memory

问题 I have a huge collection of very small objects. To ensure the data is stored very compactly I rewrote the class to store all information within a byte-array with variable-byte encoding. Most instances of these millions of objects need only 3 to 7 bytes to store all the data . After memory-profiling I found out that these byte-arrays always take at least 32 bytes . Is there a way to store the information more compactly than bit-fiddled into a byte[]? Would it be better to point to an unmanaged

问题 Scenario: Storyboard with UINavigationController as initial controller. MainVC (navigation controller's root vc) needs the user to choose a location on a map. MainVC pushes a VC containing a MapKit map and adds itself as listener for a notification the MapVC sends out when the user chooses a location. MapKit is a memory hog, we all know that. iOS gives me a memory warning, I do all the things that need to be done, then iOS deallocates all it can deallocate, including the MainVC. MapVC sends

问题 Suppose I have this simple class: public class Car { public static final int TYPE_SUV = 1; public static final int TYPE_TRUCK = 2; public String name; public int carType; } Now if I have a collection of these, I know that I am allocating a String and an int for each element in the collection, but am I also storing static int s multiple times? This contrived example class is representative of the kind of Java I wrote years ago before I learned that magic numbers like this are better served

问题 I looked into two different method to allocate memory for the elements of a matrix Method n.1 int** matrix = new int*[rows]; for (int i = 0; i < rows; ++i) matrix[i] = new int[cols]; Method n.2 int** matrix = new int*[rows]; if (rows) { matrix[0] = new int[rows * cols]; for (int i = 1; i < rows; ++i) matrix[i] = matrix[0] + i * cols; } I can figure out what Method n.1 does, but I can't figure out what exactly is supposed to do the if clause in Method n.2 (I would implement it without and it

问题 I'm coding with Swift in Xcode 6.1 and trying to create a simple automatic photo slideshow with a cross-dissolve effect between photos. I figured the best implementation would be to create a scheduled NSTimer that repeats and calls a selector method @IBOutlet var backgroundImageView: UIImageView! override func viewDidLoad() { super.viewDidLoad() backgroundImageView.image = UIImage(named: "1.jpg") let backgroundImageTimer = NSTimer.scheduledTimerWithTimeInterval( 5.0, target: self, selector:

问题 here is the prototype: void *memset(void *s, int c, size_t n) first im not sure if I have to return something because when I use the memset i do for example memset(str, 'a', 5); instead of str = memset(str, 'a', 5); here is where I am with my code: void *my_memset(void *b, int c, int len) { int i; i = 0; while(b && len > 0) { b = c; b++; len--; } return(b); } int main() { char *str; str = strdup("hello"); my_memset(str, 'a', 5); printf("%s\n", str); } I dont want to use array in this function

问题 -(IBAction)play2; { CFBundleRef mainBundle = CFBundleGetMainBundle(); CFURLRef soundFileURLRef; soundFileURLRef =CFBundleCopyResourceURL(mainBundle, (CFStringRef) @"Bear3", CFSTR ("wav"), NULL); UInt32 soundID; AudioServicesCreateSystemSoundID(soundFileURLRef, &soundID); AudioServicesPlaySystemSound(soundID); } This is giving me an error: potential leak of an object allocated " CFBundleResourceURL returns a Core Foundation object with a +1 retain count 回答1: AudioServicesCreateSystemSoundID

问题 I have 100k documents in an MonoDB Collection, the document({id : '789736363828292'}) has 20k Documents/Records. I would like find the memory utilized by that particular document. Please help me to find the memory size in MB in MongoDB console. 回答1: You can use Object.bsonsize in MongoShell which will return a BSON size (in bytes ) of one document. Try Object.bsonsize(db.col.findOne({id : '789736363828292'})) 来源： https://stackoverflow.com/questions/48960694/how-to-find-the-fhe-size-of-the

问题 I am looking for some scheduling options based on data accessed by threads. Is there any way to find the pages of cache accessed by a specific thread. If i have two threads from two different processes, is it possible to find the common data/pages accessed by both the threads 回答1: Two threads from the same process are potentially sharing the whole process memory space. If the programme does not restrict access to certain regions of memory to the threads, it might be difficult to know exactly

问题 I am interested in where string literals get allocated/stored. I did find one intriguing answer here, saying: Defining a string inline actually embeds the data in the program itself and cannot be changed (some compilers allow this by a smart trick, don't bother). But, it had to do with C++, not to mention that it says not to bother. I am bothering. =D So my question is where and how is my string literal kept? Why should I not try to alter it? Does the implementation vary by platform? Does