/*
* NAME: node->merge()
* DESCRIPTION: combine two nodes into a single node
*/
int n_merge(node *right, node *left, unsigned char *record, int *flag)
{
int i, offset;
/* copy records and offsets */
memcpy(HFS_NODEREC(*left, left->nd.ndNRecs), HFS_NODEREC(*right, 0),
right->roff[right->nd.ndNRecs] - right->roff[0]);
offset = left->roff[left->nd.ndNRecs] - right->roff[0];
for (i = 1; i <= (int)right->nd.ndNRecs; ++i)
left->roff[++left->nd.ndNRecs] = offset + right->roff[i];
/* update link pointers */
left->nd.ndFLink = right->nd.ndFLink;
if (bt_putnode(left) < 0)
return -1;
if (right->bt->hdr.bthLNode == right->nnum)
{
right->bt->hdr.bthLNode = left->nnum;
right->bt->flags |= HFS_UPDATE_BTHDR;
}
if (right->nd.ndFLink)
{
node n;
n.bt = right->bt;
n.nnum = right->nd.ndFLink;
if (bt_getnode(&n) < 0)
return -1;
n.nd.ndBLink = left->nnum;
if (bt_putnode(&n) < 0)
return -1;
}
n_free(right);
HFS_RECKEYLEN(record) = 0;
*flag = 1;
return 0;
}
/*
* NAME: join()
* DESCRIPTION: combine two nodes into a single node
*/
static
int join(node *left, node *right, byte *record, int *flag)
{
int i, offset;
/* copy records and offsets */
memcpy(HFS_NODEREC(*left, left->nd.ndNRecs),
HFS_NODEREC(*right, 0), NODEUSED(*right));
offset = left->roff[left->nd.ndNRecs] - right->roff[0];
for (i = 1; i <= right->nd.ndNRecs; ++i)
left->roff[++left->nd.ndNRecs] = offset + right->roff[i];
if (bt_putnode(left) == -1)
goto fail;
/* eliminate node and update link pointers */
if (n_free(right) == -1)
goto fail;
HFS_SETKEYLEN(record, 0);
*flag = 1;
return 0;
fail:
return -1;
}
/*
* NAME: node->free()
* DESCRIPTION: deallocate and remove a b*-tree node
*/
int n_free(node *np)
{
btree *bt = np->bt;
node sib;
if (bt->hdr.bthFNode == np->nnum)
bt->hdr.bthFNode = np->nd.ndFLink;
if (bt->hdr.bthLNode == np->nnum)
bt->hdr.bthLNode = np->nd.ndBLink;
if (np->nd.ndFLink > 0)
{
if (bt_getnode(&sib, bt, np->nd.ndFLink) == -1)
goto fail;
sib.nd.ndBLink = np->nd.ndBLink;
if (bt_putnode(&sib) == -1)
goto fail;
}
if (np->nd.ndBLink > 0)
{
if (bt_getnode(&sib, bt, np->nd.ndBLink) == -1)
goto fail;
sib.nd.ndFLink = np->nd.ndFLink;
if (bt_putnode(&sib) == -1)
goto fail;
}
BMCLR(bt->map, np->nnum);
++bt->hdr.bthFree;
bt->flags |= HFS_BT_UPDATE_HDR;
return 0;
fail:
return -1;
}
/*
* NAME: vol->putextrec()
* DESCRIPTION: store extent information
*/
int v_putextrec(const ExtDataRec *data, node *np)
{
byte pdata[HFS_EXTDATALEN], *ptr;
int len = 0;
r_packextdata(data, pdata, &len);
ptr = HFS_NODEREC(*np, np->rnum);
memcpy(HFS_RECDATA(ptr), pdata, len);
return bt_putnode(np);
}
/*
* NAME: vol->putcatrec()
* DESCRIPTION: store catalog information
*/
int v_putcatrec(CatDataRec *data, node *np)
{
unsigned char pdata[HFS_CATDATALEN], *ptr;
int len = 0;
r_packcatdata(data, pdata, &len);
ptr = HFS_NODEREC(*np, np->rnum);
memcpy(HFS_RECDATA(ptr), pdata, len);
return bt_putnode(np);
}
/*
* NAME: node->insert()
* DESCRIPTION: insert a new record into a node; return a record for parent
*/
int n_insert(node *np, byte *record, unsigned int *reclen)
{
/* check for free space */
if (np->nd.ndNRecs >= HFS_MAX_NRECS ||
*reclen + 2 > NODEFREE(*np))
return split(np, record, reclen);
n_insertx(np, record, *reclen);
*reclen = 0;
return bt_putnode(np);
}
/*
* NAME: node->insert()
* DESCRIPTION: insert a new record into a node; return a record for parent
*/
int n_insert(node *np, unsigned char *record, int *reclen)
{
n_compact(np);
/* check for free space */
if (np->nd.ndNRecs >= HFS_MAXRECS ||
*reclen + 2 > (int)NODESPACE(*np))
return n_split(np, record, reclen);
n_insertx(np, record, *reclen);
*reclen = 0;
return bt_putnode(np);
}
/*
* NAME: node->delete()
* DESCRIPTION: remove a record from a node
*/
int n_delete(node *np, byte *record, int *flag)
{
byte *rec;
rec = HFS_NODEREC(*np, np->rnum);
HFS_SETKEYLEN(rec, 0);
compact(np);
if (np->nd.ndNRecs == 0)
{
if (n_free(np) == -1)
goto fail;
HFS_SETKEYLEN(record, 0);
*flag = 1;
return 0;
}
/* see if we can join with our left sibling */
if (np->nd.ndBLink > 0)
{
node left;
if (bt_getnode(&left, np->bt, np->nd.ndBLink) == -1)
goto fail;
if (np->nd.ndNRecs + left.nd.ndNRecs <= HFS_MAX_NRECS &&
NODEUSED(*np) + 2 * np->nd.ndNRecs <= NODEFREE(left))
return join(&left, np, record, flag);
}
if (np->rnum == 0)
{
/* special case: first record changed; update parent record key */
n_index(np, record, 0);
*flag = 1;
}
return bt_putnode(np);
fail:
return -1;
}
/*
* NAME: node->delete()
* DESCRIPTION: remove a record from a node
*/
int n_delete(node *np, unsigned char *record, int *flag)
{
node left;
unsigned char *rec;
rec = HFS_NODEREC(*np, np->rnum);
HFS_RECKEYLEN(rec) = 0;
n_compact(np);
/* see if we can merge with our left sibling */
left.bt = np->bt;
left.nnum = np->nd.ndBLink;
if (left.nnum > 0)
{
if (bt_getnode(&left) < 0)
return -1;
if ((int)(np->nd.ndNRecs + left.nd.ndNRecs) <= HFS_MAXRECS &&
(int)(np->roff[np->nd.ndNRecs] - np->roff[0] +
2 * np->nd.ndNRecs) <= (int)NODESPACE(left))
return n_merge(np, &left, record, flag);
}
if (np->rnum == 0)
{
/* special case: first record changed; update parent record key */
n_index(np->bt, HFS_NODEREC(*np, 0), np->nnum, record, 0);
*flag = 1;
}
return bt_putnode(np);
}
/*
* NAME: split()
* DESCRIPTION: divide a node into two and insert a record
*/
static
int split(node *left, byte *record, unsigned int *reclen)
{
btree *bt = left->bt;
node n, *right = &n, *side = 0;
int mark, i;
/* create a second node by cloning the first */
*right = *left;
if (n_new(right) == -1)
goto fail;
left->nd.ndFLink = right->nnum;
right->nd.ndBLink = left->nnum;
/* divide all records evenly between the two nodes */
mark = (NODEUSED(*left) + 2 * left->nd.ndNRecs + *reclen + 2) >> 1;
if (left->rnum == -1)
{
side = left;
mark -= *reclen + 2;
}
for (i = 0; i < left->nd.ndNRecs; ++i)
{
node *np;
byte *rec;
np = (mark > 0) ? right : left;
rec = HFS_NODEREC(*np, i);
mark -= HFS_RECLEN(*np, i) + 2;
HFS_SETKEYLEN(rec, 0);
if (left->rnum == i)
{
side = (mark > 0) ? left : right;
mark -= *reclen + 2;
}
}
compact(left);
compact(right);
/* insert the new record and store the modified nodes */
ASSERT(side);
n_search(side, record);
n_insertx(side, record, *reclen);
if (bt_putnode(left) == -1 ||
bt_putnode(right) == -1)
goto fail;
/* create an index record in the parent for the new node */
n_index(right, record, reclen);
/* update link pointers */
if (bt->hdr.bthLNode == left->nnum)
{
bt->hdr.bthLNode = right->nnum;
bt->flags |= HFS_BT_UPDATE_HDR;
}
if (right->nd.ndFLink > 0)
{
node sib;
if (bt_getnode(&sib, right->bt, right->nd.ndFLink) == -1)
goto fail;
sib.nd.ndBLink = right->nnum;
if (bt_putnode(&sib) == -1)
goto fail;
}
return 0;
fail:
return -1;
}
/*
* NAME: node->split()
* DESCRIPTION: divide a node into two and insert a record
*/
int n_split(node *left, unsigned char *record, int *reclen)
{
node right;
int nrecs, i, mid;
unsigned char *rec;
right = *left;
right.nd.ndBLink = left->nnum;
if (n_new(&right) < 0)
return -1;
left->nd.ndFLink = right.nnum;
nrecs = left->nd.ndNRecs;
/*
* Ensure node split leaves enough room for new record.
* The size calculations used are based on the NODESPACE() macro, but
* I don't know what the extra 2's and 1's are needed for.
* John Witford <*****@*****.**>
*/
n_search(&right, record);
mid = nrecs/2;
for(;;)
{
if (right.rnum < mid)
{
if ( mid > 0
&& (int)left->roff[mid] + *reclen + 2 > HFS_BLOCKSZ - 2 * (mid + 1))
{
--mid;
if (mid > 0)
continue;
}
}
else
{
if ( mid < nrecs
&& (int)right.roff[nrecs] - (int)right.roff[mid] + (int)left->roff[0] + *reclen + 2 > HFS_BLOCKSZ - 2 * (mid + 1))
{
++mid;
if (mid < nrecs)
continue;
}
}
break;
}
for (i = 0; i < nrecs; ++i)
{
if (i < mid)
rec = HFS_NODEREC(right, i);
else
rec = HFS_NODEREC(*left, i);
HFS_RECKEYLEN(rec) = 0;
}
/* original code ...
for (i = 0; i < nrecs; ++i)
{
if (i < nrecs / 2)
rec = HFS_NODEREC(right, i);
else
rec = HFS_NODEREC(*left, i);
HFS_RECKEYLEN(rec) = 0;
}
*/
n_compact(left);
n_compact(&right);
n_search(&right, record);
if (right.rnum >= 0)
n_insertx(&right, record, *reclen);
else
{
n_search(left, record);
n_insertx(left, record, *reclen);
}
/* store the new/modified nodes */
if (bt_putnode(left) < 0 ||
bt_putnode(&right) < 0)
return -1;
/* create an index record for the new node in the parent */
n_index(right.bt, HFS_NODEREC(right, 0), right.nnum, record, reclen);
/* update link pointers */
if (left->bt->hdr.bthLNode == left->nnum)
{
left->bt->hdr.bthLNode = right.nnum;
left->bt->flags |= HFS_UPDATE_BTHDR;
}
if (right.nd.ndFLink)
{
node n;
n.bt = right.bt;
n.nnum = right.nd.ndFLink;
if (bt_getnode(&n) < 0)
return -1;
n.nd.ndBLink = right.nnum;
if (bt_putnode(&n) < 0)
return -1;
}
return 0;
}
/*
* NAME: node->split()
* DESCRIPTION: divide a node into two and insert a record
*/
int n_split(node *left, unsigned char *record, int *reclen)
{
node right;
int nrecs, i;
unsigned char *rec;
right = *left;
right.nd.ndBLink = left->nnum;
if (n_new(&right) < 0)
return -1;
left->nd.ndFLink = right.nnum;
nrecs = left->nd.ndNRecs;
for (i = 0; i < nrecs; ++i)
{
if (i < nrecs / 2)
rec = HFS_NODEREC(right, i);
else
rec = HFS_NODEREC(*left, i);
HFS_RECKEYLEN(rec) = 0;
}
n_compact(left);
n_compact(&right);
n_search(&right, record);
if (right.rnum >= 0)
n_insertx(&right, record, *reclen);
else
{
n_search(left, record);
n_insertx(left, record, *reclen);
}
/* store the new/modified nodes */
if (bt_putnode(left) < 0 ||
bt_putnode(&right) < 0)
return -1;
/* create an index record for the new node in the parent */
n_index(right.bt, HFS_NODEREC(right, 0), right.nnum, record, reclen);
/* update link pointers */
if (left->bt->hdr.bthLNode == left->nnum)
{
left->bt->hdr.bthLNode = right.nnum;
left->bt->flags |= HFS_UPDATE_BTHDR;
}
if (right.nd.ndFLink)
{
node n;
n.bt = right.bt;
n.nnum = right.nd.ndFLink;
if (bt_getnode(&n) < 0)
return -1;
n.nd.ndBLink = right.nnum;
if (bt_putnode(&n) < 0)
return -1;
}
return 0;
}
