/*
** Free memory.
*/
void sqlite3_free(void *pPrior) {
struct MemBlockHdr *pHdr;
void **pBt;
char *z;
if( pPrior==0 ) {
return;
}
assert( mem.mutex!=0 );
pHdr = sqlite3MemsysGetHeader(pPrior);
pBt = (void**)pHdr;
pBt -= pHdr->nBacktraceSlots;
sqlite3_mutex_enter(mem.mutex);
mem.nowUsed -= pHdr->iSize;
if( pHdr->pPrev ) {
assert( pHdr->pPrev->pNext==pHdr );
pHdr->pPrev->pNext = pHdr->pNext;
} else {
assert( mem.pFirst==pHdr );
mem.pFirst = pHdr->pNext;
}
if( pHdr->pNext ) {
assert( pHdr->pNext->pPrev==pHdr );
pHdr->pNext->pPrev = pHdr->pPrev;
} else {
assert( mem.pLast==pHdr );
mem.pLast = pHdr->pPrev;
}
z = (char*)pBt;
z -= pHdr->nTitle;
memset(z, 0x2b, sizeof(void*)*pHdr->nBacktraceSlots + sizeof(*pHdr) +
pHdr->iSize + sizeof(int) + pHdr->nTitle);
free(z);
sqlite3_mutex_leave(mem.mutex);
}
/*
** Free memory.
*/
static void sqlite3MemFree(void *pPrior){
struct MemBlockHdr *pHdr;
void **pBt;
char *z;
assert( sqlite3Config.bMemstat || mem.mutex!=0 );
pHdr = sqlite3MemsysGetHeader(pPrior);
pBt = (void**)pHdr;
pBt -= pHdr->nBacktraceSlots;
sqlite3_mutex_enter(mem.mutex);
if( pHdr->pPrev ){
assert( pHdr->pPrev->pNext==pHdr );
pHdr->pPrev->pNext = pHdr->pNext;
}else{
assert( mem.pFirst==pHdr );
mem.pFirst = pHdr->pNext;
}
if( pHdr->pNext ){
assert( pHdr->pNext->pPrev==pHdr );
pHdr->pNext->pPrev = pHdr->pPrev;
}else{
assert( mem.pLast==pHdr );
mem.pLast = pHdr->pPrev;
}
z = (char*)pBt;
z -= pHdr->nTitle;
adjustStats(pHdr->iSize, -1);
memset(z, 0x2b, sizeof(void*)*pHdr->nBacktraceSlots + sizeof(*pHdr) +
pHdr->iSize + sizeof(int) + pHdr->nTitle);
free(z);
sqlite3_mutex_leave(mem.mutex);
}
/*
** Return the number of bytes currently allocated at address p.
*/
static int sqlite3MemSize(void *p){
struct MemBlockHdr *pHdr;
if( !p ){
return 0;
}
pHdr = sqlite3MemsysGetHeader(p);
return pHdr->iSize;
}
/*
** Change the size of an existing memory allocation.
**
** For this debugging implementation, we *always* make a copy of the
** allocation into a new place in memory. In this way, if the
** higher level code is using pointer to the old allocation, it is
** much more likely to break and we are much more liking to find
** the error.
*/
static void *sqlite3MemRealloc(void *pPrior, int nByte){
struct MemBlockHdr *pOldHdr;
void *pNew;
assert( mem.disallow==0 );
pOldHdr = sqlite3MemsysGetHeader(pPrior);
pNew = sqlite3MemMalloc(nByte);
if( pNew ){
memcpy(pNew, pPrior, nByte<pOldHdr->iSize ? nByte : pOldHdr->iSize);
if( nByte>pOldHdr->iSize ){
memset(&((char*)pNew)[pOldHdr->iSize], 0x2b, nByte - pOldHdr->iSize);
}
sqlite3MemFree(pPrior);
}
return pNew;
}