diff options
Diffstat (limited to 'db/recno/rec_delete.c')
| -rw-r--r-- | db/recno/rec_delete.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/db/recno/rec_delete.c b/db/recno/rec_delete.c new file mode 100644 index 0000000000..a16593d4e6 --- /dev/null +++ b/db/recno/rec_delete.c @@ -0,0 +1,197 @@ +/*- + * Copyright (c) 1990, 1993, 1994 + * The Regents of the University of California. All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Mike Olson. + * + * 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_delete.c 8.7 (Berkeley) 7/14/94"; +#endif /* LIBC_SCCS and not lint */ + +#include <sys/types.h> + +#include <errno.h> +#include <stdio.h> +#include <string.h> + +#include <db.h> +#include "recno.h" + +static int rec_rdelete __P((BTREE *, recno_t)); + +/* + * __REC_DELETE -- Delete the item(s) referenced by a key. + * + * Parameters: + * dbp: pointer to access method + * key: key to delete + * flags: R_CURSOR if deleting what the cursor references + * + * Returns: + * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found. + */ +int +__rec_delete(dbp, key, flags) + const DB *dbp; + const DBT *key; + u_int flags; +{ + BTREE *t; + recno_t nrec; + int status; + + t = dbp->internal; + + /* Toss any page pinned across calls. */ + if (t->bt_pinned != NULL) { + mpool_put(t->bt_mp, t->bt_pinned, 0); + t->bt_pinned = NULL; + } + + switch(flags) { + case 0: + if ((nrec = *(recno_t *)key->data) == 0) + goto einval; + if (nrec > t->bt_nrecs) + return (RET_SPECIAL); + --nrec; + status = rec_rdelete(t, nrec); + break; + case R_CURSOR: + if (!F_ISSET(&t->bt_cursor, CURS_INIT)) + goto einval; + if (t->bt_nrecs == 0) + return (RET_SPECIAL); + status = rec_rdelete(t, t->bt_cursor.rcursor - 1); + if (status == RET_SUCCESS) + --t->bt_cursor.rcursor; + break; + default: +einval: errno = EINVAL; + return (RET_ERROR); + } + + if (status == RET_SUCCESS) + F_SET(t, B_MODIFIED | R_MODIFIED); + return (status); +} + +/* + * REC_RDELETE -- Delete the data matching the specified key. + * + * Parameters: + * tree: tree + * nrec: record to delete + * + * Returns: + * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found. + */ +static int +rec_rdelete(t, nrec) + BTREE *t; + recno_t nrec; +{ + EPG *e; + PAGE *h; + int status; + + /* Find the record; __rec_search pins the page. */ + if ((e = __rec_search(t, nrec, SDELETE)) == NULL) + return (RET_ERROR); + + /* Delete the record. */ + h = e->page; + status = __rec_dleaf(t, h, e->index); + if (status != RET_SUCCESS) { + mpool_put(t->bt_mp, h, 0); + return (status); + } + mpool_put(t->bt_mp, h, MPOOL_DIRTY); + return (RET_SUCCESS); +} + +/* + * __REC_DLEAF -- Delete a single record from a recno leaf page. + * + * Parameters: + * t: tree + * index: index on current page to delete + * + * Returns: + * RET_SUCCESS, RET_ERROR. + */ +int +__rec_dleaf(t, h, index) + BTREE *t; + PAGE *h; + u_int32_t index; +{ + RLEAF *rl; + indx_t *ip, cnt, offset; + u_int32_t nbytes; + char *from; + void *to; + + /* + * Delete a record from a recno leaf page. Internal records are never + * deleted from internal pages, regardless of the records that caused + * them to be added being deleted. Pages made empty by deletion are + * not reclaimed. They are, however, made available for reuse. + * + * Pack the remaining entries at the end of the page, shift the indices + * down, overwriting the deleted record and its index. If the record + * uses overflow pages, make them available for reuse. + */ + to = rl = GETRLEAF(h, index); + if (rl->flags & P_BIGDATA && __ovfl_delete(t, rl->bytes) == RET_ERROR) + return (RET_ERROR); + nbytes = NRLEAF(rl); + + /* + * Compress the key/data pairs. Compress and adjust the [BR]LEAF + * offsets. Reset the headers. + */ + from = (char *)h + h->upper; + memmove(from + nbytes, from, (char *)to - from); + h->upper += nbytes; + + offset = h->linp[index]; + for (cnt = &h->linp[index] - (ip = &h->linp[0]); cnt--; ++ip) + if (ip[0] < offset) + ip[0] += nbytes; + for (cnt = &h->linp[NEXTINDEX(h)] - ip; --cnt; ++ip) + ip[0] = ip[1] < offset ? ip[1] + nbytes : ip[1]; + h->lower -= sizeof(indx_t); + --t->bt_nrecs; + return (RET_SUCCESS); +} |