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-rw-r--r--utils/db1-ast/btree/bt_overflow.c228
1 files changed, 228 insertions, 0 deletions
diff --git a/utils/db1-ast/btree/bt_overflow.c b/utils/db1-ast/btree/bt_overflow.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[] = "@(#)bt_overflow.c 8.5 (Berkeley) 7/16/94";
+#endif /* LIBC_SCCS and not lint */
+
+#include <sys/param.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "../include/db.h"
+#include "btree.h"
+
+/*
+ * Big key/data code.
+ *
+ * Big key and data entries are stored on linked lists of pages. The initial
+ * reference is byte string stored with the key or data and is the page number
+ * and size. The actual record is stored in a chain of pages linked by the
+ * nextpg field of the PAGE header.
+ *
+ * The first page of the chain has a special property. If the record is used
+ * by an internal page, it cannot be deleted and the P_PRESERVE bit will be set
+ * in the header.
+ *
+ * XXX
+ * A single DBT is written to each chain, so a lot of space on the last page
+ * is wasted. This is a fairly major bug for some data sets.
+ */
+
+/*
+ * __OVFL_GET -- Get an overflow key/data item.
+ *
+ * Parameters:
+ * t: tree
+ * p: pointer to { pgno_t, u_int32_t }
+ * buf: storage address
+ * bufsz: storage size
+ *
+ * Returns:
+ * RET_ERROR, RET_SUCCESS
+ */
+int
+__ovfl_get(t, p, ssz, buf, bufsz)
+ BTREE *t;
+ void *p;
+ size_t *ssz;
+ void **buf;
+ size_t *bufsz;
+{
+ PAGE *h;
+ pgno_t pg;
+ size_t nb, plen;
+ u_int32_t sz;
+
+ memmove(&pg, p, sizeof(pgno_t));
+ memmove(&sz, (char *)p + sizeof(pgno_t), sizeof(u_int32_t));
+ *ssz = sz;
+
+#ifdef DEBUG
+ if (pg == P_INVALID || sz == 0)
+ abort();
+#endif
+ /* Make the buffer bigger as necessary. */
+ if (*bufsz < sz) {
+ *buf = (char *)(*buf == NULL ? malloc(sz) : realloc(*buf, sz));
+ if (*buf == NULL)
+ return (RET_ERROR);
+ *bufsz = sz;
+ }
+
+ /*
+ * Step through the linked list of pages, copying the data on each one
+ * into the buffer. Never copy more than the data's length.
+ */
+ plen = t->bt_psize - BTDATAOFF;
+ for (p = *buf;; p = (char *)p + nb, pg = h->nextpg) {
+ if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
+ return (RET_ERROR);
+
+ nb = MIN(sz, plen);
+ memmove(p, (char *)h + BTDATAOFF, nb);
+ mpool_put(t->bt_mp, h, 0);
+
+ if ((sz -= nb) == 0)
+ break;
+ }
+ return (RET_SUCCESS);
+}
+
+/*
+ * __OVFL_PUT -- Store an overflow key/data item.
+ *
+ * Parameters:
+ * t: tree
+ * data: DBT to store
+ * pgno: storage page number
+ *
+ * Returns:
+ * RET_ERROR, RET_SUCCESS
+ */
+int
+__ovfl_put(t, dbt, pg)
+ BTREE *t;
+ const DBT *dbt;
+ pgno_t *pg;
+{
+ PAGE *h, *last;
+ void *p;
+ pgno_t npg;
+ size_t nb, plen;
+ u_int32_t sz;
+
+ /*
+ * Allocate pages and copy the key/data record into them. Store the
+ * number of the first page in the chain.
+ */
+ plen = t->bt_psize - BTDATAOFF;
+ for (last = NULL, p = dbt->data, sz = dbt->size;;
+ p = (char *)p + plen, last = h) {
+ if ((h = __bt_new(t, &npg)) == NULL)
+ return (RET_ERROR);
+
+ h->pgno = npg;
+ h->nextpg = h->prevpg = P_INVALID;
+ h->flags = P_OVERFLOW;
+ h->lower = h->upper = 0;
+
+ nb = MIN(sz, plen);
+ memmove((char *)h + BTDATAOFF, p, nb);
+
+ if (last) {
+ last->nextpg = h->pgno;
+ mpool_put(t->bt_mp, last, MPOOL_DIRTY);
+ } else
+ *pg = h->pgno;
+
+ if ((sz -= nb) == 0) {
+ mpool_put(t->bt_mp, h, MPOOL_DIRTY);
+ break;
+ }
+ }
+ return (RET_SUCCESS);
+}
+
+/*
+ * __OVFL_DELETE -- Delete an overflow chain.
+ *
+ * Parameters:
+ * t: tree
+ * p: pointer to { pgno_t, u_int32_t }
+ *
+ * Returns:
+ * RET_ERROR, RET_SUCCESS
+ */
+int
+__ovfl_delete(t, p)
+ BTREE *t;
+ void *p;
+{
+ PAGE *h;
+ pgno_t pg;
+ size_t plen;
+ u_int32_t sz;
+
+ memmove(&pg, p, sizeof(pgno_t));
+ memmove(&sz, (char *)p + sizeof(pgno_t), sizeof(u_int32_t));
+
+#ifdef DEBUG
+ if (pg == P_INVALID || sz == 0)
+ abort();
+#endif
+ if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
+ return (RET_ERROR);
+
+ /* Don't delete chains used by internal pages. */
+ if (h->flags & P_PRESERVE) {
+ mpool_put(t->bt_mp, h, 0);
+ return (RET_SUCCESS);
+ }
+
+ /* Step through the chain, calling the free routine for each page. */
+ for (plen = t->bt_psize - BTDATAOFF;; sz -= plen) {
+ pg = h->nextpg;
+ __bt_free(t, h);
+ if (sz <= plen)
+ break;
+ if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
+ return (RET_ERROR);
+ }
+ return (RET_SUCCESS);
+}