[sql] Import reference version of SQLite 3.17..

third_party/sqlite/sqlite-src-3170000/src/malloc.c

+/*
+** 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 */
+  sqlite3_int64 alarmThreshold; /* The soft heap limit */
+
+  /*
+  ** 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 };
+
+#define mem0 GLOBAL(struct Mem0Global, mem0)
+
+/*
+** Return the memory allocator mutex. sqlite3_status() needs it.
+*/
+sqlite3_mutex *sqlite3MallocMutex(void){
+  return mem0.mutex;
+}
+
+#ifndef SQLITE_OMIT_DEPRECATED
+/*
+** Deprecated external interface.  It used to set an alarm callback
+** that was invoked when memory usage grew too large.  Now it is a
+** no-op.
+*/
+int sqlite3_memory_alarm(
+  void(*xCallback)(void *pArg, sqlite3_int64 used,int N),
+  void *pArg,
+  sqlite3_int64 iThreshold
+){
+  (void)xCallback;
+  (void)pArg;
+  (void)iThreshold;
+  return SQLITE_OK;
+}
+#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;
+  sqlite3_int64 nUsed;
+#ifndef SQLITE_OMIT_AUTOINIT
+  int rc = sqlite3_initialize();
+  if( rc ) return -1;
+#endif
+  sqlite3_mutex_enter(mem0.mutex);
+  priorLimit = mem0.alarmThreshold;
+  if( n<0 ){
+    sqlite3_mutex_leave(mem0.mutex);
+    return priorLimit;
+  }
+  mem0.alarmThreshold = n;
+  nUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);
+  mem0.nearlyFull = (n>0 && n<=nUsed);
+  sqlite3_mutex_leave(mem0.mutex);
+  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){
+  int rc;
+  if( sqlite3GlobalConfig.m.xMalloc==0 ){
+    sqlite3MemSetDefault();
+  }
+  memset(&mem0, 0, sizeof(mem0));
+  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<=0 ){
+    sqlite3GlobalConfig.pPage = 0;
+    sqlite3GlobalConfig.szPage = 0;
+  }
+  rc = sqlite3GlobalConfig.m.xInit(sqlite3GlobalConfig.m.pAppData);
+  if( rc!=SQLITE_OK ) memset(&mem0, 0, sizeof(mem0));
+  return rc;
+}
+
+/*
+** 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){
+  sqlite3_int64 res, mx;
+  sqlite3_status64(SQLITE_STATUS_MEMORY_USED, &res, &mx, 0);
+  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){
+  sqlite3_int64 res, mx;
+  sqlite3_status64(SQLITE_STATUS_MEMORY_USED, &res, &mx, resetFlag);
+  return mx;
+}
+
+/*
+** Trigger the alarm 
+*/
+static void sqlite3MallocAlarm(int nByte){
+  if( mem0.alarmThreshold<=0 ) return;
+  sqlite3_mutex_leave(mem0.mutex);
+  sqlite3_release_memory(nByte);
+  sqlite3_mutex_enter(mem0.mutex);
+}
+
+/*
+** Do a memory allocation with statistics and alarms.  Assume the
+** lock is already held.
+*/
+static void mallocWithAlarm(int n, void **pp){
+  void *p;
+  int nFull;
+  assert( sqlite3_mutex_held(mem0.mutex) );
+  assert( n>0 );
+
+  /* In Firefox (circa 2017-02-08), xRoundup() is remapped to an internal
+  ** implementation of malloc_good_size(), which must be called in debug
+  ** mode and specifically when the DMD "Dark Matter Detector" is enabled
+  ** or else a crash results.  Hence, do not attempt to optimize out the
+  ** following xRoundup() call. */
+  nFull = sqlite3GlobalConfig.m.xRoundup(n);
+
+  sqlite3StatusHighwater(SQLITE_STATUS_MALLOC_SIZE, n);
+  if( mem0.alarmThreshold>0 ){
+    sqlite3_int64 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.alarmThreshold>0 ){
+    sqlite3MallocAlarm(nFull);
+    p = sqlite3GlobalConfig.m.xMalloc(nFull);
+  }
+#endif
+  if( p ){
+    nFull = sqlite3MallocSize(p);
+    sqlite3StatusUp(SQLITE_STATUS_MEMORY_USED, nFull);
+    sqlite3StatusUp(SQLITE_STATUS_MALLOC_COUNT, 1);
+  }
+  *pp = p;
+}
+
+/*
+** Allocate memory.  This routine is like sqlite3_malloc() except that it
+** assumes the memory subsystem has already been initialized.
+*/
+void *sqlite3Malloc(u64 n){
+  void *p;
+  if( n==0 || 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((int)n, &p);
+    sqlite3_mutex_leave(mem0.mutex);
+  }else{
+    p = sqlite3GlobalConfig.m.xMalloc((int)n);
+  }
+  assert( EIGHT_BYTE_ALIGNMENT(p) );  /* IMP: R-11148-40995 */
+  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 n<=0 ? 0 : sqlite3Malloc(n);
+}
+void *sqlite3_malloc64(sqlite3_uint64 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);
+  sqlite3StatusHighwater(SQLITE_STATUS_SCRATCH_SIZE, n);
+  if( mem0.nScratchFree && sqlite3GlobalConfig.szScratch>=n ){
+    p = mem0.pScratchFree;
+    mem0.pScratchFree = mem0.pScratchFree->pNext;
+    mem0.nScratchFree--;
+    sqlite3StatusUp(SQLITE_STATUS_SCRATCH_USED, 1);
+    sqlite3_mutex_leave(mem0.mutex);
+  }else{
+    sqlite3_mutex_leave(mem0.mutex);
+    p = sqlite3Malloc(n);
+    if( sqlite3GlobalConfig.bMemstat && p ){
+      sqlite3_mutex_enter(mem0.mutex);
+      sqlite3StatusUp(SQLITE_STATUS_SCRATCH_OVERFLOW, sqlite3MallocSize(p));
+      sqlite3_mutex_leave(mem0.mutex);
+    }
+    sqlite3MemdebugSetType(p, MEMTYPE_SCRATCH);
+  }
+  assert( sqlite3_mutex_notheld(mem0.mutex) );
+
+
+#if SQLITE_THREADSAFE==0 && !defined(NDEBUG)
+  /* EVIDENCE-OF: R-12970-05880 SQLite will not use more than one scratch
+  ** buffers per thread.
+  **
+  ** This can only be checked in single-threaded mode.
+  */
+  assert( scratchAllocOut==0 );
+  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( SQLITE_WITHIN(p, sqlite3GlobalConfig.pScratch, 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 );
+      sqlite3StatusDown(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, (u8)~MEMTYPE_SCRATCH) );
+      sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
+      if( sqlite3GlobalConfig.bMemstat ){
+        int iSize = sqlite3MallocSize(p);
+        sqlite3_mutex_enter(mem0.mutex);
+        sqlite3StatusDown(SQLITE_STATUS_SCRATCH_OVERFLOW, iSize);
+        sqlite3StatusDown(SQLITE_STATUS_MEMORY_USED, iSize);
+        sqlite3StatusDown(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 SQLITE_WITHIN(p, db->lookaside.pStart, 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) );
+  return sqlite3GlobalConfig.m.xSize(p);
+}
+int sqlite3DbMallocSize(sqlite3 *db, void *p){
+  assert( p!=0 );
+  if( db==0 || !isLookaside(db,p) ){
+#if SQLITE_DEBUG
+    if( db==0 ){
+      assert( sqlite3MemdebugNoType(p, (u8)~MEMTYPE_HEAP) );
+      assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
+    }else{
+      assert( sqlite3MemdebugHasType(p, (MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
+      assert( sqlite3MemdebugNoType(p, (u8)~(MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
+    }
+#endif
+    return sqlite3GlobalConfig.m.xSize(p);
+  }else{
+    assert( sqlite3_mutex_held(db->mutex) );
+    return db->lookaside.sz;
+  }
+}
+sqlite3_uint64 sqlite3_msize(void *p){
+  assert( sqlite3MemdebugNoType(p, (u8)~MEMTYPE_HEAP) );
+  assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
+  return p ? sqlite3GlobalConfig.m.xSize(p) : 0;
+}
+
+/*
+** Free memory previously obtained from sqlite3Malloc().
+*/
+void sqlite3_free(void *p){
+  if( p==0 ) return;  /* IMP: R-49053-54554 */
+  assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
+  assert( sqlite3MemdebugNoType(p, (u8)~MEMTYPE_HEAP) );
+  if( sqlite3GlobalConfig.bMemstat ){
+    sqlite3_mutex_enter(mem0.mutex);
+    sqlite3StatusDown(SQLITE_STATUS_MEMORY_USED, sqlite3MallocSize(p));
+    sqlite3StatusDown(SQLITE_STATUS_MALLOC_COUNT, 1);
+    sqlite3GlobalConfig.m.xFree(p);
+    sqlite3_mutex_leave(mem0.mutex);
+  }else{
+    sqlite3GlobalConfig.m.xFree(p);
+  }
+}
+
+/*
+** Add the size of memory allocation "p" to the count in
+** *db->pnBytesFreed.
+*/
+static SQLITE_NOINLINE void measureAllocationSize(sqlite3 *db, void *p){
+  *db->pnBytesFreed += sqlite3DbMallocSize(db,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 ){
+      measureAllocationSize(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_LOOKASIDE|MEMTYPE_HEAP)) );
+  assert( sqlite3MemdebugNoType(p, (u8)~(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, u64 nBytes){
+  int nOld, nNew, nDiff;
+  void *pNew;
+  assert( sqlite3MemdebugHasType(pOld, MEMTYPE_HEAP) );
+  assert( sqlite3MemdebugNoType(pOld, (u8)~MEMTYPE_HEAP) );
+  if( pOld==0 ){
+    return sqlite3Malloc(nBytes); /* IMP: R-04300-56712 */
+  }
+  if( nBytes==0 ){
+    sqlite3_free(pOld); /* IMP: R-26507-47431 */
+    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((int)nBytes);
+  if( nOld==nNew ){
+    pNew = pOld;
+  }else if( sqlite3GlobalConfig.bMemstat ){
+    sqlite3_mutex_enter(mem0.mutex);
+    sqlite3StatusHighwater(SQLITE_STATUS_MALLOC_SIZE, (int)nBytes);
+    nDiff = nNew - nOld;
+    if( nDiff>0 && sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED) >= 
+          mem0.alarmThreshold-nDiff ){
+      sqlite3MallocAlarm(nDiff);
+    }
+    pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
+    if( pNew==0 && mem0.alarmThreshold>0 ){
+      sqlite3MallocAlarm((int)nBytes);
+      pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
+    }
+    if( pNew ){
+      nNew = sqlite3MallocSize(pNew);
+      sqlite3StatusUp(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-11148-40995 */
+  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
+  if( n<0 ) n = 0;  /* IMP: R-26507-47431 */
+  return sqlite3Realloc(pOld, n);
+}
+void *sqlite3_realloc64(void *pOld, sqlite3_uint64 n){
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return 0;
+#endif
+  return sqlite3Realloc(pOld, n);
+}
+
+
+/*
+** Allocate and zero memory.
+*/ 
+void *sqlite3MallocZero(u64 n){
+  void *p = sqlite3Malloc(n);
+  if( p ){
+    memset(p, 0, (size_t)n);
+  }
+  return p;
+}
+
+/*
+** Allocate and zero memory.  If the allocation fails, make
+** the mallocFailed flag in the connection pointer.
+*/
+void *sqlite3DbMallocZero(sqlite3 *db, u64 n){
+  void *p;
+  testcase( db==0 );
+  p = sqlite3DbMallocRaw(db, n);
+  if( p ) memset(p, 0, (size_t)n);
+  return p;
+}
+
+
+/* Finish the work of sqlite3DbMallocRawNN for the unusual and
+** slower case when the allocation cannot be fulfilled using lookaside.
+*/
+static SQLITE_NOINLINE void *dbMallocRawFinish(sqlite3 *db, u64 n){
+  void *p;
+  assert( db!=0 );
+  p = sqlite3Malloc(n);
+  if( !p ) sqlite3OomFault(db);
+  sqlite3MemdebugSetType(p, 
+         (db->lookaside.bDisable==0) ? MEMTYPE_LOOKASIDE : MEMTYPE_HEAP);
+  return p;
+}
+
+/*
+** Allocate memory, either lookaside (if possible) or heap.  
+** If the allocation fails, set 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.
+**
+** The sqlite3MallocRawNN() variant guarantees that the "db" parameter is
+** not a NULL pointer.
+*/
+void *sqlite3DbMallocRaw(sqlite3 *db, u64 n){
+  void *p;
+  if( db ) return sqlite3DbMallocRawNN(db, n);
+  p = sqlite3Malloc(n);
+  sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
+  return p;
+}
+void *sqlite3DbMallocRawNN(sqlite3 *db, u64 n){
+#ifndef SQLITE_OMIT_LOOKASIDE
+  LookasideSlot *pBuf;
+  assert( db!=0 );
+  assert( sqlite3_mutex_held(db->mutex) );
+  assert( db->pnBytesFreed==0 );
+  if( db->lookaside.bDisable==0 ){
+    assert( db->mallocFailed==0 );
+    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->mallocFailed ){
+    return 0;
+  }
+#else
+  assert( db!=0 );
+  assert( sqlite3_mutex_held(db->mutex) );
+  assert( db->pnBytesFreed==0 );
+  if( db->mallocFailed ){
+    return 0;
+  }
+#endif
+  return dbMallocRawFinish(db, n);
+}
+
+/* Forward declaration */
+static SQLITE_NOINLINE void *dbReallocFinish(sqlite3 *db, void *p, u64 n);
+
+/*
+** 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, u64 n){
+  assert( db!=0 );
+  if( p==0 ) return sqlite3DbMallocRawNN(db, n);
+  assert( sqlite3_mutex_held(db->mutex) );
+  if( isLookaside(db,p) && n<=db->lookaside.sz ) return p;
+  return dbReallocFinish(db, p, n);
+}
+static SQLITE_NOINLINE void *dbReallocFinish(sqlite3 *db, void *p, u64 n){
+  void *pNew = 0;
+  assert( db!=0 );
+  assert( p!=0 );
+  if( db->mallocFailed==0 ){
+    if( isLookaside(db, p) ){
+      pNew = sqlite3DbMallocRawNN(db, n);
+      if( pNew ){
+        memcpy(pNew, p, db->lookaside.sz);
+        sqlite3DbFree(db, p);
+      }
+    }else{
+      assert( sqlite3MemdebugHasType(p, (MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
+      assert( sqlite3MemdebugNoType(p, (u8)~(MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
+      sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
+      pNew = sqlite3_realloc64(p, n);
+      if( !pNew ){
+        sqlite3OomFault(db);
+      }
+      sqlite3MemdebugSetType(pNew,
+            (db->lookaside.bDisable==0 ? 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, u64 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 = strlen(z) + 1;
+  zNew = sqlite3DbMallocRaw(db, n);
+  if( zNew ){
+    memcpy(zNew, z, n);
+  }
+  return zNew;
+}
+char *sqlite3DbStrNDup(sqlite3 *db, const char *z, u64 n){
+  char *zNew;
+  assert( db!=0 );
+  if( z==0 ){
+    return 0;
+  }
+  assert( (n&0x7fffffff)==n );
+  zNew = sqlite3DbMallocRawNN(db, n+1);
+  if( zNew ){
+    memcpy(zNew, z, (size_t)n);
+    zNew[n] = 0;
+  }
+  return zNew;
+}
+
+/*
+** Free any prior content in *pz and replace it with a copy of zNew.
+*/
+void sqlite3SetString(char **pz, sqlite3 *db, const char *zNew){
+  sqlite3DbFree(db, *pz);
+  *pz = sqlite3DbStrDup(db, zNew);
+}
+
+/*
+** Call this routine to record the fact that an OOM (out-of-memory) error
+** has happened.  This routine will set db->mallocFailed, and also
+** temporarily disable the lookaside memory allocator and interrupt
+** any running VDBEs.
+*/
+void sqlite3OomFault(sqlite3 *db){
+  if( db->mallocFailed==0 && db->bBenignMalloc==0 ){
+    db->mallocFailed = 1;
+    if( db->nVdbeExec>0 ){
+      db->u1.isInterrupted = 1;
+    }
+    db->lookaside.bDisable++;
+  }
+}
+
+/*
+** This routine reactivates the memory allocator and clears the
+** db->mallocFailed flag as necessary.
+**
+** The memory allocator is not restarted if there are running
+** VDBEs.
+*/
+void sqlite3OomClear(sqlite3 *db){
+  if( db->mallocFailed && db->nVdbeExec==0 ){
+    db->mallocFailed = 0;
+    db->u1.isInterrupted = 0;
+    assert( db->lookaside.bDisable>0 );
+    db->lookaside.bDisable--;
+  }
+}
+
+/*
+** Take actions at the end of an API call to indicate an OOM error
+*/
+static SQLITE_NOINLINE int apiOomError(sqlite3 *db){
+  sqlite3OomClear(db);
+  sqlite3Error(db, SQLITE_NOMEM);
+  return SQLITE_NOMEM_BKPT;
+}
+
+/*
+** 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 an OOM as 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 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!=0 );
+  assert( sqlite3_mutex_held(db->mutex) );
+  if( db->mallocFailed || rc==SQLITE_IOERR_NOMEM ){
+    return apiOomError(db);
+  }
+  return rc & db->errMask;
+}