C和Objective-C – 正确释放无符号字符指针的方法

- (unsigned char*)getRawData
{
// First get the image into your data buffer
CGImageRef image = [self CGImage];
NSUInteger width = CGImageGetWidth(image);
NSUInteger height = CGImageGetHeight(image);

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

unsigned char *rawData = malloc(height * width * 4);
NSUInteger bytesPerPixel = 4;
NSUInteger bytesPerRow = bytesPerPixel * width;
NSUInteger bitsPerComponent = 8;
CGContextRef context = CGBitmapContextCreate(rawData,width,height,bitsPerComponent,bytesPerRow,colorSpace,kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);
CGColorSpaceRelease(colorSpace);

CGContextSetBlendMode(context,kCGBlendModeCopy);

CGContextDrawImage(context,CGRectMake(0.0f,0.0f,(CGFloat)width,(CGFloat)height),image);
CGContextRelease(context);

// Now your rawData contains the image data in the RGBA8888 pixel format.

return rawData;
}

在另一个类中,我将一个属性分配给该指针,如下所示：self.bitmapData = [image getRawData];

在这个过程中我可以释放那个malloc内存吗？当我尝试在dealloc中释放属性时,它会给我一个exc_bad_access错误.我觉得我在这里缺少一个基本的c或objective-c概念.所有帮助表示赞赏.