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Viewing changes to storage/heap/hp_rprev.c

  • Committer: Package Import Robot
  • Author(s): Otto Kekäläinen
  • Date: 2013-12-22 10:27:05 UTC
  • Revision ID: package-import@ubuntu.com-20131222102705-mndw7s12mz0szrcn
Tags: upstream-5.5.32
Import upstream version 5.5.32

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storage/heap/hp_rprev.c
 
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/* Copyright (C) 2000-2002 MySQL AB
 
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   This program is free software; you can redistribute it and/or modify
 
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   it under the terms of the GNU General Public License as published by
 
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   the Free Software Foundation; version 2 of the License.
 
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   This program is distributed in the hope that it will be useful,
 
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   but WITHOUT ANY WARRANTY; without even the implied warranty of
 
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   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 
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   GNU General Public License for more details.
 
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   You should have received a copy of the GNU General Public License
 
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   along with this program; if not, write to the Free Software
 
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   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA */
 
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#include "heapdef.h"
 
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        /* Read prev record for key */
 
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int heap_rprev(HP_INFO *info, uchar *record)
 
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{
 
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  uchar *pos;
 
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  HP_SHARE *share=info->s;
 
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  HP_KEYDEF *keyinfo;
 
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  DBUG_ENTER("heap_rprev");
 
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  if (info->lastinx < 0)
 
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    DBUG_RETURN(my_errno=HA_ERR_WRONG_INDEX);
 
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  keyinfo = share->keydef + info->lastinx;
 
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  if (keyinfo->algorithm == HA_KEY_ALG_BTREE)
 
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  {
 
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    heap_rb_param custom_arg;
 
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    /* If no active record and last was not deleted */
 
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    if (!(info->update & (HA_STATE_AKTIV | HA_STATE_NO_KEY |
 
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                          HA_STATE_DELETED)))
 
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    {
 
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      if (info->update & HA_STATE_PREV_FOUND)
 
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        pos= 0;                            /* Can't search before first row */
 
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      else
 
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      {
 
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        /* Last was 'next' after last record; search after last record */
 
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        pos= tree_search_edge(&keyinfo->rb_tree, info->parents,
 
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                              &info->last_pos, offsetof(TREE_ELEMENT, right));
 
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      }
 
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    }
 
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    else if (info->last_pos)
 
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      pos = tree_search_next(&keyinfo->rb_tree, &info->last_pos,
 
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                             offsetof(TREE_ELEMENT, right),
 
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                             offsetof(TREE_ELEMENT, left));
 
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    else
 
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    {
 
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      custom_arg.keyseg = keyinfo->seg;
 
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      custom_arg.key_length = keyinfo->length;
 
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      custom_arg.search_flag = SEARCH_SAME;
 
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      info->last_find_flag= HA_READ_KEY_OR_PREV;
 
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      pos = tree_search_key(&keyinfo->rb_tree, info->lastkey, info->parents, 
 
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                           &info->last_pos, info->last_find_flag, &custom_arg);
 
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    }
 
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    if (pos)
 
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    {
 
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      memcpy(&pos, pos + (*keyinfo->get_key_length)(keyinfo, pos),
 
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             sizeof(uchar*));
 
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      info->current_ptr = pos;
 
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    }
 
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    else
 
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    {
 
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      my_errno = HA_ERR_KEY_NOT_FOUND;
 
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    }
 
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  }
 
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  else
 
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  {
 
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    if (info->current_ptr || (info->update & HA_STATE_NEXT_FOUND))
 
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    {
 
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      if ((info->update & HA_STATE_DELETED))
 
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        pos= hp_search(info, share->keydef + info->lastinx, info->lastkey, 3);
 
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      else
 
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        pos= hp_search(info, share->keydef + info->lastinx, info->lastkey, 2);
 
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    }
 
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    else
 
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    {
 
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      pos=0;                                    /* Read next after last */
 
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      my_errno=HA_ERR_KEY_NOT_FOUND;
 
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    }
 
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  }
 
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  if (!pos)
 
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  {
 
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    info->update=HA_STATE_PREV_FOUND;           /* For heap_rprev */
 
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    if (my_errno == HA_ERR_KEY_NOT_FOUND)
 
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      my_errno=HA_ERR_END_OF_FILE;
 
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    DBUG_RETURN(my_errno);
 
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  }
 
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  memcpy(record,pos,(size_t) share->reclength);
 
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  info->update=HA_STATE_AKTIV | HA_STATE_PREV_FOUND;
 
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  DBUG_RETURN(0);
 
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}