Import SQLite 3.7.6.3.

third_party/sqlite/src/ext/fts3/fts3_hash.c

 /*
 ** 2001 September 22
 **
 ** The author disclaims copyright to this source code.  In place of
 ** a legal notice, here is a blessing:
 **
 **    May you do good and not evil.
 **    May you find forgiveness for yourself and forgive others.
 **    May you share freely, never taking more than you give.
 **
@@ skipping 38 matching lines @@
 /* Turn bulk memory into a hash table object by initializing the
 ** fields of the Hash structure.
 **
 ** "pNew" is a pointer to the hash table that is to be initialized.
 ** keyClass is one of the constants 
 ** FTS3_HASH_BINARY or FTS3_HASH_STRING.  The value of keyClass 
 ** determines what kind of key the hash table will use.  "copyKey" is
 ** true if the hash table should make its own private copy of keys and
 ** false if it should just use the supplied pointer.
 */
-void sqlite3Fts3HashInit(fts3Hash *pNew, int keyClass, int copyKey){
+void sqlite3Fts3HashInit(Fts3Hash *pNew, char keyClass, char copyKey){
   assert( pNew!=0 );
   assert( keyClass>=FTS3_HASH_STRING && keyClass<=FTS3_HASH_BINARY );
   pNew->keyClass = keyClass;
   pNew->copyKey = copyKey;
   pNew->first = 0;
   pNew->count = 0;
   pNew->htsize = 0;
   pNew->ht = 0;
 }
 
 /* Remove all entries from a hash table.  Reclaim all memory.
 ** Call this routine to delete a hash table or to reset a hash table
 ** to the empty state.
 */
-void sqlite3Fts3HashClear(fts3Hash *pH){
-  fts3HashElem *elem;         /* For looping over all elements of the table */
+void sqlite3Fts3HashClear(Fts3Hash *pH){
+  Fts3HashElem *elem;         /* For looping over all elements of the table */
 
   assert( pH!=0 );
   elem = pH->first;
   pH->first = 0;
   fts3HashFree(pH->ht);
   pH->ht = 0;
   pH->htsize = 0;
   while( elem ){
-    fts3HashElem *next_elem = elem->next;
+    Fts3HashElem *next_elem = elem->next;
     if( pH->copyKey && elem->pKey ){
       fts3HashFree(elem->pKey);
     }
     fts3HashFree(elem);
     elem = next_elem;
   }
   pH->count = 0;
 }
 
 /*
@@ skipping 62 matching lines @@
     return &fts3StrCompare;
   }else{
     assert( keyClass==FTS3_HASH_BINARY );
     return &fts3BinCompare;
   }
 }
 
 /* Link an element into the hash table
 */
 static void fts3HashInsertElement(
-  fts3Hash *pH,            /* The complete hash table */
+  Fts3Hash *pH,            /* The complete hash table */
   struct _fts3ht *pEntry,  /* The entry into which pNew is inserted */
-  fts3HashElem *pNew       /* The element to be inserted */
+  Fts3HashElem *pNew       /* The element to be inserted */
 ){
-  fts3HashElem *pHead;     /* First element already in pEntry */
+  Fts3HashElem *pHead;     /* First element already in pEntry */
   pHead = pEntry->chain;
   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;
   }
   pEntry->count++;
   pEntry->chain = pNew;
 }
 
 
 /* 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 void fts3Rehash(fts3Hash *pH, int new_size){
+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 */
+  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;
+  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;
 }
 
 /* This function (for internal use only) locates an element in an
 ** hash table that matches the given key.  The hash for this key has
 ** already been computed and is passed as the 4th parameter.
 */
-static fts3HashElem *fts3FindElementByHash(
-  const fts3Hash *pH, /* The pH to be searched */
+static Fts3HashElem *fts3FindElementByHash(
+  const Fts3Hash *pH, /* The pH to be searched */
   const void *pKey,   /* The key we are searching for */
   int nKey,
   int h               /* The hash for this key. */
 ){
-  fts3HashElem *elem;            /* Used to loop thru the element list */
+  Fts3HashElem *elem;            /* Used to loop thru the element list */
   int count;                     /* Number of elements left to test */
   int (*xCompare)(const void*,int,const void*,int);  /* comparison function */
 
   if( pH->ht ){
     struct _fts3ht *pEntry = &pH->ht[h];
     elem = pEntry->chain;
     count = pEntry->count;
     xCompare = ftsCompareFunction(pH->keyClass);
     while( count-- && elem ){
       if( (*xCompare)(elem->pKey,elem->nKey,pKey,nKey)==0 ){ 
         return elem;
       }
       elem = elem->next;
     }
   }
   return 0;
 }
 
 /* Remove a single entry from the hash table given a pointer to that
 ** element and a hash on the element's key.
 */
 static void fts3RemoveElementByHash(
-  fts3Hash *pH,         /* The pH containing "elem" */
-  fts3HashElem* elem,   /* The element to be removed from the pH */
+  Fts3Hash *pH,         /* The pH containing "elem" */
+  Fts3HashElem* elem,   /* The element to be removed from the pH */
   int h                 /* Hash value for the element */
 ){
   struct _fts3ht *pEntry;
   if( elem->prev ){
     elem->prev->next = elem->next; 
   }else{
     pH->first = elem->next;
   }
   if( elem->next ){
     elem->next->prev = elem->prev;
@@ skipping 11 matching lines @@
   }
   fts3HashFree( elem );
   pH->count--;
   if( pH->count<=0 ){
     assert( pH->first==0 );
     assert( pH->count==0 );
     fts3HashClear(pH);
   }
 }
 
-/* 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 */
+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 );
-  elem = fts3FindElementByHash(pH,pKey,nKey, h & (pH->htsize-1));
-  return elem ? elem->data : 0;
+  return fts3FindElementByHash(pH,pKey,nKey, h & (pH->htsize-1));
+}
+
+/* 
+** 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){
+  Fts3HashElem *pElem;            /* The element that matches key (if any) */
+
+  pElem = sqlite3Fts3HashFindElem(pH, pKey, nKey);
+  return pElem ? pElem->data : 0;
 }
 
 /* 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.
 */
 void *sqlite3Fts3HashInsert(
-  fts3Hash *pH,        /* The hash table to insert into */
+  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 */
+  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);
-    if( pH->htsize==0 ){
-      pH->count = 0;
-      return data;
-    }
+  if( (pH->htsize==0 && fts3Rehash(pH,8))
+   || (pH->count>=pH->htsize && fts3Rehash(pH, pH->htsize*2))
+  ){
+    pH->count = 0;
+    return data;
   }
-  new_elem = (fts3HashElem*)fts3HashMalloc( sizeof(fts3HashElem) );
+  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++;
-  if( pH->count > pH->htsize ){
-    fts3Rehash(pH,pH->htsize*2);
-  }
   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;
 }
 
 #endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */