1.获取类名

    //1. const char * class_getName(Class cls)
    const char * className = class_getName(NSPerson.class);
    NSLog(@"class name : %s",className);

2.判断是否元类

    //2.
//    BOOL isMetaClass = class_isMetaClass(NSPerson.class);
    BOOL isMetaClass = class_isMetaClass(object_getClass(NSPerson.class));
    NSLog(@"isMetaClass : %d",isMetaClass);

3.获取父类

    Class superClass = class_getSuperclass(NSPerson.class);
    NSLog(@"%@",superClass);

4.设置父类（DEPRECATED）

    /**
     __OSX_DEPRECATED(10.5, 10.5, "not recommended")
     __IOS_DEPRECATED(2.0, 2.0, "not recommended")
     __TVOS_DEPRECATED(9.0, 9.0, "not recommended")
     __WATCHOS_DEPRECATED(1.0, 1.0, "not recommended")

     */
    
//    class_setSuperclass(Class  _Nonnull __unsafe_unretained cls, Class  _Nonnull __unsafe_unretained newSuper)
    

5.class version

/**@note You can use the version number of the class definition to provide versioning of the
interface that your class represents to other classes. This is especially useful for object
serialization (that is, archiving of the object in a flattened form), where it is important to
recognize changes to the layout of the instance variables in different class-definition versions.
*/

  class_setVersion(NSPerson.class, 1);
    
   NSLog(@"class_version : %d", class_getVersion(NSPerson.class));

6.获取类的实例对象的大小

    size_t size = class_getInstanceSize(NSPerson.class);
//    size_t size = class_getInstanceSize(object_getClass(NSPerson.class));

    NSLog(@"%zd",size);

    

8.成员变量(ivar)获取

• class_getInstanceVariable
• class_getClassVariable
• class_copyIvarList

    Ivar age_ivar = class_getInstanceVariable(NSPerson.class,"_age");

    const char * age_name = ivar_getName(age_ivar);
    const char * age_type = ivar_getTypeEncoding(age_ivar);
    NSLog(@"name:%s , type: %s",age_name ,age_type);
    

    Ivar isa = class_getClassVariable(NSPerson.class,"isa");
    
    const char * isa_name = ivar_getName(isa);
    const char * isa_type = ivar_getTypeEncoding(isa);
    NSLog(@"name:%s , type: %s",isa_name ,isa_type);
    
    
    //8.class_copyIvarList
    unsigned int outCount = 0;
    Ivar *ivars = class_copyIvarList(NSPerson.class, &outCount);
    for (int i = 0; i < outCount; i++) {
        const char *name = ivar_getName(ivars[i]);
        NSLog(@"%s",name);
    }
    free(ivars);
  

9.方法(method)的获取

• class_getInstanceMethod
• class_getClassMethod
• class_getMethodImplementation
• class_respondsToSelector
• class_copyMethodList

    Method method = class_getInstanceMethod(NSPerson.class, sel_registerName("run"));
    NSLog(@"%@",NSStringFromSelector(method_getName(method)));
    NSLog(@"%s",method_getTypeEncoding(method));
    NSLog(@"%p",method_getImplementation(method));
    
    Method clsMethod = class_getClassMethod(NSPerson.class, @selector(person));
    NSLog(@"%@",NSStringFromSelector(method_getName(clsMethod)));
    NSLog(@"%s",method_getTypeEncoding(clsMethod));
    NSLog(@"%p",method_getImplementation(clsMethod));
    
    
    IMP runIMP = class_getMethodImplementation(NSPerson.class, @selector(run));
    NSLog(@"%p",runIMP);
    
//    OBJC_ARM64_UNAVAILABLE
//    class_getMethodImplementation_stret(Class  _Nullable __unsafe_unretained cls, SEL  _Nonnull name)

//    区别都调用class_respondsToSelector_inst(id inst, SEL sel, Class cls)，
    //inst 传nil
    BOOL isRun = class_respondsToSelector(NSPerson.class, @selector(run));
    NSLog(@"isRun:%d",isRun);
    
    //inst传self
    BOOL isR = [NSPerson.new respondsToSelector:@selector(run)];
    NSLog(@"isR:%d",isR);
   
    //12.class_copyMethodList
    unsigned int methodCount = 0;
    Method *methods = class_copyMethodList(object_getClass(NSPerson.class), &methodCount);
    for (int i = 0; i < methodCount; i++) {
        SEL mname = method_getName(*(methods + i));
        NSLog(@"+m%d:%@",i,NSStringFromSelector(mname));
    }
    free(methods);
    
    methods = class_copyMethodList(NSPerson.class, &methodCount);
    for (int i = 0; i < methodCount; i++) {
        SEL mname = method_getName(*(methods + i));
        NSLog(@"-m%d:%@",i,NSStringFromSelector(mname));
    }
    free(methods);

pragma mark - protocol

10.协议(protocol)的获取

• class_conformsToProtocol
• class_copyProtocolList

    BOOL isConformProtocol = class_conformsToProtocol(NSPerson.class,@protocol(NSPersonDelegate));
    
    //conformsToProtocol:遍历一个实例的类及其类的superclass然后 调用了class_conformsToProtocol，
//    BOOL isConformProtocol = [NSPerson.new conformsToProtocol:@protocol(NSPersonDelegate)];
    NSLog(@"isConformProtocol:%d",isConformProtocol);
    NSString *persond = NSStringFromProtocol(@protocol(NSPersonDelegate));
    NSLog(@"persond:%@",persond);
    
    
 unsigned int protocolCount = 0;
    Protocol * __unsafe_unretained * protocols = class_copyProtocolList(NSPerson.class, &protocolCount);
    
    for (int i = 0; i < protocolCount; i++) {
        NSLog(@"prtocol%i:%s",i,protocol_getName(*(protocols + i)));
    }
    free(protocols);
    

11.属性的获取

• class_getProperty
• class_copyPropertyList

    //T@"NSString",R,C,N,GgetName,V_name
    objc_property_t age_property = class_getProperty(NSPerson.class, "name");
    NSLog(@"%s,attr:%s",property_getName(age_property),property_getAttributes(age_property));
    
    unsigned int property_count = 0;
    objc_property_t *properties = class_copyPropertyList(NSPerson.class, &property_count);
    for (int i = 0; i < property_count; i++) {
        NSLog(@"property%i:%s",i,property_getName(*(properties + i)));
    }
    free(properties);
    

12.成员变量布局

• class_getIvarLayout
• class_getWeakIvarLayout

    

    const  uint8_t *ivar_layout = class_getIvarLayout(NSPerson.class);
    NSLog(@"ivar_layout:%s",ivar_layout);

    if(ivar_layout != NULL)
    {
        int i = 0;
        uint8_t value_s = ivar_layout[i];
        while (value_s != 0x0) {
            printf("ivar_layout:\\x%02x\n", value_s);
            value_s = ivar_layout[++i];
        }
    }
    
    const uint8_t *ivar_weak_layout = class_getWeakIvarLayout(NSPerson.class);

    if(ivar_weak_layout != NULL)
    {
        int i = 0;
        uint8_t value_s = ivar_weak_layout[i];
        while (value_s != 0x0) {
            printf("ivar_weak_layout:\\x%02x\n", value_s);
            value_s = ivar_weak_layout[++i];
        }

    }

12.向类中添加成员变量/方法/协议/属性

    //12.1.1.method add
    BOOL isAdd = class_addMethod(NSPerson.class, @selector(travel), (IMP)travel_add, "v@0:8");
    NSLog(@"isAdd:%d",isAdd);
    
    [NSPerson.new travel];
//    [NSPerson.new performSelector:@selector(travel)];
    
    
    NSLog(@"eatIMP1:%p",class_getMethodImplementation(NSPerson.class, @selector(eat)));
    
    //12.1.2.method replace
    //返回替换前方法的地址
    IMP methodIMP = class_replaceMethod(NSPerson.class, @selector(eat), (IMP)eat_replace,
                        "v@0:8");
    NSLog(@"eatIMP2:%p",class_getMethodImplementation(NSPerson.class, @selector(eat)));

    NSLog(@"methodIMP:%p",methodIMP);
    
    [NSPerson.new eat];
    
    //12.2.ivar
    Class NSCat = objc_allocateClassPair(NSObject.class, "NSCat", 0);
    
    BOOL isAddIvar = class_addIvar(NSCat, "_name", 8, 1<<0, @encode(NSString *));
    
    NSLog(@"isAddIvar:%d",isAddIvar);
    objc_registerClassPair(NSCat);
    
    
    //12.3.protocol
    BOOL is_add_protocol = class_addProtocol(NSPerson.class, @protocol(NSCopying));
    NSLog(@"is_add_protocol%d",is_add_protocol);
    
    //12.4.1.property add
    
    objc_property_attribute_t types = { "T", "@\"NSString\"" };

    objc_property_attribute_t ownership = {"C", ""}; // C = copy
//    objc_property_attribute_t ownership = {"&", ""}; // & = strong/retain

    objc_property_attribute_t atomic = {"N", ""}; // N = nonatomic

    objc_property_attribute_t rw = {"R", ""}; // R = readonly

    objc_property_attribute_t backIvar = {"V","_car"};

    objc_property_attribute_t attrs[] = { atomic,rw,types, ownership, backIvar };


    BOOL is_add_property = class_addProperty(NSPerson.class, "car", attrs, 5);
    
    NSLog(@"is_add_property:%d",is_add_property);
    
    //12.4.2.property replace
    objc_property_attribute_t age_t = {"T","@\"NSString\""};
    objc_property_attribute_t age_owner = {"C",""};
    objc_property_attribute_t age_atomic = {"N",""};
    objc_property_attribute_t age_rw = {"R",""};
    objc_property_attribute_t age_i = {"V","__age"};
    objc_property_attribute_t age_attr[] = {age_t,age_rw,age_owner,age_atomic,age_i};
    
    class_replaceProperty(NSPerson.class, "age", age_attr, 5);
    
//    unsigned int property_count = 0;
//    objc_property_t *properties = class_copyPropertyList(NSPerson.class, &property_count);
//    for (int i = 0; i < property_count; i++) {
//        NSLog(@"property%i:%s,%s",i,property_getName(*(properties + i)),property_getAttributes(*(properties + i)));
//    }
//    free(properties);

13.成员变量布局设置

#warning to learn

//    class_setIvarLayout(NSPerson.class, <#const uint8_t * _Nullable layout#>);
//    class_setWeakIvarLayout(NSPerson.class, <#const uint8_t * _Nullable layout#>)

14.创建实例

    NSPerson *person_0 = class_createInstance(NSPerson.class, 0);
    [person_0 travel];
    [person_0 run];
    [person_0 eat];

15.获取镜像(framework / dynamic library)

    const char * image = class_getImageName(NSPerson.class);
    NSLog(@"image:%s",image);