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/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
* vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
*
* Copyright (C) 2009 - 2010 Toru Maesaka
*
* 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <config.h>
#include "ha_blitz.h"
char *BlitzCursor::first_key(int *key_len) {
if (!tcbdbcurfirst(cursor))
return NULL;
return (char *)tcbdbcurkey(cursor, key_len);
}
char *BlitzCursor::final_key(int *key_len) {
if (!tcbdbcurlast(cursor))
return NULL;
return (char *)tcbdbcurkey(cursor, key_len);
}
/* It's possible that the cursor had been implicitly moved
forward. If so, we obtain the key at the current position
and return that. This can happen in delete_key(). */
char *BlitzCursor::next_key(int *key_len) {
if (!moved) {
if (!tcbdbcurnext(cursor))
return NULL;
} else
moved = false;
return (char *)tcbdbcurkey(cursor, key_len);
}
char *BlitzCursor::prev_key(int *key_len) {
if (!tcbdbcurprev(cursor))
return NULL;
return (char *)tcbdbcurkey(cursor, key_len);
}
char *BlitzCursor::next_logical_key(int *key_len) {
int origin_len, a_cmp_len, b_cmp_len;
char *rv, *origin;
/* Get the key to scan away from. */
if ((origin = (char *)tcbdbcurkey(cursor, &origin_len)) == NULL)
return NULL;
rv = NULL;
/* Traverse the tree from the cursor position until we hit
a key greater than the origin or EOF. */
while (1) {
/* Move the cursor and get the next key. */
if (!tcbdbcurnext(cursor))
break;
rv = (char *)tcbdbcurkey(cursor, key_len);
/* Compare the fetched key with origin. */
if (packed_key_cmp(this->tree, rv, origin, &a_cmp_len, &b_cmp_len) > 0)
break;
free(rv);
}
free(origin);
return rv;
}
char *BlitzCursor::prev_logical_key(int *key_len) {
int origin_len, a_cmp_len, b_cmp_len;
char *rv, *origin;
/* Get the key to scan away from. */
if ((origin = (char *)tcbdbcurkey(cursor, &origin_len)) == NULL)
return NULL;
rv = NULL;
while (1) {
if (!tcbdbcurprev(cursor))
break;
rv = (char *)tcbdbcurkey(cursor, key_len);
/* Compare the fetched key with origin. */
if (packed_key_cmp(this->tree, rv, origin, &a_cmp_len, &b_cmp_len) < 0)
break;
free(rv);
}
free(origin);
return rv;
}
/* A cursor based lookup on a B+Tree doesn't guarantee that the
returned key is identical. This is because it would return the
next logical key if one exists. */
char *BlitzCursor::find_key(const int search_mode, const char *key,
const int klen, int *rv_len) {
if (!tcbdbcurjump(cursor, (void *)key, klen))
return NULL;
char *rv = (char *)tcbdbcurkey(cursor, rv_len);
if (rv == NULL)
return NULL;
int cmp, a_cmp_len, b_cmp_len;
cmp = packed_key_cmp(this->tree, rv, key, &a_cmp_len, &b_cmp_len);
switch (search_mode) {
case drizzled::HA_READ_KEY_EXACT:
if (cmp != 0) {
free(rv);
rv = NULL;
}
break;
case drizzled::HA_READ_AFTER_KEY:
if (cmp > 0) {
break;
} else if (cmp == 0) {
free(rv);
rv = this->next_logical_key(rv_len);
} else {
free(rv);
rv = NULL;
}
break;
case drizzled::HA_READ_BEFORE_KEY:
free(rv);
rv = this->prev_logical_key(rv_len);
break;
//case drizzled::HA_READ_KEY_OR_NEXT:
//case drizzled::HA_READ_KEY_OR_PREV:
//case drizzled::HA_READ_PREFIX:
//case drizzled::HA_READ_PREFIX_LAST:
//case drizzled::HA_READ_PREFIX_LAST_OR_PREV:
default:
break;
}
return rv;
}
int BlitzCursor::delete_position(void) {
if (!tcbdbcurout(cursor))
return -1;
moved = true;
return 0;
}
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