ndbm.c revision 7257d1b4d25bfac0c802847390e98a464fd787ac
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2008 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/* All Rights Reserved */
/*
* University Copyright- Copyright (c) 1982, 1986, 1988
* The Regents of the University of California
* All Rights Reserved
*
* University Acknowledgment- Portions of this document are derived from
* software developed by the University of California, Berkeley, and its
* contributors.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include "lint.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/file.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <ndbm.h>
#include <unistd.h>
#include <string.h>
#include <pthread.h>
/* add support for batched writing for NIS */
#define _DBM_DEFWRITE 0x4
#define _DBM_DIRTY 0x8
#define _DBM_DIRDIRTY 0x10
#define dbm_dirty(db) ((db)->dbm_flags & _DBM_DIRTY)
#define dbm_dirdirty(db) ((db)->dbm_flags & _DBM_DIRDIRTY)
#define dbm_defwrite(db) ((db)->dbm_flags & _DBM_DEFWRITE)
#define dbm_setdirty(db) (db)->dbm_flags |= _DBM_DIRTY
#define dbm_clrdirty(db) (db)->dbm_flags &= ~_DBM_DIRTY
#define dbm_setdirdirty(db) (db)->dbm_flags |= _DBM_DIRDIRTY
#define dbm_clrdirdirty(db) (db)->dbm_flags &= ~_DBM_DIRDIRTY
/*
* forward declarations
*/
static datum makdatum(char *, int);
static unsigned long dcalchash(datum);
static void dbm_access(DBM *, unsigned long);
static int finddatum(char *, datum);
static int delitem(char *, int);
static int additem(char *, datum, datum);
static int cmpdatum(datum, datum);
static int setbit(DBM *);
static int getbit(DBM *);
static int dbm_flushdir(DBM *);
static int dbm_flushpag(DBM *db);
/* the following three are required by mapfile-vers */
datum dbm_do_nextkey(DBM *, datum);
int dbm_close_status(DBM *);
/* used to make a dbm file all at once instead of incrementally */
void
dbm_setdefwrite(DBM *db)
{
db->dbm_flags |= _DBM_DEFWRITE;
}
#undef dbm_error
int
dbm_error(DBM *db)
{
return (db->dbm_flags & _DBM_IOERR);
}
#undef dbm_clearerr
int
dbm_clearerr(DBM *db)
{
return (db->dbm_flags &= ~_DBM_IOERR);
}
int
dbm_flush(DBM *db)
{
int ok = 0;
if (dbm_flushpag(db) < 0)
ok = -1;
if (dbm_flushdir(db) < 0)
ok = -1;
return (ok);
}
static int
dbm_flushpag(DBM *db)
{
int ok = 0;
off64_t where;
if (dbm_dirty(db)) { /* must page out the page */
where = (((off64_t)db->dbm_pagbno) * PBLKSIZ);
if ((lseek64(db->dbm_pagf, where, L_SET) != where) ||
(write(db->dbm_pagf, db->dbm_pagbuf, PBLKSIZ) != PBLKSIZ)) {
db->dbm_flags |= _DBM_IOERR;
ok = -1;
}
dbm_clrdirty(db);
}
return (ok);
}
static int
dbm_flushdir(DBM *db)
{
int ok = 0;
off64_t where;
if (dbm_dirdirty(db)) { /* must page out the dir */
where = (((off64_t)db->dbm_dirbno) * DBLKSIZ);
if ((lseek64(db->dbm_dirf, where, L_SET) != where) ||
(write(db->dbm_dirf, db->dbm_dirbuf, DBLKSIZ) != DBLKSIZ)) {
ok = -1;
}
dbm_clrdirdirty(db);
}
return (ok);
}
#define BYTESIZ 8
#undef setbit
DBM *
dbm_open(const char *file, int flags, mode_t mode)
{
struct stat64 statb;
DBM *db;
int serrno;
if ((db = (DBM *)malloc(sizeof (*db))) == 0) {
errno = ENOMEM;
return ((DBM *)0);
}
db->dbm_flags = (flags & 03) == O_RDONLY ? _DBM_RDONLY : 0;
if ((flags & 03) == O_WRONLY)
flags = (flags & ~03) | O_RDWR;
if (strlcpy(db->dbm_pagbuf, file, sizeof (db->dbm_pagbuf)) >=
sizeof (db->dbm_pagbuf) ||
strlcat(db->dbm_pagbuf, ".pag", sizeof (db->dbm_pagbuf)) >=
sizeof (db->dbm_pagbuf)) {
/*
* file.pag does not fit into dbm_pagbuf.
* fail with ENAMETOOLONG.
*/
serrno = ENAMETOOLONG;
goto bad;
}
db->dbm_pagf = open64(db->dbm_pagbuf, flags, mode);
if (db->dbm_pagf < 0) {
serrno = errno;
goto bad;
}
/*
* We know this won't overflow so it is safe to ignore the
* return value; we use strl* to prevent false hits in
* code sweeps.
*/
(void) strlcpy(db->dbm_pagbuf, file, sizeof (db->dbm_pagbuf));
(void) strlcat(db->dbm_pagbuf, ".dir", sizeof (db->dbm_pagbuf));
db->dbm_dirf = open64(db->dbm_pagbuf, flags, mode);
if (db->dbm_dirf < 0) {
serrno = errno;
goto bad1;
}
(void) fstat64(db->dbm_dirf, &statb);
db->dbm_maxbno = statb.st_size * BYTESIZ-1;
db->dbm_pagbno = db->dbm_dirbno = -1;
return (db);
bad1:
(void) close(db->dbm_pagf);
bad:
free((char *)db);
errno = serrno;
return ((DBM *)0);
}
void
dbm_close(DBM *db)
{
(void) dbm_close_status(db);
}
/* close with return code */
int
dbm_close_status(DBM *db)
{
int ok;
ok = 0;
if (dbm_flush(db) < 0)
ok = -1;
if (close(db->dbm_dirf) < 0)
ok = -1;
if (close(db->dbm_pagf) < 0)
ok = -1;
free((char *)db);
return (ok);
}
long
dbm_forder(DBM *db, datum key)
{
unsigned long hash;
hash = dcalchash(key);
for (db->dbm_hmask = 0; ; db->dbm_hmask = (db->dbm_hmask<<1)+1) {
db->dbm_blkno = hash & db->dbm_hmask;
db->dbm_bitno = db->dbm_blkno + db->dbm_hmask;
if (getbit(db) == 0)
break;
}
return (db->dbm_blkno);
}
datum
dbm_fetch(DBM *db, datum key)
{
int i;
datum item;
if (dbm_error(db))
goto err;
dbm_access(db, dcalchash(key));
if ((i = finddatum(db->dbm_pagbuf, key)) >= 0) {
item = makdatum(db->dbm_pagbuf, i+1);
if (item.dptr != NULL)
return (item);
}
err:
item.dptr = NULL;
item.dsize = 0;
return (item);
}
int
dbm_delete(DBM *db, datum key)
{
int i;
off64_t where;
if (dbm_error(db))
return (-1);
if (dbm_rdonly(db)) {
errno = EPERM;
return (-1);
}
dbm_access(db, dcalchash(key));
if ((i = finddatum(db->dbm_pagbuf, key)) < 0)
return (-1);
if (!delitem(db->dbm_pagbuf, i))
goto err;
db->dbm_pagbno = db->dbm_blkno;
if (dbm_defwrite(db)) {
dbm_setdirty(db);
} else {
where = (((off64_t)db->dbm_blkno) * PBLKSIZ);
if ((lseek64(db->dbm_pagf, where, L_SET) != where) ||
(write(db->dbm_pagf, db->dbm_pagbuf, PBLKSIZ) != PBLKSIZ)) {
err:
db->dbm_flags |= _DBM_IOERR;
return (-1);
}
}
return (0);
}
int
dbm_store(DBM *db, datum key, datum dat, int replace)
{
int i;
datum item, item1;
char ovfbuf[PBLKSIZ];
unsigned long hashdiff, key_hash, item_hash;
off64_t where;
if (dbm_error(db))
return (-1);
if (dbm_rdonly(db)) {
errno = EPERM;
return (-1);
}
loop:
key_hash = dcalchash(key);
dbm_access(db, key_hash);
if ((i = finddatum(db->dbm_pagbuf, key)) >= 0) {
if (!replace)
return (1);
if (!delitem(db->dbm_pagbuf, i)) {
db->dbm_flags |= _DBM_IOERR;
return (-1);
}
}
if (!additem(db->dbm_pagbuf, key, dat))
goto split;
db->dbm_pagbno = db->dbm_blkno;
if (dbm_defwrite(db)) {
dbm_setdirty(db);
} else {
where = (((off64_t)db->dbm_blkno) * PBLKSIZ);
if ((lseek64(db->dbm_pagf, where, L_SET) != where) ||
(write(db->dbm_pagf, db->dbm_pagbuf, PBLKSIZ) != PBLKSIZ)) {
db->dbm_flags |= _DBM_IOERR;
return (-1);
}
}
return (0);
split:
hashdiff = 0;
if (key.dsize + dat.dsize + 3 * (int)sizeof (short) >= PBLKSIZ) {
db->dbm_flags |= _DBM_IOERR;
errno = ENOSPC;
return (-1);
}
(void) memset(ovfbuf, 0, PBLKSIZ);
for (i = 0; ; ) {
item = makdatum(db->dbm_pagbuf, i);
if (item.dptr == NULL)
break;
item_hash = dcalchash(item);
if (item_hash != key_hash) {
hashdiff++;
}
if (item_hash & (db->dbm_hmask+1)) {
item1 = makdatum(db->dbm_pagbuf, i+1);
if (item1.dptr == NULL) {
/* (void) fprintf(stderr, "ndbm: */
/* split not paired\n"); */
db->dbm_flags |= _DBM_IOERR;
break;
}
if (!additem(ovfbuf, item, item1) ||
!delitem(db->dbm_pagbuf, i)) {
db->dbm_flags |= _DBM_IOERR;
return (-1);
}
continue;
}
i += 2;
}
db->dbm_pagbno = db->dbm_blkno;
where = (((off64_t)db->dbm_blkno) * PBLKSIZ);
if ((lseek64(db->dbm_pagf, where, L_SET) != where) ||
(write(db->dbm_pagf, db->dbm_pagbuf, PBLKSIZ) != PBLKSIZ)) {
db->dbm_flags |= _DBM_IOERR;
return (-1);
}
dbm_clrdirty(db); /* clear dirty */
where = (((off64_t)db->dbm_blkno + db->dbm_hmask + 1) * PBLKSIZ);
if ((lseek64(db->dbm_pagf, where, L_SET) != where) ||
(write(db->dbm_pagf, ovfbuf, PBLKSIZ) != PBLKSIZ)) {
db->dbm_flags |= _DBM_IOERR;
return (-1);
}
if (setbit(db) < 0) {
db->dbm_flags |= _DBM_IOERR;
return (-1);
}
if (hashdiff == 0) {
db->dbm_flags |= _DBM_IOERR;
return (-1);
}
goto loop;
}
static unsigned long
dbm_hashinc(DBM *db, unsigned long hash)
{
long bit;
hash &= db->dbm_hmask;
bit = db->dbm_hmask+1;
for (;;) {
bit >>= 1;
if (bit == 0)
return (0L);
if ((hash&bit) == 0)
return (hash|bit);
hash &= ~bit;
}
}
static datum nullkey = {NULL, 0};
datum
dbm_firsthash(DBM *db, unsigned long hash)
{
int i, j;
datum item, bitem;
loop:
dbm_access(db, hash);
j = 0;
bitem = makdatum(db->dbm_pagbuf, 0);
for (i = 2; ; i += 2) {
item = makdatum(db->dbm_pagbuf, i);
if (item.dptr == NULL)
break;
if (cmpdatum(bitem, item) < 0) {
j = i;
bitem = item;
}
}
if (bitem.dptr != NULL) {
db->dbm_keyptr = j + 2;
db->dbm_blkptr = db->dbm_blkno;
return (bitem);
}
hash = dbm_hashinc(db, hash);
if (hash == 0)
return (item); /* null item */
goto loop;
}
datum
dbm_firstkey(DBM *db)
{
/*
* For some reason, the Posix specification (SUSv3)
* says that dbm_firstkey() is not a cancellation point.
* It really should be, but in order to pass the SUSv3
* test suite we make it not a cancellation point.
* XXX: fix me when the SUSv3 specification gets fixed.
*/
int cancel_state;
datum rval;
db->dbm_blkptr = 0L;
db->dbm_keyptr = 0;
(void) pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cancel_state);
rval = dbm_firsthash(db, 0L);
(void) pthread_setcancelstate(cancel_state, NULL);
return (rval);
}
datum
dbm_nextkey(DBM *db)
{
return (dbm_do_nextkey(db, nullkey));
}
/*
* this is used if keyptr-2, blocknum doesn't point to the previous
* specific key allowing the fast hash order search --
* its use indicates user tampering with our state variables,
* which some evil users might do to search from some specific place.
* It finds the first key at or after blkptr, keyptr in block seq order
* this requires looking at all sorts of emtpy blocks in many cases
*/
static
datum
dbm_slow_nextkey(DBM *db)
{
struct stat64 statb;
datum item;
off64_t where;
if (dbm_error(db) || fstat64(db->dbm_pagf, &statb) < 0)
goto err;
statb.st_size /= PBLKSIZ;
for (;;) {
if (db->dbm_blkptr != db->dbm_pagbno) {
if (dbm_dirty(db)) (void) dbm_flushpag(db);
db->dbm_pagbno = db->dbm_blkptr;
where = (((off64_t)db->dbm_blkptr) * PBLKSIZ);
if ((lseek64(db->dbm_pagf, where, L_SET) != where) ||
(read(db->dbm_pagf, db->dbm_pagbuf, PBLKSIZ) !=
PBLKSIZ))
(void) memset(db->dbm_pagbuf, 0, PBLKSIZ);
#ifdef DEBUG
else if (chkblk(db->dbm_pagbuf) < 0)
db->dbm_flags |= _DBM_IOERR;
#endif
}
/* Am I an empty block? */
if (((short *)(uintptr_t)db->dbm_pagbuf)[0] != 0) {
item = makdatum(db->dbm_pagbuf, db->dbm_keyptr);
if (item.dptr != NULL) {
db->dbm_keyptr += 2;
return (item);
}
db->dbm_keyptr = 0;
}
/* go to next sequential block */
if (++db->dbm_blkptr >= statb.st_size)
break;
}
err:
item.dptr = NULL;
item.dsize = 0;
return (item);
}
datum
dbm_do_nextkey(DBM *db, datum inkey)
{
datum item, bitem;
unsigned long hash;
datum key;
int f;
int i;
int j;
short *sp;
long n;
char *p1, *p2;
off64_t where;
if (dbm_error(db)) {
item.dptr = NULL;
item.dsize = 0;
return (item);
}
/* user has supplied lastkey */
if (inkey.dptr != NULL) {
dbm_access(db, (hash = dcalchash(inkey)));
if ((i = finddatum(db->dbm_pagbuf, inkey)) >= 0) {
db->dbm_keyptr = i + 2;
db->dbm_blkptr = db->dbm_blkno;
}
key = inkey;
} else {
/* is this a manual firstkey request? */
if (db->dbm_blkptr == 0L &&
db->dbm_keyptr == 0)
return (dbm_firsthash(db, 0L));
/* no -- get lastkey this is like dbm_access by blkptr */
if (db->dbm_blkptr != db->dbm_pagbno) {
if (dbm_dirty(db)) (void) dbm_flushpag(db);
db->dbm_pagbno = db->dbm_blkptr;
where = (((off64_t)db->dbm_blkptr) * PBLKSIZ);
if ((lseek64(db->dbm_pagf, where, L_SET) != where) ||
(read(db->dbm_pagf, db->dbm_pagbuf, PBLKSIZ) !=
PBLKSIZ))
(void) memset(db->dbm_pagbuf, 0, PBLKSIZ);
#ifdef DEBUG
else if (chkblk(db->dbm_pagbuf) < 0)
db->dbm_flags |= _DBM_IOERR;
#endif
}
/* now just make up last key datum */
if (db->dbm_keyptr >= 2)
key = makdatum(db->dbm_pagbuf, (db->dbm_keyptr-2));
else key = nullkey;
/*
* the keyptr pagbuf have failed us, the user must
* be an extra clever moron who depends on
* these variables and their former meaning.
* If we set the variables this would have got
* us the key for sure! So give him the old algorithm.
*/
if (key.dptr == NULL)
return (dbm_slow_nextkey(db));
}
/*
* at this point the last key is paged in and
* we can proceed as in old dbm -- like Ken did his.
*/
f = 1;
j = 0;
sp = (short *)(uintptr_t)db->dbm_pagbuf;
for (i = 0; ; i += 2) {
/* begin put makdatum inline */
if ((unsigned)i >= sp[0]) {
item.dptr = NULL;
item.dsize = 0;
break; /* from below */
} else {
if (i > 0) item.dsize = sp[i] - sp[i + 1];
else item.dsize = PBLKSIZ - sp[i + 1];
item.dptr = db->dbm_pagbuf+sp[i + 1];
}
/* item = makdatum(db->dbm_pagbuf, i); */
/* end put makdatum inline */
if (item.dptr == NULL)
break;
/* inline cmpdatum */
n = key.dsize;
if (n != item.dsize) {
if ((n - item.dsize) <= 0)
continue;
} else {
if (n == 0) continue;
p1 = key.dptr;
p2 = item.dptr;
do {
if (*p1++ != *p2++)
if ((*--p1 - *--p2) > 0)
goto keep_going;
else continue;
} while (--n);
continue;
}
keep_going:
/* end inline cmpdatum */
/*
* if (cmpdatum(key, item) <= 0)
* continue;
*/
if (f) {
bitem = item;
j = i;
f = 0;
} else {
/* if (cmpdatum(bitem, item) < 0) */
n = bitem.dsize;
if (n != item.dsize) {
if ((n - item.dsize) < 0) {
bitem = item;
j = i;
}
} else
if (n != 0) {
p1 = bitem.dptr;
p2 = item.dptr;
do {
if (*p1++ != *p2++) {
if ((*--p1 - *--p2) < 0) {
bitem = item;
j = i;
}
break;
}
} while (--n);
}
}
}
if (f == 0) {
db->dbm_keyptr = j + 2;
db->dbm_blkptr = db->dbm_blkno;
return (bitem);
}
/* really need hash at this point */
/* if he gave us a key we have already calculated the hash */
/* if not get it */
if (inkey.dptr == NULL)
hash = dcalchash(key);
hash = dbm_hashinc(db, hash);
if (hash == 0)
return (item); /* null */
/* get first item on next page in hash table order */
return (dbm_firsthash(db, hash));
}
static void
dbm_access(DBM *db, unsigned long hash)
{
long b, i, n;
long bn;
long my_bitno;
long my_hmask;
long my_blkno;
int j = (sizeof (my_hmask)) * 8;
off64_t where;
for (my_hmask = 0; j-- > 0; my_hmask = (my_hmask<<1) + 1) {
my_blkno = hash & my_hmask;
my_bitno = my_blkno + my_hmask;
/* getbit inline */
if (my_bitno > db->dbm_maxbno) break;
n = my_bitno % BYTESIZ;
bn = my_bitno / BYTESIZ;
i = bn % DBLKSIZ;
b = bn / DBLKSIZ;
if (b != db->dbm_dirbno) {
if (dbm_dirdirty(db))
(void) dbm_flushdir(db); /* must flush */
db->dbm_dirbno = b;
where = (((off64_t)b) * DBLKSIZ);
if ((lseek64(db->dbm_dirf, where, L_SET) != where) ||
(read(db->dbm_dirf, db->dbm_dirbuf, DBLKSIZ) !=
DBLKSIZ))
(void) memset(db->dbm_dirbuf, 0, DBLKSIZ);
}
if ((db->dbm_dirbuf[i] & (1<<n)) == 0) break;
/*
* if (getbit(db) == 0)
* break;
*/
}
/* copy */
db->dbm_blkno = my_blkno;
db->dbm_bitno = my_bitno;
db->dbm_hmask = my_hmask;
if (my_blkno != db->dbm_pagbno) {
if (dbm_dirty(db)) { /* must page out the page */
where = (((off64_t)db->dbm_pagbno) * PBLKSIZ);
if ((lseek64(db->dbm_pagf, where, L_SET) != where) ||
(write(db->dbm_pagf, db->dbm_pagbuf, PBLKSIZ) !=
PBLKSIZ)) {
db->dbm_flags |= _DBM_IOERR;
}
dbm_clrdirty(db);
}
db->dbm_pagbno = my_blkno;
where = (((off64_t)my_blkno) * PBLKSIZ);
if ((lseek64(db->dbm_pagf, where, L_SET) != where) ||
(read(db->dbm_pagf, db->dbm_pagbuf, PBLKSIZ) != PBLKSIZ))
(void) memset(db->dbm_pagbuf, 0, PBLKSIZ);
#ifdef DEBUG
else if (chkblk(db->dbm_pagbuf) < 0)
db->dbm_flags |= _DBM_IOERR;
#endif
}
}
static int
getbit(DBM *db)
{
long bn;
long b, i, n;
off64_t where;
if (db->dbm_bitno > db->dbm_maxbno)
return (0);
n = db->dbm_bitno % BYTESIZ;
bn = db->dbm_bitno / BYTESIZ;
i = bn % DBLKSIZ;
b = bn / DBLKSIZ;
if (b != db->dbm_dirbno) {
if (dbm_dirdirty(db))
(void) dbm_flushdir(db); /* must flush */
db->dbm_dirbno = b;
where = (((off64_t)b) * DBLKSIZ);
if ((lseek64(db->dbm_dirf, where, L_SET) != where) ||
(read(db->dbm_dirf, db->dbm_dirbuf, DBLKSIZ) != DBLKSIZ))
(void) memset(db->dbm_dirbuf, 0, DBLKSIZ);
}
return (db->dbm_dirbuf[i] & (1<<n));
}
static int
setbit(DBM *db)
{
long bn;
long i, n, b;
off64_t where;
if (db->dbm_bitno > db->dbm_maxbno)
db->dbm_maxbno = db->dbm_bitno;
n = db->dbm_bitno % BYTESIZ;
bn = db->dbm_bitno / BYTESIZ;
i = bn % DBLKSIZ;
b = bn / DBLKSIZ;
if (b != db->dbm_dirbno) {
if (dbm_dirdirty(db))
(void) dbm_flushdir(db);
db->dbm_dirbno = b;
where = (((off64_t)b) * DBLKSIZ);
if ((lseek64(db->dbm_dirf, where, L_SET) != where) ||
(read(db->dbm_dirf, db->dbm_dirbuf, DBLKSIZ) != DBLKSIZ))
(void) memset(db->dbm_dirbuf, 0, DBLKSIZ);
}
db->dbm_dirbuf[i] |= 1<<n;
db->dbm_dirbno = b;
if (dbm_defwrite(db)) {
dbm_setdirdirty(db);
} else {
where = (((off64_t)b) * DBLKSIZ);
if ((lseek64(db->dbm_dirf, where, L_SET) != where) ||
(write(db->dbm_dirf, db->dbm_dirbuf, DBLKSIZ) != DBLKSIZ)) {
return (-1);
}
}
return (0);
}
static datum
makdatum(char buf[PBLKSIZ], int n)
{
short *sp;
int t;
datum item;
sp = (short *)(uintptr_t)buf;
if ((unsigned)n >= sp[0]) {
item.dptr = NULL;
item.dsize = 0;
return (item);
}
t = PBLKSIZ;
if (n > 0)
t = sp[n];
item.dptr = buf + sp[n + 1];
item.dsize = t - sp[n + 1];
return (item);
}
static int
cmpdatum(datum d1, datum d2)
{
long n;
char *p1, *p2;
n = d1.dsize;
if (n != d2.dsize)
return ((int)(n - d2.dsize));
if (n == 0)
return (0);
p1 = d1.dptr;
p2 = d2.dptr;
do {
if (*p1 != *p2)
return (*p1 - *p2);
else {
p1++;
p2++;
}
} while (--n);
return (0);
}
static int
finddatum(char buf[PBLKSIZ], datum item)
{
short *sp;
int i, n, j;
sp = (short *)(uintptr_t)buf;
n = PBLKSIZ;
for (i = 0, j = sp[0]; i < j; i += 2, n = sp[i]) {
n -= sp[i + 1];
if (n != item.dsize)
continue;
if (n == 0 || memcmp(&buf[sp[i+1]], item.dptr, n) == 0)
return (i);
}
return (-1);
}
static const int hitab[16]
/*
* ken's
* {
* 055, 043, 036, 054, 063, 014, 004, 005,
* 010, 064, 077, 000, 035, 027, 025, 071,
* };
*/
= { 61, 57, 53, 49, 45, 41, 37, 33,
29, 25, 21, 17, 13, 9, 5, 1,
};
/* could consider to make it 32-bit int table to minimize memory usage */
static const long hltab[64]
= {
06100151277L, 06106161736L, 06452611562L, 05001724107L,
02614772546L, 04120731531L, 04665262210L, 07347467531L,
06735253126L, 06042345173L, 03072226605L, 01464164730L,
03247435524L, 07652510057L, 01546775256L, 05714532133L,
06173260402L, 07517101630L, 02431460343L, 01743245566L,
00261675137L, 02433103631L, 03421772437L, 04447707466L,
04435620103L, 03757017115L, 03641531772L, 06767633246L,
02673230344L, 00260612216L, 04133454451L, 00615531516L,
06137717526L, 02574116560L, 02304023373L, 07061702261L,
05153031405L, 05322056705L, 07401116734L, 06552375715L,
06165233473L, 05311063631L, 01212221723L, 01052267235L,
06000615237L, 01075222665L, 06330216006L, 04402355630L,
01451177262L, 02000133436L, 06025467062L, 07121076461L,
03123433522L, 01010635225L, 01716177066L, 05161746527L,
01736635071L, 06243505026L, 03637211610L, 01756474365L,
04723077174L, 03642763134L, 05750130273L, 03655541561L,
};
static unsigned long
dcalchash(datum item)
{
long s;
int c, j;
char *cp;
unsigned long hashl;
long hashi;
hashl = 0;
hashi = 0;
for (cp = item.dptr, s = item.dsize; --s >= 0; ) {
c = *cp++;
for (j = 0; j < BYTESIZ; j += 4) {
hashi += hitab[c&017];
hashl += hltab[hashi&63];
c >>= 4;
}
}
return (hashl);
}
/*
* Delete pairs of items (n & n+1).
*/
static int
delitem(char buf[PBLKSIZ], int n)
{
short *sp, *sp1;
int i1, i2;
sp = (short *)(uintptr_t)buf;
i2 = sp[0];
if ((unsigned)n >= i2 || (n & 1))
return (0);
if (n == i2-2) {
sp[0] -= 2;
return (1);
}
i1 = PBLKSIZ;
if (n > 0)
i1 = sp[n];
i1 -= sp[n+2];
if (i1 > 0) {
i2 = sp[i2];
(void) memmove(&buf[i2 + i1], &buf[i2], sp[n+2] - i2);
}
sp[0] -= 2;
for (sp1 = sp + sp[0], sp += n+1; sp <= sp1; sp++)
sp[0] = sp[2] + i1;
return (1);
}
/*
* Add pairs of items (item & item1).
*/
static int
additem(char buf[PBLKSIZ], datum item, datum item1)
{
short *sp;
int i1, i2;
sp = (short *)(uintptr_t)buf;
i1 = PBLKSIZ;
i2 = sp[0];
if (i2 > 0)
i1 = sp[i2];
i1 -= item.dsize + item1.dsize;
if (i1 <= (i2+3) * (int)sizeof (short))
return (0);
sp[0] += 2;
sp[++i2] = (short)(i1 + item1.dsize);
(void) memmove(&buf[i1 + item1.dsize], item.dptr, item.dsize);
sp[++i2] = i1;
(void) memmove(&buf[i1], item1.dptr, item1.dsize);
return (1);
}
#ifdef DEBUG
static int
chkblk(char buf[PBLKSIZ])
{
short *sp;
int t, i;
sp = (short *)buf;
t = PBLKSIZ;
for (i = 0; i < sp[0]; i++) {
if (sp[i + 1] > t)
return (-1);
t = sp[i + 1];
}
if (t < (sp[0] + 1) * sizeof (short))
return (-1);
return (0);
}
#endif