1 /*- 2 * Copyright (c) 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #ifndef lint 35 /* from: static char sccsid[] = "@(#)rec_seq.c 8.2 (Berkeley) 9/7/93"; */ 36 static char *rcsid = "$Id: rec_seq.c,v 1.4 1993/09/09 02:42:28 cgd Exp $"; 37 #endif /* not lint */ 38 39 #include <sys/types.h> 40 41 #include <errno.h> 42 #include <limits.h> 43 #include <stdio.h> 44 #include <string.h> 45 46 #include <db.h> 47 #include "recno.h" 48 49 /* 50 * __REC_SEQ -- Recno sequential scan interface. 51 * 52 * Parameters: 53 * dbp: pointer to access method 54 * key: key for positioning and return value 55 * data: data return value 56 * flags: R_CURSOR, R_FIRST, R_LAST, R_NEXT, R_PREV. 57 * 58 * Returns: 59 * RET_ERROR, RET_SUCCESS or RET_SPECIAL if there's no next key. 60 */ 61 int 62 __rec_seq(dbp, key, data, flags) 63 const DB *dbp; 64 DBT *key, *data; 65 u_int flags; 66 { 67 BTREE *t; 68 EPG *e; 69 recno_t nrec; 70 int status; 71 72 t = dbp->internal; 73 74 /* Toss any page pinned across calls. */ 75 if (t->bt_pinned != NULL) { 76 mpool_put(t->bt_mp, t->bt_pinned, 0); 77 t->bt_pinned = NULL; 78 } 79 80 switch(flags) { 81 case R_CURSOR: 82 if ((nrec = *(recno_t *)key->data) == 0) 83 goto einval; 84 break; 85 case R_NEXT: 86 if (ISSET(t, B_SEQINIT)) { 87 nrec = t->bt_rcursor + 1; 88 break; 89 } 90 /* FALLTHROUGH */ 91 case R_FIRST: 92 nrec = 1; 93 break; 94 case R_PREV: 95 if (ISSET(t, B_SEQINIT)) { 96 if ((nrec = t->bt_rcursor - 1) == 0) 97 return (RET_SPECIAL); 98 break; 99 } 100 /* FALLTHROUGH */ 101 case R_LAST: 102 if (!ISSET(t, R_EOF | R_INMEM) && 103 t->bt_irec(t, MAX_REC_NUMBER) == RET_ERROR) 104 return (RET_ERROR); 105 nrec = t->bt_nrecs; 106 break; 107 default: 108 einval: errno = EINVAL; 109 return (RET_ERROR); 110 } 111 112 if (t->bt_nrecs == 0 || nrec > t->bt_nrecs) { 113 if (!ISSET(t, R_EOF | R_INMEM) && 114 (status = t->bt_irec(t, nrec)) != RET_SUCCESS) 115 return (status); 116 if (t->bt_nrecs == 0 || nrec > t->bt_nrecs) 117 return (RET_SPECIAL); 118 } 119 120 if ((e = __rec_search(t, nrec - 1, SEARCH)) == NULL) 121 return (RET_ERROR); 122 123 SET(t, B_SEQINIT); 124 t->bt_rcursor = nrec; 125 126 status = __rec_ret(t, e, nrec, key, data); 127 if (ISSET(t, B_DB_LOCK)) 128 mpool_put(t->bt_mp, e->page, 0); 129 else 130 t->bt_pinned = e->page; 131 return (status); 132 } 133