Tag Archive for 'fast'

Runtime iOS Version Checking

Simple preprocessor macros to detect the current iOS version at runtime.

The NSNumericSearch compare option is very clever and can evaluate various types of numeric strings, including period separated integer strings!

Source

/*
 *  System Versioning Preprocessor Macros
 */ 

#define SYSTEM_VERSION_EQUAL_TO(v)                  ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] == NSOrderedSame)
#define SYSTEM_VERSION_GREATER_THAN(v)              ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] == NSOrderedDescending)
#define SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(v)  ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] != NSOrderedAscending)
#define SYSTEM_VERSION_LESS_THAN(v)                 ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] == NSOrderedAscending)
#define SYSTEM_VERSION_LESS_THAN_OR_EQUAL_TO(v)     ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] != NSOrderedDescending)

/*
 *  Usage
 */ 

if (SYSTEM_VERSION_LESS_THAN(@"4.0")) {
    ...
}

if (SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"3.1.1")) {
    ...
}

Faster Singleton method in Java

The fastest Singleton design pattern implementation by Bill Pugh:

public class Singleton
{
protected Singleton()
{
// ...
}

private static class SingletonHolder
{
private final static Singleton INSTANCE = new Singleton();
}

public static Singleton getInstance()
{
return SingletonHolder.INSTANCE;
}
}