// rtoa-pgatram-allinone.cpp. Crude allinone version.
// Compile with:
//   g++ -o rtoa-pgatram-allinone -std=c++20 -Wall -O3 rtoa-pgatram-allinone.cpp
// or:
//   clang++ -o rtoa-pgatram-allinone -std=c++20 -Wall -O3 rtoa-pgatram-allinone.cpp
// or:
//   g++ -o rtoa-pgatram-allinone -std=c++20 -Wall -O3 -I "$HOME/local-fast_io/fast_io/include" rtoa-pgatram-allinone.cpp
// to use the locally installed fast_io header-only library

#include <cctype>
#include <cstring>
#include <string>
// #include <vector>
#include <numeric>

#include <chrono>
#include <thread>

#include <iostream>
#include <iomanip>

// See [id://11149504] for more info on the fast_io C++ library
#include <fast_io.h>

// ---------------------------------------------------------------

typedef std::chrono::high_resolution_clock high_resolution_clock;
typedef std::chrono::high_resolution_clock::time_point time_point;
typedef std::chrono::milliseconds milliseconds;

double elaspe_time(
   time_point cend,
   time_point cstart)
{
   return double (
      std::chrono::duration_cast<milliseconds>(cend - cstart).count()
   ) * 1e-3;
}

// ---------------------------------------------------------------

// Longest roman numeral is MMMDCCCLXXXVIII (3888) of length 15
// XXX: I'm off by one somewhere because 3888 fails with
// MAX_STR_LEN_L of 16 but works with 17
#define MAX_STR_LEN_L 17

// The basic idea is to keep this struct small and without pointers to
// improve data locality/cache performance when traversing the vector
struct str_type {
   char slen;
   char str[MAX_STR_LEN_L];
};

// using vec_str_type = std::vector<str_type>;
// using vec_int_type = std::vector<int>;

// ---------------------------------------------------------------
// Though there are less than 256 initializers in this ascii table,
// the others are guaranteed by ANSI C to be initialized to zero.
static const int romtab[256] = {
    0,0,0,0,0,0,   0,   0,   0,   0,  //  00- 09
    0,0,0,0,0,0,   0,   0,   0,   0,  //  10- 19
    0,0,0,0,0,0,   0,   0,   0,   0,  //  20- 29
    0,0,0,0,0,0,   0,   0,   0,   0,  //  30- 39
    0,0,0,0,0,0,   0,   0,   0,   0,  //  40- 49
    0,0,0,0,0,0,   0,   0,   0,   0,  //  50- 59
    0,0,0,0,0,0,   0, 100, 500,   0,  //  60- 69
    0,0,0,1,0,0,  50,1000,   0,   0,  //  70- 79
    0,0,0,0,0,0,   5,   0,  10,   0,  //  80- 89
    0,0,0,0,0,0,   0,   0,   0, 100,  //  90- 99
  500,0,0,0,0,1,   0,   0,  50,1000,  // 100-109
    0,0,0,0,0,0,   0,   0,   5,   0,  // 110-119
   10,0,0,0,0,0,   0,   0,   0,   0   // 120-129
};

// Return the arabic number for a roman letter c.
// Return zero if the roman letter c is invalid.
inline int urtoa(int c) { return romtab[c]; }

inline int accfn(int t, char c) {
  return t + urtoa(c) - t % urtoa(c) * 2;
}

inline int roman_to_dec(const str_type& st) {
   return std::accumulate( st.str, st.str + st.slen, 0, accfn );
}

// Read an input file of Roman Numerals and do it all
static void do_it_all(
   const char* fname       //  in: file name containing a list of Roman Numerals
)
{
   FILE* fh;
   str_type line;
   fh = ::fopen(fname, "r");
   if ( fh == NULL ) {
      std::cerr << "Error opening '" << fname << "' : " << strerror(errno) << "\n";
      return;
   }
   while ( ::fgets( line.str, MAX_STR_LEN_L, fh ) != NULL ) {
      line.slen = ::strlen(line.str) - 1;    // -1 to strip trailing newline
      // std::cout << roman_to_dec(line) << '\n';
      fast_io::io::println( roman_to_dec(line) );
   }
   ::fclose(fh);
}

int main(int argc, char* argv[])
{
   if (argc < 2) {
      std::cerr << "usage: rtoa-pgatram-allinone file...\n";
      return 1;
   }

   // Get the list of input files from the command line
   int    nfiles = argc - 1;
   char** fname  = &argv[1];

   std::cerr << std::setprecision(3) << std::setiosflags(std::ios::fixed);
   time_point cstartall, cendall;

   cstartall = high_resolution_clock::now();
   for (int i = 0; i < nfiles; ++i)
      do_it_all( fname[i] );
   cendall = high_resolution_clock::now();

   double ctakenall = elaspe_time(cendall, cstartall);
   std::cerr << "do_it_all time    : " << std::setw(8) << ctakenall << " secs\n";

   return 0;
}