/* Copyright 2001 Blossom Associates West
   All rights reserved.
*/

/*  Converts from comma separated values to tab separated values.
    Leaves quoted commas undisturbed.
    BUG: Does not honor escape sequences \" or \\.
         Quotation marks can be included in a quote by doubling them up.
         e.g. "a quotation mark "" is included".
         However, this is not "standard".
    BUG: quotes can contain a newline character.
    Eric Blossom
*/

#include <stdio.h>

int main( int argc, char *argv[] ) {
  int c;
  enum states { start, inQuote, atQuote, error, stop };
  static enum states ourState = start;

  while ( stop != ourState && error != ourState ) {
    c = getchar();
    switch ( ourState ) {
    case start:
      switch ( c ) {
      case '"':
        ourState = inQuote;
        break;
      case EOF:
        ourState = stop;
        break;
      case ',':
	c = '\t';
      default:
        putchar( c );
      }
      break;
    case inQuote:
      switch ( c ) {
      case '"':
        ourState = atQuote;
        break;
      case EOF:
        ourState = error;
        break;
/*      case '\n':
        ourState = start; // Recover from unfinished quote. */
      default:
        putchar( c );
      }
      break;
    case atQuote:
      switch ( c ) {
      case '"':
        putchar( c );
        ourState = inQuote;
        break;
      case EOF:
        ourState = error;
        break;
      case ',':
        c = '\t';
      default:
        putchar( c );
        ourState = start;
      }
      break;
    default:
      ourState = error; // Should never happen.
    }
  }
  if ( error == ourState ) {
    fprintf( stderr, "csv2tsv: Invalid State." );
    return 1;
  }

  return 0;
}