c|protocol buffers c语言的使用数据结构|工具

以下源码示例来源于https://github.com/protobuf-c/protobuf-c/wiki/Examples

定义消息

message AMessage { required int32 a=1; optional int32 b=2; }

安装protobuf-c 我们需要把proto文件编译成c源码，才能在代码中使用，所以需要用到官方的编译工具

sudo apt-get install protobuf-c-compiler

编译

protoc-c --c_out=. amessage.proto //将会产生amessage.pb-c.camessage.pb-c.h两个文件

代码中使用序列化：

//serialize_main.c #include #include #include "amessage.pb-c.h"int main (int argc, const char * argv[]) { AMessage msg = AMESSAGE__INIT; // AMessage void *buf; // Buffer to store serialized data unsigned len; // Length of serialized dataif (argc != 2 && argc != 3) {// Allow one or two integers fprintf(stderr,"usage: amessage a [b]\n"); return 1; }msg.a = atoi(argv[1]); if (argc == 3) { msg.has_b = 1; msg.b = atoi(argv[2]); } len = amessage__get_packed_size(&msg); buf = malloc(len); amessage__pack(&msg,buf); fprintf(stderr,"Writing %d serialized bytes\n",len); // See the length of message fwrite(buf,len,1,stdout); // Write to stdout to allow direct command line pipingfree(buf); // Free the allocated serialized buffer return 0; }

【c|protocol buffers c语言的使用】反序列化：

//unserialize_main.c #include #include #include "amessage.pb-c.h" #define MAX_MSG_SIZE 1024static size_t read_buffer (unsigned max_length, uint8_t *out) { size_t cur_len = 0; size_t nread; while ((nread=fread(out + cur_len, 1, max_length - cur_len, stdin)) != 0) { cur_len += nread; if (cur_len == max_length) { fprintf(stderr, "max message length exceeded\n"); exit(1); } } return cur_len; }int main (int argc, const char * argv[]) { AMessage *msg; // Read packed message from standard-input. uint8_t buf[MAX_MSG_SIZE]; size_t msg_len = read_buffer (MAX_MSG_SIZE, buf); // Unpack the message using protobuf-c. msg = amessage__unpack(NULL, msg_len, buf); if (msg == NULL) { fprintf(stderr, "error unpacking incoming message\n"); exit(1); }// display the message's fields. printf("Received: a=%d",msg->a); // required field if (msg->has_b)// handle optional field printf("b=%d",msg->b); printf("\n"); // Free the unpacked message amessage__free_unpacked(msg, NULL); return 0; }

编译可执行程序