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diff --git a/dbm/sdbm/sdbm_pair.c b/dbm/sdbm/sdbm_pair.c
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+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * sdbm - ndbm work-alike hashed database library
+ * based on Per-Aake Larson's Dynamic Hashing algorithms. BIT 18 (1978).
+ * author: oz@nexus.yorku.ca
+ * status: ex-public domain.
+ *
+ * page-level routines
+ */
+
+#include "apr_sdbm.h"
+
+#include "sdbm_tune.h"
+#include "sdbm_pair.h"
+#include "sdbm_private.h"
+
+#include <string.h> /* for memset() */
+
+
+#define exhash(item) sdbm_hash((item).dptr, (item).dsize)
+
+/*
+ * forward
+ */
+static int seepair(char *, int, char *, int);
+
+/*
+ * page format:
+ * +------------------------------+
+ * ino | n | keyoff | datoff | keyoff |
+ * +------------+--------+--------+
+ * | datoff | - - - ----> |
+ * +--------+---------------------+
+ * | F R E E A R E A |
+ * +--------------+---------------+
+ * | <---- - - - | data |
+ * +--------+-----+----+----------+
+ * | key | data | key |
+ * +--------+----------+----------+
+ *
+ * calculating the offsets for free area: if the number
+ * of entries (ino[0]) is zero, the offset to the END of
+ * the free area is the block size. Otherwise, it is the
+ * nth (ino[ino[0]]) entry's offset.
+ */
+
+int
+fitpair(pag, need)
+char *pag;
+int need;
+{
+ register int n;
+ register int off;
+ register int avail;
+ register short *ino = (short *) pag;
+
+ off = ((n = ino[0]) > 0) ? ino[n] : PBLKSIZ;
+ avail = off - (n + 1) * sizeof(short);
+ need += 2 * sizeof(short);
+
+ debug(("avail %d need %d\n", avail, need));
+
+ return need <= avail;
+}
+
+void
+putpair(pag, key, val)
+char *pag;
+apr_sdbm_datum_t key;
+apr_sdbm_datum_t val;
+{
+ register int n;
+ register int off;
+ register short *ino = (short *) pag;
+
+ off = ((n = ino[0]) > 0) ? ino[n] : PBLKSIZ;
+/*
+ * enter the key first
+ */
+ off -= key.dsize;
+ (void) memcpy(pag + off, key.dptr, key.dsize);
+ ino[n + 1] = off;
+/*
+ * now the data
+ */
+ off -= val.dsize;
+ (void) memcpy(pag + off, val.dptr, val.dsize);
+ ino[n + 2] = off;
+/*
+ * adjust item count
+ */
+ ino[0] += 2;
+}
+
+apr_sdbm_datum_t
+getpair(pag, key)
+char *pag;
+apr_sdbm_datum_t key;
+{
+ register int i;
+ register int n;
+ apr_sdbm_datum_t val;
+ register short *ino = (short *) pag;
+
+ if ((n = ino[0]) == 0)
+ return sdbm_nullitem;
+
+ if ((i = seepair(pag, n, key.dptr, key.dsize)) == 0)
+ return sdbm_nullitem;
+
+ val.dptr = pag + ino[i + 1];
+ val.dsize = ino[i] - ino[i + 1];
+ return val;
+}
+
+int
+duppair(pag, key)
+char *pag;
+apr_sdbm_datum_t key;
+{
+ register short *ino = (short *) pag;
+ return ino[0] > 0 && seepair(pag, ino[0], key.dptr, key.dsize) > 0;
+}
+
+apr_sdbm_datum_t
+getnkey(pag, num)
+char *pag;
+int num;
+{
+ apr_sdbm_datum_t key;
+ register int off;
+ register short *ino = (short *) pag;
+
+ num = num * 2 - 1;
+ if (ino[0] == 0 || num > ino[0])
+ return sdbm_nullitem;
+
+ off = (num > 1) ? ino[num - 1] : PBLKSIZ;
+
+ key.dptr = pag + ino[num];
+ key.dsize = off - ino[num];
+
+ return key;
+}
+
+int
+delpair(pag, key)
+char *pag;
+apr_sdbm_datum_t key;
+{
+ register int n;
+ register int i;
+ register short *ino = (short *) pag;
+
+ if ((n = ino[0]) == 0)
+ return 0;
+
+ if ((i = seepair(pag, n, key.dptr, key.dsize)) == 0)
+ return 0;
+/*
+ * found the key. if it is the last entry
+ * [i.e. i == n - 1] we just adjust the entry count.
+ * hard case: move all data down onto the deleted pair,
+ * shift offsets onto deleted offsets, and adjust them.
+ * [note: 0 < i < n]
+ */
+ if (i < n - 1) {
+ register int m;
+ register char *dst = pag + (i == 1 ? PBLKSIZ : ino[i - 1]);
+ register char *src = pag + ino[i + 1];
+ register short zoo = (short) (dst - src);
+
+ debug(("free-up %d ", zoo));
+/*
+ * shift data/keys down
+ */
+ m = ino[i + 1] - ino[n];
+
+#undef DUFF /* just use memmove. it should be plenty fast. */
+#ifdef DUFF
+#define MOVB *--dst = *--src
+
+ if (m > 0) {
+ register int loop = (m + 8 - 1) >> 3;
+
+ switch (m & (8 - 1)) {
+ case 0: do {
+ MOVB; case 7: MOVB;
+ case 6: MOVB; case 5: MOVB;
+ case 4: MOVB; case 3: MOVB;
+ case 2: MOVB; case 1: MOVB;
+ } while (--loop);
+ }
+ }
+#else
+ dst -= m;
+ src -= m;
+ memmove(dst, src, m);
+#endif
+
+/*
+ * adjust offset index up
+ */
+ while (i < n - 1) {
+ ino[i] = ino[i + 2] + zoo;
+ i++;
+ }
+ }
+ ino[0] -= 2;
+ return 1;
+}
+
+/*
+ * search for the key in the page.
+ * return offset index in the range 0 < i < n.
+ * return 0 if not found.
+ */
+static int
+seepair(pag, n, key, siz)
+char *pag;
+register int n;
+register char *key;
+register int siz;
+{
+ register int i;
+ register int off = PBLKSIZ;
+ register short *ino = (short *) pag;
+
+ for (i = 1; i < n; i += 2) {
+ if (siz == off - ino[i] &&
+ memcmp(key, pag + ino[i], siz) == 0)
+ return i;
+ off = ino[i + 1];
+ }
+ return 0;
+}
+
+void
+splpage(pag, new, sbit)
+char *pag;
+char *new;
+long sbit;
+{
+ apr_sdbm_datum_t key;
+ apr_sdbm_datum_t val;
+
+ register int n;
+ register int off = PBLKSIZ;
+ char cur[PBLKSIZ];
+ register short *ino = (short *) cur;
+
+ (void) memcpy(cur, pag, PBLKSIZ);
+ (void) memset(pag, 0, PBLKSIZ);
+ (void) memset(new, 0, PBLKSIZ);
+
+ n = ino[0];
+ for (ino++; n > 0; ino += 2) {
+ key.dptr = cur + ino[0];
+ key.dsize = off - ino[0];
+ val.dptr = cur + ino[1];
+ val.dsize = ino[0] - ino[1];
+/*
+ * select the page pointer (by looking at sbit) and insert
+ */
+ (void) putpair((exhash(key) & sbit) ? new : pag, key, val);
+
+ off = ino[1];
+ n -= 2;
+ }
+
+ debug(("%d split %d/%d\n", ((short *) cur)[0] / 2,
+ ((short *) new)[0] / 2,
+ ((short *) pag)[0] / 2));
+}
+
+/*
+ * check page sanity:
+ * number of entries should be something
+ * reasonable, and all offsets in the index should be in order.
+ * this could be made more rigorous.
+ */
+int
+chkpage(pag)
+char *pag;
+{
+ register int n;
+ register int off;
+ register short *ino = (short *) pag;
+
+ if ((n = ino[0]) < 0 || n > PBLKSIZ / sizeof(short))
+ return 0;
+
+ if (n > 0) {
+ off = PBLKSIZ;
+ for (ino++; n > 0; ino += 2) {
+ if (ino[0] < 0 || ino[0] > off ||
+ ino[1] < 0 || ino[1] > off ||
+ ino[1] > ino[0])
+ return 0;
+ off = ino[1];
+ n -= 2;
+ }
+ }
+ return 1;
+}