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/** @file include/trx0rec.ic
 Transaction undo log record

 Created 3/26/1996 Heikki Tuuri
 *******************************************************/

#ifndef UNIV_HOTBACKUP
/** Reads from an undo log record the record type.
 @return record type */
UNIV_INLINE
ulint trx_undo_rec_get_type(
    const trx_undo_rec_t *undo_rec) /*!< in: undo log record */
{
  return (mach_read_from_1(undo_rec + 2) & (TRX_UNDO_CMPL_INFO_MULT - 1));
}

/** Reads from an undo log record the record compiler info.
 @return compiler info */
UNIV_INLINE
ulint trx_undo_rec_get_cmpl_info(
    const trx_undo_rec_t *undo_rec) /*!< in: undo log record */
{
  return (mach_read_from_1(undo_rec + 2) / TRX_UNDO_CMPL_INFO_MULT);
}

/** Returns TRUE if an undo log record contains an extern storage field.
 @return true if extern */
UNIV_INLINE
ibool trx_undo_rec_get_extern_storage(
    const trx_undo_rec_t *undo_rec) /*!< in: undo log record */
{
  if (mach_read_from_1(undo_rec + 2) & TRX_UNDO_UPD_EXTERN) {
    return (TRUE);
  }

  return (FALSE);
}

/** Reads the undo log record number.
 @return undo no */
UNIV_INLINE
undo_no_t trx_undo_rec_get_undo_no(
    const trx_undo_rec_t *undo_rec) /*!< in: undo log record */
{
  const byte *ptr = undo_rec + 2;
  uint8_t type_cmpl = mach_read_from_1(ptr);

  const bool blob_undo = type_cmpl & TRX_UNDO_MODIFY_BLOB;

  if (blob_undo) {
    /* The next record offset takes 2 bytes + 1 byte for
    type_cmpl flag + 1 byte for the new flag.  Total 4 bytes.*/
    ptr = undo_rec + 4;
  } else {
    ptr = undo_rec + 3;
  }
  return (mach_u64_read_much_compressed(ptr));
}

/** Copies the undo record to the heap.
 @return own: copy of undo log record */
UNIV_INLINE
trx_undo_rec_t *trx_undo_rec_copy(
    const trx_undo_rec_t *undo_rec, /*!< in: undo log record */
    mem_heap_t *heap)               /*!< in: heap where copied */
{
  ulint len;

  len = mach_read_from_2(undo_rec) - ut_align_offset(undo_rec, UNIV_PAGE_SIZE);
  ut_ad(len < UNIV_PAGE_SIZE);
  return ((trx_undo_rec_t *)mem_heap_dup(heap, undo_rec, len));
}
#endif /* !UNIV_HOTBACKUP */