/* Position node in btree so that key might be inside */
static node_buf* record_find_node(btree* tree, void *key)
{
int start, end, mid, comp; // components of a binary search
void *p = NULL;
char curr_key[tree->head.max_key_len];
// The current key under examination
hfsp_key_read readkey = tree->kread;
hfsp_key_compare key_compare = tree->kcomp;
UInt32 index;
node_buf* node = btree_node_by_index(tree, tree->head.root);
if (!node)
HFSP_ERROR(-1, "record_find_node: Cant position to root node");
while (node->desc.kind == HFSP_NODE_NDX)
{
mid = start = 0;
end = node->desc.num_rec;
comp = -1;
while (start < end)
{
mid = (start + end) >> 1;
p = btree_key_by_index(tree, node, mid);
if (!p)
HFSP_ERROR(-1, "record_find_node: unexpected error");
p = readkey (p, curr_key);
if (!p)
HFSP_ERROR(-1, "record_find_node: unexpected error");
comp = key_compare(curr_key, key);
if (comp > 0)
start = mid + 1;
else if (comp < 0)
end = mid;
else
break;
}
if (!p) // Empty tree, fascinating ...
HFSP_ERROR(-1, "record_find_node: unexpected empty node");
if (comp < 0) // mmh interesting key is before this key ...
{
if (mid == 0)
return NULL; // nothing before this key ..
p = btree_key_by_index(tree, node, mid-1);
if (!p)
HFSP_ERROR(-1, "record_find_node: unexpected error");
p = readkey (p, curr_key);
if (!p)
HFSP_ERROR(-1, "record_find_node: unexpected error");
}
index = bswabU32_inc(p);
node = btree_node_by_index(tree, index);
}
return node; // go on and use the found node
fail:
return NULL;
}
/* intialize the record with the given index entry in the btree. */
int record_init(record* r, btree* bt, node_buf* buf, UInt16 index)
{
void *p;
r-> tree = bt;
p = btree_key_by_index(bt,buf,index);
if (!p)
return -1;
p = record_readkey (p, &r->key);
if (!p)
return -1;
/* void *help = p; // se comment below */
p = record_readentry(p, &r->record);
/* This was for testing write cache only
void * help;
help = record_writeentry(help, &r->record);
if (p != help)
HFSP_ERROR(-1, "Error in write entry");
*/
if (!p)
return -1;
r->node_index = buf->index;
r-> keyind = index;
return 0;
/*
fail:
return -1;
*/
}
/* Update the record using its node- and key-index.
*
* Only use this function with a write lock, directly
* after reading the record, otherwise use update_bykey().
*/
int record_update(record* r)
{
btree *tree= r->tree;
node_buf *buf = btree_node_by_index(tree, r->node_index, NODE_DIRTY);
void *p = btree_key_by_index (tree, buf, r->keyind);
if (!p)
return -1;
p = record_writekey (p, &r->key);
if (!p)
return -1;
p = record_writeentry(p, &r->record);
if (!p)
return -1;
return 0;
}
/* intialize the record with the given index entry in the btree. */
static int record_init_extent(extent_record* r, btree* bt, node_buf* buf, UInt16 index)
{
void *p;
r-> tree = bt;
p = btree_key_by_index(bt, buf,index);
if (!p)
return -1;
p = record_extent_readkey(p, &r->key);
if (!p)
return -1;
p = volume_readextent(p, r->extent);
if (!p)
return -1;
r->node_index = buf->index;
r-> keyind = index;
return 0;
}
/* intialize the record with the given index entry in the btree. */
static int record_init(record* r, btree* bt, node_buf* buf, UInt16 index)
{
void *p;
r-> tree = bt;
p = btree_key_by_index(bt,buf,index);
if (!p)
return -1;
p = record_readkey (p, &r->key);
if (!p)
return -1;
p = record_readentry(p, &r->record);
if (!p)
return -1;
r->node_index = buf->index;
r-> keyind = index;
return 0;
}
/* search for the given key in the btree.
*
* returns pointer to memory just after key or NULL
* In any case *keyind recives the index where the
* key was found (or could be inserted.)
*/
static void *
record_find_key(btree* tree, void* key, int* keyind, UInt16* node_index)
{
node_buf* buf = record_find_node(tree, key);
if (buf)
{
int comp = -1;
int start = 0; // components of a binary search
int end = buf->desc.num_rec;
int mid = -1;
void *p = NULL;
char curr_key[tree->head.max_key_len];
hfsp_key_read readkey = tree->kread;
hfsp_key_compare key_compare = tree->kcomp;
while (start < end)
{
mid = (start + end) >> 1;
p = btree_key_by_index(tree, buf, mid);
if (!p)
HFSP_ERROR(-1, "record_init_key: unexpected error");
p = readkey (p, curr_key);
if (!p)
HFSP_ERROR(-1, "record_init_cat_key: unexpected error");
comp = key_compare(curr_key, key);
if (comp > 0)
start = mid + 1;
else if (comp < 0)
end = mid;
else
break;
}
if (!p) // Empty tree, fascinating ...
HFSP_ERROR(ENOENT, "record_init_key: unexpected empty node");
*keyind = mid;
*node_index = buf->index;
if (!comp) // found something ...
return p;
}
HFSP_ERROR(ENOENT, NULL);
fail:
return NULL;
}
