我在加载存到数据库中的pdf文件(大约14M)的二进制数据时，通过

[data appendData:[self.archiveData subdataWithRange:NSMakeRange(self.offset, len)]];加载数据

len是int类型offset是NSInteger类型。

self.offset += len;

但是当self.offset增加到差不多7M左右的时候就会报错导致程序崩溃。错误如下：

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** NSAllocateMemoryPages(14082573) failed' *** First throw call stack:

( 0 CoreFoundation 0x06345946 exceptionPreprocess + 182

1 libobjc.A.dylib 0x05fcea97 objcexceptionthrow + 44

2 CoreFoundation 0x0634586d +[NSException raise:format:] + 141

3 Foundation 0x04f800ac NSAllocateMemoryPages + 106

4 Foundation 0x04e8e643 _NSDataCreateVMDispatchData + 34

5 Foundation 0x04e8c83a -[_NSPlaceholderData initWithBytes:length:copy:deallocator:] + 252

6 Foundation 0x04e8c72d -[NSData(NSData) initWithBytes:length:copy:freeWhenDone:bytesAreVM:] + 92

7 Foundation 0x04ee9363 -[NSData(NSData) copyWithZone:] + 144

8 CoreFoundation 0x062c4ce9 -[NSCFData copyWithZone:] + 105

9 Foundation 0x04f33531 -[NSSubrangeData initWithData:range:] + 484

10 Foundation 0x04ef3727 -[NSData(NSData) subdataWithRange:] + 657

11 ESPTablet 0x00edf137 -[CWHessianUnarchiver(Private) readDataWithTag:] + 189

12 ESPTablet 0x00edf1b3 -[CWHessianUnarchiver(Private) readDataWithTag:] + 313

13 ESPTablet 0x00edf1b3 -[CWHessianUnarchiver(Private) readDataWithTag:] + 313

14 ESPTablet 0x00edf1b3 -[CWHessianUnarchiver(Private) readDataWithTag:] + 313

15 ESPTablet 0x00edf1b3 -[CWHessianUnarchiver(Private) readDataWithTag:] + 313

16 ESPTablet 0x00edf1b3 -[CWHessianUnarchiver(Private) readDataWithTag:] + 313

17 ESPTablet 0x00edf1b3 -[CWHessianUnarchiver(Private) readDataWithTag:] + 313

。。。。错误还有很多没有全贴出来

这个错误好像是分配内存失败了

请教各位大神，知道这是什么原因吗？