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 static char sccsid[] = "@(#)rec_seq.c 8.1 (Berkeley) 6/4/93"; 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 switch(flags) { 73 case R_CURSOR: 74 if ((nrec = *(recno_t *)key->data) == 0) 75 goto einval; 76 break; 77 case R_NEXT: 78 if (ISSET(t, B_SEQINIT)) { 79 nrec = t->bt_rcursor + 1; 80 break; 81 } 82 /* FALLTHROUGH */ 83 case R_FIRST: 84 nrec = 1; 85 break; 86 case R_PREV: 87 if (ISSET(t, B_SEQINIT)) { 88 if ((nrec = t->bt_rcursor - 1) == 0) 89 return (RET_SPECIAL); 90 break; 91 } 92 /* FALLTHROUGH */ 93 case R_LAST: 94 if (!ISSET(t, R_EOF | R_INMEM) && 95 t->bt_irec(t, MAX_REC_NUMBER) == RET_ERROR) 96 return (RET_ERROR); 97 nrec = t->bt_nrecs; 98 break; 99 default: 100 einval: errno = EINVAL; 101 return (RET_ERROR); 102 } 103 104 if (t->bt_nrecs == 0 || nrec > t->bt_nrecs) { 105 if (!ISSET(t, R_EOF | R_INMEM) && 106 (status = t->bt_irec(t, nrec)) != RET_SUCCESS) 107 return (status); 108 if (t->bt_nrecs == 0 || nrec > t->bt_nrecs) 109 return (RET_SPECIAL); 110 } 111 112 if ((e = __rec_search(t, nrec - 1, SEARCH)) == NULL) 113 return (RET_ERROR); 114 115 SET(t, B_SEQINIT); 116 t->bt_rcursor = nrec; 117 118 status = __rec_ret(t, e, nrec, key, data); 119 120 mpool_put(t->bt_mp, e->page, 0); 121 return (status); 122 } 123