标题

Question

我创建了两个类“ DEVICE_s”和“ DEVICE_SET_s”，如下所示：

Device_Manager.h

typedef struct DEVICE_s DEVICE_s;
typedef struct DEVICE_SET_s DEVICE_SET_s;

Device_Manager.c

struct DEVICE_s
{
    uint32_t IP;
    TYPE_e Type;
    METHOD_e Method;
    GROUP_RULE_e GroupRule;
    char Name[NAME_SIZE];
};
struct DEVICE_SET_s
{
    uint8_t     Total;
    uint8_t     Used;
    uint8_t     Available;
    DEVICE_s    Set[SET_SIZE];
};
DEVICE_s Instance;
DEVICE_SET_s Objects;

因为我将这两个类放在同一个文件中，所以所有操作变量“实例”和“对象”的函数都放在了该文件中。

考虑到模块化，我认为这种方法不好，因此我想创建另一个源文件来分别管理类“ DEVICE_SET_s”，就像：

DeviceSet_Manager.h

typedef struct DEVICE_SET_s DEVICE_SET_s;

DeviceSet_Manager.c

#include "Device_Manager.h"
#include "DeviceSet_Manager.h"
struct DEVICE_SET_s
{
    uint8_t     Total;
    uint8_t     Used;
    uint8_t     Available;
    DEVICE_s    Set[SET_SIZE];    //Oops! Incomplete Type Is Not Allowed
};

但是，就DeviceSet_Manager.c而言，类“ DEVICE_s”不可见（不是完整类型）。

该如何解决？谢谢

Answer 1

您想要的是不透明类型

DEVICE
DEVICE_SET

这对两个人来说都是相同的方式

标题，定义
- 对象结构的不完整类型。指向它的指针是不透明的类型，用于处理对象的实例并传递给其接口函数
- 接口函数的原型
的实现
- 完整类型
- 接口功能

标题

device.h

#ifndef DEVICE_H
#define DEVICE_H

struct device;

struct device * device_new(void);
void device_delete(struct device *);

#endif

device_set.h：

#ifndef DEVICE_H
#define DEVICE_H

#include "device.h"

struct device_set;

struct device_set * device_set_new(size_t);
void device_set_delete(struct device_set *);

int device_set_set_device(struct device_set *, size_t, struct device *);
struct device * device_set_get_device(struct device_set *, size_t); 


#endif

实现

device.c

#include "device.h"

struct device {
  ...
};

struct device * device_new(void)
{
  struct device * pd = malloc(sizeof * pd);
  if (NULL != pd)
  {
    /* Init members here. */
  }

  return pd;
}

void device_delete(struct device * pd)
{
  if (pd)
  {
    /* de-init (free?) members here. */
  }

  free(pd);
}

device_set.c：

#include "device_set.h"

struct device_set
{
  size_t total;
  size_t used;
  size_t available; /* what is this for? isn't it just total - used? */
  struct device ** pd;
}

struct device_set * device_set_new(size_t nb)
{
  struct device_set pds = malloc(sizeof *pds);
  if (NULL != pds)
  {
    pds->pd = malloc(nb * sizeof *pds->pd);
    if (NULL == pds->pd)
    {
      free(pds);
      pds = NULL;
    }
    else
    {
      for (size_t d = 0; d < nb; ++d)
      {
        pds->pd[d] = NULL;
      }

      pds->total = nb;
      pds->used = 0;
      pds->available = 0;
    }
  }

  return pds;
}

void device_set_delete(struct device_set * pds)
{
  if (pds)
  {
    free(pds->pd);
    free(pds)
  }

  return;
}

int device_set_set_device(struct device_set * pds, size_t d, struct device * pd)
{
  int result = 0;

  if (pds->total <= d)      
  {
    result = ERANGE;
  }
  else
  {
    pds->pd[d] = pd;
  }

  return;
}    

struct device * device_set_get_device(struct device_set * pds, size_t d); 
  int result = 0;
  struct device * pd = NULL;

  if (pds->total <= d)      
  {
    result = ERANGE;
  }
  else
  {
    pd = pds->pd[d];
  }

  return pd;
}

Answer 2

这是我通常要做的：

device.h

// insert header guards here

typedef struct DEVICE_s DEVICE_s;
struct DEVICE_s
{
   ...
};

// method declarations here
DEVICE_Init(DEVICE_s * this, ...);
DEVICE_Foo(DEVICE_s * this, ...);

device.c

#include "device.h"
// method implementations here

deviceset.h

//hguards...

#include "device.h"

typedef struct DEVICE_SET_s DEVICE_SET_s;
struct DEVICE_SET_s
{
    uint8_t     Total;
    uint8_t     Used;
    uint8_t     Available;
    DEVICE_s    Set[SET_SIZE];
};

// method declarations here
DEVICE_SET_Init(DEVICE_SET_s * this, ...);
DEVICE_SET_Foo(DEVICE_SET_s * this, ...);

deviceset.c

#include "deviceset.h"
// method implementations here

usercode.c

DEVICE_SET_s myDevices;
void func(void) {
     DEVICE_SET_Init(&myDevices, a, b, c);         
        ...
}

使用这种方法，用户有责任分配内存并在使用之前调用init函数（=构造函数）初始化对象。

它并不能真正给您封装，但是可以为分配提供最大的自由度。为了使封装效果良好，它需要语言的支持。由于C语言从一开始就是有限的语言，因此我不建议仅为了满足编程范例而添加更多的限制。

在这种情况下，如何使程序模块化以及实现信息隐藏？

2 个答案:

标题

实现