sqlcipher/src/malloc.c at master · CoderXL/sqlcipher · GitHub

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** 2001 September 15

** 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.

*************************************************************************

** Memory allocation functions used throughout sqlite.

#include "sqliteInt.h"

#include <stdarg.h>

** Attempt to release up to n bytes of non-essential memory currently

** held by SQLite. An example of non-essential memory is memory used to

** cache database pages that are not currently in use.

int sqlite3_release_memory(int n){

#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT

return sqlite3PcacheReleaseMemory(n);

#else

/* IMPLEMENTATION-OF: R-34391-24921 The sqlite3_release_memory() routine

** is a no-op returning zero if SQLite is not compiled with

** SQLITE_ENABLE_MEMORY_MANAGEMENT. */

UNUSED_PARAMETER(n);

return 0;

#endif

}

** An instance of the following object records the location of

** each unused scratch buffer.

typedef struct ScratchFreeslot {

struct ScratchFreeslot *pNext; /* Next unused scratch buffer */

} ScratchFreeslot;

** State information local to the memory allocation subsystem.

static SQLITE_WSD struct Mem0Global {

sqlite3_mutex *mutex; /* Mutex to serialize access */

** The alarm callback and its arguments. The mem0.mutex lock will

** be held while the callback is running. Recursive calls into

** the memory subsystem are allowed, but no new callbacks will be

** issued.

sqlite3_int64 alarmThreshold;

void (*alarmCallback)(void*, sqlite3_int64,int);

void *alarmArg;

** Pointers to the end of sqlite3GlobalConfig.pScratch memory

** (so that a range test can be used to determine if an allocation

** being freed came from pScratch) and a pointer to the list of

** unused scratch allocations.

void *pScratchEnd;

ScratchFreeslot *pScratchFree;

u32 nScratchFree;

** True if heap is nearly "full" where "full" is defined by the

** sqlite3_soft_heap_limit() setting.

int nearlyFull;

} mem0 = { 0, 0, 0, 0, 0, 0, 0, 0 };

#define mem0 GLOBAL(struct Mem0Global, mem0)

** This routine runs when the memory allocator sees that the

** total memory allocation is about to exceed the soft heap

** limit.

static void softHeapLimitEnforcer(

void *NotUsed,

sqlite3_int64 NotUsed2,

int allocSize

){

UNUSED_PARAMETER2(NotUsed, NotUsed2);

sqlite3_release_memory(allocSize);

}

** Change the alarm callback

static int sqlite3MemoryAlarm(

void(*xCallback)(void *pArg, sqlite3_int64 used,int N),

void *pArg,

sqlite3_int64 iThreshold

){

int nUsed;

sqlite3_mutex_enter(mem0.mutex);

mem0.alarmCallback = xCallback;

mem0.alarmArg = pArg;

mem0.alarmThreshold = iThreshold;

nUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);

mem0.nearlyFull = (iThreshold>0 && iThreshold<=nUsed);

sqlite3_mutex_leave(mem0.mutex);

return SQLITE_OK;

}

#ifndef SQLITE_OMIT_DEPRECATED

** Deprecated external interface. Internal/core SQLite code

** should call sqlite3MemoryAlarm.

int sqlite3_memory_alarm(

void(*xCallback)(void *pArg, sqlite3_int64 used,int N),

void *pArg,

sqlite3_int64 iThreshold

){

return sqlite3MemoryAlarm(xCallback, pArg, iThreshold);

}

#endif

** Set the soft heap-size limit for the library. Passing a zero or

** negative value indicates no limit.

sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 n){

sqlite3_int64 priorLimit;

sqlite3_int64 excess;

#ifndef SQLITE_OMIT_AUTOINIT

int rc = sqlite3_initialize();

if( rc ) return -1;

#endif

sqlite3_mutex_enter(mem0.mutex);

priorLimit = mem0.alarmThreshold;

sqlite3_mutex_leave(mem0.mutex);

if( n<0 ) return priorLimit;

if( n>0 ){

sqlite3MemoryAlarm(softHeapLimitEnforcer, 0, n);

}else{

sqlite3MemoryAlarm(0, 0, 0);

}

excess = sqlite3_memory_used() - n;

if( excess>0 ) sqlite3_release_memory((int)(excess & 0x7fffffff));

return priorLimit;

}

void sqlite3_soft_heap_limit(int n){

if( n<0 ) n = 0;

sqlite3_soft_heap_limit64(n);

}

** Initialize the memory allocation subsystem.

int sqlite3MallocInit(void){

if( sqlite3GlobalConfig.m.xMalloc==0 ){

sqlite3MemSetDefault();

}

memset(&mem0, 0, sizeof(mem0));

if( sqlite3GlobalConfig.bCoreMutex ){

mem0.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MEM);

}

if( sqlite3GlobalConfig.pScratch && sqlite3GlobalConfig.szScratch>=100

&& sqlite3GlobalConfig.nScratch>0 ){

int i, n, sz;

ScratchFreeslot *pSlot;

sz = ROUNDDOWN8(sqlite3GlobalConfig.szScratch);

sqlite3GlobalConfig.szScratch = sz;

pSlot = (ScratchFreeslot*)sqlite3GlobalConfig.pScratch;

n = sqlite3GlobalConfig.nScratch;

mem0.pScratchFree = pSlot;

mem0.nScratchFree = n;

for(i=0; i<n-1; i++){

pSlot->pNext = (ScratchFreeslot*)(sz+(char*)pSlot);

pSlot = pSlot->pNext;

}

pSlot->pNext = 0;

mem0.pScratchEnd = (void*)&pSlot[1];

}else{

mem0.pScratchEnd = 0;

sqlite3GlobalConfig.pScratch = 0;

sqlite3GlobalConfig.szScratch = 0;

sqlite3GlobalConfig.nScratch = 0;

}

if( sqlite3GlobalConfig.pPage==0 || sqlite3GlobalConfig.szPage<512

|| sqlite3GlobalConfig.nPage<1 ){

sqlite3GlobalConfig.pPage = 0;

sqlite3GlobalConfig.szPage = 0;

sqlite3GlobalConfig.nPage = 0;

}

return sqlite3GlobalConfig.m.xInit(sqlite3GlobalConfig.m.pAppData);

}

** Return true if the heap is currently under memory pressure - in other

** words if the amount of heap used is close to the limit set by

** sqlite3_soft_heap_limit().

int sqlite3HeapNearlyFull(void){

return mem0.nearlyFull;

}

** Deinitialize the memory allocation subsystem.

void sqlite3MallocEnd(void){

if( sqlite3GlobalConfig.m.xShutdown ){

sqlite3GlobalConfig.m.xShutdown(sqlite3GlobalConfig.m.pAppData);

}

memset(&mem0, 0, sizeof(mem0));

}

** Return the amount of memory currently checked out.

sqlite3_int64 sqlite3_memory_used(void){

int n, mx;

sqlite3_int64 res;

sqlite3_status(SQLITE_STATUS_MEMORY_USED, &n, &mx, 0);

res = (sqlite3_int64)n; /* Work around bug in Borland C. Ticket #3216 */

return res;

}

** Return the maximum amount of memory that has ever been

** checked out since either the beginning of this process

** or since the most recent reset.

sqlite3_int64 sqlite3_memory_highwater(int resetFlag){

int n, mx;

sqlite3_int64 res;

sqlite3_status(SQLITE_STATUS_MEMORY_USED, &n, &mx, resetFlag);

res = (sqlite3_int64)mx; /* Work around bug in Borland C. Ticket #3216 */

return res;

}

** Trigger the alarm

static void sqlite3MallocAlarm(int nByte){

void (*xCallback)(void*,sqlite3_int64,int);

sqlite3_int64 nowUsed;

void *pArg;

if( mem0.alarmCallback==0 ) return;

xCallback = mem0.alarmCallback;

nowUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);

pArg = mem0.alarmArg;

mem0.alarmCallback = 0;

sqlite3_mutex_leave(mem0.mutex);

xCallback(pArg, nowUsed, nByte);

sqlite3_mutex_enter(mem0.mutex);

mem0.alarmCallback = xCallback;

mem0.alarmArg = pArg;

}

** Do a memory allocation with statistics and alarms. Assume the

** lock is already held.

static int mallocWithAlarm(int n, void **pp){

int nFull;

void *p;

assert( sqlite3_mutex_held(mem0.mutex) );

nFull = sqlite3GlobalConfig.m.xRoundup(n);

sqlite3StatusSet(SQLITE_STATUS_MALLOC_SIZE, n);

if( mem0.alarmCallback!=0 ){

int nUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);

if( nUsed >= mem0.alarmThreshold - nFull ){

mem0.nearlyFull = 1;

sqlite3MallocAlarm(nFull);

}else{

mem0.nearlyFull = 0;

}

p = sqlite3GlobalConfig.m.xMalloc(nFull);

#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT

if( p==0 && mem0.alarmCallback ){

sqlite3MallocAlarm(nFull);

p = sqlite3GlobalConfig.m.xMalloc(nFull);

}

#endif

if( p ){

nFull = sqlite3MallocSize(p);

sqlite3StatusAdd(SQLITE_STATUS_MEMORY_USED, nFull);

sqlite3StatusAdd(SQLITE_STATUS_MALLOC_COUNT, 1);

}

*pp = p;

return nFull;

}

** Allocate memory. This routine is like sqlite3_malloc() except that it

** assumes the memory subsystem has already been initialized.

void *sqlite3Malloc(int n){

void *p;

if( n<=0 /* IMP: R-65312-04917 */

|| n>=0x7fffff00

){

/* A memory allocation of a number of bytes which is near the maximum

** signed integer value might cause an integer overflow inside of the

** xMalloc(). Hence we limit the maximum size to 0x7fffff00, giving

** 255 bytes of overhead. SQLite itself will never use anything near

** this amount. The only way to reach the limit is with sqlite3_malloc() */

p = 0;

}else if( sqlite3GlobalConfig.bMemstat ){

sqlite3_mutex_enter(mem0.mutex);

mallocWithAlarm(n, &p);

sqlite3_mutex_leave(mem0.mutex);

}else{

p = sqlite3GlobalConfig.m.xMalloc(n);

}

assert( EIGHT_BYTE_ALIGNMENT(p) ); /* IMP: R-04675-44850 */

return p;

}

** This version of the memory allocation is for use by the application.

** First make sure the memory subsystem is initialized, then do the

** allocation.

void *sqlite3_malloc(int n){

#ifndef SQLITE_OMIT_AUTOINIT

if( sqlite3_initialize() ) return 0;

#endif

return sqlite3Malloc(n);

}

** Each thread may only have a single outstanding allocation from

** xScratchMalloc(). We verify this constraint in the single-threaded

** case by setting scratchAllocOut to 1 when an allocation

** is outstanding clearing it when the allocation is freed.

#if SQLITE_THREADSAFE==0 && !defined(NDEBUG)

static int scratchAllocOut = 0;

#endif

** Allocate memory that is to be used and released right away.

** This routine is similar to alloca() in that it is not intended

** for situations where the memory might be held long-term. This

** routine is intended to get memory to old large transient data

** structures that would not normally fit on the stack of an

** embedded processor.

void *sqlite3ScratchMalloc(int n){

void *p;

assert( n>0 );

sqlite3_mutex_enter(mem0.mutex);

if( mem0.nScratchFree && sqlite3GlobalConfig.szScratch>=n ){

p = mem0.pScratchFree;

mem0.pScratchFree = mem0.pScratchFree->pNext;

mem0.nScratchFree--;

sqlite3StatusAdd(SQLITE_STATUS_SCRATCH_USED, 1);

sqlite3StatusSet(SQLITE_STATUS_SCRATCH_SIZE, n);

sqlite3_mutex_leave(mem0.mutex);

}else{

if( sqlite3GlobalConfig.bMemstat ){

sqlite3StatusSet(SQLITE_STATUS_SCRATCH_SIZE, n);

n = mallocWithAlarm(n, &p);

if( p ) sqlite3StatusAdd(SQLITE_STATUS_SCRATCH_OVERFLOW, n);

sqlite3_mutex_leave(mem0.mutex);

}else{

sqlite3_mutex_leave(mem0.mutex);

p = sqlite3GlobalConfig.m.xMalloc(n);

}

sqlite3MemdebugSetType(p, MEMTYPE_SCRATCH);

}

assert( sqlite3_mutex_notheld(mem0.mutex) );

#if SQLITE_THREADSAFE==0 && !defined(NDEBUG)

/* Verify that no more than two scratch allocations per thread

** are outstanding at one time. (This is only checked in the

** single-threaded case since checking in the multi-threaded case

** would be much more complicated.) */

assert( scratchAllocOut<=1 );

if( p ) scratchAllocOut++;

#endif

return p;

}

void sqlite3ScratchFree(void *p){

if( p ){

#if SQLITE_THREADSAFE==0 && !defined(NDEBUG)

/* Verify that no more than two scratch allocation per thread

** is outstanding at one time. (This is only checked in the

** single-threaded case since checking in the multi-threaded case

** would be much more complicated.) */

assert( scratchAllocOut>=1 && scratchAllocOut<=2 );

scratchAllocOut--;

#endif

if( p>=sqlite3GlobalConfig.pScratch && p<mem0.pScratchEnd ){

/* Release memory from the SQLITE_CONFIG_SCRATCH allocation */

ScratchFreeslot *pSlot;

pSlot = (ScratchFreeslot*)p;

sqlite3_mutex_enter(mem0.mutex);

pSlot->pNext = mem0.pScratchFree;

mem0.pScratchFree = pSlot;

mem0.nScratchFree++;

assert( mem0.nScratchFree <= (u32)sqlite3GlobalConfig.nScratch );

sqlite3StatusAdd(SQLITE_STATUS_SCRATCH_USED, -1);

sqlite3_mutex_leave(mem0.mutex);

}else{

/* Release memory back to the heap */

assert( sqlite3MemdebugHasType(p, MEMTYPE_SCRATCH) );

assert( sqlite3MemdebugNoType(p, ~MEMTYPE_SCRATCH) );

sqlite3MemdebugSetType(p, MEMTYPE_HEAP);

if( sqlite3GlobalConfig.bMemstat ){

int iSize = sqlite3MallocSize(p);

sqlite3_mutex_enter(mem0.mutex);

sqlite3StatusAdd(SQLITE_STATUS_SCRATCH_OVERFLOW, -iSize);

sqlite3StatusAdd(SQLITE_STATUS_MEMORY_USED, -iSize);

sqlite3StatusAdd(SQLITE_STATUS_MALLOC_COUNT, -1);

sqlite3GlobalConfig.m.xFree(p);

sqlite3_mutex_leave(mem0.mutex);

}else{

sqlite3GlobalConfig.m.xFree(p);

}

** TRUE if p is a lookaside memory allocation from db

#ifndef SQLITE_OMIT_LOOKASIDE

static int isLookaside(sqlite3 *db, void *p){

return p>=db->lookaside.pStart && p<db->lookaside.pEnd;

}

#else

#define isLookaside(A,B) 0

#endif

** Return the size of a memory allocation previously obtained from

** sqlite3Malloc() or sqlite3_malloc().

int sqlite3MallocSize(void *p){

assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );

assert( sqlite3MemdebugNoType(p, MEMTYPE_DB) );

return sqlite3GlobalConfig.m.xSize(p);

}

int sqlite3DbMallocSize(sqlite3 *db, void *p){

assert( db!=0 );

assert( sqlite3_mutex_held(db->mutex) );

if( isLookaside(db, p) ){

return db->lookaside.sz;

}else{

assert( sqlite3MemdebugHasType(p, MEMTYPE_DB) );

assert( sqlite3MemdebugHasType(p, MEMTYPE_LOOKASIDE|MEMTYPE_HEAP) );

assert( db!=0 || sqlite3MemdebugNoType(p, MEMTYPE_LOOKASIDE) );

return sqlite3GlobalConfig.m.xSize(p);

}

** Free memory previously obtained from sqlite3Malloc().

void sqlite3_free(void *p){

if( p==0 ) return; /* IMP: R-49053-54554 */

assert( sqlite3MemdebugNoType(p, MEMTYPE_DB) );

assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );

if( sqlite3GlobalConfig.bMemstat ){

sqlite3_mutex_enter(mem0.mutex);

sqlite3StatusAdd(SQLITE_STATUS_MEMORY_USED, -sqlite3MallocSize(p));

sqlite3StatusAdd(SQLITE_STATUS_MALLOC_COUNT, -1);

sqlite3GlobalConfig.m.xFree(p);

sqlite3_mutex_leave(mem0.mutex);

}else{

sqlite3GlobalConfig.m.xFree(p);

}

** Free memory that might be associated with a particular database

** connection.

void sqlite3DbFree(sqlite3 *db, void *p){

assert( db==0 || sqlite3_mutex_held(db->mutex) );

if( p==0 ) return;

if( db ){

if( db->pnBytesFreed ){

*db->pnBytesFreed += sqlite3DbMallocSize(db, p);

return;

}

if( isLookaside(db, p) ){

LookasideSlot *pBuf = (LookasideSlot*)p;

#if SQLITE_DEBUG

/* Trash all content in the buffer being freed */

memset(p, 0xaa, db->lookaside.sz);

#endif

pBuf->pNext = db->lookaside.pFree;

db->lookaside.pFree = pBuf;

db->lookaside.nOut--;

return;

}

assert( sqlite3MemdebugHasType(p, MEMTYPE_DB) );

assert( sqlite3MemdebugHasType(p, MEMTYPE_LOOKASIDE|MEMTYPE_HEAP) );

assert( db!=0 || sqlite3MemdebugNoType(p, MEMTYPE_LOOKASIDE) );

sqlite3MemdebugSetType(p, MEMTYPE_HEAP);

sqlite3_free(p);

}

** Change the size of an existing memory allocation

void *sqlite3Realloc(void *pOld, int nBytes){

int nOld, nNew, nDiff;

void *pNew;

if( pOld==0 ){

return sqlite3Malloc(nBytes); /* IMP: R-28354-25769 */

}

if( nBytes<=0 ){

sqlite3_free(pOld); /* IMP: R-31593-10574 */

return 0;

}

if( nBytes>=0x7fffff00 ){

/* The 0x7ffff00 limit term is explained in comments on sqlite3Malloc() */

return 0;

}

nOld = sqlite3MallocSize(pOld);

/* IMPLEMENTATION-OF: R-46199-30249 SQLite guarantees that the second

** argument to xRealloc is always a value returned by a prior call to

** xRoundup. */

nNew = sqlite3GlobalConfig.m.xRoundup(nBytes);

if( nOld==nNew ){

pNew = pOld;

}else if( sqlite3GlobalConfig.bMemstat ){

sqlite3_mutex_enter(mem0.mutex);

sqlite3StatusSet(SQLITE_STATUS_MALLOC_SIZE, nBytes);

nDiff = nNew - nOld;

if( sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED) >=

mem0.alarmThreshold-nDiff ){

sqlite3MallocAlarm(nDiff);

}

assert( sqlite3MemdebugHasType(pOld, MEMTYPE_HEAP) );

assert( sqlite3MemdebugNoType(pOld, ~MEMTYPE_HEAP) );

pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);

if( pNew==0 && mem0.alarmCallback ){

sqlite3MallocAlarm(nBytes);

pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);

}

if( pNew ){

nNew = sqlite3MallocSize(pNew);

sqlite3StatusAdd(SQLITE_STATUS_MEMORY_USED, nNew-nOld);

}

sqlite3_mutex_leave(mem0.mutex);

}else{

pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);

}

assert( EIGHT_BYTE_ALIGNMENT(pNew) ); /* IMP: R-04675-44850 */

return pNew;

}

** The public interface to sqlite3Realloc. Make sure that the memory

** subsystem is initialized prior to invoking sqliteRealloc.

void *sqlite3_realloc(void *pOld, int n){

#ifndef SQLITE_OMIT_AUTOINIT

if( sqlite3_initialize() ) return 0;

#endif

return sqlite3Realloc(pOld, n);

}

** Allocate and zero memory.

void *sqlite3MallocZero(int n){

void *p = sqlite3Malloc(n);

if( p ){

memset(p, 0, n);

}

return p;

}

** Allocate and zero memory. If the allocation fails, make

** the mallocFailed flag in the connection pointer.

void *sqlite3DbMallocZero(sqlite3 *db, int n){

void *p = sqlite3DbMallocRaw(db, n);

if( p ){

memset(p, 0, n);

}

return p;

}

** Allocate and zero memory. If the allocation fails, make

** the mallocFailed flag in the connection pointer.

** If db!=0 and db->mallocFailed is true (indicating a prior malloc

** failure on the same database connection) then always return 0.

** Hence for a particular database connection, once malloc starts

** failing, it fails consistently until mallocFailed is reset.

** This is an important assumption. There are many places in the

** code that do things like this:

** int *a = (int*)sqlite3DbMallocRaw(db, 100);

** int *b = (int*)sqlite3DbMallocRaw(db, 200);

** if( b ) a[10] = 9;

** In other words, if a subsequent malloc (ex: "b") worked, it is assumed

** that all prior mallocs (ex: "a") worked too.

void *sqlite3DbMallocRaw(sqlite3 *db, int n){

void *p;

assert( db==0 || sqlite3_mutex_held(db->mutex) );

assert( db==0 || db->pnBytesFreed==0 );

#ifndef SQLITE_OMIT_LOOKASIDE

if( db ){

LookasideSlot *pBuf;

if( db->mallocFailed ){

return 0;

}

if( db->lookaside.bEnabled ){

if( n>db->lookaside.sz ){

db->lookaside.anStat[1]++;

}else if( (pBuf = db->lookaside.pFree)==0 ){

db->lookaside.anStat[2]++;

}else{

db->lookaside.pFree = pBuf->pNext;

db->lookaside.nOut++;

db->lookaside.anStat[0]++;

if( db->lookaside.nOut>db->lookaside.mxOut ){

db->lookaside.mxOut = db->lookaside.nOut;

}

return (void*)pBuf;

}

#else

if( db && db->mallocFailed ){

return 0;

}

#endif

p = sqlite3Malloc(n);

if( !p && db ){

db->mallocFailed = 1;

}

sqlite3MemdebugSetType(p, MEMTYPE_DB |

((db && db->lookaside.bEnabled) ? MEMTYPE_LOOKASIDE : MEMTYPE_HEAP));

return p;

}

** Resize the block of memory pointed to by p to n bytes. If the

** resize fails, set the mallocFailed flag in the connection object.

void *sqlite3DbRealloc(sqlite3 *db, void *p, int n){

void *pNew = 0;

assert( db!=0 );

assert( sqlite3_mutex_held(db->mutex) );

if( db->mallocFailed==0 ){

if( p==0 ){

return sqlite3DbMallocRaw(db, n);

}

if( isLookaside(db, p) ){

if( n<=db->lookaside.sz ){

return p;

}

pNew = sqlite3DbMallocRaw(db, n);

if( pNew ){

memcpy(pNew, p, db->lookaside.sz);

sqlite3DbFree(db, p);

}

}else{

assert( sqlite3MemdebugHasType(p, MEMTYPE_DB) );

assert( sqlite3MemdebugHasType(p, MEMTYPE_LOOKASIDE|MEMTYPE_HEAP) );

sqlite3MemdebugSetType(p, MEMTYPE_HEAP);

pNew = sqlite3_realloc(p, n);

if( !pNew ){

sqlite3MemdebugSetType(p, MEMTYPE_DB|MEMTYPE_HEAP);

db->mallocFailed = 1;

}

sqlite3MemdebugSetType(pNew, MEMTYPE_DB |

(db->lookaside.bEnabled ? MEMTYPE_LOOKASIDE : MEMTYPE_HEAP));

}

return pNew;

}

** Attempt to reallocate p. If the reallocation fails, then free p

** and set the mallocFailed flag in the database connection.

void *sqlite3DbReallocOrFree(sqlite3 *db, void *p, int n){

void *pNew;

pNew = sqlite3DbRealloc(db, p, n);

if( !pNew ){

sqlite3DbFree(db, p);

}

return pNew;

}

** Make a copy of a string in memory obtained from sqliteMalloc(). These

** functions call sqlite3MallocRaw() directly instead of sqliteMalloc(). This

** is because when memory debugging is turned on, these two functions are

** called via macros that record the current file and line number in the

** ThreadData structure.

char *sqlite3DbStrDup(sqlite3 *db, const char *z){

char *zNew;

size_t n;

if( z==0 ){

return 0;

}

n = sqlite3Strlen30(z) + 1;

assert( (n&0x7fffffff)==n );

zNew = sqlite3DbMallocRaw(db, (int)n);

if( zNew ){

memcpy(zNew, z, n);

}

return zNew;

}

char *sqlite3DbStrNDup(sqlite3 *db, const char *z, int n){

char *zNew;

if( z==0 ){

return 0;

}

assert( (n&0x7fffffff)==n );

zNew = sqlite3DbMallocRaw(db, n+1);

if( zNew ){

memcpy(zNew, z, n);

zNew[n] = 0;

}

return zNew;

}

** Create a string from the zFromat argument and the va_list that follows.

** Store the string in memory obtained from sqliteMalloc() and make *pz

** point to that string.

void sqlite3SetString(char **pz, sqlite3 *db, const char *zFormat, ...){

va_list ap;

char *z;

va_start(ap, zFormat);

z = sqlite3VMPrintf(db, zFormat, ap);

va_end(ap);

sqlite3DbFree(db, *pz);

*pz = z;

}

** This function must be called before exiting any API function (i.e.

** returning control to the user) that has called sqlite3_malloc or

** sqlite3_realloc.

** The returned value is normally a copy of the second argument to this

** function. However, if a malloc() failure has occurred since the previous

** invocation SQLITE_NOMEM is returned instead.

** If the first argument, db, is not NULL and a malloc() error has occurred,

** then the connection error-code (the value returned by sqlite3_errcode())

** is set to SQLITE_NOMEM.

int sqlite3ApiExit(sqlite3* db, int rc){

/* If the db handle is not NULL, then we must hold the connection handle

** mutex here. Otherwise the read (and possible write) of db->mallocFailed

** is unsafe, as is the call to sqlite3Error().

assert( !db || sqlite3_mutex_held(db->mutex) );

if( db && (db->mallocFailed || rc==SQLITE_IOERR_NOMEM) ){

sqlite3Error(db, SQLITE_NOMEM, 0);

db->mallocFailed = 0;

rc = SQLITE_NOMEM;

}

return rc & (db ? db->errMask : 0xff);

}

sqlcipher/src/malloc.c at master · CoderXL/sqlcipher · GitHub

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