This source file includes following definitions.
- sqlite3HashInit
- sqlite3HashClear
- strHash
- insertElement
- rehash
- findElementGivenHash
- removeElementGivenHash
- sqlite3HashFind
- sqlite3HashInsert
#include "sqliteInt.h"
#include <assert.h>
void sqlite3HashInit(Hash *pNew){
assert( pNew!=0 );
pNew->first = 0;
pNew->count = 0;
pNew->htsize = 0;
pNew->ht = 0;
}
void sqlite3HashClear(Hash *pH){
HashElem *elem;
assert( pH!=0 );
elem = pH->first;
pH->first = 0;
sqlite3_free(pH->ht);
pH->ht = 0;
pH->htsize = 0;
while( elem ){
HashElem *next_elem = elem->next;
sqlite3_free(elem);
elem = next_elem;
}
pH->count = 0;
}
static unsigned int strHash(const char *z, int nKey){
int h = 0;
assert( nKey>=0 );
while( nKey > 0 ){
h = (h<<3) ^ h ^ sqlite3UpperToLower[(unsigned char)*z++];
nKey--;
}
return h;
}
static void insertElement(
Hash *pH,
struct _ht *pEntry,
HashElem *pNew
){
HashElem *pHead;
if( pEntry ){
pHead = pEntry->count ? pEntry->chain : 0;
pEntry->count++;
pEntry->chain = pNew;
}else{
pHead = 0;
}
if( pHead ){
pNew->next = pHead;
pNew->prev = pHead->prev;
if( pHead->prev ){ pHead->prev->next = pNew; }
else { pH->first = pNew; }
pHead->prev = pNew;
}else{
pNew->next = pH->first;
if( pH->first ){ pH->first->prev = pNew; }
pNew->prev = 0;
pH->first = pNew;
}
}
static int rehash(Hash *pH, unsigned int new_size){
struct _ht *new_ht;
HashElem *elem, *next_elem;
#if SQLITE_MALLOC_SOFT_LIMIT>0
if( new_size*sizeof(struct _ht)>SQLITE_MALLOC_SOFT_LIMIT ){
new_size = SQLITE_MALLOC_SOFT_LIMIT/sizeof(struct _ht);
}
if( new_size==pH->htsize ) return 0;
#endif
sqlite3BeginBenignMalloc();
new_ht = (struct _ht *)sqlite3Malloc( new_size*sizeof(struct _ht) );
sqlite3EndBenignMalloc();
if( new_ht==0 ) return 0;
sqlite3_free(pH->ht);
pH->ht = new_ht;
pH->htsize = new_size = sqlite3MallocSize(new_ht)/sizeof(struct _ht);
memset(new_ht, 0, new_size*sizeof(struct _ht));
for(elem=pH->first, pH->first=0; elem; elem = next_elem){
unsigned int h = strHash(elem->pKey, elem->nKey) % new_size;
next_elem = elem->next;
insertElement(pH, &new_ht[h], elem);
}
return 1;
}
static HashElem *findElementGivenHash(
const Hash *pH,
const char *pKey,
int nKey,
unsigned int h
){
HashElem *elem;
int count;
if( pH->ht ){
struct _ht *pEntry = &pH->ht[h];
elem = pEntry->chain;
count = pEntry->count;
}else{
elem = pH->first;
count = pH->count;
}
while( count-- && ALWAYS(elem) ){
if( elem->nKey==nKey && sqlite3StrNICmp(elem->pKey,pKey,nKey)==0 ){
return elem;
}
elem = elem->next;
}
return 0;
}
static void removeElementGivenHash(
Hash *pH,
HashElem* elem,
unsigned int h
){
struct _ht *pEntry;
if( elem->prev ){
elem->prev->next = elem->next;
}else{
pH->first = elem->next;
}
if( elem->next ){
elem->next->prev = elem->prev;
}
if( pH->ht ){
pEntry = &pH->ht[h];
if( pEntry->chain==elem ){
pEntry->chain = elem->next;
}
pEntry->count--;
assert( pEntry->count>=0 );
}
sqlite3_free( elem );
pH->count--;
if( pH->count<=0 ){
assert( pH->first==0 );
assert( pH->count==0 );
sqlite3HashClear(pH);
}
}
void *sqlite3HashFind(const Hash *pH, const char *pKey, int nKey){
HashElem *elem;
unsigned int h;
assert( pH!=0 );
assert( pKey!=0 );
assert( nKey>=0 );
if( pH->ht ){
h = strHash(pKey, nKey) % pH->htsize;
}else{
h = 0;
}
elem = findElementGivenHash(pH, pKey, nKey, h);
return elem ? elem->data : 0;
}
void *sqlite3HashInsert(Hash *pH, const char *pKey, int nKey, void *data){
unsigned int h;
HashElem *elem;
HashElem *new_elem;
assert( pH!=0 );
assert( pKey!=0 );
assert( nKey>=0 );
if( pH->htsize ){
h = strHash(pKey, nKey) % pH->htsize;
}else{
h = 0;
}
elem = findElementGivenHash(pH,pKey,nKey,h);
if( elem ){
void *old_data = elem->data;
if( data==0 ){
removeElementGivenHash(pH,elem,h);
}else{
elem->data = data;
elem->pKey = pKey;
assert(nKey==elem->nKey);
}
return old_data;
}
if( data==0 ) return 0;
new_elem = (HashElem*)sqlite3Malloc( sizeof(HashElem) );
if( new_elem==0 ) return data;
new_elem->pKey = pKey;
new_elem->nKey = nKey;
new_elem->data = data;
pH->count++;
if( pH->count>=10 && pH->count > 2*pH->htsize ){
if( rehash(pH, pH->count*2) ){
assert( pH->htsize>0 );
h = strHash(pKey, nKey) % pH->htsize;
}
}
if( pH->ht ){
insertElement(pH, &pH->ht[h], new_elem);
}else{
insertElement(pH, 0, new_elem);
}
return 0;
}