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-rw-r--r--db2/db/db_overflow.c383
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diff --git a/db2/db/db_overflow.c b/db2/db/db_overflow.c
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+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 1996, 1997
+ * Sleepycat Software. All rights reserved.
+ */
+/*
+ * Copyright (c) 1990, 1993, 1994, 1995, 1996
+ * Keith Bostic. All rights reserved.
+ */
+/*
+ * Copyright (c) 1990, 1993, 1994, 1995
+ * 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 "config.h"
+
+#ifndef lint
+static const char sccsid[] = "@(#)db_overflow.c 10.4 (Sleepycat) 7/2/97";
+#endif /* not lint */
+
+#ifndef NO_SYSTEM_INCLUDES
+#include <sys/types.h>
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#endif
+
+#include "db_int.h"
+#include "db_page.h"
+#include "db_am.h"
+#include "common_ext.h"
+
+/*
+ * Big key/data code.
+ *
+ * Big key and data entries are stored on linked lists of pages. The initial
+ * reference is a structure with the total length of the item and the page
+ * number where it begins. Each entry in the linked list contains a pointer
+ * to the next page of data, and so on.
+ */
+
+/*
+ * __db_goff --
+ * Get an offpage item.
+ *
+ * PUBLIC: int __db_goff __P((DB *, DBT *,
+ * PUBLIC: u_int32_t, db_pgno_t, void **, u_int32_t *));
+ */
+int
+__db_goff(dbp, dbt, tlen, pgno, bpp, bpsz)
+ DB *dbp;
+ DBT *dbt;
+ u_int32_t tlen;
+ db_pgno_t pgno;
+ void **bpp;
+ u_int32_t *bpsz;
+{
+ PAGE *h;
+ db_indx_t bytes;
+ int ret;
+ u_int32_t curoff, needed, start;
+ u_int8_t *p, *src;
+
+ /*
+ * Check if the buffer is big enough; if it is not and we are
+ * allowed to malloc space, then we'll malloc it. If we are
+ * not (DB_DBT_USERMEM), then we'll set the dbt and return
+ * appropriately.
+ */
+ if (F_ISSET(dbt, DB_DBT_PARTIAL)) {
+ start = dbt->doff;
+ needed = dbt->dlen;
+ } else {
+ start = 0;
+ needed = tlen;
+ }
+
+ /*
+ * Allocate any necessary memory.
+ *
+ * XXX: Never allocate 0 bytes;
+ */
+ if (F_ISSET(dbt, DB_DBT_USERMEM)) {
+ if (needed > dbt->ulen) {
+ dbt->size = needed;
+ return (ENOMEM);
+ }
+ } else if (F_ISSET(dbt, DB_DBT_MALLOC)) {
+ dbt->data = dbp->db_malloc == NULL ?
+ (void *)malloc(needed + 1) :
+ (void *)dbp->db_malloc(needed + 1);
+ if (dbt->data == NULL)
+ return (ENOMEM);
+ } else if (*bpsz == 0 || *bpsz < needed) {
+ *bpp = (*bpp == NULL ?
+ (void *)malloc(needed + 1) :
+ (void *)realloc(*bpp, needed + 1));
+ if (*bpp == NULL)
+ return (ENOMEM);
+ *bpsz = needed + 1;
+ dbt->data = *bpp;
+ } else
+ dbt->data = *bpp;
+
+ /*
+ * Step through the linked list of pages, copying the data on each
+ * one into the buffer. Never copy more than the total data length.
+ */
+ dbt->size = needed;
+ for (curoff = 0, p = dbt->data; pgno != P_INVALID && needed > 0;) {
+ if ((ret = memp_fget(dbp->mpf, &pgno, 0, &h)) != 0) {
+ (void)__db_pgerr(dbp, pgno);
+ return (ret);
+ }
+ /* Check if we need any bytes from this page. */
+ if (curoff + OV_LEN(h) >= start) {
+ src = (u_int8_t *)h + P_OVERHEAD;
+ bytes = OV_LEN(h);
+ if (start > curoff) {
+ src += start - curoff;
+ bytes -= start - curoff;
+ }
+ if (bytes > needed)
+ bytes = needed;
+ memcpy(p, src, bytes);
+ p += bytes;
+ needed -= bytes;
+ }
+ curoff += OV_LEN(h);
+ pgno = h->next_pgno;
+ memp_fput(dbp->mpf, h, 0);
+ }
+ return (0);
+}
+
+/*
+ * __db_poff --
+ * Put an offpage item.
+ *
+ * PUBLIC: int __db_poff __P((DB *, const DBT *, db_pgno_t *,
+ * PUBLIC: int (*)(DB *, u_int32_t, PAGE **)));
+ */
+int
+__db_poff(dbp, dbt, pgnop, newfunc)
+ DB *dbp;
+ const DBT *dbt;
+ db_pgno_t *pgnop;
+ int (*newfunc) __P((DB *, u_int32_t, PAGE **));
+{
+ PAGE *pagep, *lastp;
+ DB_LSN new_lsn, null_lsn;
+ DBT tmp_dbt;
+ db_indx_t pagespace;
+ u_int32_t sz;
+ u_int8_t *p;
+ int ret;
+
+ /*
+ * Allocate pages and copy the key/data item into them. Calculate the
+ * number of bytes we get for pages we fill completely with a single
+ * item.
+ */
+ pagespace = P_MAXSPACE(dbp->pgsize);
+
+ lastp = NULL;
+ for (p = dbt->data,
+ sz = dbt->size; sz > 0; p += pagespace, sz -= pagespace) {
+ /*
+ * Reduce pagespace so we terminate the loop correctly and
+ * don't copy too much data.
+ */
+ if (sz < pagespace)
+ pagespace = sz;
+
+ /*
+ * Allocate and initialize a new page and copy all or part of
+ * the item onto the page. If sz is less than pagespace, we
+ * have a partial record.
+ */
+ if ((ret = newfunc(dbp, P_OVERFLOW, &pagep)) != 0)
+ return (ret);
+ if (DB_LOGGING(dbp)) {
+ tmp_dbt.data = p;
+ tmp_dbt.size = pagespace;
+ ZERO_LSN(null_lsn);
+ if ((ret = __db_big_log(dbp->dbenv->lg_info, dbp->txn,
+ &new_lsn, 0, DB_ADD_BIG, dbp->log_fileid,
+ PGNO(pagep), lastp ? PGNO(lastp) : PGNO_INVALID,
+ PGNO_INVALID, &tmp_dbt, &LSN(pagep),
+ lastp == NULL ? &null_lsn : &LSN(lastp),
+ &null_lsn)) != 0)
+ return (ret);
+
+ /* Move lsn onto page. */
+ if (lastp)
+ LSN(lastp) = new_lsn;
+ LSN(pagep) = new_lsn;
+ }
+
+ P_INIT(pagep, dbp->pgsize,
+ PGNO(pagep), PGNO_INVALID, PGNO_INVALID, 0, P_OVERFLOW);
+ OV_LEN(pagep) = pagespace;
+ OV_REF(pagep) = 1;
+ memcpy((u_int8_t *)pagep + P_OVERHEAD, p, pagespace);
+
+ /*
+ * If this is the first entry, update the user's info.
+ * Otherwise, update the entry on the last page filled
+ * in and release that page.
+ */
+ if (lastp == NULL)
+ *pgnop = PGNO(pagep);
+ else {
+ lastp->next_pgno = PGNO(pagep);
+ pagep->prev_pgno = PGNO(lastp);
+ (void)memp_fput(dbp->mpf, lastp, DB_MPOOL_DIRTY);
+ }
+ lastp = pagep;
+ }
+ (void)memp_fput(dbp->mpf, lastp, DB_MPOOL_DIRTY);
+ return (0);
+}
+
+/*
+ * __db_ioff --
+ * Increment the reference count on an overflow page.
+ *
+ * PUBLIC: int __db_ioff __P((DB *, db_pgno_t));
+ */
+int
+__db_ioff(dbp, pgno)
+ DB *dbp;
+ db_pgno_t pgno;
+{
+ PAGE *h;
+ int ret;
+
+ if ((ret = memp_fget(dbp->mpf, &pgno, 0, &h)) != 0) {
+ (void)__db_pgerr(dbp, pgno);
+ return (ret);
+ }
+
+ ++OV_REF(h);
+ if (DB_LOGGING(dbp) && (ret = __db_ovref_log(dbp->dbenv->lg_info,
+ dbp->txn, &LSN(h), 0, dbp->log_fileid, h->pgno, &LSN(h))) != 0)
+ return (ret);
+
+ (void)memp_fput(dbp->mpf, h, DB_MPOOL_DIRTY);
+ return (0);
+}
+
+/*
+ * __db_doff --
+ * Delete an offpage chain of overflow pages.
+ *
+ * PUBLIC: int __db_doff __P((DB *, db_pgno_t, int (*)(DB *, PAGE *)));
+ */
+int
+__db_doff(dbp, pgno, freefunc)
+ DB *dbp;
+ db_pgno_t pgno;
+ int (*freefunc) __P((DB *, PAGE *));
+{
+ PAGE *pagep;
+ DB_LSN null_lsn;
+ DBT tmp_dbt;
+ int ret;
+
+ do {
+ if ((ret = memp_fget(dbp->mpf, &pgno, 0, &pagep)) != 0) {
+ (void)__db_pgerr(dbp, pgno);
+ return (ret);
+ }
+
+ /*
+ * If it's an overflow page and it's referenced by more than
+ * one key/data item, decrement the reference count and return.
+ */
+ if (TYPE(pagep) == P_OVERFLOW && OV_REF(pagep) > 1) {
+ --OV_REF(pagep);
+ (void)memp_fput(dbp->mpf, pagep, DB_MPOOL_DIRTY);
+ return (0);
+ }
+
+ if (DB_LOGGING(dbp)) {
+ tmp_dbt.data = (u_int8_t *)pagep + P_OVERHEAD;
+ tmp_dbt.size = OV_LEN(pagep);
+ ZERO_LSN(null_lsn);
+ if ((ret = __db_big_log(dbp->dbenv->lg_info, dbp->txn,
+ &LSN(pagep), 0, DB_REM_BIG, dbp->log_fileid,
+ PGNO(pagep), PREV_PGNO(pagep), NEXT_PGNO(pagep),
+ &tmp_dbt, &LSN(pagep), &null_lsn, &null_lsn)) != 0)
+ return (ret);
+ }
+ pgno = pagep->next_pgno;
+ if ((ret = freefunc(dbp, pagep)) != 0)
+ return (ret);
+ } while (pgno != PGNO_INVALID);
+
+ return (0);
+}
+
+/*
+ * __db_moff --
+ * Match on overflow pages.
+ *
+ * Given a starting page number and a key, return <0, 0, >0 to indicate if the
+ * key on the page is less than, equal to or greater than the key specified.
+ *
+ * PUBLIC: int __db_moff __P((DB *, const DBT *, db_pgno_t));
+ */
+int
+__db_moff(dbp, dbt, pgno)
+ DB *dbp;
+ const DBT *dbt;
+ db_pgno_t pgno;
+{
+ PAGE *pagep;
+ u_int32_t cmp_bytes, key_left;
+ int ret;
+ u_int8_t *p1, *p2;
+
+ /* While there are both keys to compare. */
+ for (ret = 0, p1 = dbt->data,
+ key_left = dbt->size; key_left > 0 && pgno != PGNO_INVALID;) {
+ if (memp_fget(dbp->mpf, &pgno, 0, &pagep) != 0) {
+ (void)__db_pgerr(dbp, pgno);
+ return (0); /* No system error return. */
+ }
+
+ cmp_bytes = OV_LEN(pagep) < key_left ? OV_LEN(pagep) : key_left;
+ key_left -= cmp_bytes;
+ for (p2 =
+ (u_int8_t *)pagep + P_OVERHEAD; cmp_bytes-- > 0; ++p1, ++p2)
+ if (*p1 != *p2) {
+ ret = (long)*p1 - (long)*p2;
+ break;
+ }
+ pgno = NEXT_PGNO(pagep);
+ (void)memp_fput(dbp->mpf, pagep, 0);
+ if (ret != 0)
+ return (ret);
+ }
+ if (key_left > 0) /* DBT is longer than page key. */
+ return (-1);
+ if (pgno != PGNO_INVALID) /* DBT is shorter than page key. */
+ return (1);
+ return (0);
+}
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