int bsetbk(BTint blk,BTint type,BTint misc,BTint nxblk,BTint nkeys,
BTint nblks,BTint dupblk)
{
int ioerr,idx;
ioerr = brdblk(blk,&idx);
if (idx < 0) {
bterr("BSETBK",QRDBLK,itostr(blk));
}
else {
bstinf(blk,ZBTYPE,type);
((btact->memrec)+idx)->infblk[ZMISC] = misc;
((btact->memrec)+idx)->infblk[ZNXBLK] = nxblk;
((btact->memrec)+idx)->infblk[ZNKEYS] = nkeys;
((btact->memrec)+idx)->infblk[ZNBLKS] = nblks;
((btact->memrec)+idx)->infblk[ZNXDUP] = dupblk;
((btact->cntrl)+idx)->writes++;
}
return(0);
}
void bdemte(BTint *cblk)
{
BTint newblk,val,link1,link2,jblk,llink,rlink;
int nkeys,type,result;
int rblke;
char tkey[ZKYLEN];
nkeys = bgtinf(btact->cntxt->lf.lfblk,ZNKEYS);
if (nkeys == 0) {
type = bgtinf(btact->cntxt->lf.lfblk,ZBTYPE);
if (type != ZROOT) {
/* pull parent */
btact->cntxt->lf.lfpos = bpull();
btact->cntxt->lf.lfblk = bpull();
nkeys = bgtinf(btact->cntxt->lf.lfblk,ZNKEYS);
if (btact->cntxt->lf.lfpos != 0) {
/* ensure that empty block is on the right */
rblke = TRUE;
btact->cntxt->lf.lfpos--;
}
else {
/* first block empty, so can't put on right */
rblke = FALSE;
}
bsrhbk(btact->cntxt->lf.lfblk,tkey,&btact->cntxt->lf.lfpos,&val,
&link1,&link2,&result);
if (result != 0) {
bterr("BDEMTE",QDEMSE,NULL);
goto fin;
}
#if DEBUG >= 1
printf("BDEMTE: Demoting key %s from blk: " ZINTFMT "\n",tkey,
btact->cntxt->lf.lfblk);
#endif
/* remove key from original block */
bremky(btact->cntxt->lf.lfblk,btact->cntxt->lf.lfpos);
/* prepare for split check */
if (rblke)
jblk = link1;
else
jblk = link2;
/* if target block for demotion is full, split it */
nkeys = bgtinf(jblk,ZNKEYS);
if (nkeys == ZMXKEY) {
bsptbk(jblk,&newblk);
if (newblk == ZNULL) {
bterr("BDEMTE",QDEMSP,NULL);
goto fin;
}
if (rblke) {
link1 = newblk;
}
}
if (!rblke) {
/* copy keys from right block to empty left block */
nkeys = bgtinf(link2,ZNKEYS);
bsetbs(link1,1);
bcpybk(link1,link2,0,0,nkeys);
bstinf(link1,ZNKEYS,nkeys);
bsetbs(link1,0);
llink = *cblk;
rlink = ZNULL; /* 0 replaced by ZNULL for C */
}
else {
llink = ZNULL; /* 0 replaced by ZNULL for C */
rlink = *cblk;
}
bputky(link1,tkey,val,llink,rlink);
bmkfre(link2);
/* set new potentially dangling block */
*cblk = link1;
}
else {
/* empty block is root; copy keys from child and then free
* the child block */
nkeys = bgtinf(*cblk,ZNKEYS);
bcpybk(btact->cntxt->lf.lfblk,*cblk,0,0,nkeys);
bstinf(btact->cntxt->lf.lfblk,ZNKEYS,nkeys);
bmkfre(*cblk);
*cblk = ZNULL;
}
}
else {
*cblk = ZNULL;
}
fin:
return;
}
