/*- * 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 rcsid[] = "$OpenBSD: rec_search.c,v 1.3 1996/08/19 08:21:08 tholo Exp $"; #endif /* LIBC_SCCS and not lint */ #include #include #include #include #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); }