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  1. #include <boost/fusion/adapted.hpp>
  2. #include <boost/spirit/include/qi.hpp>
  3. #include <boost/iostreams/device/mapped_file.hpp>
  4.  
  5. namespace qi = boost::spirit::qi;
  6.  
  7. #if 1
  8.     struct float3
  9.     {
  10.         float x,y,z;
  11.     };
  12.  
  13.     BOOST_FUSION_ADAPT_STRUCT(float3, (float, x)(float, y)(float, z))
  14.  
  15.     typedef std::vector<float3> data_t;
  16. #else
  17.     // there is no speed difference when parsing into a straight container
  18.     // (only works with the spirit implementation)
  19.     typedef std::vector<float> data_t;
  20. #endif
  21.  
  22. double scan_float(const char* str, size_t& off, size_t len);
  23.  
  24. int main()
  25. {
  26. #if 0
  27.     std::cin.unsetf(std::ios::skipws);
  28.     std::istreambuf_iterator<char> f_(std::cin), l_;
  29.  
  30.     const std::vector<char> v(f_, l_);
  31.     auto f = v.data(), l = f+v.size();
  32. #elif 1
  33.     boost::iostreams::mapped_file mmap(
  34.             "input.txt", 
  35.             boost::iostreams::mapped_file::readonly);
  36.     auto f = mmap.const_data();
  37.     auto l = f + mmap.size();
  38. #endif
  39.  
  40.     data_t data;
  41.     data.reserve(11000000);
  42.  
  43. #if 0
  44.     using namespace qi;
  45.     bool ok = phrase_parse(f,l,(double_ > double_ > double_) % eol, blank, data);
  46.     if (ok)   
  47.         std::cout << "parse success\n";
  48.     else 
  49.         std::cerr << "parse failed: '" << std::string(f,l) << "'\n";
  50.  
  51.     if (f!=l) std::cerr << "trailing unparsed: '" << std::string(f,l) << "'\n";
  52. #elif 0
  53.     errno = 0;
  54.     char* next = nullptr;
  55.     float3 tmp;
  56.     while (errno == 0 && f && f<(l-12) ) {
  57.         tmp.x = strtod(f, &next); f = next;
  58.         tmp.y = strtod(f, &next); f = next;
  59.         tmp.z = strtod(f, &next); f = next;
  60.         data.push_back(tmp);
  61.     }
  62. #elif 0
  63.     FILE* file = fopen("input.txt", "r");
  64.     if (NULL == file) {
  65.         printf("Failed to open 'input.txt'");
  66.         return 255;
  67.     }
  68.     float3 tmp;
  69.     do {
  70.         int nItemsRead = fscanf(file,"%f %f %f\n", &tmp.x, &tmp.y, &tmp.z);
  71.         if (3 != nItemsRead)
  72.             break;
  73.         data.push_back(tmp);
  74.     } while (1);
  75. #else
  76.     size_t len = std::distance(f,l);
  77.     const char* str = f;
  78.     float3 tmp;
  79.     for (size_t i=0; i<len;)
  80.     {
  81.         while (i<len && isspace(str[i])) ++i;
  82.         tmp.x = scan_float(str, i, len);
  83.         while (i<len && isspace(str[i])) ++i;
  84.         tmp.y = scan_float(str, i, len);
  85.         while (i<len && isspace(str[i])) ++i;
  86.         tmp.z = scan_float(str, i, len);
  87.  
  88.         if (i<len) // requires at least trailing newline for now
  89.             data.push_back(tmp);
  90.         //if (0 == (data.size()%1000)) std::cout << "now at " << data.size() << "/11000000\n";
  91.     }
  92. #endif
  93.  
  94.     std::cout << "data.size():   " << data.size() << "\n";
  95. }
  96.  
  97. double scan_float(const char* str, size_t& off, size_t len)
  98. {
  99.     static const double bases[13] = {
  100.         0.0, 10.0, 100.0, 1000.0, 10000.0,
  101.         100000.0, 1000000.0, 10000000.0, 100000000.0,
  102.         1000000000.0, 10000000000.0, 100000000000.0, 1000000000000.0,
  103.     };
  104.  
  105.     bool   begin = false;
  106.     bool   fail  = false;
  107.     bool   minus = false;
  108.     int    pfrac = 0;
  109.  
  110.     double dec   = 0.0;
  111.     double frac  = 0.0;
  112.  
  113.     for (; !fail && off<len; ++off)
  114.     {
  115.         char c = str[off];
  116.         if (c == '+')
  117.         {
  118.             if (!begin)
  119.                 begin = true;
  120.             else
  121.                 fail = true;
  122.         }
  123.         else if (c == '-')
  124.         {
  125.             if (!begin)
  126.                 begin = true;
  127.             else
  128.                 fail = true;
  129.             minus = true;
  130.         }
  131.         else if (c == '.')
  132.         {
  133.             if (!begin)
  134.                 begin = true;
  135.             else if (pfrac)
  136.                 fail = true;
  137.             pfrac = 1;
  138.         }
  139.         else if (c >= '0' && c <= '9')
  140.         {
  141.             if (!begin)
  142.                 begin = true;
  143.             if (pfrac == 0)
  144.             {
  145.                 dec *= 10;
  146.                 dec += c - '0';
  147.             }
  148.             else if (pfrac < 13)
  149.             {
  150.                 frac += (c - '0') / bases[pfrac];
  151.                 ++pfrac;
  152.             }
  153.         }
  154.         else
  155.         {
  156.             break;
  157.         }
  158.     }
  159.  
  160.     if (!fail)
  161.     {
  162.         double f = dec + frac;
  163.         if (minus)
  164.             f = -f;
  165.         return f;
  166.     }
  167.  
  168.     return 0.0;
  169. }
  170.  
  171.  
Compilation error #stdin compilation error #stdout 0s 0KB
comments (?)
stdin
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Standard input is empty
compilation info 
prog.cpp:1:36: fatal error: boost/fusion/adapted.hpp: No such file or directory
compilation terminated.
stdout
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Standard output is empty
https://ideone.com/yFBlpF
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
secret

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