aboutsummaryrefslogtreecommitdiffstats
path: root/main/db1-ast/btree/bt_utils.c
diff options
context:
space:
mode:
Diffstat (limited to 'main/db1-ast/btree/bt_utils.c')
-rw-r--r--main/db1-ast/btree/bt_utils.c260
1 files changed, 260 insertions, 0 deletions
diff --git a/main/db1-ast/btree/bt_utils.c b/main/db1-ast/btree/bt_utils.c
new file mode 100644
index 000000000..1416c7862
--- /dev/null
+++ b/main/db1-ast/btree/bt_utils.c
@@ -0,0 +1,260 @@
+/*-
+ * 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[] = "@(#)bt_utils.c 8.8 (Berkeley) 7/20/94";
+#endif /* LIBC_SCCS and not lint */
+
+#include <sys/param.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <db.h>
+#include "btree.h"
+
+/*
+ * __bt_ret --
+ * Build return key/data pair.
+ *
+ * Parameters:
+ * t: tree
+ * e: key/data pair to be returned
+ * key: user's key structure (NULL if not to be filled in)
+ * rkey: memory area to hold key
+ * data: user's data structure (NULL if not to be filled in)
+ * rdata: memory area to hold data
+ * copy: always copy the key/data item
+ *
+ * Returns:
+ * RET_SUCCESS, RET_ERROR.
+ */
+int
+__bt_ret(t, e, key, rkey, data, rdata, copy)
+ BTREE *t;
+ EPG *e;
+ DBT *key, *rkey, *data, *rdata;
+ int copy;
+{
+ BLEAF *bl;
+ void *p;
+
+ bl = GETBLEAF(e->page, e->index);
+
+ /*
+ * We must copy big keys/data to make them contiguous. Otherwise,
+ * leave the page pinned and don't copy unless the user specified
+ * concurrent access.
+ */
+ if (key == NULL)
+ goto dataonly;
+
+ if (bl->flags & P_BIGKEY) {
+ if (__ovfl_get(t, bl->bytes,
+ &key->size, &rkey->data, &rkey->size))
+ return (RET_ERROR);
+ key->data = rkey->data;
+ } else if (copy || F_ISSET(t, B_DB_LOCK)) {
+ if (bl->ksize > rkey->size) {
+ p = (void *)(rkey->data == NULL ?
+ malloc(bl->ksize) : realloc(rkey->data, bl->ksize));
+ if (p == NULL)
+ return (RET_ERROR);
+ rkey->data = p;
+ rkey->size = bl->ksize;
+ }
+ memmove(rkey->data, bl->bytes, bl->ksize);
+ key->size = bl->ksize;
+ key->data = rkey->data;
+ } else {
+ key->size = bl->ksize;
+ key->data = bl->bytes;
+ }
+
+dataonly:
+ if (data == NULL)
+ return (RET_SUCCESS);
+
+ if (bl->flags & P_BIGDATA) {
+ if (__ovfl_get(t, bl->bytes + bl->ksize,
+ &data->size, &rdata->data, &rdata->size))
+ return (RET_ERROR);
+ data->data = rdata->data;
+ } else if (copy || F_ISSET(t, B_DB_LOCK)) {
+ /* Use +1 in case the first record retrieved is 0 length. */
+ if (bl->dsize + 1 > rdata->size) {
+ p = (void *)(rdata->data == NULL ?
+ malloc(bl->dsize + 1) :
+ realloc(rdata->data, bl->dsize + 1));
+ if (p == NULL)
+ return (RET_ERROR);
+ rdata->data = p;
+ rdata->size = bl->dsize + 1;
+ }
+ memmove(rdata->data, bl->bytes + bl->ksize, bl->dsize);
+ data->size = bl->dsize;
+ data->data = rdata->data;
+ } else {
+ data->size = bl->dsize;
+ data->data = bl->bytes + bl->ksize;
+ }
+
+ return (RET_SUCCESS);
+}
+
+/*
+ * __BT_CMP -- Compare a key to a given record.
+ *
+ * Parameters:
+ * t: tree
+ * k1: DBT pointer of first arg to comparison
+ * e: pointer to EPG for comparison
+ *
+ * Returns:
+ * < 0 if k1 is < record
+ * = 0 if k1 is = record
+ * > 0 if k1 is > record
+ */
+int
+__bt_cmp(t, k1, e)
+ BTREE *t;
+ const DBT *k1;
+ EPG *e;
+{
+ BINTERNAL *bi;
+ BLEAF *bl;
+ DBT k2;
+ PAGE *h;
+ void *bigkey;
+
+ /*
+ * The left-most key on internal pages, at any level of the tree, is
+ * guaranteed by the following code to be less than any user key.
+ * This saves us from having to update the leftmost key on an internal
+ * page when the user inserts a new key in the tree smaller than
+ * anything we've yet seen.
+ */
+ h = e->page;
+ if (e->index == 0 && h->prevpg == P_INVALID && !(h->flags & P_BLEAF))
+ return (1);
+
+ bigkey = NULL;
+ if (h->flags & P_BLEAF) {
+ bl = GETBLEAF(h, e->index);
+ if (bl->flags & P_BIGKEY)
+ bigkey = bl->bytes;
+ else {
+ k2.data = bl->bytes;
+ k2.size = bl->ksize;
+ }
+ } else {
+ bi = GETBINTERNAL(h, e->index);
+ if (bi->flags & P_BIGKEY)
+ bigkey = bi->bytes;
+ else {
+ k2.data = bi->bytes;
+ k2.size = bi->ksize;
+ }
+ }
+
+ if (bigkey) {
+ if (__ovfl_get(t, bigkey,
+ &k2.size, &t->bt_rdata.data, &t->bt_rdata.size))
+ return (RET_ERROR);
+ k2.data = t->bt_rdata.data;
+ }
+ return ((*t->bt_cmp)(k1, &k2));
+}
+
+/*
+ * __BT_DEFCMP -- Default comparison routine.
+ *
+ * Parameters:
+ * a: DBT #1
+ * b: DBT #2
+ *
+ * Returns:
+ * < 0 if a is < b
+ * = 0 if a is = b
+ * > 0 if a is > b
+ */
+int
+__bt_defcmp(a, b)
+ const DBT *a, *b;
+{
+ register size_t len;
+ register u_char *p1, *p2;
+
+ /*
+ * XXX
+ * If a size_t doesn't fit in an int, this routine can lose.
+ * What we need is a integral type which is guaranteed to be
+ * larger than a size_t, and there is no such thing.
+ */
+ len = MIN(a->size, b->size);
+ for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2)
+ if (*p1 != *p2)
+ return ((int)*p1 - (int)*p2);
+ return ((int)a->size - (int)b->size);
+}
+
+/*
+ * __BT_DEFPFX -- Default prefix routine.
+ *
+ * Parameters:
+ * a: DBT #1
+ * b: DBT #2
+ *
+ * Returns:
+ * Number of bytes needed to distinguish b from a.
+ */
+size_t
+__bt_defpfx(a, b)
+ const DBT *a, *b;
+{
+ register u_char *p1, *p2;
+ register size_t cnt, len;
+
+ cnt = 1;
+ len = MIN(a->size, b->size);
+ for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2, ++cnt)
+ if (*p1 != *p2)
+ return (cnt);
+
+ /* a->size must be <= b->size, or they wouldn't be in this order. */
+ return (a->size < b->size ? a->size + 1 : a->size);
+}