[apple/libc.git] / db / recno / rec_delete.c

/*
 * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * Copyright (c) 1990, 1993
 *	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.
 */


#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 (!ISSET(t, B_SEQINIT))
			goto einval;
		if (t->bt_nrecs == 0)
			return (RET_SPECIAL);
		status = rec_rdelete(t, t->bt_rcursor - 1);
		if (status == RET_SUCCESS)
			--t->bt_rcursor;
		break;
	default:
einval:		errno = EINVAL;
		return (RET_ERROR);
	}

	if (status == RET_SUCCESS)
		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;
	indx_t index;
{
	register RLEAF *rl;
	register indx_t *ip, cnt, offset;
	register size_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);
}
Commit	Line	Data
e9ce8d39 A	1	/*
	2	* Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
	3	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
734aad71	6	* Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved.
e9ce8d39	7	*
734aad71 A	8	* This file contains Original Code and/or Modifications of Original Code
	9	* as defined in and that are subject to the Apple Public Source License
	10	* Version 2.0 (the 'License'). You may not use this file except in
	11	* compliance with the License. Please obtain a copy of the License at
	12	* http://www.opensource.apple.com/apsl/ and read it before using this
	13	* file.
	14	*
	15	* The Original Code and all software distributed under the License are
	16	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
e9ce8d39 A	17	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
e9ce8d39 A	18	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
734aad71 A	19	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	20	* Please see the License for the specific language governing rights and
	21	* limitations under the License.
e9ce8d39 A	22	*
	23	* @APPLE_LICENSE_HEADER_END@
	24	*/
	25	/*
	26	* Copyright (c) 1990, 1993
	27	* The Regents of the University of California. All rights reserved.
	28	*
	29	* This code is derived from software contributed to Berkeley by
	30	* Mike Olson.
	31	*
	32	* Redistribution and use in source and binary forms, with or without
	33	* modification, are permitted provided that the following conditions
	34	* are met:
	35	* 1. Redistributions of source code must retain the above copyright
	36	* notice, this list of conditions and the following disclaimer.
	37	* 2. Redistributions in binary form must reproduce the above copyright
	38	* notice, this list of conditions and the following disclaimer in the
	39	* documentation and/or other materials provided with the distribution.
	40	* 3. All advertising materials mentioning features or use of this software
	41	* must display the following acknowledgement:
	42	* This product includes software developed by the University of
	43	* California, Berkeley and its contributors.
	44	* 4. Neither the name of the University nor the names of its contributors
	45	* may be used to endorse or promote products derived from this software
	46	* without specific prior written permission.
	47	*
	48	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	49	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	50	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	51	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	52	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	53	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	54	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	55	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	56	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	57	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	58	* SUCH DAMAGE.
	59	*/
	60
	61
	62	#include <sys/types.h>
	63
	64	#include <errno.h>
	65	#include <stdio.h>
	66	#include <string.h>
	67
	68	#include <db.h>
	69	#include "recno.h"
	70
	71	static int rec_rdelete __P((BTREE *, recno_t));
	72
	73	/*
	74	* __REC_DELETE -- Delete the item(s) referenced by a key.
	75	*
	76	* Parameters:
	77	* dbp: pointer to access method
	78	* key: key to delete
	79	* flags: R_CURSOR if deleting what the cursor references
	80	*
	81	* Returns:
	82	* RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
	83	*/
	84	int
	85	__rec_delete(dbp, key, flags)
86	const DB *dbp;
87	const DBT *key;
88	u_int flags;
89	{
90	BTREE *t;
91	recno_t nrec;
92	int status;
93
94	t = dbp->internal;
95
96	/* Toss any page pinned across calls. */
97	if (t->bt_pinned != NULL) {
98	mpool_put(t->bt_mp, t->bt_pinned, 0);
99	t->bt_pinned = NULL;
100	}
101
102	switch(flags) {
103	case 0:
104	if ((nrec = (recno_t )key->data) == 0)
105	goto einval;
106	if (nrec > t->bt_nrecs)
107	return (RET_SPECIAL);
108	--nrec;
109	status = rec_rdelete(t, nrec);
110	break;
111	case R_CURSOR:
112	if (!ISSET(t, B_SEQINIT))
113	goto einval;
114	if (t->bt_nrecs == 0)
115	return (RET_SPECIAL);
116	status = rec_rdelete(t, t->bt_rcursor - 1);
117	if (status == RET_SUCCESS)
118	--t->bt_rcursor;
119	break;
120	default:
121	einval: errno = EINVAL;
122	return (RET_ERROR);
123	}
124
125	if (status == RET_SUCCESS)
126	SET(t, B_MODIFIED \| R_MODIFIED);
127	return (status);
128	}
129
130	/*
131	* REC_RDELETE -- Delete the data matching the specified key.
132	*
133	* Parameters:
134	* tree: tree
135	* nrec: record to delete
136	*
137	* Returns:
138	* RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
139	*/
140	static int
141	rec_rdelete(t, nrec)
142	BTREE *t;
143	recno_t nrec;
144	{
145	EPG *e;
146	PAGE *h;
147	int status;
148
149	/* Find the record; __rec_search pins the page. */
150	if ((e = __rec_search(t, nrec, SDELETE)) == NULL)
151	return (RET_ERROR);
152
153	/* Delete the record. */
154	h = e->page;
155	status = __rec_dleaf(t, h, e->index);
156	if (status != RET_SUCCESS) {
157	mpool_put(t->bt_mp, h, 0);
158	return (status);
159	}
160	mpool_put(t->bt_mp, h, MPOOL_DIRTY);
161	return (RET_SUCCESS);
162	}
163
164	/*
165	* __REC_DLEAF -- Delete a single record from a recno leaf page.
166	*
167	* Parameters:
168	* t: tree
169	* index: index on current page to delete
170	*
171	* Returns:
172	* RET_SUCCESS, RET_ERROR.
173	*/
174	int
175	__rec_dleaf(t, h, index)
176	BTREE *t;
177	PAGE *h;
178	indx_t index;
179	{
180	register RLEAF *rl;
181	register indx_t *ip, cnt, offset;
182	register size_t nbytes;
183	char *from;
184	void *to;
185
186	/*
187	* Delete a record from a recno leaf page. Internal records are never
188	* deleted from internal pages, regardless of the records that caused
189	* them to be added being deleted. Pages made empty by deletion are
190	* not reclaimed. They are, however, made available for reuse.
191	*
192	* Pack the remaining entries at the end of the page, shift the indices
193	* down, overwriting the deleted record and its index. If the record
194	* uses overflow pages, make them available for reuse.
195	*/
196	to = rl = GETRLEAF(h, index);
197	if (rl->flags & P_BIGDATA && __ovfl_delete(t, rl->bytes) == RET_ERROR)
198	return (RET_ERROR);
199	nbytes = NRLEAF(rl);
200
201	/*
202	* Compress the key/data pairs. Compress and adjust the [BR]LEAF
203	* offsets. Reset the headers.
204	*/
205	from = (char *)h + h->upper;
206	memmove(from + nbytes, from, (char *)to - from);
207	h->upper += nbytes;
208
209	offset = h->linp[index];
210	for (cnt = &h->linp[index] - (ip = &h->linp[0]); cnt--; ++ip)
211	if (ip[0] < offset)
212	ip[0] += nbytes;
213	for (cnt = &h->linp[NEXTINDEX(h)] - ip; --cnt; ++ip)
214	ip[0] = ip[1] < offset ? ip[1] + nbytes : ip[1];
215	h->lower -= sizeof(indx_t);
216	--t->bt_nrecs;
217	return (RET_SUCCESS);
218	}