利用runtime进行归档解

- (void)encodeWithCoder:(NSCoder *)encoder {
    Class cls = [self class];
    while (cls != [NSObject class]) {
        unsigned int numberOfIvars = 0;
        Ivar *ivars = class_copyIvarList(cls, &numberOfIvars);
        for (int i = 0; i < numberOfIvars; ++i) {
            const char *type = ivar_getTypeEncoding(ivars[i]);
            NSString *key = [NSString stringWithUTF8String:ivar_getName(ivars[i])];
            if (key == nil || key.length == 0) {
                continue;
            }
            id value = [self valueForKey:key];
            if (value) {
                switch (type[0]) {
                    case _C_STRUCT_B: {
                        NSUInteger ivarSize = 0;
                        NSUInteger ivarAlignment = 0;
                        NSGetSizeAndAlignment(type, &ivarSize, &ivarAlignment);
                        NSData *data = [NSData dataWithBytes:(const char *)self + ivar_getOffset(ivars[i]) length:ivarSize];
                        [encoder encodeObject:data forKey:key];
                    } break;
                    default:
                        [encoder encodeObject:value forKey:key];
                        break;
                }
            }
        }
        if (ivars) {
            free(ivars);
        }

        cls = class_getSuperclass(cls);
    }
}

- (id)initWithCoder:(NSCoder *)decoder {
    self = [super init];
    if (self) {
        Class cls = [self class];
        while (cls != [NSObject class]) {
            unsigned int numberOfIvars = 0;
            Ivar *ivars = class_copyIvarList(cls, &numberOfIvars);
            for (int i = 0; i < numberOfIvars; ++i) {
                const char *type = ivar_getTypeEncoding(ivars[i]);
                NSString *key = [NSString stringWithUTF8String:ivar_getName(ivars[i])];
                if (key == nil || key.length == 0) {
                    continue;
                }
                id value = [decoder decodeObjectForKey:key];
                if (value) {
                    switch (type[0]) {
                        case _C_STRUCT_B: {
                            NSUInteger ivarSize = 0;
                            NSUInteger ivarAlignment = 0;
                            NSGetSizeAndAlignment(type, &ivarSize, &ivarAlignment);
                            NSData *data = [decoder decodeObjectForKey:key];
                            char *sourceIvarLocation = (char *)self + ivar_getOffset(ivars[i]);
                            [data getBytes:sourceIvarLocation length:ivarSize];
                            memcpy((char *)self + ivar_getOffset(ivars[i]), sourceIvarLocation, ivarSize);
                        } break;
                        default:
                            [self setValue:value forKey:key];
                            break;
                    }
                }
            }

            if (ivars) {
                free(ivars);
            }
            cls = class_getSuperclass(cls);
        }
    }

    return self;
}