Question

在过去的几个月里，我一直在尝试使用纯C进行编码，并尽可能地避免使用C ++（出于个人原因，C ++是一种很好的语言），但偶尔会出现这样的情况：当我用C ++编写代码时，我会错过一些我过去经常使用的概念，C语言中没有明显的等价物，其中一个概念是“接口”。经过几个小时的研究后，我想出了这个解决方案，但我担心我的代码将来可能会出错。以下是我想要做的示例代码：

#include <stdlib.h>
#include <string.h>
#include <stdio.h>

typedef int (*on_affected_cb) (const char *msg);

typedef struct affectee_t affectee_t;
typedef struct type_a_t type_a_t;
typedef struct type_b_t type_b_t;
typedef struct type_c_t type_c_t;
typedef struct owner_t owner_t;

//******************************************************************************

struct affectee_t{ //interface
  on_affected_cb on_affected;
};

void affectee_notify(affectee_t* self, const char* msg){
  self->on_affected(msg);
}

//******************************************************************************

struct type_a_t{ //implementor a
  affectee_t affectee;
  int num;
};

static int type_a_on_affected (const char *msg){
  printf("this is type a reading msg: %s\n", msg);
  return 1000;
}

void type_a_init(type_a_t* self){
  self->num = 0;
  self->affectee.on_affected = type_a_on_affected;
}

//******************************************************************************

struct type_b_t{ //implementor b
  affectee_t affectee;
  char name[128];
};

static int type_b_on_affected (const char *msg){
  printf("this is type b reading msg: %s\n", msg);
  return 2000;
}

void type_b_init(type_b_t* self){
  memset(self->name, 0, sizeof(self->name));
  self->affectee.on_affected = type_b_on_affected;
}

//******************************************************************************

struct owner_t{ // ordinary struct/class
  type_a_t ta;
  type_b_t tb;
};

void owner_init(owner_t* self){
  type_a_init(&self->ta);
  type_b_init(&self->tb);
}

void owner_notify(owner_t* self){
  const char msg[] = "what the f...!";
  affectee_notify((affectee_t*)&self->ta, msg); //<- pointer casting!!!
  affectee_notify((affectee_t*)&self->tb, msg); //<- same here
}

//******************************************************************************

int main(int argc, char **argv){
  owner_t owner;
  owner_init(&owner);
  owner_notify(&owner);
}

这是在纯C中定义和使用“接口”的正确/安全方式吗？

0 个答案: