~drizzle-trunk/drizzle/development

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/* Copyright (C) 2000-2002 MySQL AB

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program 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 for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */

#include "heapdef.h"

#include <string.h>

	/* Read prev record for key */


int heap_rprev(HP_INFO *info, unsigned char *record)
{
  unsigned char *pos;
  HP_SHARE *share=info->s;
  HP_KEYDEF *keyinfo;

  if (info->lastinx < 0)
    return(my_errno=HA_ERR_WRONG_INDEX);
  keyinfo = share->keydef + info->lastinx;
  if (keyinfo->algorithm == HA_KEY_ALG_BTREE)
  {
    heap_rb_param custom_arg;

    if (info->last_pos)
      pos = (unsigned char *)tree_search_next(&keyinfo->rb_tree,
                                              &info->last_pos,
                                              offsetof(TREE_ELEMENT, right),
                                              offsetof(TREE_ELEMENT, left));
    else
    {
      custom_arg.keyseg = keyinfo->seg;
      custom_arg.key_length = keyinfo->length;
      custom_arg.search_flag = SEARCH_SAME;
      pos = (unsigned char *)tree_search_key(&keyinfo->rb_tree,
                                             info->lastkey, info->parents,
                                             &info->last_pos,
                                             info->last_find_flag,
                                             &custom_arg);
    }
    if (pos)
    {
      memcpy(&pos, pos + (*keyinfo->get_key_length)(keyinfo, pos),
	     sizeof(unsigned char*));
      info->current_ptr = pos;
    }
    else
    {
      my_errno = HA_ERR_KEY_NOT_FOUND;
    }
  }
  else
  {
    if (info->current_ptr || (info->update & HA_STATE_NEXT_FOUND))
    {
      if ((info->update & HA_STATE_DELETED))
        pos= hp_search(info, share->keydef + info->lastinx, info->lastkey, 3);
      else
        pos= hp_search(info, share->keydef + info->lastinx, info->lastkey, 2);
    }
    else
    {
      pos=0;					/* Read next after last */
      my_errno=HA_ERR_KEY_NOT_FOUND;
    }
  }
  if (!pos)
  {
    info->update=HA_STATE_PREV_FOUND;		/* For heap_rprev */
    if (my_errno == HA_ERR_KEY_NOT_FOUND)
      my_errno=HA_ERR_END_OF_FILE;
    return(my_errno);
  }
  hp_extract_record(share, record, pos);
  info->update=HA_STATE_AKTIV | HA_STATE_PREV_FOUND;
  return(0);
}