纳米PB 帮助！对嵌套的重复项目进行编码，但不确定我是否正确定义了架构

Question

我正在为电池组定义故障。包由一个或多个模块组成。模块由 6 个单元组成。

我已经能够得到减去重复模块的包信息。我相信我重复的模块现在正在编码但出现错误： Decoding failed: parent stream too short

目前我的原型是这样的

    syntax = "proto2";
    
    package TeslaBMS;
    
    message Pack { 
      required int32 numberOfModules = 2;
      required float currentVoltage = 3;
      required float averagePacktemp = 4;
      repeated Module modules = 5;
    
        message Module {
          required int32 id = 1;
          required float moduleVoltage = 2;
          required float moduleTemp = 3;
          required float lowestCellVolt = 4;
          required float highestCellVolt = 5;
      //   repeated Cell cells = 6;
    
      //  message Cell{
      //       required int32 cellId = 1;
      //       required float cellVolt = 2;
      //       required string balanceState = 3;
      //  }
    
      }
    }

产生这些结构定义

/* Struct definitions */
typedef struct _TeslaBMS_Pack {
    int32_t numberOfModules;
    float currentVoltage;
    float averagePacktemp;
    pb_callback_t modules;
} TeslaBMS_Pack;

typedef struct _TeslaBMS_Pack_Module {
    int32_t id;
    float moduleVoltage;
    float moduleTemp;
    float lowestCellVolt;
    float highestCellVolt;
} TeslaBMS_Pack_Module;

我制作了一个 typedef 结构来保存模块数组

typedef struct{
    TeslaBMS_Pack_Module modarr[MAX_MODULE_ADDR];
    int listSize = 0;
}
ModuleList;

这些是构建模块数组的一些辅助函数 modulelist_add_module 用于解码，module_array_maker 用于编码

根据我能找到的示例，这是我的 encode/decode。

编码：

void encoder(){
    // Setup pack message
    TeslaBMS_Pack mypack = TeslaBMS_Pack_init_zero;
    
    // stream to write buffer
    pb_ostream_t stream = pb_ostream_from_buffer(buffer, sizeof(buffer));

    // set deffinitions     
    mypack.averagePacktemp = bms.getAvgTemperature();
    mypack.currentVoltage = bms.getPackVoltage();
    mypack.numberOfModules = bms.getNumOfModules();

    ModuleList modArr;
    module_array_maker(&modArr);

      // set the arg to data needed
    mypack.modules.arg = &modArr;

      // encode the modules
    mypack.modules.funcs.encode = modules_encode;

      //encode the pack
    status = pb_encode(&stream, TeslaBMS_Pack_fields, &mypack);
    message_length = stream.bytes_written;
        
        if (!status) printf("Encoding failed: %s\n", PB_GET_ERROR(&stream));
}

对重复模块字段的回调进行编码

bool modules_encode(pb_ostream_t *stream, const pb_field_iter_t *field, void * const *arg)
{    
    ModuleList *source = (ModuleList*)(*arg);

    for(int i=0; i<bms.getNumOfModules();i++)
    {
        printf(" \n Mod %i is at %f \n",(int)source->modarr[i].id, source->modarr[i].moduleVoltage);
        if (!pb_encode_tag_for_field(stream, field))
        {
            const char * error = PB_GET_ERROR(stream);
            printf("encode_modules error: %s", error);
            return false;
        }
        if (!(stream, TeslaBMS_Pack_Module_fields, &source->modarr[i]))
        {
            const char * error = PB_GET_ERROR(stream);
            printf("SimpleMessage_encode_numbers error: %s", error);
            return false;
        }
    }
    return true;
}

解码：

void decode(){
    /* Allocate space for the decoded message. */
    TeslaBMS_Pack myPack = TeslaBMS_Pack_init_zero;
    
    /* Create a stream that reads from the buffer. */
    
    ModuleList modArr;
    module_array_maker(&modArr);
    myPack.modules.arg = &modArr;
    myPack.modules.funcs.decode = modules_decode;

    pb_istream_t stream = pb_istream_from_buffer(buffer, message_length);
    /* Now we are ready to decode the message. */
    status = pb_decode(&stream, TeslaBMS_Pack_fields, &myPack);
    
    /* Check for errors... */
    if (!status)
    {
        printf("Decoding failed: %s\n", PB_GET_ERROR(&stream));
    }
    else
    {
        /* Print the data contained in the message. */
        printf("\n********MESSAGE FROM NANOPB!*********\n");
        // printf("Number Of Modules in Pack: ", myPack.numberOfModules);
        printf("Pack Voltage: %.3f\n", myPack.currentVoltage);
        printf("Average Temp: %.3f\n", myPack.averagePacktemp);
        printf("Number of modules: %i\n", (int)myPack.numberOfModules);
        for (size_t i = 0; i < myPack.numberOfModules ; i++)
        {
            printf("\n    ************  Module %i  ************\n", modArr.modarr[i].id);
            printf("       Voltage: %.3f Temperature: %.3f \n" ,modArr.modarr[i].moduleVoltage, modArr.modarr[i].moduleTemp);
        }        
        printf("********MESSAGE FROM NANOPB!*********\n");
    }
}

解码模块回调

bool modules_decode(pb_istream_t *istream, const pb_field_t *field, void **arg){
    ModuleList * dest = (ModuleList*)(*arg);

    TeslaBMS_Pack_Module module;
    if(!pb_decode(istream, TeslaBMS_Pack_Module_fields, &module)){
        const char * error = PB_GET_ERROR(istream);
        printf("module_decode error: %s", error);
        return false;
    }
    
    modulelist_add_module(dest, module);
    return true;
}

Answer 1

忘记更新了。看来我们只需要为消息多 space 一点。我们采用了预期的最大消息大小，并添加了更多字节以传递到编码器函数并将编码器函数从：void encoder() 更改为： size_t encoder(pb_byte_t *buffer, size_t length)

设置和调用编码和解码

pb_byte_t buffer[128];

size_t msg_length = encoder(buffer, sizeof(buffer));
decode(buffer, msg_length);

编码函数：

size_t encoder(pb_byte_t *buffer, size_t length) {
    // Setup pack message
    TeslaBMS_Pack mypack = TeslaBMS_Pack_init_zero;
    // stream to write buffer
    pb_ostream_t stream = pb_ostream_from_buffer(buffer, length);
    // set definitions     
    mypack.averagePacktemp = bms.getAvgTemperature();
    mypack.currentVoltage = bms.getPackVoltage();
    mypack.numberOfModules = bms.getNumOfModules();

    ModuleList modArr;
    module_array_maker(&modArr);
    mypack.modules.arg = &modArr;
    mypack.modules.funcs.encode = modules_encode;
    
    //encode the pack
    bool status = pb_encode(&stream, TeslaBMS_Pack_fields, &mypack);
    if (!status) {
        printf("Encoding failed: %s\n", PB_GET_ERROR(&stream));
    }
    printf("Encoded %d bytes\n", stream.bytes_written);
    return stream.bytes_written;
}

解码函数已更改为接受 2 个参数

void decode(pb_byte_t *buffer, size_t message_length){
    /* Allocate space for the decoded message. */
    TeslaBMS_Pack myPack = TeslaBMS_Pack_init_zero;
        
    ModuleList modArr;
    module_array_maker(&modArr);
    myPack.modules.arg = &modArr;
    myPack.modules.funcs.decode = modules_decode;
    
    pb_istream_t stream = pb_istream_from_buffer(buffer, message_length);
    bool status = pb_decode(&stream, TeslaBMS_Pack_fields, &myPack);
    if (!status)
    {
        printf("Decoding failed: %s\n", PB_GET_ERROR(&stream));
        return;
    }
    /* Print the data contained in the message. */
    printf("\n********MESSAGE FROM NANOPB!*********\n");
    // printf("Number Of Modules in Pack: ", myPack.numberOfModules);
    printf("Pack Voltage: %.3f\n", myPack.currentVoltage);
    printf("Average Temp: %.3f\n", myPack.averagePacktemp);
    printf("Number of modules: %i\n", (int)myPack.numberOfModules);
    for (size_t i = 0; i < myPack.numberOfModules ; i++)
    {
        printf("\n    ************  Module %i  ************\n", modArr.modarr[i].id);
        printf("       Voltage: %.3f Temperature: %.3f \n" ,modArr.modarr[i].moduleVoltage, modArr.modarr[i].moduleTemp);
    }        
    printf("********MESSAGE FROM NANOPB!*********\n");
}

纳米PB 帮助！对嵌套的重复项目进行编码，但不确定我是否正确定义了架构

NanoPB Help! encoding nested repeated items and not sure I have the schema defined properly

encode

decode

nanopb