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/* Copyright (C) 2000 MySQL AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/* Quick & light hash implementation for tab completion purposes
*
* by Andi Gutmans <andi@zend.com>
* and Zeev Suraski <zeev@zend.com>
* Small portability changes by Monty. Changed also to use my_malloc/my_free
*/
#include <my_global.h>
#include <m_string.h>
#undef SAFEMALLOC // Speed things up
#include <my_sys.h>
#include "completion_hash.h"
uint hashpjw(const char *arKey, uint nKeyLength)
{
uint h = 0, g, i;
for (i = 0; i < nKeyLength; i++) {
h = (h << 4) + arKey[i];
if ((g = (h & 0xF0000000))) {
h = h ^ (g >> 24);
h = h ^ g;
}
}
return h;
}
int completion_hash_init(HashTable *ht, uint nSize)
{
ht->arBuckets = (Bucket **) my_malloc(nSize* sizeof(Bucket *),
MYF(MY_ZEROFILL | MY_WME));
if (!ht->arBuckets)
{
ht->initialized = 0;
return FAILURE;
}
init_alloc_root(&ht->mem_root, 8192, 0);
ht->pHashFunction = hashpjw;
ht->nTableSize = nSize;
ht->initialized = 1;
return SUCCESS;
}
int completion_hash_update(HashTable *ht, char *arKey, uint nKeyLength,
char *str)
{
uint h, nIndex;
Bucket *p;
h = ht->pHashFunction(arKey, nKeyLength);
nIndex = h % ht->nTableSize;
if (nKeyLength <= 0) {
return FAILURE;
}
p = ht->arBuckets[nIndex];
while (p)
{
if ((p->h == h) && (p->nKeyLength == nKeyLength)) {
if (!memcmp(p->arKey, arKey, nKeyLength)) {
entry *n;
if (!(n = (entry *) alloc_root(&ht->mem_root,sizeof(entry))))
return FAILURE;
n->pNext = p->pData;
n->str = str;
p->pData = n;
p->count++;
return SUCCESS;
}
}
p = p->pNext;
}
if (!(p = (Bucket *) alloc_root(&ht->mem_root, sizeof(Bucket))))
return FAILURE;
p->arKey = arKey;
p->nKeyLength = nKeyLength;
p->h = h;
if (!(p->pData = (entry*) alloc_root(&ht->mem_root, sizeof(entry))))
return FAILURE;
p->pData->str = str;
p->pData->pNext = 0;
p->count = 1;
p->pNext = ht->arBuckets[nIndex];
ht->arBuckets[nIndex] = p;
return SUCCESS;
}
static Bucket *completion_hash_find(HashTable *ht, const char *arKey,
uint nKeyLength)
{
uint h, nIndex;
Bucket *p;
h = ht->pHashFunction(arKey, nKeyLength);
nIndex = h % ht->nTableSize;
p = ht->arBuckets[nIndex];
while (p)
{
if ((p->h == h) && (p->nKeyLength == nKeyLength)) {
if (!memcmp(p->arKey, arKey, nKeyLength)) {
return p;
}
}
p = p->pNext;
}
return (Bucket*) 0;
}
int completion_hash_exists(HashTable *ht, char *arKey, uint nKeyLength)
{
uint h, nIndex;
Bucket *p;
h = ht->pHashFunction(arKey, nKeyLength);
nIndex = h % ht->nTableSize;
p = ht->arBuckets[nIndex];
while (p)
{
if ((p->h == h) && (p->nKeyLength == nKeyLength))
{
if (!strcmp(p->arKey, arKey)) {
return 1;
}
}
p = p->pNext;
}
return 0;
}
Bucket *find_all_matches(HashTable *ht, const char *str, uint length,
uint *res_length)
{
Bucket *b;
b = completion_hash_find(ht,str,length);
if (!b) {
*res_length = 0;
return (Bucket*) 0;
} else {
*res_length = length;
return b;
}
}
Bucket *find_longest_match(HashTable *ht, char *str, uint length,
uint *res_length)
{
Bucket *b,*return_b;
char *s;
uint count;
uint lm;
b = completion_hash_find(ht,str,length);
if (!b) {
*res_length = 0;
return (Bucket*) 0;
}
count = b->count;
lm = length;
s = b->pData->str;
return_b = b;
while (s[lm]!=0 && (b=completion_hash_find(ht,s,lm+1))) {
if (b->count<count) {
*res_length=lm;
return return_b;
}
return_b=b;
lm++;
}
*res_length=lm;
return return_b;
}
void completion_hash_clean(HashTable *ht)
{
free_root(&ht->mem_root,MYF(0));
bzero((char*) ht->arBuckets,ht->nTableSize*sizeof(Bucket *));
}
void completion_hash_free(HashTable *ht)
{
completion_hash_clean(ht);
my_free(ht->arBuckets, MYF(0));
}
void add_word(HashTable *ht,char *str)
{
int i;
char *pos=str;
for (i=1; *pos; i++, pos++)
completion_hash_update(ht, str, i, str);
}
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