/*
btsync: sync memory blocks with B tree index file
returns zero if no errors, error code otherwise
*/
int btsync()
{
int i,ioerr;
if (btact->idxunt != NULL) {
/* write out all in-memory blocks */
for (i=0;i<ZMXBLK;i++) {
ioerr = bwrblk(((btact->cntrl)+i)->inmem);
if (ioerr != 0) {
bterr("BTSYNC",QWRBLK,itostr(((btact->cntrl)+i)->inmem));
goto fin;
}
}
/* write super block if necessary */
if (btact->cntxt->super.smod != 0) {
if ( bwrsup() != 0) goto fin;
btact->cntxt->super.smod = 0;
}
}
/* force writes to disk */
fflush(btact->idxunt);
/* re-initialise control blocks to ensure blocks will be re-read
from disk */
initcntrl(btact);
fin:
return(btgerr());
}
int btcls(BTA* b)
{
int ioerr;
bterr("",0,NULL);
if ((ioerr=bvalap("BTCLS",b)) != 0) return(ioerr);
btact = b; /* set context pointer */
/* Undo any locks and flush buffers before closing file */
while (btact->lckcnt > 0) bulock();
/* close index file and free context memory */
ioerr = fclose(btact->idxunt);
if (ioerr != 0) {
bterr("BTCLS",QCLSIO,btact->idxfid);
}
else {
btact->idxunt = NULL;
bacfre(btact);
}
return(btgerr());
}
int binsky(BTA *b, char *key,BTint val)
{
BTint lval,dups_allowed;
int status;
KEYENT keyent;
bterr("",0,NULL);
if ((status=bvalap("BINSKY",b)) != 0) return(status);
btact = b;
if (btact->shared) {
if (!block()) {
bterr("BINSKY",QBUSY,NULL);
goto fin;
}
}
if (b->cntxt->super.smode != 0) {
/* read only, can't insert */
bterr("BINSKY",QNOWRT,NULL);
}
else {
dups_allowed = bgtinf(btact->cntxt->super.scroot,ZMISC);
strncpy(keyent.key,key,ZKYLEN);
keyent.key[ZKYLEN-1] = '\0';
keyent.val = val;
keyent.dup = ZNULL;
status = bfndky(b,keyent.key,&lval);
if (status == QNOKEY || (status == 0 && dups_allowed)) {
/* QNOKEY is not an error in this context; remove it */
bterr("",0,NULL);
if (status == 0) {
/* inserting duplicate key */
btdupkey(key,val);
}
else {
bleaf(1);
bputky(btact->cntxt->lf.lfblk,&keyent,ZNULL,ZNULL);
}
}
else {
bterr("BINSKY",QDUP,key);
}
}
fin:
if (btact->shared) bulock();
return(btgerr());
}
int bfndky(BTA *b,char *key,BTint *val)
{
BTint cblk, link1, link2, newblk;
int index, result, nkeys, status;
char lkey[ZKYLEN];
bterr("",0,NULL);
status = QNOKEY;
if ((result=bvalap("BFNDKY",b)) != 0) return(result);
btact = b; /* set context pointer */
if (btact->shared) {
if (!block()) {
bterr("BFNDKY",QBUSY,NULL);
goto fin;
}
}
/* take local copy of key, truncating if necessary */
strncpy(lkey,key,ZKYLEN);
lkey[ZKYLEN-1] = '\0';
/* initialise stack etc */
btact->cntxt->lf.lfexct = FALSE;
cblk = btact->cntxt->super.scroot;
bstkin();
btact->cntxt->lf.lfblk = -1;
btact->cntxt->lf.lfpos = -1;
strcpy(btact->cntxt->lf.lfkey,lkey);
while (cblk >= 0) {
#if DEBUG >= 2
fprintf(stderr,"BFNDKY: searching block " ZINTFMT "\n",cblk);
#endif
nkeys = bgtinf(cblk,ZNKEYS);
if (nkeys == ZMXKEY && btact->cntxt->super.smode == 0) {
/* split if block full and updating permitted */
bsptbk(cblk,&newblk);
if (newblk < 0) {
bterr("BFNDKY",QSPLIT,NULL);
break;
}
/* if split occured, then must re-examine parent */
if (cblk != btact->cntxt->super.scroot) {
index = btact->cntxt->lf.lfpos;
cblk = btact->cntxt->lf.lfblk;
btact->cntxt->lf.lfpos = bpull();
btact->cntxt->lf.lfblk = bpull();
}
}
else {
index = -1;
bpush(btact->cntxt->lf.lfblk);
bpush(btact->cntxt->lf.lfpos);
bsrhbk(cblk,lkey,&index,val,&link1,&link2,&result);
btact->cntxt->lf.lfblk = cblk;
btact->cntxt->lf.lfpos = index; /* if block is empty, leave lfpos at -1 */
if (result < 0) {
/* must examine left block */
cblk = link1;
continue;
}
else if (result > 0) {
/* must examine right block */
cblk = link2;
/* increment index to indicate this key "visited" */
btact->cntxt->lf.lfpos++;
continue;
}
else {
status = 0;
btact->cntxt->lf.lfexct = TRUE;
break;
}
}
}
fin:
if (btact->shared) bulock();
/* non-zero status indicates no such key found */
if (status) bterr("BFNDKY",QNOKEY,lkey);
return(btgerr());
}
int bnxtky(BTA* b,char *key,BTint *val)
{
int idx,nkeys,status;
int found;
bterr("",0,NULL);
if ((status=bvalap("BNXTKY",b)) != 0) return(status);
btact = b; /* set global context pointer */
if (btact->shared) {
if (!block()) {
bterr("BNXTKY",QBUSY,NULL);
goto fin;
}
}
/* handle duplicate positioning */
found = btduppos(ZNEXT,val);
if (found > 0) {
goto fin;
}
else if (found == 0) {
strncpy(key,btact->cntxt->lf.lfkey,ZKYLEN);
key[ZKYLEN-1] = '\0';
goto fin;
}
if (btact->shared && btact->cntxt->lf.lfblk != ZNULL) {
/* position to last found key via bfndky, since context could
* have been invalidated by concurrent updates by other users.
* Note we don't care if the key is found or not, so the error
* status is always cleared. */
status = bfndky(btact,btact->cntxt->lf.lfkey,val);
bterr("",0,NULL);
}
found = FALSE;
while (btact->cntxt->lf.lfblk != ZNULL && !found) {
status = brdblk(btact->cntxt->lf.lfblk,&idx);
if (idx < 0) {
bterr("BNXTKY",QRDBLK,itostr(btact->cntxt->lf.lfblk));
break;
}
nkeys = bgtinf(btact->cntxt->lf.lfblk,ZNKEYS);
#if DEBUG >= 1
printf("BNXTKY: lfblk: " ZINTFMT ", lfpos: %d, nkeys: %d\n",
btact->cntxt->lf.lfblk,btact->cntxt->lf.lfpos,nkeys);
#endif
if (btact->cntxt->lf.lfpos >= nkeys || nkeys == 0) {
/* finished with this block (or no key was found at all),
* get parent from stack */
btact->cntxt->lf.lfpos = bpull();
btact->cntxt->lf.lfblk = bpull();
btact->cntxt->lf.lfexct = FALSE;
continue;
}
if (!btact->cntxt->lf.lfexct) {
btact->cntxt->lf.lfexct = TRUE;
}
else {
btact->cntxt->lf.lfpos++;
/* invalidate existing dup chain */
btact->cntxt->lf.draddr = ZNULL;
idx = bleaf(0);
if (idx < 0) continue;
}
if (btact->cntxt->lf.lfpos < nkeys) {
found = TRUE;
strncpy(key,
((btact->memrec)+idx)->keyblk[btact->cntxt->lf.lfpos].key,
ZKYLEN);
key[ZKYLEN-1] = '\0';
/* remember found key (need for shared mode) */
strncpy(btact->cntxt->lf.lfkey,key,ZKYLEN);
btact->cntxt->lf.lfkey[ZKYLEN-1] = '\0';
*val = ((btact->memrec)+idx)->keyblk[btact->cntxt->lf.lfpos].val;
btduppos(ZNEXT,val);
}
}
if (btact->cntxt->lf.lfblk == ZNULL) {
/* end of index reached */
bclrlf();
bterr("BNXTKY",QNOKEY,NULL);
}
fin:
if (btact->shared) bulock();
return btgerr();
}