sqlite 3.5.1 windows source

1 files changed, 229 insertions, 0 deletions

diff --git a/libraries/sqlite/win32/mem1.c b/libraries/sqlite/win32/mem1.c
new file mode 100755
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+++ b/libraries/sqlite/win32/mem1.c
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+/*
+** 2007 August 14
+**
+** 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.
+**
+*************************************************************************
+** This file contains the C functions that implement a memory
+** allocation subsystem for use by SQLite.  
+**
+** $Id: mem1.c,v 1.10 2007/09/02 17:50:35 drh Exp $
+*/
+
+/*
+** This version of the memory allocator is the default.  It is
+** used when no other memory allocator is specified using compile-time
+** macros.
+*/
+#if !defined(SQLITE_MEMDEBUG) && !defined(SQLITE_OMIT_MEMORY_ALLOCATION)
+
+/*
+** We will eventually construct multiple memory allocation subsystems
+** suitable for use in various contexts:
+**
+**    *  Normal multi-threaded builds
+**    *  Normal single-threaded builds
+**    *  Debugging builds
+**
+** This initial version is suitable for use in normal multi-threaded
+** builds.  We envision that alternative versions will be stored in
+** separate source files.  #ifdefs will be used to select the code from
+** one of the various memN.c source files for use in any given build.
+*/
+#include "sqliteInt.h"
+
+/*
+** All of the static variables used by this module are collected
+** into a single structure named "mem".  This is to keep the
+** static variables organized and to reduce namespace pollution
+** when this module is combined with other in the amalgamation.
+*/
+static struct {
+  /*
+  ** The alarm callback and its arguments.  The mem.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;
+  
+  /*
+  ** Mutex to control access to the memory allocation subsystem.
+  */
+  sqlite3_mutex *mutex;
+  
+  /*
+  ** Current allocation and high-water mark.
+  */
+  sqlite3_int64 nowUsed;
+  sqlite3_int64 mxUsed;
+  
+ 
+} mem;
+
+/*
+** Enter the mutex mem.mutex. Allocate it if it is not already allocated.
+*/
+static void enterMem(void){
+  if( mem.mutex==0 ){
+    mem.mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MEM);
+  }
+  sqlite3_mutex_enter(mem.mutex);
+}
+
+/*
+** Return the amount of memory currently checked out.
+*/
+sqlite3_int64 sqlite3_memory_used(void){
+  sqlite3_int64 n;
+  enterMem();
+  n = mem.nowUsed;
+  sqlite3_mutex_leave(mem.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;
+  enterMem();
+  n = mem.mxUsed;
+  if( resetFlag ){
+    mem.mxUsed = mem.nowUsed;
+  }
+  sqlite3_mutex_leave(mem.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
+){
+  enterMem();
+  mem.alarmCallback = xCallback;
+  mem.alarmArg = pArg;
+  mem.alarmThreshold = iThreshold;
+  sqlite3_mutex_leave(mem.mutex);
+  return SQLITE_OK;
+}
+
+/*
+** Trigger the alarm 
+*/
+static void sqlite3MemsysAlarm(int nByte){
+  void (*xCallback)(void*,sqlite3_int64,int);
+  sqlite3_int64 nowUsed;
+  void *pArg;
+  if( mem.alarmCallback==0 || mem.alarmBusy  ) return;
+  mem.alarmBusy = 1;
+  xCallback = mem.alarmCallback;
+  nowUsed = mem.nowUsed;
+  pArg = mem.alarmArg;
+  sqlite3_mutex_leave(mem.mutex);
+  xCallback(pArg, nowUsed, nByte);
+  sqlite3_mutex_enter(mem.mutex);
+  mem.alarmBusy = 0;
+}
+
+/*
+** Allocate nBytes of memory
+*/
+void *sqlite3_malloc(int nBytes){
+  sqlite3_int64 *p = 0;
+  if( nBytes>0 ){
+    enterMem();
+    if( mem.alarmCallback!=0 && mem.nowUsed+nBytes>=mem.alarmThreshold ){
+      sqlite3MemsysAlarm(nBytes);
+    }
+    p = malloc(nBytes+8);
+    if( p==0 ){
+      sqlite3MemsysAlarm(nBytes);
+      p = malloc(nBytes+8);
+    }
+    if( p ){
+      p[0] = nBytes;
+      p++;
+      mem.nowUsed += nBytes;
+      if( mem.nowUsed>mem.mxUsed ){
+        mem.mxUsed = mem.nowUsed;
+      }
+    }
+    sqlite3_mutex_leave(mem.mutex);
+  }
+  return (void*)p; 
+}
+
+/*
+** Free memory.
+*/
+void sqlite3_free(void *pPrior){
+  sqlite3_int64 *p;
+  int nByte;
+  if( pPrior==0 ){
+    return;
+  }
+  assert( mem.mutex!=0 );
+  p = pPrior;
+  p--;
+  nByte = (int)*p;
+  sqlite3_mutex_enter(mem.mutex);
+  mem.nowUsed -= nByte;
+  free(p);
+  sqlite3_mutex_leave(mem.mutex);  
+}
+
+/*
+** Change the size of an existing memory allocation
+*/
+void *sqlite3_realloc(void *pPrior, int nBytes){
+  int nOld;
+  sqlite3_int64 *p;
+  if( pPrior==0 ){
+    return sqlite3_malloc(nBytes);
+  }
+  if( nBytes<=0 ){
+    sqlite3_free(pPrior);
+    return 0;
+  }
+  p = pPrior;
+  p--;
+  nOld = (int)p[0];
+  assert( mem.mutex!=0 );
+  sqlite3_mutex_enter(mem.mutex);
+  if( mem.nowUsed+nBytes-nOld>=mem.alarmThreshold ){
+    sqlite3MemsysAlarm(nBytes-nOld);
+  }
+  p = realloc(p, nBytes+8);
+  if( p==0 ){
+    sqlite3MemsysAlarm(nBytes);
+    p = realloc(p, nBytes+8);
+  }
+  if( p ){
+    p[0] = nBytes;
+    p++;
+    mem.nowUsed += nBytes-nOld;
+    if( mem.nowUsed>mem.mxUsed ){
+      mem.mxUsed = mem.nowUsed;
+    }
+  }
+  sqlite3_mutex_leave(mem.mutex);
+  return (void*)p;
+}
+
+#endif /* !SQLITE_MEMDEBUG && !SQLITE_OMIT_MEMORY_ALLOCATION */