source/tag-parser.hh

   1 #include <vector>
   2 #include <iostream>
   3 #include <fstream>
   4
   5
   6 class Tag {
   7 public:
   8
   9   Tag(const std::string& i_short_name,
  10           const std::string& i_name,
  11           const std::string& i_long_name)
  12     : short_name(i_short_name), name(i_name),
  13       long_name(i_long_name)
  14   {
  15   }
  16
  17   virtual ~Tag(){};
  18
  19   void Clear ()
  20   {
  21     value.clear();
  22     ClearImpl ();
  23   }
  24
  25   virtual std::istream& Read(std::istream& is)
  26   {
  27     return is;
  28   }
  29   virtual std::ostream& Write(std::ostream& os)
  30   {
  31     return os;
  32   }
  33
  34   virtual void ClearImpl() {}
  35
  36   std::string short_name;
  37   std::string name;
  38   std::string long_name;
  39
  40   std::string value;
  41 };
  42
  43
  44 class TagParser
  45 {
  46 protected:
  47
  48   TagParser () {}
  49   virtual ~TagParser () {}
  50
  51 public:
  52
  53   // erases all tag's data
  54   void Clear() {
  55     for (std::vector<Tag*>::size_type i = 0;
  56          i < tags.size(); ++i)
  57         tags[i]->Clear();
  58   }
  59
  60   bool Parse(const std::string& file)
  61   {
  62     int error = 0;
  63
  64     // parse
  65     std::ifstream src_file(file.c_str());
  66
  67     if (!src_file) {
  68       std::cerr << file << ": Can not open file!" << std::endl;
  69       return false;
  70     }
  71
  72     std::string line;
  73     std::string tag, value;
  74     for (int linenr = 0; src_file; ++linenr) {
  75       std::getline(src_file, line);
  76
  77       if (line.size() == 0)
  78         continue;
  79
  80       // skip comments (maybe we also need to compress
  81       // whitespaces? -ReneR
  82       if (line[0] == '#' || line[0] == ' ')
  83         continue;
  84
  85       if (line.size() < 3) {
  86         ++error;
  87         std::cerr << file << ":"
  88                   << linenr << ": only garbage in this line." << std::endl
  89                   << "  '" << line << "'" << std::endl;
  90       }
  91
  92       std::string::size_type idx = line.find(' ');
  93       if (idx == std::string::npos)
  94         idx = line.size();
  95
  96       if (line[0] != '[' || line[idx - 1] != ']') {
  97         ++error;
  98         std::cerr << file << ":" << linenr << ": this line contains no tag." << std::endl
  99                   << "  '" << line << "'" << std::endl;
 100         continue;
 101       }
 102
 103       tag.erase();
 104       tag.append(line, 1, idx - 2);
 105       value.erase();
 106       value.append(line, idx, std::string::npos);
 107
 108       // search thru "registered" tags
 109       bool tag_found = false;
 110       for (std::vector<Tag*>::size_type i = 0;
 111            i < tags.size(); ++i) {
 112         if (tag == tags[i]->short_name ||
 113             tag == tags[i]->long_name ||
 114             tag == tags[i]->name)
 115           {
 116             tags[i]->value.append (value + '\n');
 117             //std::cerr << line << std::endl;
 118             //std::cerr << tag << ": " << value << std::endl;
 119             tag_found = true;
 120             break;
 121           }
 122       }
 123
 124       if (!tag_found) {
 125         ++error;
 126         std::cerr << file << ":" << linenr << ": Unknown tag '" << tag << "'" << std::endl;
 127       }
 128     }
 129     return error == 0;
 130   }
 131
 132   // derived class has to fill this vector
 133   std::vector<Tag*> tags;
 134
 135 };