iOS---学习研究大牛Git高星项目YYCategories（三）

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本文是接着上一篇博客iOS---学习研究大牛Git高星项目YYCategories（二）

大神果真是大神，一个简单的宏定义类，就有如此多的需要注意的地方。在一篇文章中写篇幅过长就分开写。

tip6：

/**
 Synthsize a weak or strong reference.
 */
#ifndef weakify
    #if DEBUG
        #if __has_feature(objc_arc)
        #define weakify(object) autoreleasepool{} __weak __typeof__(object) weak##_##object = object;
        #else
        #define weakify(object) autoreleasepool{} __block __typeof__(object) block##_##object = object;
        #endif
    #else
        #if __has_feature(objc_arc)
        #define weakify(object) try{} @finally{} {} __weak __typeof__(object) weak##_##object = object;
        #else
        #define weakify(object) try{} @finally{} {} __block __typeof__(object) block##_##object = object;
        #endif
    #endif
#endif

#ifndef strongify
    #if DEBUG
        #if __has_feature(objc_arc)
        #define strongify(object) autoreleasepool{} __typeof__(object) object = weak##_##object;
        #else
        #define strongify(object) autoreleasepool{} __typeof__(object) object = block##_##object;
        #endif
    #else
        #if __has_feature(objc_arc)
        #define strongify(object) try{} @finally{} __typeof__(object) object = weak##_##object;
        #else
        #define strongify(object) try{} @finally{} __typeof__(object) object = block##_##object;
        #endif
    #endif
#endif 

生成一个弱引用或者强引用。可以直接使用。

Example:
    @weakify(self)
    [self doSomething^{
        @strongify(self)
        if (!self) return;
        ...
    }];

tip7：

/**
 Convert CFRange to NSRange
 @param range CFRange @return NSRange
 */
static inline NSRange YYNSRangeFromCFRange(CFRange range) {
    return NSMakeRange(range.location, range.length);
}

/**
 Convert NSRange to CFRange
 @param range NSRange @return CFRange
 */
static inline CFRange YYCFRangeFromNSRange(NSRange range) {
    return CFRangeMake(range.location, range.length);
}

/**
 Same as CFAutorelease(), compatible for iOS6
 @param arg CFObject @return same as input
 */
static inline CFTypeRef YYCFAutorelease(CFTypeRef CF_RELEASES_ARGUMENT arg) {
    if (((long)CFAutorelease + 1) != 1) {
        return CFAutorelease(arg);
    } else {
        id __autoreleasing obj = CFBridgingRelease(arg);
        return (__bridge CFTypeRef)obj;
    }
}

这只是一些转换。

tip8：

/**
 Profile time cost.
 @param block     code to benchmark
 @param complete  code time cost (millisecond)
 
 Usage:
    YYBenchmark(^{
        // code
    }, ^(double ms) {
        NSLog("time cost: %.2f ms",ms);
    });
 
 */
static inline void YYBenchmark(void (^block)(void), void (^complete)(double ms)) {
    // <QuartzCore/QuartzCore.h> version
    /*
    extern double CACurrentMediaTime (void);
    double begin, end, ms;
    begin = CACurrentMediaTime();
    block();
    end = CACurrentMediaTime();
    ms = (end - begin) * 1000.0;
    complete(ms);
    */
    
    // <sys/time.h> version
    struct timeval t0, t1;
    gettimeofday(&t0, NULL);
    block();
    gettimeofday(&t1, NULL);
    double ms = (double)(t1.tv_sec - t0.tv_sec) * 1e3 + (double)(t1.tv_usec - t0.tv_usec) * 1e-3;
    complete(ms);
}

这个函数还是挺实用的,可以用来计算block内代码的执行时间,通过该函数来测试写的代码执行效率.

返回值为毫秒,double类型.

tip9：

static inline NSDate *_YYCompileTime(const char *data, const char *time) {
    NSString *timeStr = [NSString stringWithFormat:@"%s %s",data,time];
    NSLocale *locale = [[NSLocale alloc] initWithLocaleIdentifier:@"en_US"];
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    [formatter setDateFormat:@"MMM dd yyyy HH:mm:ss"];
    [formatter setLocale:locale];
    return [formatter dateFromString:timeStr];
}

/**
 Get compile timestamp.
 @return A new date object set to the compile date and time.
 */
#ifndef YYCompileTime
// use macro to avoid compile warning when use pch file
#define YYCompileTime() _YYCompileTime(__DATE__, __TIME__)
#endif

获取编译开始时间.格式为"MMM dd yyyy HH:mm:ss"

这两个方法的使用代码：

    @weakify(self)
    
    YYBenchmark(^{
        self.headView.clickHeadViewButtonTypeBlock = ^(ManagerHEadViewButtonType type) {
            if (type == ManagerHEadViewButtonLeft) {
                NSLog(@"标书归档");
                @strongify(self)
                self.headView.backgroundColor = [UIColor redColor];
            } else {
                NSLog(@"合同备案");
            }
        };
    }, ^(double ms) {
         NSLog(@"time cost: %.2f ms",ms);
    });
    
    NSLog(@"%@", YYCompileTime());

 

结果显示：