//Code 93
//(c) 2011 by Tomasz Lubinski
//www.algorytm.org

   var special_1 = '\u0080'; // ($)
   var special_2 = '\u0081'; // (%)
   var special_3 = '\u0082'; // (/)
   var special_4 = '\u0083'; // (+)
	
   var code93signs = [
      '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
      'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
      'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
      'U', 'V', 'W', 'X', 'Y', 'Z', '-', '.', ' ', '$',
      '/', '+', '%', special_1, special_2, special_3, special_4];

   var code93bars = [
      [1, 0, 0, 0, 1, 0, 1, 0, 0],
      [1, 0, 1, 0, 0, 1, 0, 0, 0],
      [1, 0, 1, 0, 0, 0, 1, 0, 0],
      [1, 0, 1, 0, 0, 0, 0, 1, 0],
      [1, 0, 0, 1, 0, 1, 0, 0, 0],
      [1, 0, 0, 1, 0, 0, 1, 0, 0],
      [1, 0, 0, 1, 0, 0, 0, 1, 0],
      [1, 0, 1, 0, 1, 0, 0, 0, 0],
      [1, 0, 0, 0, 1, 0, 0, 1, 0],
      [1, 0, 0, 0, 0, 1, 0, 1, 0],
      [1, 1, 0, 1, 0, 1, 0, 0, 0],
      [1, 1, 0, 1, 0, 0, 1, 0, 0],
      [1, 1, 0, 1, 0, 0, 0, 1, 0],
      [1, 1, 0, 0, 1, 0, 1, 0, 0],
      [1, 1, 0, 0, 1, 0, 0, 1, 0],
      [1, 1, 0, 0, 0, 1, 0, 1, 0],
      [1, 0, 1, 1, 0, 1, 0, 0, 0],
      [1, 0, 1, 1, 0, 0, 1, 0, 0],
      [1, 0, 1, 1, 0, 0, 0, 1, 0],
      [1, 0, 0, 1, 1, 0, 1, 0, 0],
      [1, 0, 0, 0, 1, 1, 0, 1, 0],
      [1, 0, 1, 0, 1, 1, 0, 0, 0],
      [1, 0, 1, 0, 0, 1, 1, 0, 0],
      [1, 0, 1, 0, 0, 0, 1, 1, 0],
      [1, 0, 0, 1, 0, 1, 1, 0, 0],
      [1, 0, 0, 0, 1, 0, 1, 1, 0],
      [1, 1, 0, 1, 1, 0, 1, 0, 0],
      [1, 1, 0, 1, 1, 0, 0, 1, 0],
      [1, 1, 0, 1, 0, 1, 1, 0, 0],
      [1, 1, 0, 1, 0, 0, 1, 1, 0],
      [1, 1, 0, 0, 1, 0, 1, 1, 0],
      [1, 1, 0, 0, 1, 1, 0, 1, 0],
      [1, 0, 1, 1, 0, 1, 1, 0, 0],
      [1, 0, 1, 1, 0, 0, 1, 1, 0],
      [1, 0, 0, 1, 1, 0, 1, 1, 0],
      [1, 0, 0, 1, 1, 1, 0, 1, 0],
      [1, 0, 0, 1, 0, 1, 1, 1, 0],
      [1, 1, 1, 0, 1, 0, 1, 0, 0],
      [1, 1, 1, 0, 1, 0, 0, 1, 0],
      [1, 1, 1, 0, 0, 1, 0, 1, 0],
      [1, 0, 1, 1, 0, 1, 1, 1, 0],
      [1, 0, 1, 1, 1, 0, 1, 1, 0],
      [1, 1, 0, 1, 0, 1, 1, 1, 0],
      [1, 0, 0, 1, 0, 0, 1, 1, 0],
      [1, 1, 1, 0, 1, 1, 0, 1, 0],
      [1, 1, 1, 0, 1, 0, 1, 1, 0],
      [1, 0, 0, 1, 1, 0, 0, 1, 0]
   ];

   var start_stop = [ 1, 0, 1, 0, 1, 1, 1, 1, 0 ];

   var termination_bar = [ 1 ];

/* Check if code is correct */
function check(code93)
{
   for (var i=0; i<code93.length; i++)
   {
      var letterIndex = getLetterIndex(code93[i]);
      if (letterIndex == -1 || letterIndex >= code93signs.length - 4)
         return false;
   }
   return true;
}

/* Return letter index, or -1 if not correct */
function getLetterIndex(ch)
{
   for (var i=0; i<code93signs.length; i++)
   {
      if (code93signs[i] == ch)
         return i;
   }
   return -1;
}

/* Return check digit C */
function checkDigitC(code93)
{
   var sum = 0;
   var w = 0;

   for (var i=code93.length-1; i>=0; i--)
   {
      sum += (getLetterIndex(code93[i]) * ((w % 20) + 1));
      w++;
   }

   return (sum % 47);
}	
	  
/* Return check digit K */
function checkDigitK(code93)
{
   var sum = checkDigitC(code93);
   var w = 1;

   for (var i=code93.length-1; i>=0; i--)
   {
      sum += (getLetterIndex(code93[i]) * ((w % 15) + 1));
      w++;
   }

   return (sum % 47);
}
	  
/* Convert code to bars */
function convert(code93) 
{

   /* inccorect code return null */
   if (check(code93) == false)
   {
      return null;
   }

   var bars = new Array(9*(code93.length+4) + 1);

   /* add start bars */
   for (var j=0; j<9; j++)
   {
       bars[j] = start_stop[j];
   }

   /* add character codes */
   for (var i=0; i<code93.length; i++)
   {
      var toCopy = code93bars[getLetterIndex(code93[i])];
      for (var j=0; j<9; j++)
      {
          bars[i*9 + 9 + j] = toCopy[j];
      }
   }

   /* add check digit C */
   var toCopy = code93bars[checkDigitC(code93)];
   for (var j=0; j<9; j++) 
   {
       bars[(code93.length+1)*9 + j] = toCopy[j];
   }
   
   /* add check digit K */
   var toCopy = code93bars[checkDigitK(code93)];
   for (var j=0; j<9; j++) 
   {
       bars[(code93.length+2)*9 + j] = toCopy[j];
   }
   
   /* add stop bars */
   for (var j=0; j<9; j++)
   {
       bars[(code93.length+3)*9 + j] = start_stop[j];
   }
   
   /* add termination bar */
   bars[(code93.length+4)*9] = termination_bar[0];

   return bars;
}

//initialize data
function generate(code93)
{
   var canvas = document.getElementById("canvas");
   var ctx = canvas.getContext("2d");

   /* clear canvas and set its width */
   canvas.width = code93.length*18+93;
   
   /* prepare style */
   ctx.fillStyle    = "rgb(0,0,0)";
   ctx.font         = "10pt Arial";
   ctx.textBaseline = "top";
   ctx.textAlign    = "left";

   code93 = code93.toUpperCase();
   var bars = convert(code93);
   if (bars != null)
   {
      for (i=0; i<bars.length; i++)
      {
         /* Black bar */
         if (bars[i] == 1)
         {
            ctx.fillRect(10+2*i, 10, 2, 70);
         }
      }

      for (i=0; i<code93.length; i++) 
      {
         ctx.fillText(code93[i], i*18+35, 90);
      }
   }
   else
   {
      ctx.fillText("Nieprawidłowy", 10, 10);
      ctx.fillText("kod", 10, 25);
      ctx.fillText("Incorrect", 10, 50);
      ctx.fillText("code", 10, 65);
   }
}