diff options
Diffstat (limited to 'db/hash/hash_page.c')
| -rw-r--r-- | db/hash/hash_page.c | 944 |
1 files changed, 0 insertions, 944 deletions
diff --git a/db/hash/hash_page.c b/db/hash/hash_page.c deleted file mode 100644 index e1dfe6b8d6..0000000000 --- a/db/hash/hash_page.c +++ /dev/null @@ -1,944 +0,0 @@ -/*- - * 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 <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; - 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) { - (void)write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1); - 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) { - (void)write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1); - 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) { - (void)write(STDERR_FILENO, OVMSG, - sizeof(OVMSG) - 1); - 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 |