(garbage >= need);

  page_header_set_field(page, page_zip, PAGE_GARBAGE, garbage - need);
}

/** Calculates free space if a page is emptied.
 @return free space */
UNIV_INLINE
ulint page_get_free_space_of_empty(
    ulint comp) /*!< in: nonzero=compact page layout */
{
  if (comp) {
    return ((ulint)(UNIV_PAGE_SIZE - PAGE_NEW_SUPREMUM_END - PAGE_DIR -
                    2 * PAGE_DIR_SLOT_SIZE));
  }

  return ((ulint)(UNIV_PAGE_SIZE - PAGE_OLD_SUPREMUM_END - PAGE_DIR -
                  2 * PAGE_DIR_SLOT_SIZE));
}

#ifndef UNIV_HOTBACKUP
/** Write a 32-bit field in a data dictionary record. */
UNIV_INLINE
void page_rec_write_field(rec_t *rec, /*!< in/out: record to update */
                          ulint i,    /*!< in: index of the field to update */
                          ulint val,  /*!< in: value to write */
                          mtr_t *mtr) /*!< in/out: mini-transaction */
{
  byte *data;
  ulint len;

  data = rec_get_nth_field_old(rec, i, &len);

  ut_ad(len == 4);

  mlog_write_ulint(data, val, MLOG_4BYTES, mtr);
}
#endif /* !UNIV_HOTBACKUP */

/** Each user record on a page, and also the deleted user records in the heap
 takes its size plus the fraction of the dir cell size /
 PAGE_DIR_SLOT_MIN_N_OWNED bytes for it. If the sum of these exceeds the
 value of page_get_free_space_of_empty, the insert is impossible, otherwise
 it is allowed. This function returns the maximum combined size of records
 which can be inserted on top of the record heap.
 @return maximum combined size for inserted records */
UNIV_INLINE
ulint page_get_max_insert_size(const page_t *page, /*!< in: index page */
                               ulint n_recs)       /*!< in: number of records */
{
  ulint occupied;
  ulint free_space;

  if (page_is_comp(page)) {
    occupied =
        page_header_get_field(page, PAGE_HEAP_TOP) - PAGE_NEW_SUPREMUM_END +
        page_dir_calc_reserved_space(n_recs + page_dir_get_n_heap(page) - 2);

    free_space = page_get_free_space_of_empty(TRUE);
  } else {
    occupied =
        page_header_get_field(page, PAGE_HEAP_TOP) - PAGE_OLD_SUPREMUM_END +
        page_dir_calc_reserved_space(n_recs + page_dir_get_n_heap(page) - 2);

    free_space = page_get_free_space_of_empty(FALSE);
  }

  /* Above the 'n_recs +' part reserves directory space for the new
  inserted records; the '- 2' excludes page infimum and supremum
  records */

  if (occupied > free_space) {
    return (0);
  }

  return (free_space - occupied);
}

/** Returns the maximum combined size of records which can be inserted on top
 of the record heap if a page is first reorganized.
 @return maximum combined size for inserted records */
UNIV_INLINE
ulint page_get_max_insert_size_after_reorganize(
    const page_t *page, /*!< in: index page */
    ulint n_recs)       /*!< in: number of records */
{
  ulint occupied;
  ulint free_space;

  occupied = page_get_data_size(page) +
             page_dir_calc_reserved_space(n_recs + page_get_n_recs(page));

  free_space = page_get_free_space_of_empty(page_is_comp(page));

  if (occupied > free_space) {
    return (0);
  }

  return (free_space - occupied);
}

/** Puts a record to free list. */
UNIV_INLINE
void page_mem_free(page_t *page,              /*!< in/out: index page */
                   page_zip_des_t *page_zip,  /*!< in/out: compressed page,
                                              or NULL */
                   rec_t *rec,                /*!< in: pointer to the
                                              (origin of) record */
                   const dict_index_t *index, /*!< in: index of rec */
                   const ulint *offsets)      /*!< in: array returned by
                                              rec_get_offsets() */
{
  rec_t *free;
  ulint garbage;

  ut_ad(rec_offs_validate(rec, index, offsets));
  free = page_header_get_ptr(page, PAGE_FREE);

  page_rec_set_next(rec, free);
  page_header_set_ptr(page, page_zip, PAGE_FREE, rec);

  garbage = page_header_get_field(page, PAGE_GARBAGE);

  page_header_set_field(page, page_zip, PAGE_GARBAGE,
                        garbage + rec_offs_size(offsets));

  if (page_zip) {
    page_zip_dir_delete(page_zip, rec, index, offsets, free);
  } else {
    page_header_set_field(page, page_zip, PAGE_N_RECS,
                          page_get_n_recs(page) - 1);
  }
}

/** Check that a page_size is correct for InnoDB.
If correct, set the associated page_size_shift which is the power of 2
for this page size.
@param[in]	page_size	Page Size to evaluate
@return an associated page_size_shift if valid, 0 if invalid. */
inline ulong page_size_validate(ulong page_size) {
  for (ulong n = UNIV_PAGE_SIZE_SHIFT_MIN; n <= UNIV_PAGE_SIZE_SHIFT_MAX; n++) {
    if (page_size == static_cast<ulong>(1 << n)) {
      return (n);
    }
  }
  return (0);
}

#ifdef UNIV_MATERIALIZE
#undef UNIV_INLINE
#define UNIV_INLINE UNIV_INLINE_ORIGINAL
#endif