/*
** 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.
**
** $Id: malloc.c,v 1.20 2008/06/18 18:12:04 drh Exp $
*/
#include "sqliteInt.h"
#include <stdarg.h>
#include <ctype.h>
/*
** 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 inUse,
int allocSize
){
sqlite3_release_memory(allocSize);
}
/*
** Set the soft heap-size limit for the current thread. Passing a
** zero or negative value indicates no limit.
*/
void sqlite3_soft_heap_limit(int n){
sqlite3_uint64 iLimit;
int overage;
if( n<0 ){
iLimit = 0;
}else{
iLimit = n;
}
sqlite3_initialize();
if( iLimit>0 ){
sqlite3_memory_alarm(softHeapLimitEnforcer, 0, iLimit);
}else{
sqlite3_memory_alarm(0, 0, 0);
}
overage = sqlite3_memory_used() - n;
if( overage>0 ){
sqlite3_release_memory(overage);
}
}
/*
** Release memory held by SQLite instances created by the current thread.
*/
int sqlite3_release_memory(int n){
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
int nRet = sqlite3VdbeReleaseMemory(n);
nRet += sqlite3PagerReleaseMemory(n-nRet);
return nRet;
#else
return SQLITE_OK;
#endif
}
/*
** State information local to the memory allocation subsystem.
*/
static struct {
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. The alarmBusy variable is set to prevent recursive
** callbacks.
*/
sqlite3_int64 alarmThreshold;
void (*alarmCallback)(void*, sqlite3_int64,int);
void *alarmArg;
int alarmBusy;
/*
** Pointers to the end of sqlite3Config.pScratch and
** sqlite3Config.pPage to a block of memory that records
** which pages are available.
*/
u32 *aScratchFree;
u32 *aPageFree;
/* Number of free pages for scratch and page-cache memory */
u32 nScratchFree;
u32 nPageFree;
/*
** Performance statistics
*/
sqlite3_int64 nowUsed; /* Main memory currently in use */
sqlite3_int64 mxUsed; /* Highwater mark for nowUsed */
int mxReq; /* Max request size for ordinary mallocs */
int mxScratchReq; /* Max request size for xTemp mallocs */
} mem0;
/*
** Initialize the memory allocation subsystem.
*/
int sqlite3MallocInit(void){
if( sqlite3Config.m.xMalloc==0 ){
sqlite3MemSetDefault();
}
memset(&mem0, 0, sizeof(mem0));
if( sqlite3Config.bCoreMutex ){
mem0.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MEM);
}
if( sqlite3Config.pScratch && sqlite3Config.szScratch>=3000
&& sqlite3Config.nScratch>0 ){
int i;
mem0.aScratchFree = (u32*)&((char*)sqlite3Config.pScratch)
[sqlite3Config.szScratch*sqlite3Config.nScratch];
for(i=0; i<sqlite3Config.nScratch; i++){ mem0.aScratchFree[i] = i; }
mem0.nScratchFree = sqlite3Config.nScratch;
}else{
sqlite3Config.pScratch = 0;
}
if( sqlite3Config.pPage && sqlite3Config.szPage>=512
&& sqlite3Config.nPage>0 ){
int i;
mem0.aPageFree = (u32*)&((char*)sqlite3Config.pPage)
[sqlite3Config.szPage*sqlite3Config.nPage];
for(i=0; i<sqlite3Config.nPage; i++){ mem0.aPageFree[i] = i; }
mem0.nPageFree = sqlite3Config.nPage;
}else{
sqlite3Config.pPage = 0;
}
return sqlite3Config.m.xInit(sqlite3Config.m.pAppData);
}
/*
** Deinitialize the memory allocation subsystem.
*/
void sqlite3MallocEnd(void){
sqlite3Config.m.xShutdown(sqlite3Config.m.pAppData);
memset(&mem0, 0, sizeof(mem0));
}
/*
** Return the amount of memory currently checked out.
*/
sqlite3_int64 sqlite3_memory_used(void){
sqlite3_int64 n;
sqlite3_initialize();
sqlite3_mutex_enter(mem0.mutex);
n = mem0.nowUsed;
sqlite3_mutex_leave(mem0.mutex);
return n;
}
/*
** 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){
sqlite3_int64 n;
sqlite3_initialize();
sqlite3_mutex_enter(mem0.mutex);
n = mem0.mxUsed;
if( resetFlag ){
mem0.mxUsed = mem0.nowUsed;
}
sqlite3_mutex_leave(mem0.mutex);
return n;
}
/*
** Change the alarm callback
*/
int sqlite3_memory_alarm(
void(*xCallback)(void *pArg, sqlite3_int64 used,int N),
void *pArg,
sqlite3_int64 iThreshold
){
sqlite3_mutex_enter(mem0.mutex);
mem0.alarmCallback = xCallback;
mem0.alarmArg = pArg;
mem0.alarmThreshold = iThreshold;
sqlite3_mutex_leave(mem0.mutex);
return SQLITE_OK;
}
/*
** Trigger the alarm
*/
static void sqlite3MallocAlarm(int nByte){
void (*xCallback)(void*,sqlite3_int64,int);
sqlite3_int64 nowUsed;
void *pArg;
if( mem0.alarmCallback==0 || mem0.alarmBusy ) return;
mem0.alarmBusy = 1;
xCallback = mem0.alarmCallback;
nowUsed = mem0.nowUsed;
pArg = mem0.alarmArg;
sqlite3_mutex_leave(mem0.mutex);
xCallback(pArg, nowUsed, nByte);
sqlite3_mutex_enter(mem0.mutex);
mem0.alarmBusy = 0;
}
/*
** 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;
int nFull;
if( n<=0 ){
return 0;
}else if( sqlite3Config.bMemstat ){
nFull = sqlite3Config.m.xRoundup(n);
sqlite3_mutex_enter(mem0.mutex);
if( n>mem0.mxReq ) mem0.mxReq = n;
if( mem0.alarmCallback!=0 && mem0.nowUsed+nFull>=mem0.alarmThreshold ){
sqlite3MallocAlarm(nFull);
}
if( sqlite3FaultStep(SQLITE_FAULTINJECTOR_MALLOC) ){
p = 0;
}else{
p = sqlite3Config.m.xMalloc(nFull);
if( p==0 ){
sqlite3MallocAlarm(nFull);
p = malloc(nFull);
}
}
if( p ){
mem0.nowUsed += nFull;
if( mem0.nowUsed>mem0.mxUsed ){
mem0.mxUsed = mem0.nowUsed;
}
}
sqlite3_mutex_leave(mem0.mutex);
}else{
p = sqlite3Config.m.xMalloc(n);
}
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 );
if( sqlite3FaultStep(SQLITE_FAULTINJECTOR_MALLOC) ){
return 0;
}
#if SQLITE_THREADSAFE==0 && !defined(NDEBUG)
/* Verify that no more than one 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==0 );
scratchAllocOut = 1;
#endif
sqlite3_mutex_enter(mem0.mutex);
if( n>mem0.mxScratchReq ) mem0.mxScratchReq = n;
if( mem0.nScratchFree==0 || sqlite3Config.szScratch>=n ){
p = sqlite3Config.m.xMalloc(n);
}else{
int i;
i = mem0.aScratchFree[--mem0.nScratchFree];
i *= sqlite3Config.szScratch;
p = (void*)&((char*)sqlite3Config.pScratch)[i];
}
sqlite3_mutex_leave(mem0.mutex);
return p;
}
void sqlite3ScratchFree(void *p){
if( p ){
#if SQLITE_THREADSAFE==0 && !defined(NDEBUG)
/* Verify that no more than one 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 = 0;
#endif
if( sqlite3Config.pScratch==0
|| p<sqlite3Config.pScratch
|| p>=(void*)mem0.aScratchFree ){
sqlite3Config.m.xFree(p);
}else{
int i;
sqlite3_mutex_enter(mem0.mutex);
assert( mem0.nScratchFree<sqlite3Config.nScratch );
i = p - sqlite3Config.pScratch;
i /= sqlite3Config.szScratch;
assert( i>=0 && i<sqlite3Config.nScratch );
mem0.aScratchFree[mem0.nScratchFree++] = i;
sqlite3_mutex_leave(mem0.mutex);
}
}
}
/*
** Place holders for the page-cache memory allocator.
*/
void *sqlite3PageMalloc(int iSize){
return sqlite3Malloc(iSize);
}
void sqlite3PageFree(void *pOld){
sqlite3_free(pOld);
}
/*
** Return the size of a memory allocation previously obtained from
** sqlite3Malloc() or sqlite3_malloc().
*/
int sqlite3MallocSize(void *p){
return sqlite3Config.m.xSize(p);
}
/*
** Free memory previously obtained from sqlite3Malloc().
*/
void sqlite3_free(void *p){
if( p==0 ) return;
if( sqlite3Config.bMemstat ){
sqlite3_mutex_enter(mem0.mutex);
mem0.nowUsed -= sqlite3MallocSize(p);
sqlite3Config.m.xFree(p);
sqlite3_mutex_leave(mem0.mutex);
}else{
sqlite3Config.m.xFree(p);
}
}
/*
** Change the size of an existing memory allocation
*/
void *sqlite3Realloc(void *pOld, int nBytes){
int nOld, nNew;
void *pNew;
if( pOld==0 ){
return sqlite3Malloc(nBytes);
}
if( nBytes<=0 ){
sqlite3_free(pOld);
return 0;
}
nOld = sqlite3MallocSize(pOld);
if( sqlite3Config.bMemstat ){
sqlite3_mutex_enter(mem0.mutex);
if( nBytes>mem0.mxReq ) mem0.mxReq = nBytes;
nNew = sqlite3Config.m.xRoundup(nBytes);
if( nOld==nNew ){
pNew = pOld;
}else{
if( mem0.nowUsed+nNew-nOld>=mem0.alarmThreshold ){
sqlite3MallocAlarm(nNew-nOld);
}
if( sqlite3FaultStep(SQLITE_FAULTINJECTOR_MALLOC) ){
pNew = 0;
}else{
pNew = sqlite3Config.m.xRealloc(pOld, nNew);
if( pNew==0 ){
sqlite3MallocAlarm(nBytes);
pNew = sqlite3Config.m.xRealloc(pOld, nNew);
}
}
if( pNew ){
mem0.nowUsed += nNew-nOld;
if( mem0.nowUsed>mem0.mxUsed ){
mem0.mxUsed = mem0.nowUsed;
}
}
}
sqlite3_mutex_leave(mem0.mutex);
}else{
pNew = sqlite3Config.m.xRealloc(pOld, nBytes);
}
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.
*/
void *sqlite3DbMallocRaw(sqlite3 *db, int n){
void *p = 0;
if( !db || db->mallocFailed==0 ){
p = sqlite3Malloc(n);
if( !p && db ){
db->mallocFailed = 1;
}
}
return p;
}
/*
** Resize the block of memory pointed to by p to n bytes. If the
** resize fails, set the mallocFailed flag inthe connection object.
*/
void *sqlite3DbRealloc(sqlite3 *db, void *p, int n){
void *pNew = 0;
if( db->mallocFailed==0 ){
pNew = sqlite3_realloc(p, n);
if( !pNew ){
db->mallocFailed = 1;
}
}
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 ){
sqlite3_free(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 *sqlite3StrDup(const char *z){
char *zNew;
int n;
if( z==0 ) return 0;
n = strlen(z)+1;
zNew = sqlite3Malloc(n);
if( zNew ) memcpy(zNew, z, n);
return zNew;
}
char *sqlite3StrNDup(const char *z, int n){
char *zNew;
if( z==0 ) return 0;
zNew = sqlite3Malloc(n+1);
if( zNew ){
memcpy(zNew, z, n);
zNew[n] = 0;
}
return zNew;
}
char *sqlite3DbStrDup(sqlite3 *db, const char *z){
char *zNew = sqlite3StrDup(z);
if( z && !zNew ){
db->mallocFailed = 1;
}
return zNew;
}
char *sqlite3DbStrNDup(sqlite3 *db, const char *z, int n){
char *zNew = sqlite3StrNDup(z, n);
if( z && !zNew ){
db->mallocFailed = 1;
}
return zNew;
}
/*
** Create a string from the 2nd and subsequent arguments (up to the
** first NULL argument), store the string in memory obtained from
** sqliteMalloc() and make the pointer indicated by the 1st argument
** point to that string. The 1st argument must either be NULL or
** point to memory obtained from sqliteMalloc().
*/
void sqlite3SetString(char **pz, ...){
va_list ap;
int nByte;
const char *z;
char *zResult;
assert( pz!=0 );
nByte = 1;
va_start(ap, pz);
while( (z = va_arg(ap, const char*))!=0 ){
nByte += strlen(z);
}
va_end(ap);
sqlite3_free(*pz);
*pz = zResult = sqlite3Malloc(nByte);
if( zResult==0 ){
return;
}
*zResult = 0;
va_start(ap, pz);
while( (z = va_arg(ap, const char*))!=0 ){
int n = strlen(z);
memcpy(zResult, z, n);
zResult += n;
}
zResult[0] = 0;
va_end(ap);
}
/*
** 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 occured since the previous
** invocation SQLITE_NOMEM is returned instead.
**
** If the first argument, db, is not NULL and a malloc() error has occured,
** 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 ){
sqlite3Error(db, SQLITE_NOMEM, 0);
db->mallocFailed = 0;
rc = SQLITE_NOMEM;
}
return rc & (db ? db->errMask : 0xff);
}