javascript printf

// printf.js - version 1.1.0
//
//  http://www.onicos.com/staff/iz/amuse/javascript/expert/printf.txt
//
//  This library is free software; you can redistribute it and/or
//  modify it under the terms of the GNU Lesser General Public
//  License as published by the Free Software Foundation; either
//  version 2.1 of the License, or (at your option) any later version.
//
//  This library is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
//  Lesser General Public License for more details.
//
//  You should have received a copy of the GNU Lesser General Public
//  License along with this library; if not, write to the Free Software
//  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//
//
// SYNOPSIS:
//   printf("format", ...);
//   str = sprintf("format", ...);
//
// Chages:
// 2002-02-04  Masanao Izumo <mo@goice.co.jp>
//             - Fixed bug about sprintf("%%") will return "%%".
//             - Evaluate undefined "%" argument.  That is:
//                   numerical value ===> 0 (%d, %x, %o, etc)
//                   string value    ===> ''    (%s)

// printf(format, ...);
function printf() {
  document.write(va_sprintf(printf.arguments));
}

// str = sprintf(format, ...);
function sprintf() {
  return va_sprintf(sprintf.arguments);
}

function va_sprintf(args) {
  var ch;
  var value;
  var longflag;
  var ljust;
  var len, llen;
  var zpad;
  var p;
  var output;
  var format_index, arg_index;
  var argc, argv;
  var specin;
  var format;

  output = '';
  format_index = 0;
  arg_index = 1;
  argv = args;
  argc = args.length;
  format = args[0];

  while (format_index < format.length) {
    ch = format.substr(format_index++, 1);
    if (ch != '%' || format_index == format.length) {
      output += ch;
    } else {
      // ch == '%'
      ljust = len = zpad = longflag = 0;
      llen = -1;
      p = format_index;
      specin = true;

      while (specin) {
    ch = format.substr(format_index++, 1);
    switch(ch) {
    case '-':
      ljust = 1;
          continue;

    case '0':         // set zero padding if len not set
      if(len == 0)
        zpad = 1;
      // FALLTHROUGH
    case '1': case '2': case '3':
    case '4': case '5': case '6':
    case '7': case '8': case '9':
      len = len * 10 + parseInt(ch);
      continue;

    case '.':
      llen = len;
      len = 0;
      continue;

    case '*':
      if (arg_index < argc)
        len = parseInt(argv[arg_index++]);
      else
        len = 0;
      if (len < 0) {
        ljust = 1;
        len = -len;
      }
      continue;

    case 'l':
      longflag = 1;
      continue;

    case 'u': case 'U':
      if (arg_index < argc) {
        if (longflag) {
          value = parseInt(argv[arg_index++]);
        } else {
          value = parseInt(argv[arg_index++]);
          value %= 4294967296;
        }
      } else {
        value = 0;
      }
      output += _dopr_fmtnum(value, 10,0, ljust, len, zpad);
      break;

    case 'o': case 'O':
      if (arg_index < argc) {
        if (longflag) {
          value = parseInt(argv[arg_index++]);
        } else {
          value = parseInt(argv[arg_index++]);
          value %= 4294967296;
        }
      } else {
        value = 0;
      }
      output += _dopr_fmtnum(value, 8,0, ljust, len, zpad);
      break;

    case 'd': case 'D':
      if (arg_index < argc) {
        if (longflag) {
          value = parseInt(argv[arg_index++]);
        } else {
          value = parseInt(argv[arg_index++]);
          value %= 4294967296;
        }
      } else {
        value = 0;
      }
      output += _dopr_fmtnum(value, 10,1, ljust, len, zpad);
      break;

    case 'x':
      if (arg_index < argc) {
        if (longflag) {
          value = parseInt(argv[arg_index++]);
        } else {
          value = parseInt(argv[arg_index++]);
          value %= 4294967296;
        }
      } else {
        value = 0;
      }
      output += _dopr_fmtnum(value, 16,0, ljust, len, zpad);
      break;

    case 'X':
      if (arg_index < argc) {
        if (longflag) {
          value = parseInt(argv[arg_index++]);
        } else {
          value = parseInt(argv[arg_index++]);
          value %= 4294967296;
        }
      } else {
        value = 0;
      }
      output += _dopr_fmtnum(value, -16,0, ljust, len, zpad);
      break;

    case 's':
      if (arg_index < argc) {
        value = argv[arg_index++];
        if(value == null)
          value = "(null)";
        else
          value = value + "";   // toString
      } else {
        value = '';
      }
      output += _dopr_fmtstr(value, ljust, len, llen);
      break;

    case 'c':
      if (arg_index < argc) {
        value = parseInt(argv[arg_index++]);
      } else {
        value = 0;
      }
      output += _dopr_fromCharCode(value);
      break;

    case '%':
      output += '%';
      break;

/* Not supported
    case 'f': case 'e': case 'E': case 'g': case 'G':
      if (arg_index < argc) {
        value = argv[arg_index++];
      } else {
        value = 0.0;
      }
      output += _dopr_fmtdouble(format.substr(p, format_index - p), value);
      break;
*/

    default:
      if(p + 1 == format_index) {
        output += '%';
        output += ch;
      }
      else {
        // alert("format error: " + format);
      }
      break;
    }
    specin = false;
      }
    }
  }
  return output;
}

// Private function
function _dopr_fmtnum(value, base, dosign, ljust, len, zpad)
{
  var signvalue = '';
  var uvalue;
  var place = 0;
  var padlen;       // amount to pad
  var caps = 0;
  var convert;
  var output;

  convert = '';
  output = '';

  if(value >= 0)
    uvalue = value;
  else
    uvalue = (value % 4294967296) + 4294967296;

  if (dosign) {
    if (value < 0) {
      signvalue = '-';
      uvalue = -value;
    }
  }

  if (base < 0) {
    caps = 1;
    base = -base;
  }

  if(uvalue == 0) {
    convert = '0';
    place = 1;
  } else {
    while (uvalue) {
      if(caps)
    convert = '0123456789ABCDEF'.substr(uvalue % base, 1) + convert;
      else
    convert = '0123456789abcdef'.substr(uvalue % base, 1) + convert;
      uvalue = parseInt(uvalue / base);
      place++;
    }
  }

  padlen = len - place;
  if (padlen < 0) padlen = 0;
  if (ljust) padlen = -padlen;

  if (zpad && padlen > 0) {
    if(signvalue) {
      output += signvalue;
      --padlen;
      signvalue = 0;
    }

    while (padlen > 0) {
      output += '0';
      --padlen;
    }
  }

  while (padlen > 0) {
    output += ' ';
    --padlen;
  }
  if (signvalue) {
    output += signvalue;
  }

  output += convert;

  while(padlen < 0) {
    output += ' ';
    ++padlen;
  }
  return output;
}

// Private function
function _dopr_fmtstr(value, ljust, field_len, llen)
{
  var padlen;           // amount to pad
  var slen, truncstr = 0;
  var output = '';

  slen = value.length;

  if (llen != -1) {
    var rlen;

    rlen = field_len;
    if (slen > rlen) {
      truncstr = 1;
      slen = rlen;
    }
    field_len = llen;
  }
  padlen = field_len - slen;

  if (padlen < 0)
    padlen = 0;
  if (ljust)
    padlen = -padlen;
  while (padlen > 0) {
    output += ' ';
    --padlen;
  }
  if (truncstr) {
    output += value.substr(0, slen);
  } else {
    output += value;
  }

  while (padlen < 0) {
    output += ' ';
    ++padlen;
  }
  return output;
}

// Private function
var _dopr_fromCharCode_chars = null;
function _dopr_fromCharCode(code)
{
  if(String.fromCharCode)
    return String.fromCharCode(code);
  if(!_dopr_fromCharCode_chars)
    _dopr_fromCharCode_chars =
      "\000\001\002\003\004\005\006\007\010\011\012\013\014\015\016\017\020" +
      "\021\022\023\024\025\026\027\030\031\032\033\034\035\036\037 !\"#$%&" +
      "'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghi" +
      "jklmnopqrstuvwxyz{|}~\177\200\201\202\203\204\205\206\207\210\211" +
      "\212\213\214\215\216\217\220\221\222\223\224\225\226\227\230\231\232" +
      "\233\234\235\236\237\240\241\242\243\244\245\246\247\250\251\252\253" +
      "\254\255\256\257\260\261\262\263\264\265\266\267\270\271\272\273\274" +
      "\275\276\277\300\301\302\303\304\305\306\307\310\311\312\313\314\315" +
      "\316\317\320\321\322\323\324\325\326\327\330\331\332\333\334\335\336" +
      "\337\340\341\342\343\344\345\346\347\350\351\352\353\354\355\356\357" +
      "\360\361\362\363\364\365\366\367\370\371\372\373\374\375\376\377";
  if(code < 0)
    return "";
  if(code <= 255)
    return _dopr_fromCharCode_chars.substr(code, 1);
  return eval(sprintf("\"\\u%04x\"", code));
}