功能从中间开始

Question

我正在尝试解析SIP REQUEST消息。当我调用函数解析消息时，它从中间开始没有任何理由。

输入是：

SIP/2.0 401 Unauthorized
Via: SIP/2.0/UDP 127.0.0.1:5060;branch=z9hG4bK1448207213;received=127.0.0.1;rport=52447
From: <sip:croolman@127.0.0.1>;tag=glitchy1448207213
To: <sip:croolman@127.0.0.1>;tag=as4589087f
Call-ID: croolman1448207213
CSeq: 1 REGISTER
Server: Asterisk PBX 11.7.0~dfsg-1ubuntu1
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO, PUBLISH
Supported: replaces, timer
WWW-Authenticate: Digest algorithm=MD5, realm="asterisk", nonce="3adf9b5b"
Content-Length: 0

解析函数：

void generateOutput(string input, int response){
  string help = "";
  cout << "***********EXAMPLE - INPUT *************" << endl;
  cout << input << endl;
  int i = 0;      
  cout << to_string(global_iterator) << " "; // prints the number at the start of the output
  global_iterator++;
  size_t pozic;
  if(response == 1){
    while(input[i] != ' '){ // get to 401
        i++;
    }
    i++;
    while(input[i] != ' '){ // print 401
        cout << input[i];
        i++;
    }
    i++;
    cout << " ";
    while(input[i] != '\n'){ // print Unauthorized
        cout << input[i];
        i++;
    }
    pozic = input.find("From:"); // find From:
    pozic += 5;                   // get to position where adress starts
    while(input[pozic] != ':'){
        pozic++;
    }
    pozic++;
    while(input[pozic] != '>'){
       cout << input[pozic];
       pozic++;
    }
    cout << " ";
    pozic = input.find("To:");
    pozic += 3;
    while(input[pozic] != ':'){
        pozic++;
    }
    pozic++;
    while(input[pozic] != '>'){
        cout << input[pozic];
        pozic++;
    }
    cout << endl;
  }else{
    while(input[i] != ' '){
       cout << input[i]; 
       i++;
    }
    cout << " ";
    pozic = input.find("From:");
    pozic += 5;
    while(input[pozic] != ':'){
        pozic++;
    }
    pozic++;
    while(input[pozic] != '>'){
       cout << input[pozic];
       pozic++;
    }
    cout << " ";
    pozic = input.find("To:");
    pozic += 3;
    while(input[pozic] != ':'){
        pozic++;
    }
    pozic++;
    while(input[pozic] != '>'){
        cout << input[pozic];
        pozic++;
    }
    cout << endl;
  }

全局迭代器是计算消息的全局变量。 预期的输出是：

1 401 Unauthorized croolman@127.0.0.1 croolman@127.0.0.1

我得到的结果：

1 REGISTER croolman@127.0.0.1 croolman@127.0.0.1
***********EXAMPLE - INPUT *************
SIP/2.0 401 Unauthorized
Via: SIP/2.0/UDP 127.0.0.1:5060;branch=z9hG4bK1448215167;received=127.0.0.1;rport=53191
From: <sip:croolman@127.0.0.1>;tag=glitchy1448215167
To: <sip:croolman@127.0.0.1>;tag=as017834f4
Call-ID: croolman1448215167
CSeq: 1 REGISTER
Server: Asterisk PBX 11.7.0~dfsg-1ubuntu1
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO, PUBLISH
Supported: replaces, timer
WWW-Authenticate: Digest algorithm=MD5, realm="asterisk", nonce="28af07e9"
Content-Length: 0


croolman@127.0.0.1 croolman@127.0.0.1