diff options
| author | bernard <[email protected]> | 2017-11-02 13:50:42 +0800 |
|---|---|---|
| committer | bernard <[email protected]> | 2017-11-02 13:50:42 +0800 |
| commit | b2057f506a09e2adef81fc77efd697d16ae14bec (patch) | |
| tree | 3affefabfe376a0ec1b3ac4a5eef957c1dd58dc8 /components/external/SQLite-3.8.1/src/hash.c | |
| parent | 23582c8129228b4961ad35319cfd2d270039345f (diff) | |
[External] Remove external from RT-Thread
Diffstat (limited to 'components/external/SQLite-3.8.1/src/hash.c')
| -rw-r--r-- | components/external/SQLite-3.8.1/src/hash.c | 281 |
1 files changed, 0 insertions, 281 deletions
diff --git a/components/external/SQLite-3.8.1/src/hash.c b/components/external/SQLite-3.8.1/src/hash.c deleted file mode 100644 index e81dcf95e4..0000000000 --- a/components/external/SQLite-3.8.1/src/hash.c +++ /dev/null @@ -1,281 +0,0 @@ -/* -** 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, int nKey){ - int h = 0; - assert( nKey>=0 ); - while( nKey > 0 ){ - h = (h<<3) ^ h ^ sqlite3UpperToLower[(unsigned char)*z++]; - nKey--; - } - 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, elem->nKey) % 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 has -** already been computed and is passed as the 4th parameter. -*/ -static HashElem *findElementGivenHash( - const Hash *pH, /* The pH to be searched */ - const char *pKey, /* The key we are searching for */ - int nKey, /* Bytes in key (not counting zero terminator) */ - unsigned int h /* The hash for this key. */ -){ - HashElem *elem; /* Used to loop thru the element list */ - int count; /* Number of elements left to test */ - - 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; -} - -/* 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,nKey. 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, int nKey){ - HashElem *elem; /* The element that matches key */ - unsigned int h; /* A hash on key */ - - 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; -} - -/* 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 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, int nKey, 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 ); - 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; -} |
