static void
dbm_access(DBM *db, long hash)
{
int b, i, n;
long bn;
long my_bitno;
long my_hmask;
long my_blkno;
for (my_hmask=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)) dbm_flushdir(db); /*must flush*/
db->dbm_dirbno = b;
(void) lseek(db->dbm_dirf, (long)(b*DBLKSIZ), L_SET);
if (read(db->dbm_dirf, db->dbm_dirbuf, DBLKSIZ) != DBLKSIZ)
bzero(db->dbm_dirbuf, 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*/
(void) lseek(db->dbm_pagf, (long)(db->dbm_pagbno*PBLKSIZ), L_SET);
if (write(db->dbm_pagf, db->dbm_pagbuf, PBLKSIZ) != PBLKSIZ) {
db->dbm_flags |= _DBM_IOERR;
}
dbm_clrdirty(db);
}
db->dbm_pagbno = my_blkno;
(void) lseek(db->dbm_pagf, (long)(my_blkno*PBLKSIZ), L_SET);
if (read(db->dbm_pagf, db->dbm_pagbuf, PBLKSIZ) != PBLKSIZ)
bzero(db->dbm_pagbuf, PBLKSIZ);
#ifdef DEBUG
else if (chkblk(db->dbm_pagbuf) < 0)
db->dbm_flags |= _DBM_IOERR;
#endif
}
}
void ckd_chkmem ( void )
{
int32 i;
assert ((n_memblk >= 0) && (n_memblk < max_memblk));
for (i = 0; i < n_memblk; i++)
chkblk (i);
E_INFO("%d blks OK\n", n_memblk);
}
static datum
dbm_slow_nextkey(DBM *db)
{
struct stat statb;
datum item;
if (dbm_error(db) || fstat(db->dbm_pagf, &statb) < 0)
goto err;
statb.st_size /= PBLKSIZ;
for (;;) {
if (db->dbm_blkptr != db->dbm_pagbno) {
if (dbm_dirty(db)) dbm_flushpag(db);
db->dbm_pagbno = db->dbm_blkptr;
(void) lseek(db->dbm_pagf, (long)(db->dbm_blkptr*PBLKSIZ), L_SET);
if (read(db->dbm_pagf, db->dbm_pagbuf, PBLKSIZ) != PBLKSIZ)
bzero(db->dbm_pagbuf, PBLKSIZ);
#ifdef DEBUG
else if (chkblk(db->dbm_pagbuf) < 0)
db->dbm_flags |= _DBM_IOERR;
#endif
}
/*Am I an empty block?*/
if (((short *)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;
long hash;
datum key;
int f;
int i;
int j;
short *sp;
int n;
char *p1, *p2;
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)) dbm_flushpag(db);
db->dbm_pagbno = db->dbm_blkptr;
(void) lseek(db->dbm_pagf, (long)(db->dbm_blkptr*PBLKSIZ), L_SET);
if (read(db->dbm_pagf, db->dbm_pagbuf, PBLKSIZ) != PBLKSIZ)
bzero(db->dbm_pagbuf, 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 *)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 { }
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));
}