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-rw-r--r--utils/db1-ast/recno/rec_delete.c197
1 files changed, 197 insertions, 0 deletions
diff --git a/utils/db1-ast/recno/rec_delete.c b/utils/db1-ast/recno/rec_delete.c
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+/*-
+ * 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 "../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, idx)
+ BTREE *t;
+ PAGE *h;
+ u_int32_t idx;
+{
+ 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, idx);
+ 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[idx];
+ for (cnt = &h->linp[idx] - (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);
+}