hash_bigkey-fbsd.c [plain text]
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)hash_bigkey.c 8.3 (Berkeley) 5/31/94";
#endif
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/lib/libc/db/hash/hash_bigkey.c,v 1.10 2009/03/28 06:47:05 delphij Exp $");
#include <sys/param.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef DEBUG
#include <assert.h>
#endif
#include <db.h>
#include "hash.h"
#include "page.h"
#include "hash_extern.h"
static int collect_key(HTAB *, BUFHEAD *, int, DBT *, int);
static int collect_data(HTAB *, BUFHEAD *, int, int);
int
__big_insert(HTAB *hashp, BUFHEAD *bufp, const DBT *key, const DBT *val)
{
u_int16_t *p;
int key_size, n;
unsigned int val_size;
u_int16_t space, move_bytes, off;
char *cp, *key_data, *val_data;
cp = bufp->page;
p = (u_int16_t *)cp;
key_data = (char *)key->data;
key_size = key->size;
val_data = (char *)val->data;
val_size = val->size;
for (space = FREESPACE(p) - BIGOVERHEAD; key_size;
space = FREESPACE(p) - BIGOVERHEAD) {
move_bytes = MIN(space, key_size);
off = OFFSET(p) - move_bytes;
memmove(cp + off, key_data, move_bytes);
key_size -= move_bytes;
key_data += move_bytes;
n = p[0];
p[++n] = off;
p[0] = ++n;
FREESPACE(p) = off - PAGE_META(n);
OFFSET(p) = off;
p[n] = PARTIAL_KEY;
bufp = __add_ovflpage(hashp, bufp);
if (!bufp)
return (-1);
n = p[0];
if (!key_size) {
space = FREESPACE(p);
if (space) {
move_bytes = MIN(space, val_size);
if (space == val_size && val_size == val->size)
goto toolarge;
off = OFFSET(p) - move_bytes;
memmove(cp + off, val_data, move_bytes);
val_data += move_bytes;
val_size -= move_bytes;
p[n] = off;
p[n - 2] = FULL_KEY_DATA;
FREESPACE(p) = FREESPACE(p) - move_bytes;
OFFSET(p) = off;
} else {
toolarge:
p[n - 2] = FULL_KEY;
}
}
p = (u_int16_t *)bufp->page;
cp = bufp->page;
bufp->flags |= BUF_MOD;
}
for (space = FREESPACE(p) - BIGOVERHEAD; val_size;
space = FREESPACE(p) - BIGOVERHEAD) {
move_bytes = MIN(space, val_size);
if (space == val_size && val_size == val->size)
move_bytes--;
off = OFFSET(p) - move_bytes;
memmove(cp + off, val_data, move_bytes);
val_size -= move_bytes;
val_data += move_bytes;
n = p[0];
p[++n] = off;
p[0] = ++n;
FREESPACE(p) = off - PAGE_META(n);
OFFSET(p) = off;
if (val_size) {
p[n] = FULL_KEY;
bufp = __add_ovflpage(hashp, bufp);
if (!bufp)
return (-1);
cp = bufp->page;
p = (u_int16_t *)cp;
} else
p[n] = FULL_KEY_DATA;
bufp->flags |= BUF_MOD;
}
return (0);
}
int
__big_delete(HTAB *hashp, BUFHEAD *bufp)
{
BUFHEAD *last_bfp, *rbufp;
u_int16_t *bp, pageno;
int key_done, n;
rbufp = bufp;
last_bfp = NULL;
bp = (u_int16_t *)bufp->page;
pageno = 0;
key_done = 0;
while (!key_done || (bp[2] != FULL_KEY_DATA)) {
if (bp[2] == FULL_KEY || bp[2] == FULL_KEY_DATA)
key_done = 1;
if (bp[2] == FULL_KEY_DATA && FREESPACE(bp))
break;
pageno = bp[bp[0] - 1];
rbufp->flags |= BUF_MOD;
rbufp = __get_buf(hashp, pageno, rbufp, 0);
if (last_bfp)
__free_ovflpage(hashp, last_bfp);
last_bfp = rbufp;
if (!rbufp)
return (-1);
bp = (u_int16_t *)rbufp->page;
}
n = bp[0];
pageno = bp[n - 1];
bp = (u_int16_t *)bufp->page;
if (n > 2) {
bp[1] = pageno;
bp[2] = OVFLPAGE;
bufp->ovfl = rbufp->ovfl;
} else
bufp->ovfl = NULL;
n -= 2;
bp[0] = n;
FREESPACE(bp) = hashp->BSIZE - PAGE_META(n);
OFFSET(bp) = hashp->BSIZE;
bufp->flags |= BUF_MOD;
if (rbufp)
__free_ovflpage(hashp, rbufp);
if (last_bfp && last_bfp != rbufp)
__free_ovflpage(hashp, last_bfp);
hashp->NKEYS--;
return (0);
}
int
__find_bigpair(HTAB *hashp, BUFHEAD *bufp, int ndx, char *key, int size)
{
u_int16_t *bp;
char *p;
int ksize;
u_int16_t bytes;
char *kkey;
bp = (u_int16_t *)bufp->page;
p = bufp->page;
ksize = size;
kkey = key;
for (bytes = hashp->BSIZE - bp[ndx];
bytes <= size && bp[ndx + 1] == PARTIAL_KEY;
bytes = hashp->BSIZE - bp[ndx]) {
if (memcmp(p + bp[ndx], kkey, bytes))
return (-2);
kkey += bytes;
ksize -= bytes;
bufp = __get_buf(hashp, bp[ndx + 2], bufp, 0);
if (!bufp)
return (-3);
p = bufp->page;
bp = (u_int16_t *)p;
ndx = 1;
}
if (bytes != ksize || memcmp(p + bp[ndx], kkey, bytes)) {
#ifdef HASH_STATISTICS
++hash_collisions;
#endif
return (-2);
} else
return (ndx);
}
u_int16_t
__find_last_page(HTAB *hashp, BUFHEAD **bpp)
{
BUFHEAD *bufp;
u_int16_t *bp, pageno;
int n;
bufp = *bpp;
bp = (u_int16_t *)bufp->page;
for (;;) {
n = bp[0];
if (bp[2] == FULL_KEY_DATA &&
((n == 2) || (bp[n] == OVFLPAGE) || (FREESPACE(bp))))
break;
pageno = bp[n - 1];
bufp = __get_buf(hashp, pageno, bufp, 0);
if (!bufp)
return (0);
bp = (u_int16_t *)bufp->page;
}
*bpp = bufp;
if (bp[0] > 2)
return (bp[3]);
else
return (0);
}
int
__big_return(HTAB *hashp, BUFHEAD *bufp, int ndx, DBT *val, int set_current)
{
BUFHEAD *save_p;
u_int16_t *bp, len, off, save_addr;
char *tp;
bp = (u_int16_t *)bufp->page;
while (bp[ndx + 1] == PARTIAL_KEY) {
bufp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
if (!bufp)
return (-1);
bp = (u_int16_t *)bufp->page;
ndx = 1;
}
if (bp[ndx + 1] == FULL_KEY) {
bufp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
if (!bufp)
return (-1);
bp = (u_int16_t *)bufp->page;
save_p = bufp;
save_addr = save_p->addr;
off = bp[1];
len = 0;
} else
if (!FREESPACE(bp)) {
off = bp[bp[0]];
len = bp[1] - off;
save_p = bufp;
save_addr = bufp->addr;
bufp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
if (!bufp)
return (-1);
bp = (u_int16_t *)bufp->page;
} else {
tp = (char *)bp;
off = bp[bp[0]];
val->data = (u_char *)tp + off;
val->size = bp[1] - off;
if (set_current) {
if (bp[0] == 2) {
hashp->cpage = NULL;
hashp->cbucket++;
hashp->cndx = 1;
} else {
hashp->cpage = __get_buf(hashp,
bp[bp[0] - 1], bufp, 0);
if (!hashp->cpage)
return (-1);
hashp->cndx = 1;
if (!((u_int16_t *)
hashp->cpage->page)[0]) {
hashp->cbucket++;
hashp->cpage = NULL;
}
}
}
return (0);
}
val->size = (size_t)collect_data(hashp, bufp, (int)len, set_current);
if (val->size == (size_t)-1)
return (-1);
if (save_p->addr != save_addr) {
errno = EINVAL;
return (-1);
}
memmove(hashp->tmp_buf, (save_p->page) + off, len);
val->data = (u_char *)hashp->tmp_buf;
return (0);
}
static int
collect_data(HTAB *hashp, BUFHEAD *bufp, int len, int set)
{
u_int16_t *bp;
char *p;
BUFHEAD *xbp;
u_int16_t save_addr;
int mylen, totlen;
p = bufp->page;
bp = (u_int16_t *)p;
mylen = hashp->BSIZE - bp[1];
save_addr = bufp->addr;
if (bp[2] == FULL_KEY_DATA) {
totlen = len + mylen;
if (hashp->tmp_buf)
free(hashp->tmp_buf);
if ((hashp->tmp_buf = (char *)malloc(totlen)) == NULL)
return (-1);
if (set) {
hashp->cndx = 1;
if (bp[0] == 2) {
hashp->cpage = NULL;
hashp->cbucket++;
} else {
hashp->cpage =
__get_buf(hashp, bp[bp[0] - 1], bufp, 0);
if (!hashp->cpage)
return (-1);
else if (!((u_int16_t *)hashp->cpage->page)[0]) {
hashp->cbucket++;
hashp->cpage = NULL;
}
}
}
} else {
xbp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
if (!xbp || ((totlen =
collect_data(hashp, xbp, len + mylen, set)) < 1))
return (-1);
}
if (bufp->addr != save_addr) {
errno = EINVAL;
return (-1);
}
memmove(&hashp->tmp_buf[len], (bufp->page) + bp[1], mylen);
return (totlen);
}
int
__big_keydata(HTAB *hashp, BUFHEAD *bufp, DBT *key, DBT *val, int set)
{
key->size = (size_t)collect_key(hashp, bufp, 0, val, set);
if (key->size == (size_t)-1)
return (-1);
key->data = (u_char *)hashp->tmp_key;
return (0);
}
static int
collect_key(HTAB *hashp, BUFHEAD *bufp, int len, DBT *val, int set)
{
BUFHEAD *xbp;
char *p;
int mylen, totlen;
u_int16_t *bp, save_addr;
p = bufp->page;
bp = (u_int16_t *)p;
mylen = hashp->BSIZE - bp[1];
save_addr = bufp->addr;
totlen = len + mylen;
if (bp[2] == FULL_KEY || bp[2] == FULL_KEY_DATA) {
if (hashp->tmp_key != NULL)
free(hashp->tmp_key);
if ((hashp->tmp_key = (char *)malloc(totlen)) == NULL)
return (-1);
if (__big_return(hashp, bufp, 1, val, set))
return (-1);
} else {
xbp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
if (!xbp || ((totlen =
collect_key(hashp, xbp, totlen, val, set)) < 1))
return (-1);
}
if (bufp->addr != save_addr) {
errno = EINVAL;
return (-1);
}
memmove(&hashp->tmp_key[len], (bufp->page) + bp[1], mylen);
return (totlen);
}
int
__big_split(HTAB *hashp,
BUFHEAD *op,
BUFHEAD *np,
BUFHEAD *big_keyp,
int addr,
u_int32_t obucket,
SPLIT_RETURN *ret)
{
BUFHEAD *bp, *tmpp;
DBT key, val;
u_int32_t change;
u_int16_t free_space, n, off, *tp;
bp = big_keyp;
if (__big_keydata(hashp, big_keyp, &key, &val, 0))
return (-1);
change = (__call_hash(hashp, key.data, key.size) != obucket);
if ( (ret->next_addr = __find_last_page(hashp, &big_keyp)) ) {
if (!(ret->nextp =
__get_buf(hashp, ret->next_addr, big_keyp, 0)))
return (-1);
} else
ret->nextp = NULL;
#ifdef DEBUG
assert(np->ovfl == NULL);
#endif
if (change)
tmpp = np;
else
tmpp = op;
tmpp->flags |= BUF_MOD;
#ifdef DEBUG1
(void)fprintf(stderr,
"BIG_SPLIT: %d->ovfl was %d is now %d\n", tmpp->addr,
(tmpp->ovfl ? tmpp->ovfl->addr : 0), (bp ? bp->addr : 0));
#endif
tmpp->ovfl = bp;
tp = (u_int16_t *)tmpp->page;
#ifdef DEBUG
assert(FREESPACE(tp) >= OVFLSIZE);
#endif
n = tp[0];
off = OFFSET(tp);
free_space = FREESPACE(tp);
tp[++n] = (u_int16_t)addr;
tp[++n] = OVFLPAGE;
tp[0] = n;
OFFSET(tp) = off;
FREESPACE(tp) = free_space - OVFLSIZE;
ret->newp = np;
ret->oldp = op;
tp = (u_int16_t *)big_keyp->page;
big_keyp->flags |= BUF_MOD;
if (tp[0] > 2) {
n = tp[4];
free_space = FREESPACE(tp);
off = OFFSET(tp);
tp[0] -= 2;
FREESPACE(tp) = free_space + OVFLSIZE;
OFFSET(tp) = off;
tmpp = __add_ovflpage(hashp, big_keyp);
if (!tmpp)
return (-1);
tp[4] = n;
} else
tmpp = big_keyp;
if (change)
ret->newp = tmpp;
else
ret->oldp = tmpp;
return (0);
}