Linux Mint下Nanopb的简单使用

一、安装依赖包

$sudo apt-get install build-essential

二、安装Protobuf

1、下载Protobuf，我使用的是Protobuf2.6.1

$ wget https://github.com/google/protobuf/releases/download/v2.6.1/protobuf-2.6.1.tar.gz

2、解压

$ sudo chmod 777 protobuf-2.6.1.tar.gz
$ tar -vxzf protobuf-2.6.1.tar.gz

3、安装

$ cd protobuf-2.6.1/
$ ./configure
$ make
$ sudo make install

4、添加环境变量

vim ～/.profile

加入：

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib

保存后退出,编译

source ~/.profile  

5、测试

protoc --version

三、安装nanopb

1、下载

wget http://koti.kapsi.fi/~jpa/nanopb/download/nanopb-0.3.5-linux-x86.tar.gz

2、解压

 $ tar -zxvf nanopb-0.3.5-linux-x86.tar.gz 

3、复制

$ sudo cp nanopb-0.3.5-linux-x86 /opt/

四、生成文件

1、制作proto文件，Message.proto

message Person{
    required int32  age = 1;
    required string name = 2;
}

2、制作option文件，Message.options

Person.name   max_size:16

3、生成C语言文件

$ /opt/nanopb-0.3.5-linux-x86/generator-bin/protoc --nanopb_out=. Message.proto

4、生成java语言文件

protoc --java_out=. Message.proto 

五、测试代码

1、将解压的nanopb-0.3.5-linux-86文件夹下的pb.h, pb_common.c, pb_common.h, pb_decode.c, pb_decode.h, pb_encode.c, pb_encode.h复制到proto文件目录下。

2、新建main.c，内容如下：

#include "Message.pb.h"
#include "pb.h"
#include "pb_encode.h"
#include "pb_decode.h"
#include <string.h>
#include <stdlib.h>
#include <stdio.h>

int main()
{
    /* This is the buffer where we will store our message. */
    uint8_t buffer[128];
    size_t message_length;
    bool status;
    uint8_t i;

    /* Encode our message */
    {
        /* Allocate space on the stack to store the message data.
         *
         * Nanopb generates simple struct definitions for all the messages.
         * - check out the contents of simple.pb.h!
         * It is a good idea to always initialize your structures
         * so that you do not have garbage data from RAM in there.
         */
        Person person = Person_init_zero;

        memset(buffer, 0, 128);
        /* Create a stream that will write to our buffer. */
        pb_ostream_t stream = pb_ostream_from_buffer(buffer, sizeof(buffer));

        person.age = 20;
        strcpy(&person.name, "zhujun");

        /* Now we are ready to encode the message! */
        status = pb_encode(&stream, Person_fields, &person);
        message_length = stream.bytes_written;
        printf("encode ok\r\n");
        for (i = 0; i < message_length; i++)
        {
            printf("%d,", buffer[i]);
        }
        printf("\r\n");
        /* Then just check for any errors.. */
        if (!status)
        {
            printf("Encoding failed: %s\n", PB_GET_ERROR(&stream));
            return 1;
        }
    }

    /* Now we could transmit the message over network, store it in a file or
     * wrap it to a pigeon's leg.
     */

    /* But because we are lazy, we will just decode it immediately. */

    {
        /* Allocate space for the decoded message. */
        Person person = Person_init_zero;

        /* Create a stream that reads from the buffer. */
        pb_istream_t stream = pb_istream_from_buffer(buffer, message_length);

        /* Now we are ready to decode the message. */
        status = pb_decode(&stream, Person_fields, &person);

        /* Check for errors... */
        if (!status)
        {
            printf("Decoding failed: %s\n", PB_GET_ERROR(&stream));
            return -1;
        }

        /* Print the data contained in the message. */
        printf("age  was [%d].\n", person.age);
        printf("name was [%s].\n", person.name);
    }
    return 0;
}

六、问题

1、C在使用string类型的时候，必须通过options，限定string的长度，否则运行将出错。

2、nanopb可通过python生成.c和.h文件，但我没有成功，不知道缺少了哪个库。