pbc应用分析

pbc源码：https://github.com/cloudwu/pbc

https://blog.codingnow.com/2011/12/protocol_buffers_for_c.html

pbc应用例子

安装protobuf，源码：https://github.com/google/protobuf

建立protobuf文件address.proto：

syntax = "proto2";// See README.txt for information and build instructions.package tutorial;option java_package = "com.example.tutorial";option java_outer_classname = "AddressBookProtos";message Profile {  optional string nick_name = 1;  optional string icon = 2;}message Person {  required string name = 1;  required int32 id = 2;        // Unique ID number for this person.  optional string email = 3;  enum PhoneType {    MOBILE = 0;    HOME = 1;    WORK = 2;  }  message PhoneNumber {    required string number = 1;    optional PhoneType type = 2 [default = HOME];  }  repeated PhoneNumber phone = 4;  repeated int32 test = 5 [packed=true];  optional Profile profile = 6;  extensions 10 to max; }message Ext {  extend Person {    optional int32 test = 10;  }}// Our address book file is just one of these.message AddressBook {  repeated Person person = 1;}

建立C文件addressbook.c :

#include "pbc.h"#include <stdlib.h>#include <stdio.h>#include <stdint.h>#include <stddef.h>#include "readfile.h"static voiddump(uint8_t *buffer, int sz) {    int i , j;    for (i=0;i<sz;i++) {        printf("%02X ",buffer[i]);        if (i % 16 == 15) {            for (j = 0 ;j <16 ;j++) {                char c = buffer[i/16 * 16+j];                if (c>=32 && c<127) {                    printf("%c",c);                } else {                    printf(".");                }            }            printf("\n");        }    }    printf("\n");}static voidtest_rmessage(struct pbc_env *env, struct pbc_slice *slice) {    struct pbc_rmessage * m = pbc_rmessage_new(env, "tutorial.Person", slice);    if (m==NULL) {        printf("Error : %s",pbc_error(env));        return;    }    printf("name = %s\n", pbc_rmessage_string(m , "name" , 0 , NULL));    printf("id = %d\n", pbc_rmessage_integer(m , "id" , 0 , NULL));    printf("email = %s\n", pbc_rmessage_string(m , "email" , 0 , NULL));    int phone_n = pbc_rmessage_size(m, "phone");    int i;    const char * field_name;    pbc_type(env, "tutorial.Person", "phone", &field_name);    printf("phone type [%s]\n",field_name);    for (i=0;i<phone_n;i++) {        struct pbc_rmessage * p = pbc_rmessage_message(m , "phone", i);        printf("\tnumber[%d] = %s\n",i,pbc_rmessage_string(p , "number", i ,NULL));        printf("\ttype[%d] = %s\n",i,pbc_rmessage_string(p, "type", i, NULL));    }    int n = pbc_rmessage_size(m , "test");    for (i=0;i<n;i++) {        printf("test[%d] = %d\n",i, pbc_rmessage_integer(m , "test" , i , NULL));    }    printf("tutorial.Ext.test = %d\n", pbc_rmessage_integer(m,"tutorial.Ext.test",0,NULL));    pbc_rmessage_delete(m);}static struct pbc_wmessage *test_wmessage(struct pbc_env * env){    struct pbc_wmessage * msg = pbc_wmessage_new(env, "tutorial.Person");    pbc_wmessage_string(msg, "name", "Alice", -1);    pbc_wmessage_integer(msg, "id" , 12345, 0);    pbc_wmessage_string(msg, "email", "alice@unkown", -1);    struct pbc_wmessage * phone = pbc_wmessage_message(msg , "phone");    pbc_wmessage_string(phone , "number", "87654321" , -1);    phone = pbc_wmessage_message(msg , "phone");    pbc_wmessage_string(phone , "number", "13901234567" , -1);    pbc_wmessage_string(phone , "type" , "MOBILE" , -1);    pbc_wmessage_integer(msg, "test", -123,0);    pbc_wmessage_integer(msg, "test", 12345,0);    pbc_wmessage_integer(msg, "test", 1234567,0);    pbc_wmessage_integer(msg, "tutorial.Ext.test", 54321 , 0);    return msg;}intmain(){    struct pbc_slice slice; //数据存放buffer, len     read_file("addressbook.pb", &slice); //读取protoc生成的pb文件    if (slice.buffer == NULL)            return 1;    struct pbc_env * env = pbc_new();  //新建pbc的数据环境    int r = pbc_register(env, &slice); //讲slice数据消息regist到pbc的环境    if (r) {        printf("Error : %s", pbc_error(env));        return 1;    }    free(slice.buffer);//释放slice数据空间    struct pbc_wmessage *msg = test_wmessage(env); //解析protobuf消息数据    pbc_wmessage_buffer(msg, &slice);//将protobuf数据放入slice    dump(slice.buffer, slice.len); //打印出protobuf数据    test_rmessage(env, &slice); //将protobuf数据解析成可读数据    pbc_wmessage_delete(msg);  //清除数据    pbc_delete(env);        //清环境    return 0;}

编译，生成addressbook.pb文件以及可执行文件addressbook

执行命令，结果如下：