1 /*- 2 * Copyright (c) 1991, 1993, 1994 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 static char sccsid[] = "@(#)rec_seq.c 8.3 (Berkeley) 7/14/94"; 36 #endif /* not lint */ 37 38 #include <sys/types.h> 39 40 #include <errno.h> 41 #include <limits.h> 42 #include <stdio.h> 43 #include <string.h> 44 45 #include <db.h> 46 #include "recno.h" 47 48 /* 49 * __REC_SEQ -- Recno sequential scan interface. 50 * 51 * Parameters: 52 * dbp: pointer to access method 53 * key: key for positioning and return value 54 * data: data return value 55 * flags: R_CURSOR, R_FIRST, R_LAST, R_NEXT, R_PREV. 56 * 57 * Returns: 58 * RET_ERROR, RET_SUCCESS or RET_SPECIAL if there's no next key. 59 */ 60 int 61 __rec_seq(dbp, key, data, flags) 62 const DB *dbp; 63 DBT *key, *data; 64 u_int flags; 65 { 66 BTREE *t; 67 EPG *e; 68 recno_t nrec; 69 int status; 70 71 t = dbp->internal; 72 73 /* Toss any page pinned across calls. */ 74 if (t->bt_pinned != NULL) { 75 mpool_put(t->bt_mp, t->bt_pinned, 0); 76 t->bt_pinned = NULL; 77 } 78 79 switch(flags) { 80 case R_CURSOR: 81 if ((nrec = *(recno_t *)key->data) == 0) 82 goto einval; 83 break; 84 case R_NEXT: 85 if (F_ISSET(&t->bt_cursor, CURS_INIT)) { 86 nrec = t->bt_cursor.rcursor + 1; 87 break; 88 } 89 /* FALLTHROUGH */ 90 case R_FIRST: 91 nrec = 1; 92 break; 93 case R_PREV: 94 if (F_ISSET(&t->bt_cursor, CURS_INIT)) { 95 if ((nrec = t->bt_cursor.rcursor - 1) == 0) 96 return (RET_SPECIAL); 97 break; 98 } 99 /* FALLTHROUGH */ 100 case R_LAST: 101 if (!F_ISSET(t, R_EOF | R_INMEM) && 102 t->bt_irec(t, MAX_REC_NUMBER) == RET_ERROR) 103 return (RET_ERROR); 104 nrec = t->bt_nrecs; 105 break; 106 default: 107 einval: errno = EINVAL; 108 return (RET_ERROR); 109 } 110 111 if (t->bt_nrecs == 0 || nrec > t->bt_nrecs) { 112 if (!F_ISSET(t, R_EOF | R_INMEM) && 113 (status = t->bt_irec(t, nrec)) != RET_SUCCESS) 114 return (status); 115 if (t->bt_nrecs == 0 || nrec > t->bt_nrecs) 116 return (RET_SPECIAL); 117 } 118 119 if ((e = __rec_search(t, nrec - 1, SEARCH)) == NULL) 120 return (RET_ERROR); 121 122 F_SET(&t->bt_cursor, CURS_INIT); 123 t->bt_cursor.rcursor = nrec; 124 125 status = __rec_ret(t, e, nrec, key, data); 126 if (F_ISSET(t, B_DB_LOCK)) 127 mpool_put(t->bt_mp, e->page, 0); 128 else 129 t->bt_pinned = e->page; 130 return (status); 131 } 132