diff options
Diffstat (limited to 'db/recno/rec_search.c')
| -rw-r--r-- | db/recno/rec_search.c | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/db/recno/rec_search.c b/db/recno/rec_search.c new file mode 100644 index 0000000000..acc109e992 --- /dev/null +++ b/db/recno/rec_search.c @@ -0,0 +1,126 @@ +/*- + * Copyright (c) 1990, 1993 + * The Regents of the University of California. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#if defined(LIBC_SCCS) && !defined(lint) +static char sccsid[] = "@(#)rec_search.c 8.4 (Berkeley) 7/14/94"; +#endif /* LIBC_SCCS and not lint */ + +#include <sys/types.h> + +#include <errno.h> +#include <stdio.h> + +#include <db.h> +#include "recno.h" + +/* + * __REC_SEARCH -- Search a btree for a key. + * + * Parameters: + * t: tree to search + * recno: key to find + * op: search operation + * + * Returns: + * EPG for matching record, if any, or the EPG for the location of the + * key, if it were inserted into the tree. + * + * Returns: + * The EPG for matching record, if any, or the EPG for the location + * of the key, if it were inserted into the tree, is entered into + * the bt_cur field of the tree. A pointer to the field is returned. + */ +EPG * +__rec_search(t, recno, op) + BTREE *t; + recno_t recno; + enum SRCHOP op; +{ + register indx_t index; + register PAGE *h; + EPGNO *parent; + RINTERNAL *r; + pgno_t pg; + indx_t top; + recno_t total; + int sverrno; + + BT_CLR(t); + for (pg = P_ROOT, total = 0;;) { + if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL) + goto err; + if (h->flags & P_RLEAF) { + t->bt_cur.page = h; + t->bt_cur.index = recno - total; + return (&t->bt_cur); + } + for (index = 0, top = NEXTINDEX(h);;) { + r = GETRINTERNAL(h, index); + if (++index == top || total + r->nrecs > recno) + break; + total += r->nrecs; + } + + BT_PUSH(t, pg, index - 1); + + pg = r->pgno; + switch (op) { + case SDELETE: + --GETRINTERNAL(h, (index - 1))->nrecs; + mpool_put(t->bt_mp, h, MPOOL_DIRTY); + break; + case SINSERT: + ++GETRINTERNAL(h, (index - 1))->nrecs; + mpool_put(t->bt_mp, h, MPOOL_DIRTY); + break; + case SEARCH: + mpool_put(t->bt_mp, h, 0); + break; + } + + } + /* Try and recover the tree. */ +err: sverrno = errno; + if (op != SEARCH) + while ((parent = BT_POP(t)) != NULL) { + if ((h = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL) + break; + if (op == SINSERT) + --GETRINTERNAL(h, parent->index)->nrecs; + else + ++GETRINTERNAL(h, parent->index)->nrecs; + mpool_put(t->bt_mp, h, MPOOL_DIRTY); + } + errno = sverrno; + return (NULL); +} |