关于memcpy、std::string 二进制数据

例子说明：

char buffer[100];

memset(buffer,'\0',100);

char * p = buffer;

 

int type = 3;

memcpy(p,(char *)(&type),sizeof(int));

p += sizeof(int);

 

std::string id = "TS20090506001";

int length = id.length() + 1;

memcpy(p,id.c_str(),length);

p += length;

 

std::string sendString = buffer;(出现问题)

int guessLength = sendString.length();

m_socket->send(sendString.c_str(),guessLength);

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guessLength是多少，答案是1;问题出在了

std::string sendString = buffer;

因为sendString拷贝到buffer中的'\0'就不再进行拷贝了

 

正确的写法是：

 

char buffer[100];

memset(buffer,'\0',100);

char * p = buffer;

 

int type = 3;

memcpy(p,(char *)(&type),sizeof(int));

p += sizeof(int);

 

std::string id = "TS20090506001";

int length = id.length() + 1;

memcpy(p,id.c_str(),length);

p += length;

 

int guessLength = p - buffer;

m_socket->send(buffer,guessLength);

 

解析的时候也很好解析：

int type = 0;

char * p = buffer;

memcpy(&type,p,sizeof(int));

p += sizeof(int);

 

std::string id;

id = p;//std::string operator =()

int length = id.length() +1;

p += length;