engine/sqlite/src/malloc.cpp
changeset 2 29cda98b007e
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/engine/sqlite/src/malloc.cpp	Thu Feb 25 14:29:19 2010 +0000
@@ -0,0 +1,241 @@
+/*
+** 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.cpp 1282 2008-11-13 09:31:33Z LarsPson $
+*/
+#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.
+*/
+EXPORT_C void sqlite3_soft_heap_limit(int n){
+  sqlite3_uint64 iLimit;
+  int overage;
+  if( n<0 ){
+    iLimit = 0;
+  }else{
+    iLimit = n;
+  }
+  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.
+*/
+EXPORT_C int sqlite3_release_memory(int n){
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+  return sqlite3PagerReleaseMemory(n);
+#else
+  return SQLITE_OK;
+#endif
+}
+
+
+/*
+** Allocate and zero memory.
+*/ 
+void *sqlite3MallocZero(unsigned n){
+
+  void *p = sqlite3_malloc(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, unsigned 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, unsigned n){
+  void *p = 0;
+  if( !db || db->mallocFailed==0 ){
+    p = sqlite3_malloc(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 = (char*)sqlite3_malloc(n);
+  if( zNew ) memcpy(zNew, z, n);
+  return zNew;
+}
+char *sqlite3StrNDup(const char *z, int n){
+  char *zNew;
+  if( z==0 ) return 0;
+  zNew = (char*)sqlite3_malloc(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 = (char*)sqlite3_malloc(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);
+}