C Coding Standard

深藏阁楼爱情的钟 2022-08-07 06:48 576阅读 0赞

### 1 通用  ###

#### Rule 1 编译的Warnings不能被忽略掉  ####

#### Rule 2 在已有Code或者三方的code基础上的修改，允许使用原来的coding standard ####

#### Rule 3 如果允许C和C++都访问的相同的C的header 文件, extern C 必须在header文件里  ####

#ifdef __cplusplus
    extern "C" {
    #endif
    
    /* body of header */
    
    #ifdef __cplusplus
    }
    #endif

### 2 命名规则  ###

#### Rule4 所有名字的定义在16个字节范围内，最多不要超过31个 ####

#### Rule5 名字的定义只有字母数字和下划线 ####

#### Rule6 不要使用保留名字 ####

#### Rule7 代码文件以.h, .c 结尾 ####

#### Rule8 代码的文件格式必须保持UNIX file format ####

#### Rule9 文件名小写，当超过一个单词描述时，用下划线分隔 ####

structured_data_display.h	
    structured_data_display.c

#### Rule10 Typedefs, and enumerated types, structure types and union types 小写并用下划线分隔多个单词描述, 结尾应以type结尾 ####

typedef UINT8 user_data_struct_type

#### Rule11 宏定义, Enum的值，必须大写并以下划线分隔多个单词  ####

#define USER_DATA_MAX_ERROR_CODES    15
    enum user_data_struct_type
    {
        USER_DATA_ERROR_INVALID_DATA,
        USER_DATA_ERROR_FAILURE
     };

#### Rule12 函数名必须是动词并且小写和下划线分隔多个单词 ####

handle_error 
    check_for_error               /* NOT errorCheck */

#### Rule13 全局变量必须以g开头并以下划线分隔单词 ####

g\_default\_interface

#### Rule14 函数的参数小写单词 ####

void start_engine(engine_type*        myengine, 
                            UINT8          engine_id,
                            const UINT32*  protected_data);

#### Rule15 structure的成员变量有以下规则 ####

<table> 
 <tbody> 
  <tr> 
   <th>名字</th> 
   <th>标记</th> 
   <th>示例</th> 
  </tr> 
  <tr> 
   <td>static</td> 
   <td>s_</td> 
   <td>static UINT8 s_some_number</td> 
  </tr> 
  <tr> 
   <td>static</td> 
   <td>s_</td> 
   <td>static UINT8 s_some_number</td> 
  </tr> 
  <tr> 
   <td>constant</td> 
   <td>c_</td> 
   <td>const UINT8 c_some_number</td> 
  </tr> 
  <tr> 
   <td>&nbsp;</td> 
   <td>cp_</td> 
   <td>const user_data_type* cp_user_data</td> 
  </tr> 
 </tbody> 
</table>

### 3 Files  ###

#### Rule16 每个include的必须有机制防止多重包含 ####

#ifndef FOO_H
    #define FOO_H
            
    /* The rest of the file*/
      	      
    #endif

#### Rule17 相对路径的linux文件不允许出现在\#include里 ####

// NOT ALLOWED
    #include <../foo/include/foo.h>

#### Rule18 头文件不允许有实现的代码 ####

#### Rule19 每个头文件只include 其他有依赖的，包含相关定义的头文件，不include 全局性的头文件 ####

#### Rule20 代码文件（.c)需要include 全局头文件以及相关头文件 ####

### 4 代码风格和间隔  ###

#### Rule21 在任何改动的文件都需要加上公司confidential的标识  ####

/* -------------------------------------------------------------------------------
         Copyright (C) 2011, Nollec Wireless  CO. LTD. All Rights Reserved
    
         Revision History:
           Bug/Feature ID         Author                   Modification Date                      Description 
         ------------------       -------------------         ------------------            ---------------------
          BugID/FeatureID      developer name       YYYY/MM/DD                          brief discription
    
    ----------------------------------------------------------------------------------*/

#### Rule22 在任何改动或者新建的文件都需要加上公司confidential的标识  ####

#### Rule23 Revision History 在Feature开发完成或Bug解决完成后必须更新  ####

#### Rule24 所有的Comments必须用英文填写, 并且不能嵌入 ####

#### Rule25 代码缩进的时候不要用Tab，用4个空格代替  ####

（跟编辑器有关,可设置）
    void func()
    ｛
          if (something bad)
          {
              ...
              if (another thing bad)
             {
    
             }
     }

#### Rule26 Switch 必须有default  ####

switch (testValue)
    {
        case VALUE_1:
            /* Body for case 1. */
            break;
        case VALUE_2:
            /* Body for case 2. */
            break;
        default:
            /* Body for default. */
            break;
    }

#### Rule27 不要在 . 或-> 前后有空格  ####

#### Rule28 变量的声明应尽量控制到小的范围内  ####

#### Rule29 指针 \* 应该紧跟类型之后， 地址 &应该在变量名之前  ####

#### Rule30 变量常量定义一定要有意义，不要用magic number  ####

x = 100\*10+1; //NOT ALLOWEDnumber = 100\*10+1;

#### Rule31 每个变量定义都要分行写，而且一定要给初值 ####

UINT8 i, j;              /* NOT RECOMMENDED */
    UINT8 i = INIT_VALUE;    /* GOOD */
    UINT8 j = INIT_VALUE;    /* GOOD */

#### Rule31 所有状态变量或者enum的变量要明确赋予其值 ####

/* INCORRECT*/
    if (cpCurrentState == CP_L3_STATE_TYPE_D1)
    {
        cpCurrentState++;
    } 
    /*CORRECT*/
    if (cp_currentState == CP_L3_STATE_TYPE_D1)
    {
        cp_currentState = CP_L3_STATE_TYPE_D2;
    }

#### Rule32 所有global的声明都要在一个header文件里 ####

#### Rule33 常量声明需要有明确含义  ####

(Does not meet requirements)
    #define ONE			1
    #define TWO			2
    
     (Meets requirements)
    #define NUM_LOOPS_FOR_AD_READ	4
    #define NUM_SAMPLES_TAKEN		8

#### Rule34 一个constant不能付给另外一个constant ####

#### Rule35 NULL只用于指针的初始化和比较 ####

#### Rule36 常量用在编译开关时候，一定要在编译控制的区域内 ####

#define DEBUG 4  
     /* if undefined, disables debugging */
    /* set to 1 - 4 for desired debugging level */
    /* This usage of DEBUG in the for loop control statement is  
     * allowed since the statement is fully enclosed within the
     * conditionally compiled section of code.
     */
    #ifdef DEBUG 
    for (i = 0; i < DEBUG; i++)  
    {
        printf("i = %d\n", i);
    }
    #endif
    
    Example 31 -	Example (Incorrect Usage)
    #define DEBUG 4
    #ifdef DEBUG       /* usage here is fine */ 
        /* do something special */
    #endif
    /* the code statement below is outside the segment controlled by 
     * the #ifdef and therefore should NOT use DEBUG.
     */
    for (i = 0; ((i < 5) && DEBUG); i++) 
    {
        printf("i = %d\n", i);
    }

#### Rule37 \#ifdef \#endif 用于编译时要有足够的注释，而且\#endif要有 //注释对应的\#ifdef ####

#### Rule38 用typedef 而不是\#define来定义类型 ####

#### Rule39 The following types shall be defined in a global header file and shall be used in place of the C language int types: ####

•	INT8: This type stores 8-bit signed numeric values.
    •	UINT8: This type stores 8-bit unsigned numeric values.
    •	INT16: This type stores 16-bit signed numeric values.
    •	UINT16: This type stores 16-bit unsigned numeric values.
    •	INT32: This type stores 32-bit signed numeric values.
    •	UINT32: This type stores 32-bit unsigned numeric values.
    •	BOOLEAN: Ideally, this type is an enumerated type that names the boolean values TRUE (1) and FALSE (0). However, some compilers may not store this efficiently. An alternative is typedef UINT8 BOOLEAN;
    That simply defines BOOLEAN as an 8-bit unsigned value which is distinct from UINT8. In this case, the constants TRUE and FALSE will have to be defined constants.

#### Rule31 一个函数应该只有一个return出口 ####

#### Rule32 不要使用没有明确定义的参数 ####

#### Rule33 函数return指针如果failure，则需要return NULL ####

#### Rule34 函数参数是单列数组不需要明确大小 ####

(Correct Usage)
    void functionName
    (
        UINT8 x[],  /* array with "size" elements */
        UINT8 size  /* number of elements in x */
    );
    (Incorrect Usage)
    void functionName (UINT8 x[10]);

#### Rule35 任何宏定义的拓展需要加上括号来限定 ####

(Correct):
    #define A_CONSTANT	(ANOTHER_CONSTANT + 1)
    a = ACONSTANT * 2;
    (Incorrect):
    #define A_CONSTANT	ANOTHER_CONSTANT + 1
    a = ACONSTANT * 2;

### Flow control, expressions  ###

#### Rule36 Switch case必须要有break结束 ####

#### Rule37 Switch default必须要有来控制以外情况 ####

#### Rule38 不要使用Goto ####

#### Rule39 在比较的时候 左边要放常量  ####

// NOT RECOMMENDED, imagine you forget one of the “=” signs
    If (PHONE == IS_RESET)
    {
    }
    // GOOD, the following statement eliminates the possible errors explained above 
    // and easier to follow the value that you are looking for
    If (IS_RESET == PHONE)
    {
    }

#### Rule40 在使用else if的时候，else的部分需要加上  ####

#### Rule41 if/else/while/for/do的区块无论一行还是多行，一定要加｛｝ ####

// NOT RECOMMENDED
    if (something)
       if (something else)
           doThis();
       else
           while (input)
               doThat();
    
    // GOOD
    if (something)
    {
       if (something else)
       {
           doThis();
       }
       else
       {
           while (input)
           {
               doThat();
           }
       }
    }

### Memory  ###

#### Rule42 一定保证从调用函数分配的内存在使用完毕后释放内存, 一定在此调用函数注释提醒  ####

Dangerous memory management   
    error_code_type* myfunction(void)
    {
        error_code_type* p_temp = malloc (sizeof(error_code_type));
        return p_temp;
        /* p_temp is never de-allocated and the user of myFunc cannot de-allocate*/
        /* because a temporary copy of that instance is returned.*/
        /* Calling user code shall take of the memory deallocating which will create*/
        /* complexity and confusion*/
    }

#### Rule43 在deference引用指针之前一定要对指针判定是否为NULL ####

UINT32\* p\_number = NULL;if (NULL == p\_number)\{\}

### 其他 ###

#### Rule44 编译器相关的扩展在有必要的时候使用 ####

#ifdef _HC11_
    #define DIRECT _direct_ram
    #else /* not _HC11_ */
    #define DIRECT
    #endif
    
    /* nSize located in direct RAM in embedded, normal RAM in UNIX */
    DIRECT UINT8 nSize;

#### Rule45 编译器相关的扩展在有必要的时候使用 ####

#### Rule46 所有丢失性的类型转换要明确cast ####

INT8   signed_value;
    UINT16 long_value;
    UINT8  short_value;
    
    /* Loss here is in accuracy going from signed to unsigned */
    signed_value= (UINT8) short_value;
    /* Loss here is in size, going from a 16 bit value to an 8 bit */
    signed_value= (INT8) long_value;

#### Rule47 数组的访问只能用方括号的形式访问，不要使用deference \* 来访问 ####

/*INCORRECT*/
    *(masterList + 10) = 0;
    
    /*CORRECT*/
    masterList[10] = 0;

#### Rule48 在condition判定的情况尽量使用肯定逻辑 ####