Index: third_party/sqlite/sqlite-src-3080704/src/hash.c |
diff --git a/third_party/sqlite/sqlite-src-3080704/src/hash.c b/third_party/sqlite/sqlite-src-3080704/src/hash.c |
new file mode 100644 |
index 0000000000000000000000000000000000000000..b5886e064152b8face140874a447ec596c11832d |
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+++ b/third_party/sqlite/sqlite-src-3080704/src/hash.c |
@@ -0,0 +1,267 @@ |
+/* |
+** 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. |
+** |
+************************************************************************* |
+** This is the implementation of generic hash-tables |
+** used in SQLite. |
+*/ |
+#include "sqliteInt.h" |
+#include <assert.h> |
+ |
+/* 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. |
+*/ |
+void sqlite3HashInit(Hash *pNew){ |
+ assert( pNew!=0 ); |
+ 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 sqlite3HashClear(Hash *pH){ |
+ HashElem *elem; /* For looping over all elements of the table */ |
+ |
+ 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; |
+} |
+ |
+/* |
+** The hashing function. |
+*/ |
+static unsigned int strHash(const char *z){ |
+ unsigned int h = 0; |
+ unsigned char c; |
+ while( (c = (unsigned char)*z++)!=0 ){ |
+ h = (h<<3) ^ h ^ sqlite3UpperToLower[c]; |
+ } |
+ return h; |
+} |
+ |
+ |
+/* Link pNew element into the hash table pH. If pEntry!=0 then also |
+** insert pNew into the pEntry hash bucket. |
+*/ |
+static void insertElement( |
+ Hash *pH, /* The complete hash table */ |
+ struct _ht *pEntry, /* The entry into which pNew is inserted */ |
+ HashElem *pNew /* The element to be inserted */ |
+){ |
+ HashElem *pHead; /* First element already in pEntry */ |
+ 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; |
+ } |
+} |
+ |
+ |
+/* Resize the hash table so that it cantains "new_size" buckets. |
+** |
+** The hash table might fail to resize if sqlite3_malloc() fails or |
+** if the new size is the same as the prior size. |
+** Return TRUE if the resize occurs and false if not. |
+*/ |
+static int rehash(Hash *pH, unsigned int new_size){ |
+ struct _ht *new_ht; /* The new hash table */ |
+ HashElem *elem, *next_elem; /* For looping over existing elements */ |
+ |
+#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 |
+ |
+ /* The inability to allocates space for a larger hash table is |
+ ** a performance hit but it is not a fatal error. So mark the |
+ ** allocation as a benign. Use sqlite3Malloc()/memset(0) instead of |
+ ** sqlite3MallocZero() to make the allocation, as sqlite3MallocZero() |
+ ** only zeroes the requested number of bytes whereas this module will |
+ ** use the actual amount of space allocated for the hash table (which |
+ ** may be larger than the requested amount). |
+ */ |
+ 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) % new_size; |
+ next_elem = elem->next; |
+ insertElement(pH, &new_ht[h], elem); |
+ } |
+ return 1; |
+} |
+ |
+/* This function (for internal use only) locates an element in an |
+** hash table that matches the given key. The hash for this key is |
+** also computed and returned in the *pH parameter. |
+*/ |
+static HashElem *findElementWithHash( |
+ const Hash *pH, /* The pH to be searched */ |
+ const char *pKey, /* The key we are searching for */ |
+ unsigned int *pHash /* Write the hash value here */ |
+){ |
+ HashElem *elem; /* Used to loop thru the element list */ |
+ int count; /* Number of elements left to test */ |
+ unsigned int h; /* The computed hash */ |
+ |
+ if( pH->ht ){ |
+ struct _ht *pEntry; |
+ h = strHash(pKey) % pH->htsize; |
+ pEntry = &pH->ht[h]; |
+ elem = pEntry->chain; |
+ count = pEntry->count; |
+ }else{ |
+ h = 0; |
+ elem = pH->first; |
+ count = pH->count; |
+ } |
+ *pHash = h; |
+ while( count-- ){ |
+ assert( elem!=0 ); |
+ if( sqlite3StrICmp(elem->pKey,pKey)==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 removeElementGivenHash( |
+ Hash *pH, /* The pH containing "elem" */ |
+ HashElem* elem, /* The element to be removed from the pH */ |
+ unsigned int h /* Hash value for the element */ |
+){ |
+ 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); |
+ } |
+} |
+ |
+/* Attempt to locate an element of the hash table pH with a key |
+** that matches pKey. Return the data for this element if it is |
+** found, or NULL if there is no match. |
+*/ |
+void *sqlite3HashFind(const Hash *pH, const char *pKey){ |
+ HashElem *elem; /* The element that matches key */ |
+ unsigned int h; /* A hash on key */ |
+ |
+ assert( pH!=0 ); |
+ assert( pKey!=0 ); |
+ elem = findElementWithHash(pH, pKey, &h); |
+ return elem ? elem->data : 0; |
+} |
+ |
+/* Insert an element into the hash table pH. The key is pKey |
+** and the data is "data". |
+** |
+** If no element exists with a matching key, then a new |
+** element is created and 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 *sqlite3HashInsert(Hash *pH, const char *pKey, void *data){ |
+ unsigned int h; /* the hash of the key modulo hash table size */ |
+ HashElem *elem; /* Used to loop thru the element list */ |
+ HashElem *new_elem; /* New element added to the pH */ |
+ |
+ assert( pH!=0 ); |
+ assert( pKey!=0 ); |
+ elem = findElementWithHash(pH,pKey,&h); |
+ if( elem ){ |
+ void *old_data = elem->data; |
+ if( data==0 ){ |
+ removeElementGivenHash(pH,elem,h); |
+ }else{ |
+ elem->data = data; |
+ elem->pKey = pKey; |
+ } |
+ 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->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) % pH->htsize; |
+ } |
+ } |
+ insertElement(pH, pH->ht ? &pH->ht[h] : 0, new_elem); |
+ return 0; |
+} |