/* Insert an element into the hash table pH. The key is pKey,nKey
** and the data is "data".
**
** If no element exists with a matching key, then a new
** element is created. A copy of the key is made if the copyKey
** flag is set. NULL is returned.
**
** If another element already exists with the same key, then the
** new data replaces the old data and the old data is returned.
** The key is not copied in this instance. If a malloc fails, then
** the new data is returned and the hash table is unchanged.
**
** If the "data" parameter to this function is NULL, then the
** element corresponding to "key" is removed from the hash table.
*/
SQLITE_PRIVATE void *sqlite3Fts3HashInsert(
Fts3Hash *pH, /* The hash table to insert into */
const void *pKey, /* The key */
int nKey, /* Number of bytes in the key */
void *data /* The data */
) {
int hraw; /* Raw hash value of the key */
int h; /* the hash of the key modulo hash table size */
Fts3HashElem *elem; /* Used to loop thru the element list */
Fts3HashElem *new_elem; /* New element added to the pH */
int (*xHash)(const void*,int); /* The hash function */
assert( pH!=0 );
xHash = ftsHashFunction(pH->keyClass);
assert( xHash!=0 );
hraw = (*xHash)(pKey, nKey);
assert( (pH->htsize & (pH->htsize-1))==0 );
h = hraw & (pH->htsize-1);
elem = fts3FindElementByHash(pH,pKey,nKey,h);
if( elem ) {
void *old_data = elem->data;
if( data==0 ) {
fts3RemoveElementByHash(pH,elem,h);
} else {
elem->data = data;
}
return old_data;
}
if( data==0 ) return 0;
if( (pH->htsize==0 && fts3Rehash(pH,8))
|| (pH->count>=pH->htsize && fts3Rehash(pH, pH->htsize*2))
) {
pH->count = 0;
return data;
}
assert( pH->htsize>0 );
new_elem = (Fts3HashElem*)fts3HashMalloc( sizeof(Fts3HashElem) );
if( new_elem==0 ) return data;
if( pH->copyKey && pKey!=0 ) {
new_elem->pKey = fts3HashMalloc( nKey );
if( new_elem->pKey==0 ) {
fts3HashFree(new_elem);
return data;
}
memcpy((void*)new_elem->pKey, pKey, nKey);
} else {
new_elem->pKey = (void*)pKey;
}
new_elem->nKey = nKey;
pH->count++;
assert( pH->htsize>0 );
assert( (pH->htsize & (pH->htsize-1))==0 );
h = hraw & (pH->htsize-1);
fts3HashInsertElement(pH, &pH->ht[h], new_elem);
new_elem->data = data;
return 0;
}
/* Attempt to locate an element of the hash table pH with a key
** that matches pKey,nKey. Return the data for this element if it is
** found, or NULL if there is no match.
*/
void *sqlite3Fts3HashFind(const Fts3Hash *pH, const void *pKey, int nKey){
int h; /* A hash on key */
Fts3HashElem *elem; /* The element that matches key */
int (*xHash)(const void*,int); /* The hash function */
if( pH==0 || pH->ht==0 ) return 0;
xHash = ftsHashFunction(pH->keyClass);
assert( xHash!=0 );
h = (*xHash)(pKey,nKey);
assert( (pH->htsize & (pH->htsize-1))==0 );
elem = fts3FindElementByHash(pH,pKey,nKey, h & (pH->htsize-1));
return elem ? elem->data : 0;
}
SQLITE_PRIVATE Fts3HashElem *sqlite3Fts3HashFindElem(
const Fts3Hash *pH,
const void *pKey,
int nKey
) {
int h; /* A hash on key */
int (*xHash)(const void*,int); /* The hash function */
if( pH==0 || pH->ht==0 ) return 0;
xHash = ftsHashFunction(pH->keyClass);
assert( xHash!=0 );
h = (*xHash)(pKey,nKey);
assert( (pH->htsize & (pH->htsize-1))==0 );
return fts3FindElementByHash(pH,pKey,nKey, h & (pH->htsize-1));
}
/* Resize the hash table so that it cantains "new_size" buckets.
** "new_size" must be a power of 2. The hash table might fail
** to resize if sqliteMalloc() fails.
**
** Return non-zero if a memory allocation error occurs.
*/
static int fts3Rehash(Fts3Hash *pH, int new_size) {
struct _fts3ht *new_ht; /* The new hash table */
Fts3HashElem *elem, *next_elem; /* For looping over existing elements */
int (*xHash)(const void*,int); /* The hash function */
assert( (new_size & (new_size-1))==0 );
new_ht = (struct _fts3ht *)fts3HashMalloc( new_size*sizeof(struct _fts3ht) );
if( new_ht==0 ) return 1;
fts3HashFree(pH->ht);
pH->ht = new_ht;
pH->htsize = new_size;
xHash = ftsHashFunction(pH->keyClass);
for(elem=pH->first, pH->first=0; elem; elem = next_elem) {
int h = (*xHash)(elem->pKey, elem->nKey) & (new_size-1);
next_elem = elem->next;
fts3HashInsertElement(pH, &new_ht[h], elem);
}
return 0;
}
