/* ** 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; }