void *dict_find(dict_t *dict, void *key, size_t bytes)
{
unsigned int index = _dict_index(dict, key, bytes);
/* not founded in the index-th bucket, then insert */
bucket_elem_t *elem = _bucket_find(&dict->table[index], key, bytes);
return elem == NULL ? NULL : elem->value;
}
int bucket_remove(struct bucket *bkt,char *term)
{
unsigned short pos;
unsigned int len;
char *posptr;
int size;
unsigned short i;
unsigned short true_invertedlen;
if(_bucket_find(bkt,term,&pos) != 0)
return -1;
/* remove inverted list */
true_invertedlen = (bkt->record[pos].invertedlen==USHRT_MAX) ? (sizeof(int)+sizeof(off_t)):bkt->record[pos].invertedlen;
len = bkt->record[pos].termlen + true_invertedlen;
posptr = (char*)bkt->head+bkt->record[pos].offset;
size = posptr - START_OF_INVERTEDLIST;
memmove(START_OF_INVERTEDLIST+len,START_OF_INVERTEDLIST,size);
bkt->head->ptr += len;
/* remove entry in record */
memmove(&bkt->record[pos],&bkt->record[pos+1],(bkt->head->num-pos-1)*sizeof(struct RECORD));
bkt->head->num--;
/* update entry's offset in record */
for(i=0; i<bkt->head->num; i++)
{
if((char*)bkt->head+bkt->record[i].offset < posptr)
bkt->record[i].offset += len;
}
bkt->page->dirty = true;
return 0;
}
char* bucket_find(struct bucket *bkt,const char *term,unsigned int *invertedlen)
{
unsigned short pos;
if(_bucket_find(bkt,term,&pos) != 0)
return NULL;
*invertedlen = bkt->record[pos].invertedlen;
return (char*)bkt->head + bkt->record[pos].offset + bkt->record[pos].termlen;
}
/* NOTE:assume the term isn't in bucket,otherwise you must remove it before insert!!! */
int bucket_insert(struct bucket *bkt,char *term,void *invertedlist,unsigned short invertedlen)
{
unsigned short pos;
int termlen;
int big;
char string[256];
unsigned short true_invertedlen;
true_invertedlen = (invertedlen==USHRT_MAX) ? (sizeof(int)+sizeof(off_t)):invertedlen;
if(bkt->head->num == 0)
{
termlen = strlen(term);
if((char*)&bkt->record[1] > START_OF_INVERTEDLIST-true_invertedlen-termlen)
return -2;
bkt->head->ptr = bkt->head->ptr-true_invertedlen-termlen;
memcpy(START_OF_INVERTEDLIST,term,termlen);
memcpy(START_OF_INVERTEDLIST+termlen,invertedlist,true_invertedlen);
bkt->record[0].offset = bkt->head->ptr;
bkt->record[0].termlen = termlen;
bkt->record[0].invertedlen = invertedlen;
bkt->head->num++;
bkt->page->dirty = true;
return 0;
}
if(_bucket_find(bkt,term,&pos) == 0)
return -1;
termlen = bkt->record[pos].termlen;
memcpy(string,(char*)bkt->head+bkt->record[pos].offset,termlen);
string[termlen] = '\0';
termlen = strlen(term);
if(START_OF_INVERTEDLIST-true_invertedlen-termlen < (char*)&bkt->record[bkt->head->num]+sizeof(struct RECORD)) /* not enough space */
return -2;
big = strcmp(term,string);
if(big < 0) /* insert before pos */
{
/* modify for record */
memmove(&bkt->record[pos+1],&bkt->record[pos],(bkt->head->num-pos)*sizeof(struct RECORD));
bkt->record[pos].termlen = termlen;
bkt->record[pos].invertedlen = invertedlen;
bkt->record[pos].offset = START_OF_INVERTEDLIST-true_invertedlen-termlen-(char*)bkt->head;
bkt->head->ptr = bkt->head->ptr-true_invertedlen-termlen;
memcpy(START_OF_INVERTEDLIST,term,termlen); /* modify inverted list */
memcpy(START_OF_INVERTEDLIST+termlen,invertedlist,true_invertedlen);
bkt->head->num++;
}
else /* insert after pos */
{
if(pos+1 < bkt->head->num) /* modify record */
memmove(&bkt->record[pos+2],&bkt->record[pos+1],(bkt->head->num-pos-1)*sizeof(struct RECORD));
bkt->record[pos+1].termlen = termlen;
bkt->record[pos+1].invertedlen = invertedlen;
bkt->record[pos+1].offset = START_OF_INVERTEDLIST-true_invertedlen-termlen-(char*)bkt->head;
bkt->head->ptr = bkt->head->ptr-true_invertedlen-termlen;
memcpy(START_OF_INVERTEDLIST,term,termlen); /* modify inverted list */
memcpy(START_OF_INVERTEDLIST+termlen,invertedlist,true_invertedlen);
bkt->head->num++;
}
bkt->page->dirty = true;
assert(START_OF_INVERTEDLIST >= (char*)&bkt->record[bkt->head->num]);
return 0;
}
