Objective C 中的位掩码

Objective-C中的位掩码是一种常见的编程技术，用于处理和管理多个布尔变量或选项的状态。位掩码通过将多个布尔变量的状态压缩到一个整数中，从而节省内存空间并提高代码的可读性和效率。

objective-c
typedef NS_OPTIONS(NSUInteger, MusicPlayerOptions) {
    MusicPlayerOptionRepeat = 1 << 0,        // 0001
    MusicPlayerOptionShuffle = 1 << 1,       // 0010
    MusicPlayerOptionLoop = 1 << 2           // 0100
};

objective-c
@interface MusicPlayer : NSObject
@property (nonatomic, assign) MusicPlayerOptions options;
- (void)setOption:(MusicPlayerOptions)option;
- (void)clearOption:(MusicPlayerOptions)option;
- (BOOL)checkOption:(MusicPlayerOptions)option;
@end
@implementation MusicPlayer
- (void)setOption:(MusicPlayerOptions)option {
    self.options |= option;
}
- (void)clearOption:(MusicPlayerOptions)option {
    self.options &= ~option;
}
- (BOOL)checkOption:(MusicPlayerOptions)option {
    return (self.options & option) == option;
}
@end

objective-c
MusicPlayer *player = [[MusicPlayer alloc] init];
[player setOption:MusicPlayerOptionRepeat];
[player setOption:MusicPlayerOptionShuffle];
NSLog(@"Repeat: %@", [player checkOption:MusicPlayerOptionRepeat] ? @"Enabled" : @"Disabled");
NSLog(@"Shuffle: %@", [player checkOption:MusicPlayerOptionShuffle] ? @"Enabled" : @"Disabled");
NSLog(@"Loop: %@", [player checkOption:MusicPlayerOptionLoop] ? @"Enabled" : @"Disabled");