[嵌入式开发模块]通用接收状态机模块

本是古典何须时尚 2022-05-23 00:13 165阅读 0赞

### 文章目录 ###

*  前言
 *  模块相关概念和逻辑
 *   *  接收机状态
     *  标志字符序列
     *  flush
     *  接收机类
     *  过滤器
     *  onGetHeader事件
     *  接收机运行逻辑
     *  边际条件
 *  相关代码
 *   *  接收机代码
     *   *  RxMac.h
         *  RxMacPrivate.h
         *  RxMac.c
     *  测试/示例代码
 *  v1.0代码
 *   *  接收机代码
     *  测试/示例代码
 *  后记
 *  更新历史

# 前言 #

在软件开发的过程中，只要涉及到通信，就会涉及到数据接收机的编写，通信协议虽然多种多样，但是数据包的形式确是很相似的(暂时没看到特别复杂，此模块解决不了的)，为此可以把其中通用的部分抽象出来，然后就成了这个模块。

# 模块相关概念和逻辑 #

## 接收机状态 ##

接收机有两个基本状态：

*  状态A：preRx 等待帧头中，这个时候接收机会不断判断是否收到了特殊序列、帧头和强帧尾。如果收到了帧头，则(默认)会把帧头填入缓冲区的最前面，然后进入状态B。
 *  状态B：Rxing 等待帧尾中，收到的数据会按序填入接收缓冲区，同时不断查找帧尾、强帧头以及强特殊序列，不管找到了哪一个都会触发flush。如果，找到的是强帧头，则仍然在状态B，否则恢复状态A。

不管在哪一个状态下，如果接受缓冲区满了，都会触发flush并回到状态A。

## 标志字符序列 ##

接收机定义了以下标志序列类型：

<table> 
 <thead> 
  <tr> 
   <th align="center">类型</th> 
   <th align="center">模块中标记</th> 
   <th align="left">描述</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td align="center">帧头</td> 
   <td align="center">header</td> 
   <td align="left">只在状态A起作用；找到时会导致之前接收区内的数据被flush，然后默认会填入接收区的最前面，可以通过选项来改变这个行为，然后接收机进入状态B。</td> 
  </tr> 
  <tr> 
   <td align="center">强帧头</td> 
   <td align="center">strong-header</td> 
   <td align="left">在状态B也会起作用，其他行为与普通帧头一样</td> 
  </tr> 
  <tr> 
   <td align="center">帧尾</td> 
   <td align="center">ender</td> 
   <td align="left">只在状态B起作用；找到时会导致当前接收区内的数据被flush，默认会处于回调时给用户的buffer的最后面，可以通过选项来改变这个行为，然后接收机回到状态A。</td> 
  </tr> 
  <tr> 
   <td align="center">强帧头</td> 
   <td align="center">strong-header</td> 
   <td align="left">在状态A也会起作用，其他行为与普通帧尾一样</td> 
  </tr> 
  <tr> 
   <td align="center">特殊序列</td> 
   <td align="center">unique</td> 
   <td align="left">只在状态A起作用；找到时会导致之前接收区内的数据被flush，然后自己被填入接收区内后再次触发flush，然后接收机回到状态A。</td> 
  </tr> 
  <tr> 
   <td align="center">强特殊序列</td> 
   <td align="center">strong-unique</td> 
   <td align="left">在状态B也会起作用，其他行为与特殊序列一样</td> 
  </tr> 
 </tbody> 
</table>

对应模块中的结构体为：

// receive flag
    typedef struct RXFLAG_STRUCT{
        
       uint8_t const * pBuf;
       uint8_t len;
       uint8_t option;
    } RXFLAG_STRUCT;
    typedef RXFLAG_STRUCT const * RxFlag;

一般的流程中，初始化接收机前，用户需要准备好接收机使用的所有标志序列，标志好每个序列的类型。模块提供宏函数以抽象这个过程：

// void RxFlag_Init(RXFLAG_STRUCT * flag,uint8_t const * buf,uint8_t len,uint8_t opt);
    // to  initialize a receive flag
    //    flag    point to the target RXFLAG_STRUCT.
    //    buf     pointer to the flag buffer
    //    size    size of flag 
    //    opt     see  RXFLAG_OPTION_XXXXX, bit mode
    #define RxFlag_Init(flag,buf,size,opt)     \
      {(flag)->pBuf =(buf);(flag)->len =(size);(flag)->option = (opt);}

## flush ##

每当接收机根据标志字符序列找到一个完整或不完整的数据包时，接收机会进行回调以通知用户处理这个数据包，这个行为被称为flush，这个回调函数叫做onFlushed。

此函数的原型如下

typedef void (* RXMAC_FLUSH_EVENT)(RxMac sender,RxMacPtr buf,uint16_t len,RxState state,
                                       RxFlag HorU,RxFlag Ender);

整个数据包为buf指向的长度为len的区域。

数据包的状态可以通过state参数得知，RX\_STATE 的类型定义如下

typedef struct RXSTATE_STRUCT{
        
      unsigned int headerFound: 1;     // 1: have get header
      unsigned int enderFound : 1;     // 1: have get ender
      unsigned int isFull     : 1;     // 1: the buffer is full
      unsigned int uniqueFound: 1;     // 1: this is unique flag.
    } RxState;

通过判断每个标志位是否置1，可以得知当前数据包的状态。  
如果headerFound == 1，说明数据包是有帧头的，可以通过pHorU获得帧头  
如果enderFound == 1，说明数据包是有帧尾的，可以通过pEnder获得帧尾  
如果isFull == 1，说明此数据包是因为接收区满了放不下了而产生的回调，在一些需要根据某个字段来判断数据包真正大小的协议里，可以通过调整接收缓冲区的大小来恰当的产生flush。  
如果UniqueFound == 1，说明此数据包是标志序列，这时缓冲区内的内容等于pHorU指向的那个标志序列

## 接收机类 ##

V1.0版本中要求用户自己分配结构体的空间，为了更加面向对象，现已改为动态分配，而把具体结构体和对应方法封装在模块内部。

typedef struct RXMAC_STRUCT * RxMac;

模块提供Create函数来创建接收机实例并返回指向实例的指针。

// to create an instance of RxMac
    //  flags       标志字符串结构体的数组
    //  flagsCnt    标志字符串结构体的个数
    //  buf         用户提供给接收机用的缓冲区 
    //  bufLen      缓冲区的大小(起码应该要能放的下最长的标志字符串)
    //  onFeeded    在每次被Feed时触发
    //  onGetHeader 获得头标志位时触发。
    //  onFlushed   收到一帧数据时的回调函数
    RxMac RxMac_Create(RXFLAG_STRUCT const flags[], uint8_t flagsCnt, RxMacPtr buf, uint16_t bufLen, 
                    RXMAC_FILTER onFeeded, RXMAC_FLAG_EVENT onGetHeader, RXMAC_FLUSH_EVENT onFlushed);

调用实例的方法时把这个指针作为第一个参数以模拟面向对象操作。

## 过滤器 ##

接收机每次被feed时，都会触发onFeeded事件(可以在配置中取消这个事件以节省点代码)。原型如下：

typedef void (* RXMAC_FILTER)(RxMac sender,uint8_t * pCurChar,uint16_t bytesCnt);

pCurChar ：指向接收区中刚收到的字符  
bytesCnt ：这个字符是接收区中的第几个字符

此时，接收机已经将其放入接收区但是还没进一步进行判断，用户可以修改字符/配置接收机以改变接收机的行为，比如将收到的字母全变为小写。或者根据收到的数据来决定还要收多少数据。

## onGetHeader事件 ##

当找到任意帧头时会触发。

## 接收机运行逻辑 ##

接收机的运作逻辑如下：

![70][]

## 边际条件 ##

标志序列尽量不要有重合，如果同时可能匹配两个标志序列，最终行为是未定义的，不保证正确执行，最终结果可能与标志序列的位置以及类型有关系。

同一个标志串可以同时是多种类型，比如同时是帧头与帧尾，但要小心类型间不要有冲突，否则不保证正确执行。

对于标志序列匹配到一半发生了接收缓冲区满，从而导致发生标志序列匹配时，接收缓冲区中只有半个标志序列的情况：  
如果标志序列是(强)特殊序列或(强)帧头的情况，可以保证功能正常运行。  
如果标志序列是强帧尾的情况，缓冲区内会只剩下后半段的帧尾，但可以根据pEnder参数来得知真正的帧尾。  
帧尾不会发生这种边际条件。

# 相关代码 #

此模块使用了我自己写的Buffer模块作为内部缓冲区来判断标志字符串。  
[https://blog.csdn.net/lin\_strong/article/details/88236566][https_blog.csdn.net_lin_strong_article_details_88236566]

## 接收机代码 ##

### RxMac.h ###

/*
    *******************************************************************************************
    *
    *
    *                                  Universal Receive State Machine
    *                                          通用接收状态机
    *
    * File : RxMac.h
    * By   : Lin Shijun(https://blog.csdn.net/lin_strong)
    * Date: 2019/03/07
    * version: 2.1
    * History: 2018/05/29 1.0 the prototype
    *          2019/01/23 2.0 modify the type names to more readable ones, though preserve
    *                       the old-style for forward compatibility;
    *                         change init method to create method which use malloc to alloc
    *                       instance, and the corresponding destroy method.
    *                         change the internal buffer module from RINGQUEUE to BufferArray,
    *                       so user no longer need to know the internal flags management and
    *                       allocate the space for it.
    *                         add RxMac_FeedDatas method for convenient.
    *          2019/03/07 2.1 some modification to the malloc configuration
    *
    * NOTE(s):  1. the receive process has two basic state
    *              A. preRx: when haven't found any header, the RxMac will search for the unique
    *                        flag, header and strong-ender. Only when a header is found will come
    *                        to next step.
    *              B. Rxing: the RxMac will put the successive bytes into the buffer, and search
    *                        for the strong-unique, strong-header, ender. 
    *           2. the module is drived by the RxMac_FeedData(), user should get the the char 
    *              from data stream and pass the data one by one to the RxMac through RxMac_FeedData()
    *              or RxMac_FeedDatas().
    *           3. each time RxMac find a frame(complete or incomplete),it will call the onFlushed
    *              to notify the results; user can judge the frame through the state parameter; 
    *               state.headerFound == 1:   find any header, the header is passed by HorU
    *               state.enderFound  == 1:   find any ender,  the ender  is passed by Ender
    *               state.isFull      == 1:   the buffer is full, maybe you should check headerFound
    *                                         to see whether a header has been found.
    *               state.uniqueFound == 1:   find any unique flag. In this case, other parameters will
    *                                         always be 0 ,the data in the buffer will be the flag,
    *                                         and the unique flag is passed by HorU.
    *           4. To use this module, for each receive machine:
    *              A. define malloc to configure the module, see CONFIGURATION
    *              B. allocate the space for buffer and FLAGS.
    *                   RXFLAG_STRUCT flags[2];
    *                   uint8_t buf[300];
    *              C. set the flags according to the protocol, define the callback functions
    *                  according to your need.
    *                   static void onGetHeader(RxMac sender,RxFlag pFlag){ ...... };
    *                   static void onFlushed(RxMac sender,RxMacPtr pBuf,uint16_t len,
    *                      RxState state,RxFlag HorU,RxFlag Ender){ ...... };
    *                   const uint8_t HeaderFlag[] = "Header";
    *                   const uint8_t EnderFlag[] = "\r\n";
    *                   RxFlag_Init(flags,HeaderFlag,StrSize(HeaderFlag),RXFLAG_OPTION_HEADER);
    *                   RxFlag_Init(&flags[1],EnderFlag,StrSize(EnderFlag),RXFLAG_OPTION_ENDER |
    *                                 RXFLAG_OPTION_NOTFILL_ENDER);
    *              D. create the receive machine:
    *                   RxMac mac;
    *                   mac = RxMac_Create(flags,sizeof(flags)/sizeof(flags[0]),buf,300,NULL, 
    *                                 onGetHeader, onFlushed );
    *              E. feed the receive machine:
    *                   while(1){
    *                     c = GetNextChar();
    *                     RxMac_FeedData(mac,c);
    *                   }
    *              F. destroy the receive machine if need.
    *                  RxMac_Destroy(mac);
    *******************************************************************************************
    */
    
    #ifndef RX_MAC_H
    #define RX_MAC_H
    
    /*
    *******************************************************************************************
    *                                       INCLUDES
    *******************************************************************************************
    */
    
    #include <stdint.h>
    
    /*
    *******************************************************************************************
    *                                  CONFIGURATION  配置
    *******************************************************************************************
    */
    // #define RXMAC_ARGUMENT_CHECK_DISABLE to disable the argument check functions of this module
    //#define RXMAC_ARGUMENT_CHECK_DISABLE
    
    // #define RXMAC_NOTFILL_DISABLE to disable the notFill option
    //#define RXMAC_NOTFILL_DISABLE
    
    // #define RXMAC_ONFEEDED_DISABLE to disable the onFeeded event.
    //#define RXMAC_ONFEEDED_DISABLE
    
    // #define RXMAC_SINGLETON_EN to use singleton pattern,so argument pRxMac of interfaces is 
    // useless, and user don't need to allocate space for RX_MAC, but you still need to allocate
    // buffer and call init();
    //#define RXMAC_SINGLETON_EN
    
    // #define RXMAC_BUF_RPAGE if you want receive machine use the paged array as buffer.
    // and don't forget to define CODEWARRIOR malloc
    //#define RXMAC_BUF_RPAGE
    /*
    *******************************************************************************************
    *                                 ADDRESSING MODE 寻址模式
    *******************************************************************************************
    */
    
    #ifdef RXMAC_BUF_RPAGE
    #ifdef CODEWARRIOR
    #define RXMAC_BUF_ADDRESSING_MODE  __rptr
    #endif
    #endif
    
    #ifndef RXMAC_BUF_ADDRESSING_MODE
    #define RXMAC_BUF_ADDRESSING_MODE
    #endif
    typedef uint8_t * RXMAC_BUF_ADDRESSING_MODE RxMacPtr;
     
    /*
    *********************************************************************************************
    *                                    ERROR CODE
    *********************************************************************************************
    */
    
    #define RXMAC_ERR_NONE           0
    #define RXMAC_ERR_ARGUMENT       1
    #define RXMAC_ERR_POINTERNULL    2
    #define RXMAC_ERR_UNKNOWN        3
    #define RXMAC_ERR_INIT           4
    
    /*
    *********************************************************************************************
    *                                RECEIVE FLAG STRUCT
    *********************************************************************************************
    */
    
    // normal header, RxMac will only check it in Step A
    #define RXFLAG_OPTION_HEADER               0x01
    // strong header, RxMac will always check it.
    #define RXFLAG_OPTION_STRONG_HEADER        0x03
    // the header will not be filled into buffer when found.(only valid when is header)
    #define RXFLAG_OPTION_NOTFILL_HEADER       0x04
    // normal ender, RxMac will only check it in Step B
    #define RXFLAG_OPTION_ENDER                0x08
    // strong header, RxMac will always check it.
    #define RXFLAG_OPTION_STRONG_ENDER         0x18
    // the ender will not be filled into buffer when found.(only valid when is ender)
    #define RXFLAG_OPTION_NOTFILL_ENDER        0x20
    // normal unique, RxMac will only check it in Step A
    #define RXFLAG_OPTION_UNIQUE               0x40
    // strong unique, RxMac will always check it.
    #define RXFLAG_OPTION_STRONG_UNIQUE        0xC0
    
    // receive flag
    typedef struct RXFLAG_STRUCT{
        
       uint8_t const * pBuf;
       uint8_t len;
       uint8_t option;
    } RXFLAG_STRUCT;
    typedef RXFLAG_STRUCT const * RxFlag;
    
    // void RxFlag_Init(RXFLAG_STRUCT * flag,uint8_t const * buf,uint8_t len,uint8_t opt);
    // to  initialize a receive flag
    //    flag    point to the target RXFLAG_STRUCT.
    //    buf     pointer to the flag buffer
    //    size    size of flag 
    //    opt     see  RXFLAG_OPTION_XXXXX, bit mode
    #define RxFlag_Init(flag,buf,size,opt)     \
    {(flag)->pBuf =(buf);(flag)->len =(size);(flag)->option = (opt);}
    
    
    /*
    *********************************************************************************************
    *                                   TYPE DEFINITION
    *********************************************************************************************
    */
    
    typedef struct RXSTATE_STRUCT{
        
      unsigned int headerFound: 1;     // 1: have get header
      unsigned int enderFound : 1;     // 1: have get ender
      unsigned int isFull     : 1;     // 1: the buffer is full
      unsigned int uniqueFound: 1;     // 1: this is unique flag.
    } RxState;
    
    typedef struct RXMAC_STRUCT * RxMac;
    
    typedef void (* RXMAC_FLUSH_EVENT)(RxMac sender,RxMacPtr buf,uint16_t len,RxState state,
                                       RxFlag HorU,RxFlag Ender);
    typedef void (* RXMAC_FLAG_EVENT)(RxMac sender,RxFlag flag);
    typedef void (* RXMAC_FILTER)(RxMac sender,uint8_t * pCurChar,uint16_t bytesCnt);
    
    /*
    *******************************************************************************************
    *                                  FUNCTION DECLARATION
    *******************************************************************************************
    */
    
    // to create an instance of RxMac
    //  flags       标志字符串结构体的数组
    //  flagsCnt    标志字符串结构体的个数
    //  buf         用户提供给接收机用的缓冲区 
    //  bufLen      缓冲区的大小(起码应该要能放的下最长的标志字符串)
    //  onFeeded    在每次被Feed时触发
    //  onGetHeader 获得头标志位时触发。
    //  onFlushed   收到一帧数据时的回调函数
    RxMac RxMac_Create(RXFLAG_STRUCT const flags[], uint8_t flagsCnt, RxMacPtr buf, uint16_t bufLen, RXMAC_FILTER onFeeded, RXMAC_FLAG_EVENT onGetHeader, RXMAC_FLUSH_EVENT onFlushed);
    // to destroy the RxMac
    void RxMac_Destroy(RxMac mac);
    // 向接收机内喂字节
    void RxMac_FeedDatas(RxMac mac, uint8_t const * buf, uint16_t len);
    void RxMac_FeedData(RxMac mac, uint8_t c);
    // 重置接收区长度为最长那个长度
    //uint8_t RxMac_ResetRxSize(RxMac mac);
    // 设置最大接收到多少个字节
    uint8_t RxMac_SetRxSize(RxMac mac, uint16_t size);
    // 重置接收机的状态
    uint8_t RxMac_ResetState(RxMac mac);
    // 强制接收机flush
    uint8_t RxMac_Flush(RxMac mac);
    // 设置onFeeded
    uint8_t RxMac_SetOnFeeded(RxMac mac, RXMAC_FILTER onFeeded);
    // 设置onGetHeader
    uint8_t RxMac_SetOnGetHeader(RxMac mac, RXMAC_FLAG_EVENT onGetHeader);
    // 设置onFlushed
    uint8_t RxMac_SetOnFlushed(RxMac mac, RXMAC_FLUSH_EVENT onFlushed);
    
    #include "RxMacPrivate.h"
    
    #endif // of RX_MAC_H

### RxMacPrivate.h ###

/*
    *******************************************************************************************
    *
    *
    *                       Private Declarations for Universal Receive State Machine
    *
    * File : RxMacPrivate.h
    * By   : Lin Shijun(https://blog.csdn.net/lin_strong)
    * Date: 2019/03/07
    * version: 2.1
    * History: 
    * NOTE(s): 
    *******************************************************************************************
    */
    
    
    /*
    *******************************************************************************************
    *                                  FUNCTION DECLARATION
    *******************************************************************************************
    */
    // 打印内部缓冲区，返回缓冲区的长度
    uint16_t _RxMac_printBuffer(RxMac mac,uint8_t * buf);
    
    /*
    *******************************************************************************************
    *                                      RECEIVE FLAG STRUCT
    *******************************************************************************************
    */
    
    // struct of RXFLAG_STRUCT.option 
    /*typedef struct RXFLAG_OPTION{
      unsigned int isHeader : 1;  // 1: the flag is the head of the frame
      unsigned int strong_H : 1;  // 1: strong-header, RxMac will 
      unsigned int notfill_H: 1;  // 0: fill the flag into the buffer when found as header
      unsigned int isEnder  : 1;  // 1: the flag is the end of the frame
      unsigned int strong_E : 1;  // 
      unsigned int notfill_E: 1;  // 0: fill the flag into the buffer when found as ender
      unsigned int isUnique : 1;  // 1: the flag is a unique flag which is treated as single frame.
      unsigned int strong_U : 1;  // 0: when receiving a frame, RxMac will not 
    }; //*/
    // normal header, RxMac will only check it in Step A
    #define RXFLAG_OPTBIT_HEADER               0x01
    // strong header, RxMac will always check it.
    #define RXFLAG_OPTBIT_STRONG_HEADER        0x02
    // the header will not be filled into buffer when found.(only valid when is header)
    #define RXFLAG_OPTBIT_NOTFILL_HEADER       0x04
    // normal ender, RxMac will only check it in Step B
    #define RXFLAG_OPTBIT_ENDER                0x08
    // strong header, RxMac will always check it.
    #define RXFLAG_OPTBIT_STRONG_ENDER         0x10
    // the ender will not be filled into buffer when found.(only valid when is ender)
    #define RXFLAG_OPTBIT_NOTFILL_ENDER        0x20
    // normal unique, RxMac will only check it in Step A
    #define RXFLAG_OPTBIT_UNIQUE               0x40
    // strong unique, RxMac will always check it.
    #define RXFLAG_OPTBIT_STRONG_UNIQUE        0x80
    
    #define STATEMASK_STEPA   \
      (RXFLAG_OPTBIT_HEADER | RXFLAG_OPTBIT_UNIQUE | RXFLAG_OPTBIT_STRONG_ENDER)
    #define STATEMASK_STEPB   \
      (RXFLAG_OPTBIT_STRONG_UNIQUE | RXFLAG_OPTBIT_ENDER | RXFLAG_OPTBIT_STRONG_HEADER)
    #define RXFLAGMASK_USUHSH   \
      (RXFLAG_OPTBIT_HEADER | RXFLAG_OPTBIT_STRONG_HEADER | \
      RXFLAG_OPTBIT_UNIQUE | RXFLAG_OPTBIT_STRONG_UNIQUE)
    
    // BOOL _RxFlag_isHeader(RxFlag flag);
    #define _RxFlag_isHeader(flag)   \
      ((flag)->option & (RXFLAG_OPTION_STRONG_HEADER | RXFLAG_OPTION_HEADER))
    // BOOL _RxFlag_isEnder(RxFlag flag);
    #define _RxFlag_isEnder(flag)    \
      ((flag)->option & (RXFLAG_OPTION_STRONG_ENDER  | RXFLAG_OPTION_ENDER))
    // BOOL _RxFlag_isUnique(RxFlag flag);
    #define _RxFlag_isUnique(flag)   \
      ((flag)->option & (RXFLAG_OPTION_STRONG_UNIQUE | RXFLAG_OPTION_UNIQUE))
    // BOOL _RxFlag_dontFillHeader(RxFlag flag);
    #define _RxFlag_dontFillHeader(flag) \
      ((flag)->option & RXFLAG_OPTBIT_NOTFILL_HEADER)
    // BOOL _RxFlag_dontFillEnder(RxFlag flag);
    #define _RxFlag_dontFillEnder(flag) \
      ((flag)->option & RXFLAG_OPTBIT_NOTFILL_ENDER)
    
    /*
    *******************************************************************************************
    *                                    FORWARD COMPATIBILITY
    *******************************************************************************************
    */
    // 以下仅为前向兼容
    typedef RxMacPtr          pRB_BYTE;
    typedef RXFLAG_STRUCT     RX_FLAG,*pRX_FLAG;
    typedef RxMac             pRX_MAC;
    typedef RxState           RX_STATE;
    #define FLAG_OPTION_HEADER             RXFLAG_OPTION_HEADER
    #define FLAG_OPTION_STRONG_HEADER      RXFLAG_OPTION_STRONG_HEADER
    #define FLAG_OPTION_NOTFILL_HEADER     RXFLAG_OPTION_NOTFILL_HEADER
    #define FLAG_OPTION_ENDER              RXFLAG_OPTION_ENDER
    #define FLAG_OPTION_STRONG_ENDER       RXFLAG_OPTION_STRONG_ENDER
    #define FLAG_OPTION_NOTFILL_ENDER      RXFLAG_OPTION_NOTFILL_ENDER
    #define FLAG_OPTION_UNIQUE             RXFLAG_OPTION_UNIQUE
    #define FLAG_OPTION_STRONG_UNIQUE      RXFLAG_OPTION_STRONG_UNIQUE
    #define RX_FLAG_INIT                   RxFlag_Init

### RxMac.c ###

/*
    *******************************************************************************************
    *
    *
    *                         Implementation of the Universal Receive State Machine
    *                                          通用接收状态机
    *
    * File : RxMac.c
    * By   : Lin Shijun(https://blog.csdn.net/lin_strong)
    * Date: 2019/03/07
    * version: 2.1
    * History: 2018/05/29 1.0 the prototype
    *          2019/01/23 2.0 In addition to the content in RxMac.h:
    *                           abstract the flag management part as RxFlagMgr and the
    *                          corresponding methods.
    *                           refactor the code.
    *          2019/03/07 2.1 some modification to the malloc configuration
    * NOTE(s): 
    *
    *******************************************************************************************
    */
    
    /*
    *******************************************************************************************
    *                                       INCLUDES
    *******************************************************************************************
    */
    #include <stddef.h>
    #include <stdlib.h>
    #include <string.h>
    #include "RxMac.h"
    #include "BufferMallocArray.h"
    
    /*
    *******************************************************************************************
    *                                   RECEIVE FLAGS MANAGER
    *******************************************************************************************
    */
    
    typedef struct RXFLAGMGR_STRUCT {
        
      // buffer to hold the pre-data which hasn't matched any flag.
      BufferUINT8Indexed BufForFlag;
      // the flag array to be matched.
      RxFlag   Flags;
      // count of flags.
      uint8_t  FlagsCnt;
      // current state, in which headerFound will influence the match behavior. 
      // controlled by the child class.
      RxState  state;
    }RXFLAGMGR_STRUCT;
    
    static RxFlag _RxFlagMgr_GetNextMatchedAtThisState(RxMac mac,uint8_t nextByte);
    static BOOL _RxFlagMgr_Init(RxMac mac,RxFlag flags,uint8_t flagsCnt,uint8_t maxLen);
    static void _RxFlagMgr_Destroy(RxMac mac);
    static void _RxFlagMgr_Reset(RxMac mac);
    
    /*
    *******************************************************************************************
    *                                   STRUCT DIFINITION
    *******************************************************************************************
    */
    
    typedef struct RXMAC_STRUCT{
        
      // manage the flag matches.
      RXFLAGMGR_STRUCT FlagMgr;
      // record the Header or Unique flag.
      RxFlag   pHorU;
      // internal buffer to hold data.
      RxMacPtr pRxBuf;
      // length of the internal buffer
      uint16_t RxBufSize;
      // Count of the bytes in the internal buffer/ the index for next feeded byte
      uint16_t RxCnt;
      RXMAC_FILTER onFeeded;
      RXMAC_FLAG_EVENT onGetHeader;
      RXMAC_FLUSH_EVENT onFlushed;
    } RXMAC_STRUCT;
    
    /*
    *******************************************************************************************
    *                          LOCAL  FUNCITON  DECLARATION
    *******************************************************************************************
    */
    #ifndef RXMAC_SINGLETON_EN
      #define _pMac          mac
      #define _BufForFlag   (_pMac->FlagMgr.BufForFlag)
      #define _Flags        (_pMac->FlagMgr.Flags)
      #define _FlagsCnt     (_pMac->FlagMgr.FlagsCnt)
      #define _state        (_pMac->FlagMgr.state)
      #define _pHorU        (_pMac->pHorU)
      #define _pRxBuf       (_pMac->pRxBuf)
      #define _RxBufSize    (_pMac->RxBufSize)
      #define _RxCnt        (_pMac->RxCnt)
      #define _fonFeeded    (_pMac->onFeeded)
      #define _fonGetHeader (_pMac->onGetHeader)
      #define _fonFlushed   (_pMac->onFlushed)
      #define _RxMac_Destroy()    (free(mac))
    #else
      static RXMAC_STRUCT _mac;
      // 单例模式中，这个指针用于标识是否单例已初始化过
      static RxMac _pMac = NULL;
      #define _BufForFlag   (_mac.FlagMgr.BufForFlag)
      #define _Flags        (_mac.FlagMgr.Flags)
      #define _FlagsCnt     (_mac.FlagMgr.FlagsCnt)
      #define _state        (_mac.FlagMgr.state)
      #define _pHorU        (_mac.pHorU)
      #define _pRxBuf       (_mac.pRxBuf)
      #define _RxBufSize    (_mac.RxBufSize)
      #define _RxCnt        (_mac.RxCnt)
      #define _fonFeeded    (_mac.onFeeded)
      #define _fonGetHeader (_mac.onGetHeader)
      #define _fonFlushed   (_mac.onFlushed)
      #define _RxMac_Destroy()  (_pMac = NULL)
    #endif
    
    #define _stateByte      (*(uint8_t *)(&_state))
    #define _isRxBufFull()  (_RxCnt >= _RxBufSize)
    
    #ifndef RXMAC_ONFEEDED_DISABLE
      #define _onFeeded(pChar,cnt)    if(_fonFeeded != NULL)  _fonFeeded(_pMac,pChar,cnt);
    #else
      #define _onFeeded(pChar,cnt)
    #endif
    #define  _onGetHeader(headerFlag)       if(_fonGetHeader != NULL) _fonGetHeader(_pMac,headerFlag);
    
    #undef _DONT_CHECK_MAC
    #ifdef RXMAC_ARGUMENT_CHECK_DISABLE
    #define _DONT_CHECK_MAC
    #endif
    #ifdef RXMAC_SINGLETON_EN
    #define _DONT_CHECK_MAC
    #endif
    
    #ifdef _DONT_CHECK_MAC
      #define _checkMacNotNull()
      #define _checkMacNotNull_void()
    #else
      #define _checkMacNotNull()       if(_pMac == NULL)  return RXMAC_ERR_POINTERNULL;
      #define _checkMacNotNull_void()  if(_pMac == NULL)  return;
    #endif
    
    
    #ifdef RXMAC_BUF_RPAGE
    #ifdef CODEWARRIOR
    static RxMacPtr _memcpy_internal(RxMacPtr dest, RxMacPtr src, size_t n);
    #define memcpy(dest,src,n)   _memcpy_internal(dest,src,n)
    #endif
    #endif
    // 冲刷缓冲区
    static void _flush(RxMac mac,RxFlag ender);
    // 往接收机缓冲区内放数据
    static void _BufIn(RxMac mac,RxMacPtr buf,uint16_t len);
    
    static void _RxMac_FlushIfFull(RxMac mac);
    static void _RxMac_RecordAndFlushPreBytesIfGotHeaderOrUnique(RxMac mac,RxFlag flagJustGot);
    static void _RxMac_GetHeaderProcess(RxMac mac,RxFlag flagJustGot);
    static void _RxMac_GetUniqueProcess(RxMac mac,RxFlag flagJustGot);
    static void _RxMac_GetEnderProcess(RxMac mac,RxFlag flagJustGot);
    /*
    *******************************************************************************************
    *                                      RxMac_Create()
    *
    * Description : To create a receive machine instance.    创建一个接收机实例
    *
    * Arguments   : flags      pointer to the flags(an array); 指向标志串(数组)的指针
    *               flagsCnt   the count of the flags;         有多少个标志串;
    *               buf        pointer to the buffer provided to the RxMac;提供给接收机使用的缓存
    *               bufLen     the size of the buffer.         缓存的大小
    *               onFeeded   the callback func that will be called everytime feeded, you
    *                          can modify the feeded byte in this callback.
    *                          每次被feed时会调用的回调函数，如改变对应数据值会影响标志位的判断
    *               onGetHeader the callback func that will be called when find a header.
    *                          当发现帧头时会调用的回调函数
    *               onFlushed  the callback func that will be called when flushed.
    *                          当Flush时会调用的回调函数
    *
    * Return      : Pointer to the created instance.
    *               NULL      if any error.
    *
    * Note(s)     : 1. size of buffer should bigger than the longest flag, or the flag will be 
    *               useless.
    *               2. if flagsCnt > 0, flags can't point to NULL.
    *               3. you must provide a buffer.
    *               4. if you enable the RXMAC_SINGLETON_EN, multi-create will pointer to the
    *                  same instance initialized as the last create.
    *
    *               void onGetHeader(RxMac sender,RxFlag flag):
    *                sender   the pointer to the RxMac which call this function
    *                flag     the header matched
    *
    *               void onFeeded(RxMac sender,uint8_t * pCurChar,uint16_t bytesCnt):
    *                sender    the pointer to the RxMac which call this function
    *                pCurChar  point to the byte just received, you can change it before any other process.
    *                bytesCnt  the number of bytes in the buffer including the char just feeded.
    *
    *               void onFlushed(RxMac sender,RxMacPtr pBuf,uint16_t len,RxState state,RxFlag HorU,
    *                  RxFlag Ender);
    *                sender    the pointer to the RxMac which call this function
    *                buf       the pointer to the frame.
    *                len       the length of frame.
    *                state     the state of frame.
    *                HorU      point to the header flag if state.headerFound == 1, or unique flag if 
    *                          state.uniqueFound == 1.
    *                Ender     point to the ender flag if state.enderFound == 1.
    *******************************************************************************************
    */
    RxMac RxMac_Create(RXFLAG_STRUCT const flags[],uint8_t flagsCnt,RxMacPtr buf,uint16_t bufLen,RXMAC_FILTER onFeeded,RXMAC_FLAG_EVENT onGetHeader,RXMAC_FLUSH_EVENT onFlushed){
        
      uint8_t i, maxLen = 0;
    #ifndef RXMAC_SINGLETON_EN
      RxMac mac;
    #endif
    #ifndef RXMAC_ARGUMENT_CHECK_DISABLE
      if((flags == NULL && flagsCnt > 0 ) || buf == NULL)
        return NULL;
    #endif
      // find out the max length of flags.
      for(i = 0; i < flagsCnt; i++){
        
        if(flags[i].len > maxLen)
          maxLen = flags[i].len;
      }
    #ifndef RXMAC_ARGUMENT_CHECK_DISABLE
      if(bufLen < maxLen){
        
        return NULL;
      }
    #endif
    #ifdef RXMAC_SINGLETON_EN
      if(_pMac != NULL)            // if have created one instance, free the previous FlagBuf
        _RxFlagMgr_Destroy(&_mac);
      else
        _pMac = &_mac;
    #else
      if((mac = (RxMac)malloc(sizeof(RXMAC_STRUCT))) == NULL){
        
        return NULL;
      }
    #endif
      if(!_RxFlagMgr_Init(_pMac,flags,flagsCnt,maxLen)){
        
        _RxMac_Destroy();
        return NULL;
      }
      _pHorU = NULL;
      _pRxBuf = buf;
      _RxCnt = 0;
      _RxBufSize = bufLen;
      _fonFeeded = onFeeded;
      _fonGetHeader = onGetHeader;
      _fonFlushed = onFlushed;
      return _pMac;
    }
    /*
    *******************************************************************************************
    *                                        RxMac_Destroy()
    *
    * Description : Destroy a receive machine instance.
    *
    * Arguments   : mac     the target receive machine.     目标接收机
    *
    * Return      : 
    *
    * Note(s)     : 
    *
    *******************************************************************************************
    */
    void RxMac_Destroy(RxMac mac){
        
      if(_pMac == NULL)
        return;
      _RxFlagMgr_Destroy(mac);
      _RxMac_Destroy();
    }
    /*
    *******************************************************************************************
    *                                        RxMac_FeedData(s)
    *
    * Description : To feed RxMac the next char(s).    用于给接收机下一个字符
    *
    * Arguments   : mac    the target receive machine.     目标接收机
    *               c      the char to feed;               下一个字符
    *
    * Return      : 
    *
    * Note(s)     : 
    *******************************************************************************************
    */
    
    void RxMac_FeedDatas(RxMac mac, uint8_t const * buf, uint16_t len){
        
      uint16_t i;
      for(i = 0; i < len; i++)
        RxMac_FeedData(mac,buf[i]);
    }
    
    void RxMac_FeedData(RxMac mac,uint8_t c){
        
      RxFlag curFlag;
      _checkMacNotNull_void();
      _onFeeded(&c,_RxCnt + 1);
      _pRxBuf[_RxCnt++] = c;
      curFlag = _RxFlagMgr_GetNextMatchedAtThisState(mac,c);
      if(curFlag == NULL){
                // if no flag match
        _RxMac_FlushIfFull(mac);
        return;
      }
      _RxMac_RecordAndFlushPreBytesIfGotHeaderOrUnique(mac,curFlag);
      if(_RxFlag_isHeader(curFlag)){
        
        _RxMac_GetHeaderProcess(mac,curFlag);
      }else if(_RxFlag_isUnique(curFlag)){
        
        _RxMac_GetUniqueProcess(mac,curFlag);
      }else{
           // if(_RxFlag_isEnder(curFlag))
        _RxMac_GetEnderProcess(mac,curFlag);
      }
    }
    /*
    *******************************************************************************************
    *                                        RxMac_SetRxSize()
    *
    * Description : set the size of RxBuf.   设置接收缓冲区的大小
    *
    * Arguments   : mac     the target receive machine.     目标接收机
    *               size    the size to set;
    *
    * Return      : RXMAC_ERR_NONE            if Success;
    *               RXMAC_ERR_POINTERNULL     if mac == NULL
    *               RXMAC_ERR_ARGUMENT        if size is wrong.
    * Note(s)     : the size should bigger than the current number of chars in the RxBuf.
    *               
    *******************************************************************************************
    */
    uint8_t RxMac_SetRxSize(RxMac mac, uint16_t size){
        
      _checkMacNotNull();
    #ifndef RXMAC_ARGUMENT_CHECK_DISABLE
      if(size <= _RxCnt)
        return RXMAC_ERR_ARGUMENT;
    #endif
      _RxBufSize = size;
      return RXMAC_ERR_NONE;
    }
    /*
    *******************************************************************************************
    *                                        RxMac_ResetState()
    *
    * Description : reset the state of receive machine.   重置接收机的状态
    *
    * Arguments   : mac    the target receive machine.    目标接收机
    *
    * Return      : RXMAC_ERR_NONE            if Success;
    *               RXMAC_ERR_POINTERNULL     if mac == NULL
    * Note(s)     : it will not trigger call-back of onFlush.
    *******************************************************************************************
    */
    uint8_t RxMac_ResetState(RxMac mac){
        
      _checkMacNotNull();
      // 复位接收机
      Buffer_Cleanup((Buffer)_BufForFlag);
      _RxCnt = 0;
      _stateByte = 0;
      _pHorU = NULL;
      return RXMAC_ERR_NONE;
    }
    /*
    *******************************************************************************************
    *                                        RxMac_Flush()
    *
    * Description : force receive machine to flush.
    *
    * Arguments   : mac     the target receive machine.     目标接收机
    *
    * Return      : RXMAC_ERR_NONE            if Success;
    *               RXMAC_ERR_POINTERNULL     if mac == NULL
    *
    * Note(s)     : it will force receive machine to flush, if there is any data in the RxBuffer,
    *
    *******************************************************************************************
    */
    
    uint8_t RxMac_Flush(RxMac mac){
        
      _checkMacNotNull();
      _flush(_pMac,NULL);
      return RXMAC_ERR_NONE;
    }
    
    /*
    ******************************************************************************************
    *                                        RxMac_SetOnFeeded()
    *
    * Description : set the onFeeded callback function.
    *
    * Arguments   : mac       the target receive machine.     目标接收机
    *               onFeeded  the callback function to set;   要设置的回调函数
    *
    * Return      : RXMAC_ERR_NONE            if Success;
    *               RXMAC_ERR_POINTERNULL     if mac == NULL
    *
    * Note(s)     :
    *
    ******************************************************************************************
    */
    uint8_t RxMac_SetOnFeeded(RxMac mac,RXMAC_FILTER onFeeded){
        
      _checkMacNotNull();
      _fonFeeded = onFeeded;
      return RXMAC_ERR_NONE;
    }
    /*
    ******************************************************************************************
    *                                        RxMac_SetOnGetHeader()
    *
    * Description : set the onGetHeader callback function.
    *
    * Arguments   : mac          the target receive machine.     目标接收机
    *               onGetHeader  the callback function to set;   要设置的回调函数
    *
    * Return      : RXMAC_ERR_NONE            if Success;
    *               RXMAC_ERR_POINTERNULL     if mac == NULL
    *
    * Note(s)     :
    *
    ******************************************************************************************
    */
    uint8_t RxMac_SetOnGetHeader(RxMac mac,RXMAC_FLAG_EVENT onGetHeader){
        
      _checkMacNotNull();
      _fonGetHeader = onGetHeader;
      return RXMAC_ERR_NONE;
    }
    /*
    ******************************************************************************************
    *                                        RxMac_SetOnFlushed()
    *
    * Description : set the onFlushed callback function.
    *
    * Arguments   : mac          the target receive machine.     目标接收机
    *               onFlushed    the callback function to set;   要设置的回调函数
    *
    * Return      : RXMAC_ERR_NONE            if Success;
    *               RXMAC_ERR_POINTERNULL     if pRxMac == NULL
    *
    * Note(s)     :
    *
    ******************************************************************************************
    */
    uint8_t RxMac_SetOnFlushed(RxMac mac,RXMAC_FLUSH_EVENT onFlushed){
        
      _checkMacNotNull();
      _fonFlushed = onFlushed;
      return RXMAC_ERR_NONE;
    }
    /*
    ******************************************************************************************
    *                                        _RxMac_printBuffer()
    *
    * Description : print the internal buffer, just for developer.
    *               给开发者用于查看内部缓存的
    *
    * Arguments   : mac          the target receive machine.     目标接收机
    *               onFlushed    the callback function to set;   要设置的回调函数
    *
    * Return      : the len of buffer printed.
    *
    * Note(s)     :
    *
    ******************************************************************************************
    */
    
    uint16_t _RxMac_printBuffer(RxMac mac,uint8_t * buf){
        
      memcpy(buf,_pRxBuf,_RxCnt);
      return _RxCnt;
    }
    
    /*
    ******************************************************************************************
    *                                   LOCAL  FUNCITON 
    ******************************************************************************************
    */
    static RxMacPtr _memcpy_internal(RxMacPtr dest, RxMacPtr src, size_t n){
        
      RxMacPtr p = dest;
      while(n-- > 0)
        *p++ = *src++;
      return dest;
    }
    
    static void _BufIn(RxMac mac,RxMacPtr buf,uint16_t len){
        
      memcpy(_pRxBuf+_RxCnt,buf,len);
      _RxCnt += len;
    }
    
    static void _flush(RxMac mac,RxFlag ender){
        
      // 触发回调
      if((_RxCnt > 0 || ender != NULL) && _fonFlushed != NULL)
        _fonFlushed(_pMac,_pRxBuf,_RxCnt,_state,_pHorU,ender);
      // 复位接收机
      _RxCnt = 0;
      _stateByte = 0;
      _pHorU = NULL;
    }
    
    BOOL BufferUINT8Indexed_BackMatch(BufferUINT8Indexed buf,uint8_t const *toMatch,uint16_t len){
        
      uint16_t cnt = _Buffer_getCount(buf);
      if(len > cnt) 
        return FALSE;
      while(len > 0){
        
        if(_BufferUINT8Indexed_get(buf,--cnt) != toMatch[--len])
          return FALSE;
      }
      return TRUE;
    }
    
    
    static void _RxMac_FlushIfFull(RxMac mac){
        
      if(_isRxBufFull()){
        
        _state.isFull = 1;
        _flush(_pMac,NULL);
      }
    }
    
    static void _RxMac_RecordAndFlushPreBytesIfGotHeaderOrUnique(RxMac mac,RxFlag flagJustGot){
        
      if(flagJustGot->option & RXFLAGMASK_USUHSH){
        
        if(_RxCnt > flagJustGot->len){
        
          _RxCnt -= flagJustGot->len;
          _flush(_pMac,NULL);
        }else{
        
          _RxCnt = 0;
        }
        _pHorU = flagJustGot;
      }
    }
    
    static void _RxMac_GetHeaderProcess(RxMac mac,RxFlag flagJustGot){
        
    #ifndef RXMAC_NOTFILL_DISABLE
      if(!_RxFlag_dontFillHeader(flagJustGot))
    #endif
        _BufIn(_pMac,(RxMacPtr)flagJustGot->pBuf,flagJustGot->len);
      _state.headerFound = 1;
      _onGetHeader(flagJustGot);
      _RxMac_FlushIfFull(mac);
    }
    
    static void _RxMac_GetUniqueProcess(RxMac mac,RxFlag flagJustGot){
        
      _state.uniqueFound = 1;
      _BufIn(_pMac,(RxMacPtr)flagJustGot->pBuf,flagJustGot->len);
      _flush(_pMac,NULL);
    }
    
    static void _RxMac_GetEnderProcess(RxMac mac,RxFlag flagJustGot){
        
      _state.enderFound = 1;
      if(_RxCnt < flagJustGot->len){
                  // if part of the flag has been manually flushed.
        _RxCnt = 0;                           // restore the buffer.
        _BufIn(_pMac,(RxMacPtr)flagJustGot->pBuf,flagJustGot->len); 
      }
    #ifndef RXMAC_NOTFILL_DISABLE
      if(_RxFlag_dontFillEnder(flagJustGot))
        if(_RxCnt > flagJustGot->len)
          _RxCnt -= flagJustGot->len;
        else
          _RxCnt = 0;
    #endif
      _flush(_pMac,flagJustGot);
    }
    
    static RxFlag _RxFlagMgr_GetNextMatchedAtThisState(RxMac mac,uint8_t nextByte){
        
      uint8_t i,mask;
      if(_Buffer_isFull(_BufForFlag))
        BufferUINT8_FrontOut((BufferUINT8)_BufForFlag);
      BufferUINT8_BackIn((BufferUINT8)_BufForFlag,nextByte);
      // mask to identify possible flag
      mask = (_state.headerFound)?STATEMASK_STEPB:STATEMASK_STEPA;
      for(i = 0; i < _FlagsCnt; i++){
        
        if((_Flags[i].option & mask) && 
          BufferUINT8Indexed_BackMatch(_BufForFlag,_Flags[i].pBuf,_Flags[i].len)){
        
            Buffer_Cleanup((Buffer)_BufForFlag);
            return &_Flags[i];
        }
      }
      return NULL;
    }
    
    static BOOL _RxFlagMgr_Init(RxMac mac,RxFlag flags,uint8_t flagsCnt,uint8_t maxLen){
        
      if(_BufForFlag = (BufferIndexed)BufferUINT8MallocArray_Create(maxLen)){
        
        _Flags = flags;
        _FlagsCnt = flagsCnt;
        _stateByte = 0;
      }
      return _BufForFlag != NULL;
    }
    
    static void _RxFlagMgr_Destroy(RxMac mac){
        
      Buffer_Destroy(_BufForFlag);
    }
    
    static void _RxFlagMgr_Reset(RxMac mac){
        
      Buffer_Cleanup((Buffer)_BufForFlag);
    }

## 测试/示例代码 ##

已略去非必要代码

#include <stdio.h>
    #include "RxMac.h"
    
    /*
    *********************************************************************************************************
    *                                      LOCAL  FUNCTION  DECLARE
    *********************************************************************************************************
    */
    
    static void onGetData(RxMac sender,uint8_t * pCurChar,uint16_t bytesCnt);
    static void onFlushed(RxMac sender,RxMacPtr buf,uint16_t len,RxState state,RxFlag HorU,RxFlag Ender);
    static void onGetHeader(RxMac sender,RxFlag flag);
    static void onGetHeader2(RxMac sender,RxFlag flag);
    
    /*
    *********************************************************************************************************
    *                                           LOVAL VARIABLE
    *********************************************************************************************************
    */
    static RxMac  mac = NULL;
    static RXFLAG_STRUCT flags[4];
    #define BUF_SIZE  20
    static uint8_t buffer[BUF_SIZE];
    
    // 协议示例1：
    // 帧头    :HEADER 或者 START
    // 强帧尾  :END
    // 强特殊串:12345  
    // 
    static void protocol1_init(void){
        
      RX_FLAG_INIT(&flags[0],"HEADER",6,FLAG_OPTION_HEADER);
      RX_FLAG_INIT(&flags[1],"START",5,FLAG_OPTION_HEADER);
      RX_FLAG_INIT(&flags[2],"END",3,FLAG_OPTION_STRONG_ENDER);
      RX_FLAG_INIT(&flags[3],"12345",5,FLAG_OPTION_STRONG_UNIQUE);
      mac = RxMac_Create(flags,4,buffer,BUF_SIZE,NULL,onGetHeader,onFlushed);
    }
    // 协议示例2：
    // 帧头    : START
    // 帧头后的第1个字符表示后面还要接收多少个字符 1-9,'4'表示4个，如果不是数字或为'0'，则等待帧尾
    // 帧尾    : END
    // 特殊串:  NOW
    // 
    static void protocol2_init(void){
        
      RX_FLAG_INIT(&flags[0],"START",5,FLAG_OPTION_HEADER);
      RX_FLAG_INIT(&flags[1],"END",3,FLAG_OPTION_ENDER);
      RX_FLAG_INIT(&flags[2],"NOW",3,FLAG_OPTION_UNIQUE);
      mac = RxMac_Create(flags,3,buffer,BUF_SIZE,NULL,onGetHeader2,onFlushed);
    }
    /*
    *********************************************************************************************************
    *                                           CALLBACK FUNCITON
    *********************************************************************************************************
    */
    
    static void onGetData(RxMac sender,uint8_t * pCurChar,uint16_t bytesCnt){
        
      // 因为发现帧头后才挂载事件，所以下一次回掉正好是说明字符数的那个字符,否则还得根据bytesCnt来判断当前位置
      RxMac_SetOnFeeded(sender,NULL);
      if(*pCurChar > '0' && *pCurChar <= '9' ){
        
        // bytesCnt是当前收到了多少个字符，所以接收区大小为当前字符数加上还要接收的
        RxMac_SetRxSize(sender,*pCurChar - '0' + bytesCnt);
      }
    }
    static void onFlushed(RxMac sender,RxMacPtr buf,uint16_t len,RxState state,RxFlag HorU,RxFlag Ender){
        
      buf[len] = '\0';
      printf("\nFlushed:");
      if(state.headerFound)
        printf("headerFound,");
      if(state.enderFound)
        printf("enderFound,");
      if(state.isFull)
        printf("full,");
      if(state.uniqueFound)
        printf("unique,");
      printf("\nDatas:%s\n",buf);
      RxMac_SetRxSize(sender,BUF_SIZE);
    }
    static void onGetHeader(RxMac sender,RxFlag flag){
        
      printf("\nFoundHeader:%s\n",flag->pBuf);
    }
    static void onGetHeader2(RxMac sender,RxFlag flag){
        
      printf("\nFoundHeader:%s\n",flag->pBuf);
      RxMac_SetOnFeeded(sender,onGetData);
    }
    /*
    *********************************************************************************************************
    *                                           MAIN FUNCTION
    *********************************************************************************************************
    */
    
    void main(void) {
        
      // 选择想要实验的协议来初始化
      protocol1_init();
      // protocol2_init();
      while (1) {
        
        c = getchar();
        // 回显
        putchar(c);
        RxMac_FeedData(mac,c);
      }
    }

示例协议1测试结果  
![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpbl9zdHJvbmc_size_16_color_FFFFFF_t_70][]

示例协议2测试结果  
![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpbl9zdHJvbmc_size_16_color_FFFFFF_t_70 1][]  
可以看到，第二个协议中我们通过改变缓冲区大小成功控制了数据包的长度。

虽然这里的示例都是基于ASCII的，但这只是为了观察起来方便，普通的基于二进制的协议也是可以使用这个模块的。

# v1.0代码 #

旧版代码中引用了我自己写的(现已弃用)环形缓冲区模块：  
[https://blog.csdn.net/lin\_strong/article/details/73604561][https_blog.csdn.net_lin_strong_article_details_73604561]

## 接收机代码 ##

头文件

源文件：

/*
    *********************************************************************************************************
    *
    *
    *                                  Universal Receive State Machine
    *                                          通用接收状态机
    *
    * File : RxMac.c
    *
    * By   : Lin Shijun(https://blog.csdn.net/lin_strong)
    * Date: 2018/05/29
    * version: 1.0
    * History: 
    * NOTE(s): 
    *
    *********************************************************************************************************
    */
    
    /*
    *********************************************************************************************************
    *                                       INCLUDES
    *********************************************************************************************************
    */
    #include "RxMac.h"
    
    #include <string.h>
    #include <stddef.h>
    /*
    *********************************************************************************************************
    *                                       CONSTANT
    *********************************************************************************************************
    */
    // normal header, RxMac will only check it in Step A
    #define FLAG_OPTBIT_HEADER               0x01
    // strong header, RxMac will always check it.
    #define FLAG_OPTBIT_STRONG_HEADER        0x02
    // the header will not be filled into buffer when found.(only valid when is header)
    #define FLAG_OPTBIT_NOTFILL_HEADER       0x04
    // normal ender, RxMac will only check it in Step B
    #define FLAG_OPTBIT_ENDER                0x08
    // strong header, RxMac will always check it.
    #define FLAG_OPTBIT_STRONG_ENDER         0x10
    // the ender will not be filled into buffer when found.(only valid when is ender)
    #define FLAG_OPTBIT_NOTFILL_ENDER        0x20
    // normal unique, RxMac will only check it in Step A
    #define FLAG_OPTBIT_UNIQUE               0x40
    // strong unique, RxMac will always check it.
    #define FLAG_OPTBIT_STRONG_UNIQUE        0x80
    
    #define STATEMASK_STEPA   (FLAG_OPTBIT_HEADER | FLAG_OPTBIT_UNIQUE | FLAG_OPTBIT_STRONG_ENDER)
    #define STATEMASK_STEPB   (FLAG_OPTBIT_STRONG_UNIQUE | FLAG_OPTBIT_ENDER | FLAG_OPTBIT_STRONG_HEADER)
    #define FLAGMASK_USUHSH   (FLAG_OPTBIT_HEADER | FLAG_OPTBIT_STRONG_HEADER | FLAG_OPTION_UNIQUE | FLAG_OPTBIT_STRONG_UNIQUE)
    
    /*
    *********************************************************************************************************
    *                                   LOCAL  FUNCITON  DECLARATION
    *********************************************************************************************************
    */
    #if(RXMAC_SINGLETON_EN == FALSE)
      #define _pRxMac       pRxMac
    #else
      static RX_MAC _RxMac;
      #define _pRxMac       (&_RxMac)
    #endif
    
    #define _FlagQueue   (_pRxMac->FlagQueue)
    #define _Flags       (_pRxMac->Flags)
    #define _FlagsCnt    (_pRxMac->FlagsCnt)
    #define _state       (_pRxMac->state)
    #define _stateByte   (*(INT8U *)(&_state))
    #define _pHorU       (_pRxMac->pHorU)
    #define _pRxBuf      (_pRxMac->pRxBuf)
    #define _RxBufSize   (_pRxMac->RxBufSize)
    #define _pCur        (_pRxMac->pCur)
    #define _onFeeded    (_pRxMac->onFeeded)
    #define _onGetHeader (_pRxMac->onGetHeader)
    #define _onFlushed   (_pRxMac->onFlushed)
    #define _isRxBufFull()  ((_pCur - _pRxBuf) >= _RxBufSize)
    
    
    // 因为不能保证用户把数据放在非分页区，只好自己实现一个,实际使用中如果确定在非分页区可以把下面的宏替换为库函数memcpy
    static pRB_BYTE _memcpy_internal(pRB_BYTE dest, pRB_BYTE src, size_t n);
    #define _memcpy(dest,src,n)   _memcpy_internal(dest,src,n)
    // 冲刷缓冲区
    static void _flush(pRX_MAC pRxMac,pRX_FLAG ender);
    // 往接收机缓冲区内放数据
    static void _BufIn(pRX_MAC pRxMac,pRB_BYTE pBuf,INT16U len);
    
    /*
    *********************************************************************************************************
    *                                        RxMac_Init()
    *
    * Description : To initialize a RxMac.    初始化接收机
    *
    * Arguments   : pRxMac    pointer to the RxMac struct;    指向接收机结构体的指针
    *               Flags     pointer to the flags(an array); 指向标志串(数组)的指针
    *               FlagsCnt  the count of the flags;         有多少个标志串;
    *               maxLenOfFlags  the max length of flags;   标志字符串最长的长度 
    *               pBuf      pointer to the buffer provided to the RxMac;提供给接收机使用的缓存
    *               BufLen    the size of the buffer.         缓存的大小
    *               onFeeded   the callback func that will be called when feeded.
    *                          每次被feed时会调用的回调函数，如改变对应数据值会影响标志位的判断
    *               onGetHeader the callback func that will be called when find a header.
    *                          当发现帧头时会调用的回调函数
    *               onFlushed  the callback func that will be called when flushed.
    *                          当Flush时会调用的回调函数
    *
    * Return      : RXMAC_ERR_NONE        if success
    *               RXMAC_ERR_ARGUMENT    if the length of longest Flags bigger than Buflen,or one of them is 0
    *               RXMAC_ERR_POINTERNULL if empty pointer 
    *
    * Note(s)     : size of buffer should bigger than  the longest flag plus the longest frame 
    *               that may be received(so at least 2 * maxLenOfFlags).
    *               the buffer is allocate as follow:
    *                 <----------------------  BufLen  ---------------------->
    *                |                 RxBuffer             |                 |   
    *                 <------------- RxBufSize ------------> <-maxLenOfFlags->
    * 
    *               void onGetHeader(pRX_MAC sender,pRX_FLAG pFlag):
    *                sender   the pointer to the RxMac which call this function
    *                pFlag    the header matched
    *
    *               void onFeeded(pRX_MAC sender,pRB_BYTE pCurChar,INT16U bytesCnt):
    *                sender    the pointer to the RxMac which call this function
    *                pCurChar  point to the char in the buffer just received.
    *                bytesCnt  the number of bytes in the buffer including the char just feeded.
    *
    *               void onFlushed(pRX_MAC sender,pRB_BYTE pBuf,INT16U len,RX_STATE state,pRX_FLAG pHorU,
    *                  pRX_FLAG pEnder);
    *                sender    the pointer to the RxMac which call this function
    *                pBuf      the pointer to the frame.
    *                len       the length of frame.
    *                state     the state of frame.
    *                pHorU     point to the header flag if state.headerFound == 1, or unique flag if 
    *                          state.uniqueFound == 1.
    *                pEnder    point to the ender flag if state.enderFound == 1.
    *********************************************************************************************************
    */
    INT8U RxMac_Init
      (pRX_MAC pRxMac,RX_FLAG Flags[],INT8U FlagsCnt,INT8U maxLenOfFlags,pRB_BYTE pBuf,INT16U BufLen,
        RXMAC_FILTER onFeeded,RXMAC_FLAG_EVENT onGetHeader,RXMAC_FLUSH_EVENT onFlushed){
        
        //INT8U maxLen = 0;
        INT8U i;
    #if(RXMAC_ARGUMENT_CHECK_EN)
        if( 
    #if(!RXMAC_SINGLETON_EN)
          _pRxMac == NULL || 
    #endif
          Flags == NULL || pBuf == NULL)
          return RXMAC_ERR_POINTERNULL;
    #endif
        // find out the max length of flags.
        //for(i = 0; i < FlagsCnt; i++){
        
        //  if(Flags[i].len > maxLen)
        //    maxLen = Flags[i].len;
        //}
    #if(RXMAC_ARGUMENT_CHECK_EN)
        if(maxLenOfFlags == 0 || (maxLenOfFlags * 2) > BufLen || BufLen == 0 || FlagsCnt == 0 ||
          maxLenOfFlags == 0)
          return RXMAC_ERR_ARGUMENT;
    #endif
        BufLen -= maxLenOfFlags;
        // 把buffer的最后一段分配给环形缓冲区
        RingQueueInit(&_FlagQueue,pBuf + BufLen,maxLenOfFlags,&i);
        _Flags = Flags;
        _FlagsCnt = FlagsCnt;
        _stateByte = 0;
        _pHorU = NULL;
        _pRxBuf = pBuf;
        _RxBufSize = BufLen;
        _pCur = pBuf;
        _onFeeded = onFeeded;
        _onGetHeader = onGetHeader;
        _onFlushed = onFlushed;
        return RXMAC_ERR_NONE;
    }
    /*
    *********************************************************************************************************
    *                                        RxMac_FeedData()
    *
    * Description : To feed RxMac the next char.    用于给接收机下一个字符
    *
    * Arguments   : pRxMac    pointer to the RxMac struct;    指向接收机结构体的指针
    *               c         the char to feed;               下一个字符
    *
    * Return      : 
    *
    * Note(s)     : 
    *********************************************************************************************************
    */
    void RxMac_FeedData(pRX_MAC pRxMac,INT8U c){
        
      INT8U i,mask;
      pRX_FLAG pFlag = NULL;
    #if(RXMAC_ONFEEDED_EN)
      pRB_BYTE pCurChar = _pCur;
    #endif
    #if(RXMAC_ARGUMENT_CHECK_EN && !RXMAC_SINGLETON_EN)
      if(_pRxMac == NULL)
        return;
    #endif
      *_pCur++ = c;    // 填入缓冲区
    #if(RXMAC_ONFEEDED_EN)
      if(_onFeeded != NULL)
        _onFeeded(_pRxMac,pCurChar,_pCur - _pRxBuf);
      RingQueueIn(&_FlagQueue,*pCurChar,RQ_OPTION_WHEN_FULL_DISCARD_FIRST,&i);
    #else
      RingQueueIn(&_FlagQueue,c,RQ_OPTION_WHEN_FULL_DISCARD_FIRST,&i);
    #endif
      // _state.headerFound == 1  说明在等待帧尾，否则在等待帧头
      mask = (_state.headerFound)?STATEMASK_STEPB:STATEMASK_STEPA;
      // 寻找匹配的标志串
      for(i = 0; i < _FlagsCnt; i++){
        
        if((_Flags[i].option & mask) && 
          (RingQueueMatch(&_FlagQueue,(pRQTYPE)_Flags[i].pBuf,_Flags[i].len) >= 0)){
        
            RingQueueClear(&_FlagQueue);
            pFlag = &_Flags[i];
            break;
        }
      }
      // 如果没有发现标志串，检查下有没满了，满了就Flush
      if(pFlag == NULL){
        
        if(_isRxBufFull()){
        
          _state.isFull = 1;
          _flush(_pRxMac,NULL);
        }
        return;
      }
      // 这4种标志串要_flush掉前面的东西
      if(pFlag->option & FLAGMASK_USUHSH){
        
        _pCur -= pFlag->len;
        _flush(_pRxMac,NULL);
        _pHorU = pFlag;
      }
      // 如果是帧头的处理
      if(pFlag->option & (FLAG_OPTION_STRONG_HEADER | FLAG_OPTION_HEADER)){
        
    #if(RXMAC_NOTFILL_EN == TRUE)
        if(!(pFlag->option & FLAG_OPTION_NOTFILL_HEADER))
    #endif
          _BufIn(_pRxMac,(pRQTYPE)pFlag->pBuf,pFlag->len);
        _state.headerFound = 1;
        if(_onGetHeader != NULL)
          _onGetHeader(_pRxMac,pFlag);
        return;
      }
      // 如果是Unique的处理
      if(pFlag->option & (FLAG_OPTION_STRONG_UNIQUE | FLAG_OPTION_UNIQUE)){
        
        _state.uniqueFound = 1;
        _BufIn(_pRxMac,(pRQTYPE)pFlag->pBuf,pFlag->len);
        _flush(_pRxMac,NULL);
      }else{
           // 能到这里说明是帧尾
        _state.enderFound = 1;
    #if(RXMAC_NOTFILL_EN == TRUE)
        if(pFlag->option & FLAG_OPTION_NOTFILL_ENDER)
          _pCur -= pFlag->len;
    #endif
        _flush(_pRxMac,pFlag);
      }
      return;
    }
    /*
    *********************************************************************************************************
    *                                        RxMac_ResetRxSize()
    *
    * Description : reset the size of RxBuf to the max size.   重置接收缓冲区
    *
    * Arguments   : pRxMac    pointer to the RxMac struct;    指向接收机结构体的指针
    *
    * Return      : RXMAC_ERR_NONE            if Success;
    *               RXMAC_ERR_POINTERNULL     if pRxMac == NULL
    *               RXMAC_ERR_INIT            if RxMac hasn't inited or any error in initialization
    * Note(s)     : 
    *********************************************************************************************************
    */
    INT8U RxMac_ResetRxSize(pRX_MAC pRxMac){
        
      int size;
    #if(RXMAC_ARGUMENT_CHECK_EN && !RXMAC_SINGLETON_EN)
      if(_pRxMac == NULL)
        return RXMAC_ERR_POINTERNULL;
    #endif
      size = _FlagQueue.RingBuf - _pRxBuf;
    #if(RXMAC_ARGUMENT_CHECK_EN)
      if(size < 0)
        return RXMAC_ERR_INIT;
    #endif
      _RxBufSize = (INT16U)size;
      return RXMAC_ERR_NONE;
    }
    /*
    *********************************************************************************************************
    *                                        RxMac_SetRxSize()
    *
    * Description : set the size of RxBuf to the max size.   重置接收缓冲区
    *
    * Arguments   : pRxMac    pointer to the RxMac struct;    指向接收机结构体的指针
    *               size      the size to set;                
    *
    * Return      : RXMAC_ERR_NONE            if Success;
    *               RXMAC_ERR_POINTERNULL     if pRxMac == NULL
    *               RXMAC_ERR_ARGUMENT        if size is wrong.
    * Note(s)     : the size shouldn't be bigger than the initial value, and should bigger than
    *               the current number of chars in the RxBuf.
    *               
    *********************************************************************************************************
    */
    INT8U RxMac_SetRxSize(pRX_MAC pRxMac, INT16U size){
        
    #if(RXMAC_ARGUMENT_CHECK_EN)
     #if (!RXMAC_SINGLETON_EN)
      if(_pRxMac == NULL)
        return RXMAC_ERR_POINTERNULL;
     #endif
      if(_FlagQueue.RingBuf - _pRxBuf < size || size <= _pCur - _pRxBuf)
        return RXMAC_ERR_ARGUMENT;
    #endif
      _RxBufSize = size;
      return RXMAC_ERR_NONE;
    }
    /*
    *********************************************************************************************************
    *                                        RxMac_ResetState()
    *
    * Description : reset the state of receive machine.   重置接收机的状态
    *
    * Arguments   : pRxMac    pointer to the RxMac struct;    指向接收机结构体的指针
    *
    * Return      : RXMAC_ERR_NONE            if Success;
    *               RXMAC_ERR_POINTERNULL     if pRxMac == NULL
    * Note(s)     : it will not trigger call-back of onFlush.
    *********************************************************************************************************
    */
    INT8U RxMac_ResetState(pRX_MAC pRxMac){
        
    #if(RXMAC_ARGUMENT_CHECK_EN  && !RXMAC_SINGLETON_EN)
      if(_pRxMac == NULL)
        return RXMAC_ERR_POINTERNULL;
    #endif
      // 复位接收机
      RingQueueClear(&_FlagQueue);
      _pCur = _pRxBuf;
      _stateByte = 0;
      _pHorU = NULL;
      return RXMAC_ERR_NONE;
    }
    /*
    *********************************************************************************************************
    *                                        RxMac_Flush()
    *
    * Description : force receive machine to flush.
    *
    * Arguments   : pRxMac    pointer to the RxMac struct;    指向接收机结构体的指针
    *
    * Return      : RXMAC_ERR_NONE            if Success;
    *               RXMAC_ERR_POINTERNULL     if pRxMac == NULL
    *
    * Note(s)     : it will force receive machine to flush, if there is any data in the RxBuffer,
    *
    *********************************************************************************************************
    */
    INT8U RxMac_Flush(pRX_MAC pRxMac){
        
    #if(RXMAC_ARGUMENT_CHECK_EN  && !RXMAC_SINGLETON_EN)
      if(_pRxMac == NULL)
        return RXMAC_ERR_POINTERNULL;
    #endif
      _flush(_pRxMac,NULL);
      return RXMAC_ERR_NONE;
    }
    /*
    *********************************************************************************************************
    *                                        RxMac_SetOnFeeded()
    *
    * Description : set the onFeeded callback function.
    *
    * Arguments   : pRxMac    pointer to the RxMac struct;    指向接收机结构体的指针
    *               onFeeded  the callback function to set;   要设置的回调函数
    *
    * Return      : RXMAC_ERR_NONE            if Success;
    *               RXMAC_ERR_POINTERNULL     if pRxMac == NULL
    *
    * Note(s)     :
    *
    *********************************************************************************************************
    */
    INT8U RxMac_SetOnFeeded(pRX_MAC pRxMac,RXMAC_FILTER onFeeded){
        
    #if(RXMAC_ARGUMENT_CHECK_EN  && !RXMAC_SINGLETON_EN)
      if(_pRxMac == NULL)
        return RXMAC_ERR_POINTERNULL;
    #endif
      _onFeeded = onFeeded;
      return RXMAC_ERR_NONE;
    }
    /*
    *********************************************************************************************************
    *                                        RxMac_SetOnGetHeader()
    *
    * Description : set the onGetHeader callback function.
    *
    * Arguments   : pRxMac       pointer to the RxMac struct;    指向接收机结构体的指针
    *               onGetHeader  the callback function to set;   要设置的回调函数
    *
    * Return      : RXMAC_ERR_NONE            if Success;
    *               RXMAC_ERR_POINTERNULL     if pRxMac == NULL
    *
    * Note(s)     :
    *
    *********************************************************************************************************
    */
    INT8U RxMac_SetOnGetHeader(pRX_MAC pRxMac,RXMAC_FLAG_EVENT onGetHeader){
        
    #if(RXMAC_ARGUMENT_CHECK_EN  && !RXMAC_SINGLETON_EN)
      if(_pRxMac == NULL)
        return RXMAC_ERR_POINTERNULL;
    #endif
      _onGetHeader = onGetHeader;
      return RXMAC_ERR_NONE;
    }
    /*
    *********************************************************************************************************
    *                                        RxMac_SetOnFlushed()
    *
    * Description : set the onFlushed callback function.
    *
    * Arguments   : pRxMac       pointer to the RxMac struct;    指向接收机结构体的指针
    *               onFlushed    the callback function to set;   要设置的回调函数
    *
    * Return      : RXMAC_ERR_NONE            if Success;
    *               RXMAC_ERR_POINTERNULL     if pRxMac == NULL
    *
    * Note(s)     :
    *
    *********************************************************************************************************
    */
    INT8U RxMac_SetOnFlushed(pRX_MAC pRxMac,RXMAC_FLUSH_EVENT onFlushed){
        
    #if(RXMAC_ARGUMENT_CHECK_EN  && !RXMAC_SINGLETON_EN)
      if(_pRxMac == NULL)
        return RXMAC_ERR_POINTERNULL;
    #endif
      _onFlushed = onFlushed;
      return RXMAC_ERR_NONE;
    }
    /*
    *********************************************************************************************************
    *                                   LOCAL  FUNCITON 
    *********************************************************************************************************
    */
    static pRB_BYTE _memcpy_internal(pRB_BYTE dest, pRB_BYTE src, size_t n){
        
      pRB_BYTE p = dest;
      while(n-- > 0)
        *p++ = *src++;
      return dest;
    }
    
    static void _BufIn(pRX_MAC pRxMac,pRB_BYTE pBuf,INT16U len){
        
      _memcpy(_pCur,pBuf,len);
      _pCur += len;
    }
    
    static void _flush(pRX_MAC pRxMac,pRX_FLAG ender){
        
      // 触发回调
      if(_pCur-_pRxBuf > 0 && _onFlushed != NULL)
        _onFlushed(_pRxMac,_pRxBuf,_pCur-_pRxBuf,_state,_pHorU,ender);
      // 复位接收机
      _pCur = _pRxBuf;
      _stateByte = 0;
      _pHorU = NULL;
    }

## 测试/示例代码 ##

/*
    *********************************************************************************************************
    *                                                uC/OS-II
    *                                          The Real-Time Kernel
    *                                               Framework
    *
    * By  : Lin Shijun
    * Note: This is a framework for uCos-ii project with only S12CPU, none float, banked memory model.
    *       You can use this framework with same modification as the start point of your project.
    *       I've removed the os_probe module,since I thought it useless in most case.
    *       This framework is adapted from the official release.
    *********************************************************************************************************
    */
    
    #include "includes.h"
    #include "SCI_def.h"
    #include "RxMac.h"
    /*
    *********************************************************************************************************
    *                                      STACK SPACE DECLARATION
    *********************************************************************************************************
    */
    static  OS_STK  AppTaskStartStk[APP_TASK_START_STK_SIZE];
    
    /*
    *********************************************************************************************************
    *                                      TASK FUNCTION DECLARATION
    *********************************************************************************************************
    */
    
    static  void    AppTaskStart(void *p_arg);
    
    /*
    *********************************************************************************************************
    *                                           CALLBACK FUNCITON
    *********************************************************************************************************
    */
    void onGetData(pRX_MAC sender,pRB_BYTE pCurChar,INT16U bytesCnt){
        
      // 因为发现帧头后才挂载事件，所以下一次回掉正好是说明字符数的那个字符,否则还得根据bytesCnt来判断当前位置
      RxMac_SetOnFeeded(sender,NULL);
      if(*pCurChar > '0' && *pCurChar <= '9' ){
        
        // bytesCnt是当前收到了多少个字符，所以接收区大小为当前字符数加上还要接收的
        RxMac_SetRxSize(sender,*pCurChar - '0' + bytesCnt);
      }
    }
    void onFlushed(pRX_MAC sender,pRB_BYTE pBuf,INT16U len,RX_STATE state,pRX_FLAG pHorU,pRX_FLAG pEnder){
        
      SCI_PutCharsB(SCI0,"\nFlushed:",9,0);
      if(state.headerFound)
        SCI_PutCharsB(SCI0,"headerFound,",12,0);
      if(state.enderFound)
        SCI_PutCharsB(SCI0,"enderFound,",11,0);
      if(state.isFull)
        SCI_PutCharsB(SCI0,"full,",5,0);
      if(state.uniqueFound)
        SCI_PutCharsB(SCI0,"unique,",7,0);
      SCI_PutCharsB(SCI0,"\nDatas:",7,0);
      SCI_PutCharsB(SCI0,pBuf,len,0);
      SCI_PutCharsB(SCI0,"\n",1,0);
      RxMac_ResetRxSize(sender);
    }
    void onGetHeader(pRX_MAC sender,pRX_FLAG pFlag){
        
      SCI_PutCharsB(SCI0,"\nFoundHeader:",13,0);
      SCI_PutCharsB(SCI0,pFlag->pBuf,pFlag->len,0);
      SCI_PutCharsB(SCI0,"\n",1,0);
    }
    void onGetHeader2(pRX_MAC sender,pRX_FLAG pFlag){
        
      SCI_PutCharsB(SCI0,"\nFoundHeader:",13,0);
      SCI_PutCharsB(SCI0,pFlag->pBuf,pFlag->len,0);
      SCI_PutCharsB(SCI0,"\n",1,0);
      RxMac_SetOnFeeded(sender,onGetData);
    }
    /*
    *********************************************************************************************************
    *                                           FLAGS
    *********************************************************************************************************
    */
    RX_MAC  _rxmac;
    #define BUF_SIZE  20
    INT8U  buffer[BUF_SIZE];
    RX_FLAG flags[4];
    
    // 协议示例1：
    // 帧头    :HEADER 或者 START
    // 强帧尾  :END
    // 强特殊串:12345  
    // 
    static void protocol1_init(){
        
      RX_FLAG_INIT(&flags[0],"HEADER",6,FLAG_OPTION_HEADER);
      RX_FLAG_INIT(&flags[1],"START",5,FLAG_OPTION_HEADER);
      RX_FLAG_INIT(&flags[2],"END",3,FLAG_OPTION_STRONG_ENDER);
      RX_FLAG_INIT(&flags[3],"12345",5,FLAG_OPTION_STRONG_UNIQUE);
      RxMac_Init(&_rxmac,flags,4,6,buffer,BUF_SIZE,NULL,onGetHeader,onFlushed);
    }
    // 协议示例2：
    // 帧头    : START
    // 帧头后的第1个字符表示后面还要接收多少个字符 1-9,'4'表示4个，如果不是数字或为'0'，则等待帧尾
    // 帧尾    : END
    // 特殊串:  NOW
    // 
    static void protocol2_init(){
        
      RX_FLAG_INIT(&flags[0],"START",5,FLAG_OPTION_HEADER);
      RX_FLAG_INIT(&flags[1],"END",3,FLAG_OPTION_ENDER);
      RX_FLAG_INIT(&flags[2],"NOW",3,FLAG_OPTION_UNIQUE);
      RxMac_Init(&_rxmac,flags,3,5,buffer,BUF_SIZE,NULL,onGetHeader2,onFlushed);
    }
    
    /*
    *********************************************************************************************************
    *                                           MAIN FUNCTION
    *********************************************************************************************************
    */
    
    
    void main(void) {
        
        INT8U  err;    
        BSP_IntDisAll();                                                    /* Disable ALL interrupts to the interrupt controller       */
        OSInit();                                                           /* Initialize uC/OS-II                                      */
    
        err = OSTaskCreate(AppTaskStart,
                              NULL,
                              (OS_STK *)&AppTaskStartStk[APP_TASK_START_STK_SIZE - 1],
                              APP_TASK_START_PRIO);                     
        OSStart();
    }
    
    static  void  AppTaskStart (void *p_arg)
    {
        
      INT8U c,err;
      (void)p_arg;                      /* Prevent compiler warning  */
      BSP_Init(); 
      SCI_Init(SCI0);
      SCI_EnableTrans(SCI0);
      SCI_EnableRecv(SCI0);
      SCI_EnableRxInt(SCI0);
      SCI_BufferInit();
      // 选择想要实验的协议来初始化
      protocol1_init();
      //protocol2_init();
      while (DEF_TRUE) 
      {
        
        // 获取下一个字符
        c = SCI_GetCharB(SCI0,0,&err);
        // 回显
        SCI_PutCharB(SCI0,c,0);
        // 喂给接收机
        RxMac_FeedData(&_rxmac,c);
      }
    }

# 后记 #

此模块已经通过单元测试，但难保不会有一些未发现的bug，如果使用中发现任何问题或者有任何建议意见请立刻联系我，谢谢。

# 更新历史 #

2018/05/29 V1.0  
2019/03/07 V2.1

[70]: /images/20220523/d2d0376d9f924572a5cc741444550c9f.png
[https_blog.csdn.net_lin_strong_article_details_88236566]: https://blog.csdn.net/lin_strong/article/details/88236566
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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpbl9zdHJvbmc_size_16_color_FFFFFF_t_70 1]: /images/20220523/5685f0f859d14015bdcf0e8101e46cbe.png
[https_blog.csdn.net_lin_strong_article_details_73604561]: https://blog.csdn.net/lin_strong/article/details/73604561