1 //
2 // chat_message.hpp
3 // ~~~~~~~~~~~~~~~~
4 //
5 // Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
6 //
7 // Distributed under the Boost Software License, Version 1.0. (See accompanying
8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
9 //
10 
11 #ifndef CHAT_MESSAGE_HPP
12 #define CHAT_MESSAGE_HPP
13 
14 #include <cstdio>
15 #include <cstdlib>
16 #include <cstring>
17 
18 class chat_message
19 {
20 public:
21   enum { header_length = 4 };
22   enum { max_body_length = 512 };
23 
chat_message()24   chat_message()
25     : body_length_(0)
26   {
27   }
28 
data() const29   const char* data() const
30   {
31     return data_;
32   }
33 
data()34   char* data()
35   {
36     return data_;
37   }
38 
length() const39   std::size_t length() const
40   {
41     return header_length + body_length_;
42   }
43 
body() const44   const char* body() const
45   {
46     return data_ + header_length;
47   }
48 
body()49   char* body()
50   {
51     return data_ + header_length;
52   }
53 
body_length() const54   std::size_t body_length() const
55   {
56     return body_length_;
57   }
58 
body_length(std::size_t new_length)59   void body_length(std::size_t new_length)
60   {
61     body_length_ = new_length;
62     if (body_length_ > max_body_length)
63       body_length_ = max_body_length;
64   }
65 
decode_header()66   bool decode_header()
67   {
68     char header[header_length + 1] = "";
69     std::strncat(header, data_, header_length);
70     body_length_ = std::atoi(header);
71     if (body_length_ > max_body_length)
72     {
73       body_length_ = 0;
74       return false;
75     }
76     return true;
77   }
78 
encode_header()79   void encode_header()
80   {
81     char header[header_length + 1] = "";
82     std::sprintf(header, "%4d", static_cast<int>(body_length_));
83     std::memcpy(data_, header, header_length);
84   }
85 
86 private:
87   char data_[header_length + max_body_length];
88   std::size_t body_length_;
89 };
90 
91 #endif // CHAT_MESSAGE_HPP
92