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-rw-r--r--utils/db1-ast/hash/hash_page.c946
1 files changed, 946 insertions, 0 deletions
diff --git a/utils/db1-ast/hash/hash_page.c b/utils/db1-ast/hash/hash_page.c
new file mode 100644
index 0000000..52571c5
--- /dev/null
+++ b/utils/db1-ast/hash/hash_page.c
@@ -0,0 +1,946 @@
+/*-
+ * 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
+ * Margo Seltzer.
+ *
+ * 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[] = "@(#)hash_page.c 8.7 (Berkeley) 8/16/94";
+#endif /* LIBC_SCCS and not lint */
+
+/*
+ * PACKAGE: hashing
+ *
+ * DESCRIPTION:
+ * Page manipulation for hashing package.
+ *
+ * ROUTINES:
+ *
+ * External
+ * __get_page
+ * __add_ovflpage
+ * Internal
+ * overflow_page
+ * open_temp
+ */
+
+#include <sys/types.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#ifdef DEBUG
+#include <assert.h>
+#endif
+
+#include "../include/db.h"
+#include "hash.h"
+#include "page.h"
+#include "extern.h"
+
+static u_int32_t *fetch_bitmap __P((HTAB *, int));
+static u_int32_t first_free __P((u_int32_t));
+static int open_temp __P((HTAB *));
+static u_int16_t overflow_page __P((HTAB *));
+static void putpair __P((char *, const DBT *, const DBT *));
+static void squeeze_key __P((u_int16_t *, const DBT *, const DBT *));
+static int ugly_split
+ __P((HTAB *, u_int32_t, BUFHEAD *, BUFHEAD *, int, int));
+
+#define PAGE_INIT(P) { \
+ ((u_int16_t *)(P))[0] = 0; \
+ ((u_int16_t *)(P))[1] = hashp->BSIZE - 3 * sizeof(u_int16_t); \
+ ((u_int16_t *)(P))[2] = hashp->BSIZE; \
+}
+
+/*
+ * This is called AFTER we have verified that there is room on the page for
+ * the pair (PAIRFITS has returned true) so we go right ahead and start moving
+ * stuff on.
+ */
+static void
+putpair(p, key, val)
+ char *p;
+ const DBT *key, *val;
+{
+ register u_int16_t *bp, n, off;
+
+ bp = (u_int16_t *)p;
+
+ /* Enter the key first. */
+ n = bp[0];
+
+ off = OFFSET(bp) - key->size;
+ memmove(p + off, key->data, key->size);
+ bp[++n] = off;
+
+ /* Now the data. */
+ off -= val->size;
+ memmove(p + off, val->data, val->size);
+ bp[++n] = off;
+
+ /* Adjust page info. */
+ bp[0] = n;
+ bp[n + 1] = off - ((n + 3) * sizeof(u_int16_t));
+ bp[n + 2] = off;
+}
+
+/*
+ * Returns:
+ * 0 OK
+ * -1 error
+ */
+extern int
+__delpair(hashp, bufp, ndx)
+ HTAB *hashp;
+ BUFHEAD *bufp;
+ register int ndx;
+{
+ register u_int16_t *bp, newoff;
+ register int n;
+ u_int16_t pairlen;
+
+ bp = (u_int16_t *)bufp->page;
+ n = bp[0];
+
+ if (bp[ndx + 1] < REAL_KEY)
+ return (__big_delete(hashp, bufp));
+ if (ndx != 1)
+ newoff = bp[ndx - 1];
+ else
+ newoff = hashp->BSIZE;
+ pairlen = newoff - bp[ndx + 1];
+
+ if (ndx != (n - 1)) {
+ /* Hard Case -- need to shuffle keys */
+ register int i;
+ register char *src = bufp->page + (int)OFFSET(bp);
+ register char *dst = src + (int)pairlen;
+ memmove(dst, src, bp[ndx + 1] - OFFSET(bp));
+
+ /* Now adjust the pointers */
+ for (i = ndx + 2; i <= n; i += 2) {
+ if (bp[i + 1] == OVFLPAGE) {
+ bp[i - 2] = bp[i];
+ bp[i - 1] = bp[i + 1];
+ } else {
+ bp[i - 2] = bp[i] + pairlen;
+ bp[i - 1] = bp[i + 1] + pairlen;
+ }
+ }
+ }
+ /* Finally adjust the page data */
+ bp[n] = OFFSET(bp) + pairlen;
+ bp[n - 1] = bp[n + 1] + pairlen + 2 * sizeof(u_int16_t);
+ bp[0] = n - 2;
+ hashp->NKEYS--;
+
+ bufp->flags |= BUF_MOD;
+ return (0);
+}
+/*
+ * Returns:
+ * 0 ==> OK
+ * -1 ==> Error
+ */
+extern int
+__split_page(hashp, obucket, nbucket)
+ HTAB *hashp;
+ u_int32_t obucket, nbucket;
+{
+ register BUFHEAD *new_bufp, *old_bufp;
+ register u_int16_t *ino;
+ register char *np;
+ DBT key, val;
+ int n, ndx, retval;
+ u_int16_t copyto, diff, off, moved;
+ char *op;
+
+ copyto = (u_int16_t)hashp->BSIZE;
+ off = (u_int16_t)hashp->BSIZE;
+ old_bufp = __get_buf(hashp, obucket, NULL, 0);
+ if (old_bufp == NULL)
+ return (-1);
+ new_bufp = __get_buf(hashp, nbucket, NULL, 0);
+ if (new_bufp == NULL)
+ return (-1);
+
+ old_bufp->flags |= (BUF_MOD | BUF_PIN);
+ new_bufp->flags |= (BUF_MOD | BUF_PIN);
+
+ ino = (u_int16_t *)(op = old_bufp->page);
+ np = new_bufp->page;
+
+ moved = 0;
+
+ for (n = 1, ndx = 1; n < ino[0]; n += 2) {
+ if (ino[n + 1] < REAL_KEY) {
+ retval = ugly_split(hashp, obucket, old_bufp, new_bufp,
+ (int)copyto, (int)moved);
+ old_bufp->flags &= ~BUF_PIN;
+ new_bufp->flags &= ~BUF_PIN;
+ return (retval);
+
+ }
+ key.data = (u_char *)op + ino[n];
+ key.size = off - ino[n];
+
+ if (__call_hash(hashp, key.data, key.size) == obucket) {
+ /* Don't switch page */
+ diff = copyto - off;
+ if (diff) {
+ copyto = ino[n + 1] + diff;
+ memmove(op + copyto, op + ino[n + 1],
+ off - ino[n + 1]);
+ ino[ndx] = copyto + ino[n] - ino[n + 1];
+ ino[ndx + 1] = copyto;
+ } else
+ copyto = ino[n + 1];
+ ndx += 2;
+ } else {
+ /* Switch page */
+ val.data = (u_char *)op + ino[n + 1];
+ val.size = ino[n] - ino[n + 1];
+ putpair(np, &key, &val);
+ moved += 2;
+ }
+
+ off = ino[n + 1];
+ }
+
+ /* Now clean up the page */
+ ino[0] -= moved;
+ FREESPACE(ino) = copyto - sizeof(u_int16_t) * (ino[0] + 3);
+ OFFSET(ino) = copyto;
+
+#ifdef DEBUG3
+ (void)fprintf(stderr, "split %d/%d\n",
+ ((u_int16_t *)np)[0] / 2,
+ ((u_int16_t *)op)[0] / 2);
+#endif
+ /* unpin both pages */
+ old_bufp->flags &= ~BUF_PIN;
+ new_bufp->flags &= ~BUF_PIN;
+ return (0);
+}
+
+/*
+ * Called when we encounter an overflow or big key/data page during split
+ * handling. This is special cased since we have to begin checking whether
+ * the key/data pairs fit on their respective pages and because we may need
+ * overflow pages for both the old and new pages.
+ *
+ * The first page might be a page with regular key/data pairs in which case
+ * we have a regular overflow condition and just need to go on to the next
+ * page or it might be a big key/data pair in which case we need to fix the
+ * big key/data pair.
+ *
+ * Returns:
+ * 0 ==> success
+ * -1 ==> failure
+ */
+static int
+ugly_split(hashp, obucket, old_bufp, new_bufp, copyto, moved)
+ HTAB *hashp;
+ u_int32_t obucket; /* Same as __split_page. */
+ BUFHEAD *old_bufp, *new_bufp;
+ int copyto; /* First byte on page which contains key/data values. */
+ int moved; /* Number of pairs moved to new page. */
+{
+ register BUFHEAD *bufp; /* Buffer header for ino */
+ register u_int16_t *ino; /* Page keys come off of */
+ register u_int16_t *np; /* New page */
+ register u_int16_t *op; /* Page keys go on to if they aren't moving */
+
+ BUFHEAD *last_bfp; /* Last buf header OVFL needing to be freed */
+ DBT key, val;
+ SPLIT_RETURN ret;
+ u_int16_t n, off, ov_addr, scopyto;
+ char *cino; /* Character value of ino */
+
+ bufp = old_bufp;
+ ino = (u_int16_t *)old_bufp->page;
+ np = (u_int16_t *)new_bufp->page;
+ op = (u_int16_t *)old_bufp->page;
+ last_bfp = NULL;
+ scopyto = (u_int16_t)copyto; /* ANSI */
+
+ n = ino[0] - 1;
+ while (n < ino[0]) {
+ if (ino[2] < REAL_KEY && ino[2] != OVFLPAGE) {
+ if (__big_split(hashp, old_bufp,
+ new_bufp, bufp, bufp->addr, obucket, &ret))
+ return (-1);
+ old_bufp = ret.oldp;
+ if (!old_bufp)
+ return (-1);
+ op = (u_int16_t *)old_bufp->page;
+ new_bufp = ret.newp;
+ if (!new_bufp)
+ return (-1);
+ np = (u_int16_t *)new_bufp->page;
+ bufp = ret.nextp;
+ if (!bufp)
+ return (0);
+ cino = (char *)bufp->page;
+ ino = (u_int16_t *)cino;
+ last_bfp = ret.nextp;
+ } else if (ino[n + 1] == OVFLPAGE) {
+ ov_addr = ino[n];
+ /*
+ * Fix up the old page -- the extra 2 are the fields
+ * which contained the overflow information.
+ */
+ ino[0] -= (moved + 2);
+ FREESPACE(ino) =
+ scopyto - sizeof(u_int16_t) * (ino[0] + 3);
+ OFFSET(ino) = scopyto;
+
+ bufp = __get_buf(hashp, ov_addr, bufp, 0);
+ if (!bufp)
+ return (-1);
+
+ ino = (u_int16_t *)bufp->page;
+ n = 1;
+ scopyto = hashp->BSIZE;
+ moved = 0;
+
+ if (last_bfp)
+ __free_ovflpage(hashp, last_bfp);
+ last_bfp = bufp;
+ }
+ /* Move regular sized pairs of there are any */
+ off = hashp->BSIZE;
+ for (n = 1; (n < ino[0]) && (ino[n + 1] >= REAL_KEY); n += 2) {
+ cino = (char *)ino;
+ key.data = (u_char *)cino + ino[n];
+ key.size = off - ino[n];
+ val.data = (u_char *)cino + ino[n + 1];
+ val.size = ino[n] - ino[n + 1];
+ off = ino[n + 1];
+
+ if (__call_hash(hashp, key.data, key.size) == obucket) {
+ /* Keep on old page */
+ if (PAIRFITS(op, (&key), (&val)))
+ putpair((char *)op, &key, &val);
+ else {
+ old_bufp =
+ __add_ovflpage(hashp, old_bufp);
+ if (!old_bufp)
+ return (-1);
+ op = (u_int16_t *)old_bufp->page;
+ putpair((char *)op, &key, &val);
+ }
+ old_bufp->flags |= BUF_MOD;
+ } else {
+ /* Move to new page */
+ if (PAIRFITS(np, (&key), (&val)))
+ putpair((char *)np, &key, &val);
+ else {
+ new_bufp =
+ __add_ovflpage(hashp, new_bufp);
+ if (!new_bufp)
+ return (-1);
+ np = (u_int16_t *)new_bufp->page;
+ putpair((char *)np, &key, &val);
+ }
+ new_bufp->flags |= BUF_MOD;
+ }
+ }
+ }
+ if (last_bfp)
+ __free_ovflpage(hashp, last_bfp);
+ return (0);
+}
+
+/*
+ * Add the given pair to the page
+ *
+ * Returns:
+ * 0 ==> OK
+ * 1 ==> failure
+ */
+extern int
+__addel(hashp, bufp, key, val)
+ HTAB *hashp;
+ BUFHEAD *bufp;
+ const DBT *key, *val;
+{
+ register u_int16_t *bp, *sop;
+ int do_expand;
+
+ bp = (u_int16_t *)bufp->page;
+ do_expand = 0;
+ while (bp[0] && (bp[2] < REAL_KEY || bp[bp[0]] < REAL_KEY))
+ /* Exception case */
+ if (bp[2] == FULL_KEY_DATA && bp[0] == 2)
+ /* This is the last page of a big key/data pair
+ and we need to add another page */
+ break;
+ else if (bp[2] < REAL_KEY && bp[bp[0]] != OVFLPAGE) {
+ bufp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
+ if (!bufp)
+ return (-1);
+ bp = (u_int16_t *)bufp->page;
+ } else
+ /* Try to squeeze key on this page */
+ if (FREESPACE(bp) > PAIRSIZE(key, val)) {
+ squeeze_key(bp, key, val);
+ return (0);
+ } else {
+ bufp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
+ if (!bufp)
+ return (-1);
+ bp = (u_int16_t *)bufp->page;
+ }
+
+ if (PAIRFITS(bp, key, val))
+ putpair(bufp->page, key, val);
+ else {
+ do_expand = 1;
+ bufp = __add_ovflpage(hashp, bufp);
+ if (!bufp)
+ return (-1);
+ sop = (u_int16_t *)bufp->page;
+
+ if (PAIRFITS(sop, key, val))
+ putpair((char *)sop, key, val);
+ else
+ if (__big_insert(hashp, bufp, key, val))
+ return (-1);
+ }
+ bufp->flags |= BUF_MOD;
+ /*
+ * If the average number of keys per bucket exceeds the fill factor,
+ * expand the table.
+ */
+ hashp->NKEYS++;
+ if (do_expand ||
+ (hashp->NKEYS / (hashp->MAX_BUCKET + 1) > hashp->FFACTOR))
+ return (__expand_table(hashp));
+ return (0);
+}
+
+/*
+ *
+ * Returns:
+ * pointer on success
+ * NULL on error
+ */
+extern BUFHEAD *
+__add_ovflpage(hashp, bufp)
+ HTAB *hashp;
+ BUFHEAD *bufp;
+{
+ register u_int16_t *sp;
+ u_int16_t ndx, ovfl_num;
+#ifdef DEBUG1
+ int tmp1, tmp2;
+#endif
+ sp = (u_int16_t *)bufp->page;
+
+ /* Check if we are dynamically determining the fill factor */
+ if (hashp->FFACTOR == DEF_FFACTOR) {
+ hashp->FFACTOR = sp[0] >> 1;
+ if (hashp->FFACTOR < MIN_FFACTOR)
+ hashp->FFACTOR = MIN_FFACTOR;
+ }
+ bufp->flags |= BUF_MOD;
+ ovfl_num = overflow_page(hashp);
+#ifdef DEBUG1
+ tmp1 = bufp->addr;
+ tmp2 = bufp->ovfl ? bufp->ovfl->addr : 0;
+#endif
+ if (!ovfl_num || !(bufp->ovfl = __get_buf(hashp, ovfl_num, bufp, 1)))
+ return (NULL);
+ bufp->ovfl->flags |= BUF_MOD;
+#ifdef DEBUG1
+ (void)fprintf(stderr, "ADDOVFLPAGE: %d->ovfl was %d is now %d\n",
+ tmp1, tmp2, bufp->ovfl->addr);
+#endif
+ ndx = sp[0];
+ /*
+ * Since a pair is allocated on a page only if there's room to add
+ * an overflow page, we know that the OVFL information will fit on
+ * the page.
+ */
+ sp[ndx + 4] = OFFSET(sp);
+ sp[ndx + 3] = FREESPACE(sp) - OVFLSIZE;
+ sp[ndx + 1] = ovfl_num;
+ sp[ndx + 2] = OVFLPAGE;
+ sp[0] = ndx + 2;
+#ifdef HASH_STATISTICS
+ hash_overflows++;
+#endif
+ return (bufp->ovfl);
+}
+
+/*
+ * Returns:
+ * 0 indicates SUCCESS
+ * -1 indicates FAILURE
+ */
+extern int
+__get_page(hashp, p, bucket, is_bucket, is_disk, is_bitmap)
+ HTAB *hashp;
+ char *p;
+ u_int32_t bucket;
+ int is_bucket, is_disk, is_bitmap;
+{
+ register int fd, page, size;
+ int rsize;
+ u_int16_t *bp;
+
+ fd = hashp->fp;
+ size = hashp->BSIZE;
+
+ if ((fd == -1) || !is_disk) {
+ PAGE_INIT(p);
+ return (0);
+ }
+ if (is_bucket)
+ page = BUCKET_TO_PAGE(bucket);
+ else
+ page = OADDR_TO_PAGE(bucket);
+ if ((lseek(fd, (off_t)page << hashp->BSHIFT, SEEK_SET) == -1) ||
+ ((rsize = read(fd, p, size)) == -1))
+ return (-1);
+ bp = (u_int16_t *)p;
+ if (!rsize)
+ bp[0] = 0; /* We hit the EOF, so initialize a new page */
+ else
+ if (rsize != size) {
+ errno = EFTYPE;
+ return (-1);
+ }
+ if (!is_bitmap && !bp[0]) {
+ PAGE_INIT(p);
+ } else
+ if (hashp->LORDER != BYTE_ORDER) {
+ register int i, max;
+
+ if (is_bitmap) {
+ max = hashp->BSIZE >> 2; /* divide by 4 */
+ for (i = 0; i < max; i++)
+ M_32_SWAP(((int *)p)[i]);
+ } else {
+ M_16_SWAP(bp[0]);
+ max = bp[0] + 2;
+ for (i = 1; i <= max; i++)
+ M_16_SWAP(bp[i]);
+ }
+ }
+ return (0);
+}
+
+/*
+ * Write page p to disk
+ *
+ * Returns:
+ * 0 ==> OK
+ * -1 ==>failure
+ */
+extern int
+__put_page(hashp, p, bucket, is_bucket, is_bitmap)
+ HTAB *hashp;
+ char *p;
+ u_int32_t bucket;
+ int is_bucket, is_bitmap;
+{
+ register int fd, page, size;
+ int wsize;
+
+ size = hashp->BSIZE;
+ if ((hashp->fp == -1) && open_temp(hashp))
+ return (-1);
+ fd = hashp->fp;
+
+ if (hashp->LORDER != BYTE_ORDER) {
+ register int i;
+ register int max;
+
+ if (is_bitmap) {
+ max = hashp->BSIZE >> 2; /* divide by 4 */
+ for (i = 0; i < max; i++)
+ M_32_SWAP(((int *)p)[i]);
+ } else {
+ max = ((u_int16_t *)p)[0] + 2;
+ for (i = 0; i <= max; i++)
+ M_16_SWAP(((u_int16_t *)p)[i]);
+ }
+ }
+ if (is_bucket)
+ page = BUCKET_TO_PAGE(bucket);
+ else
+ page = OADDR_TO_PAGE(bucket);
+ if ((lseek(fd, (off_t)page << hashp->BSHIFT, SEEK_SET) == -1) ||
+ ((wsize = write(fd, p, size)) == -1))
+ /* Errno is set */
+ return (-1);
+ if (wsize != size) {
+ errno = EFTYPE;
+ return (-1);
+ }
+ return (0);
+}
+
+#define BYTE_MASK ((1 << INT_BYTE_SHIFT) -1)
+/*
+ * Initialize a new bitmap page. Bitmap pages are left in memory
+ * once they are read in.
+ */
+extern int
+__ibitmap(hashp, pnum, nbits, ndx)
+ HTAB *hashp;
+ int pnum, nbits, ndx;
+{
+ u_int32_t *ip;
+ int clearbytes, clearints;
+
+ if ((ip = (u_int32_t *)malloc(hashp->BSIZE)) == NULL)
+ return (1);
+ hashp->nmaps++;
+ clearints = ((nbits - 1) >> INT_BYTE_SHIFT) + 1;
+ clearbytes = clearints << INT_TO_BYTE;
+ (void)memset((char *)ip, 0, clearbytes);
+ (void)memset(((char *)ip) + clearbytes, 0xFF,
+ hashp->BSIZE - clearbytes);
+ ip[clearints - 1] = ALL_SET << (nbits & BYTE_MASK);
+ SETBIT(ip, 0);
+ hashp->BITMAPS[ndx] = (u_int16_t)pnum;
+ hashp->mapp[ndx] = ip;
+ return (0);
+}
+
+static u_int32_t
+first_free(map)
+ u_int32_t map;
+{
+ register u_int32_t i, mask;
+
+ mask = 0x1;
+ for (i = 0; i < BITS_PER_MAP; i++) {
+ if (!(mask & map))
+ return (i);
+ mask = mask << 1;
+ }
+ return (i);
+}
+
+static u_int16_t
+overflow_page(hashp)
+ HTAB *hashp;
+{
+ register u_int32_t *freep = 0;
+ register int max_free, offset, splitnum;
+ u_int16_t addr;
+ int bit, first_page, free_bit, free_page, i, in_use_bits, j;
+#ifdef DEBUG2
+ int tmp1, tmp2;
+#endif
+ splitnum = hashp->OVFL_POINT;
+ max_free = hashp->SPARES[splitnum];
+
+ free_page = (max_free - 1) >> (hashp->BSHIFT + BYTE_SHIFT);
+ free_bit = (max_free - 1) & ((hashp->BSIZE << BYTE_SHIFT) - 1);
+
+ /* Look through all the free maps to find the first free block */
+ first_page = hashp->LAST_FREED >>(hashp->BSHIFT + BYTE_SHIFT);
+ for ( i = first_page; i <= free_page; i++ ) {
+ if (!(freep = (u_int32_t *)hashp->mapp[i]) &&
+ !(freep = fetch_bitmap(hashp, i)))
+ return (0);
+ if (i == free_page)
+ in_use_bits = free_bit;
+ else
+ in_use_bits = (hashp->BSIZE << BYTE_SHIFT) - 1;
+
+ if (i == first_page) {
+ bit = hashp->LAST_FREED &
+ ((hashp->BSIZE << BYTE_SHIFT) - 1);
+ j = bit / BITS_PER_MAP;
+ bit = bit & ~(BITS_PER_MAP - 1);
+ } else {
+ bit = 0;
+ j = 0;
+ }
+ for (; bit <= in_use_bits; j++, bit += BITS_PER_MAP)
+ if (freep[j] != ALL_SET)
+ goto found;
+ }
+
+ /* No Free Page Found */
+ hashp->LAST_FREED = hashp->SPARES[splitnum];
+ hashp->SPARES[splitnum]++;
+ offset = hashp->SPARES[splitnum] -
+ (splitnum ? hashp->SPARES[splitnum - 1] : 0);
+
+#define OVMSG "HASH: Out of overflow pages. Increase page size\n"
+ if (offset > SPLITMASK) {
+ if (++splitnum >= NCACHED) {
+ if (write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1) < 0) {
+ }
+ return (0);
+ }
+ hashp->OVFL_POINT = splitnum;
+ hashp->SPARES[splitnum] = hashp->SPARES[splitnum-1];
+ hashp->SPARES[splitnum-1]--;
+ offset = 1;
+ }
+
+ /* Check if we need to allocate a new bitmap page */
+ if (free_bit == (hashp->BSIZE << BYTE_SHIFT) - 1) {
+ free_page++;
+ if (free_page >= NCACHED) {
+ if (write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1) < 0) {
+ }
+ return (0);
+ }
+ /*
+ * This is tricky. The 1 indicates that you want the new page
+ * allocated with 1 clear bit. Actually, you are going to
+ * allocate 2 pages from this map. The first is going to be
+ * the map page, the second is the overflow page we were
+ * looking for. The init_bitmap routine automatically, sets
+ * the first bit of itself to indicate that the bitmap itself
+ * is in use. We would explicitly set the second bit, but
+ * don't have to if we tell init_bitmap not to leave it clear
+ * in the first place.
+ */
+ if (__ibitmap(hashp,
+ (int)OADDR_OF(splitnum, offset), 1, free_page))
+ return (0);
+ hashp->SPARES[splitnum]++;
+#ifdef DEBUG2
+ free_bit = 2;
+#endif
+ offset++;
+ if (offset > SPLITMASK) {
+ if (++splitnum >= NCACHED) {
+ if (write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1) < 0) {
+ }
+ return (0);
+ }
+ hashp->OVFL_POINT = splitnum;
+ hashp->SPARES[splitnum] = hashp->SPARES[splitnum-1];
+ hashp->SPARES[splitnum-1]--;
+ offset = 0;
+ }
+ } else {
+ /*
+ * Free_bit addresses the last used bit. Bump it to address
+ * the first available bit.
+ */
+ free_bit++;
+ SETBIT(freep, free_bit);
+ }
+
+ /* Calculate address of the new overflow page */
+ addr = OADDR_OF(splitnum, offset);
+#ifdef DEBUG2
+ (void)fprintf(stderr, "OVERFLOW_PAGE: ADDR: %d BIT: %d PAGE %d\n",
+ addr, free_bit, free_page);
+#endif
+ return (addr);
+
+found:
+ bit = bit + first_free(freep[j]);
+ SETBIT(freep, bit);
+#ifdef DEBUG2
+ tmp1 = bit;
+ tmp2 = i;
+#endif
+ /*
+ * Bits are addressed starting with 0, but overflow pages are addressed
+ * beginning at 1. Bit is a bit addressnumber, so we need to increment
+ * it to convert it to a page number.
+ */
+ bit = 1 + bit + (i * (hashp->BSIZE << BYTE_SHIFT));
+ if (bit >= hashp->LAST_FREED)
+ hashp->LAST_FREED = bit - 1;
+
+ /* Calculate the split number for this page */
+ for (i = 0; (i < splitnum) && (bit > hashp->SPARES[i]); i++);
+ offset = (i ? bit - hashp->SPARES[i - 1] : bit);
+ if (offset >= SPLITMASK)
+ return (0); /* Out of overflow pages */
+ addr = OADDR_OF(i, offset);
+#ifdef DEBUG2
+ (void)fprintf(stderr, "OVERFLOW_PAGE: ADDR: %d BIT: %d PAGE %d\n",
+ addr, tmp1, tmp2);
+#endif
+
+ /* Allocate and return the overflow page */
+ return (addr);
+}
+
+/*
+ * Mark this overflow page as free.
+ */
+extern void
+__free_ovflpage(hashp, obufp)
+ HTAB *hashp;
+ BUFHEAD *obufp;
+{
+ register u_int16_t addr;
+ u_int32_t *freep;
+ int bit_address, free_page, free_bit;
+ u_int16_t ndx;
+
+ addr = obufp->addr;
+#ifdef DEBUG1
+ (void)fprintf(stderr, "Freeing %d\n", addr);
+#endif
+ ndx = (((u_int16_t)addr) >> SPLITSHIFT);
+ bit_address =
+ (ndx ? hashp->SPARES[ndx - 1] : 0) + (addr & SPLITMASK) - 1;
+ if (bit_address < hashp->LAST_FREED)
+ hashp->LAST_FREED = bit_address;
+ free_page = (bit_address >> (hashp->BSHIFT + BYTE_SHIFT));
+ free_bit = bit_address & ((hashp->BSIZE << BYTE_SHIFT) - 1);
+
+ if (!(freep = hashp->mapp[free_page]))
+ freep = fetch_bitmap(hashp, free_page);
+#ifdef DEBUG
+ /*
+ * This had better never happen. It means we tried to read a bitmap
+ * that has already had overflow pages allocated off it, and we
+ * failed to read it from the file.
+ */
+ if (!freep)
+ assert(0);
+#endif
+ CLRBIT(freep, free_bit);
+#ifdef DEBUG2
+ (void)fprintf(stderr, "FREE_OVFLPAGE: ADDR: %d BIT: %d PAGE %d\n",
+ obufp->addr, free_bit, free_page);
+#endif
+ __reclaim_buf(hashp, obufp);
+}
+
+/*
+ * Returns:
+ * 0 success
+ * -1 failure
+ */
+static int
+open_temp(hashp)
+ HTAB *hashp;
+{
+ sigset_t set, oset;
+ static char namestr[] = "_hashXXXXXX";
+
+ /* Block signals; make sure file goes away at process exit. */
+ (void)sigfillset(&set);
+ (void)sigprocmask(SIG_BLOCK, &set, &oset);
+ if ((hashp->fp = mkstemp(namestr)) != -1) {
+ (void)unlink(namestr);
+ (void)fcntl(hashp->fp, F_SETFD, 1);
+ }
+ (void)sigprocmask(SIG_SETMASK, &oset, (sigset_t *)NULL);
+ return (hashp->fp != -1 ? 0 : -1);
+}
+
+/*
+ * We have to know that the key will fit, but the last entry on the page is
+ * an overflow pair, so we need to shift things.
+ */
+static void
+squeeze_key(sp, key, val)
+ u_int16_t *sp;
+ const DBT *key, *val;
+{
+ register char *p;
+ u_int16_t free_space, n, off, pageno;
+
+ p = (char *)sp;
+ n = sp[0];
+ free_space = FREESPACE(sp);
+ off = OFFSET(sp);
+
+ pageno = sp[n - 1];
+ off -= key->size;
+ sp[n - 1] = off;
+ memmove(p + off, key->data, key->size);
+ off -= val->size;
+ sp[n] = off;
+ memmove(p + off, val->data, val->size);
+ sp[0] = n + 2;
+ sp[n + 1] = pageno;
+ sp[n + 2] = OVFLPAGE;
+ FREESPACE(sp) = free_space - PAIRSIZE(key, val);
+ OFFSET(sp) = off;
+}
+
+static u_int32_t *
+fetch_bitmap(hashp, ndx)
+ HTAB *hashp;
+ int ndx;
+{
+ if (ndx >= hashp->nmaps)
+ return (NULL);
+ if ((hashp->mapp[ndx] = (u_int32_t *)malloc(hashp->BSIZE)) == NULL)
+ return (NULL);
+ if (__get_page(hashp,
+ (char *)hashp->mapp[ndx], hashp->BITMAPS[ndx], 0, 1, 1)) {
+ free(hashp->mapp[ndx]);
+ return (NULL);
+ }
+ return (hashp->mapp[ndx]);
+}
+
+#ifdef DEBUG4
+int
+print_chain(addr)
+ int addr;
+{
+ BUFHEAD *bufp;
+ short *bp, oaddr;
+
+ (void)fprintf(stderr, "%d ", addr);
+ bufp = __get_buf(hashp, addr, NULL, 0);
+ bp = (short *)bufp->page;
+ while (bp[0] && ((bp[bp[0]] == OVFLPAGE) ||
+ ((bp[0] > 2) && bp[2] < REAL_KEY))) {
+ oaddr = bp[bp[0] - 1];
+ (void)fprintf(stderr, "%d ", (int)oaddr);
+ bufp = __get_buf(hashp, (int)oaddr, bufp, 0);
+ bp = (short *)bufp->page;
+ }
+ (void)fprintf(stderr, "\n");
+}
+#endif