简书 MarkDown 代码框的使用

还是第一次使用简书的markDown

代码框
runtime method swizzling

//静态就交换静态，实例方法就交换实例方法
void Swizzle(Class c, SEL origSEL, SEL newSEL)
{
    Method origMethod = class_getInstanceMethod(c, origSEL);
    Method newMethod = nil;
    if (!origMethod) {
        origMethod = class_getClassMethod(c, origSEL);
        if (!origMethod) {
            return;
        }
        newMethod = class_getClassMethod(c, newSEL);
        if (!newMethod) {
            return;
        }
    }else{
        newMethod = class_getInstanceMethod(c, newSEL);
        if (!newMethod) {
            return;
        }
    }
    
    //自身已经有了就添加不成功，直接交换即可
    if(class_addMethod(c, origSEL, method_getImplementation(newMethod), method_getTypeEncoding(newMethod))){
        class_replaceMethod(c, newSEL, method_getImplementation(origMethod), method_getTypeEncoding(origMethod));
    }else{
        method_exchangeImplementations(origMethod, newMethod);
    }
}