function sprintf() {
/*
 * Copyright (c) 2013 Kevin van Zonneveld (http://kvz.io)
 * and Contributors (http://phpjs.org/authors)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
 * of the Software, and to permit persons to whom the Software is furnished to do
 * so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
*/
  //  discuss at: http://phpjs.org/functions/sprintf/
  // original by: Ash Searle (http://hexmen.com/blog/)
  // improved by: Michael White (http://getsprink.com)
  // improved by: Jack
  // improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
  // improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
  // improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
  // improved by: Dj
  // improved by: Allidylls
  //    input by: Paulo Freitas
  //    input by: Brett Zamir (http://brett-zamir.me)
  //   example 1: sprintf("%01.2f", 123.1);
  //   returns 1: 123.10
  //   example 2: sprintf("[%10s]", 'monkey');
  //   returns 2: '[    monkey]'
  //   example 3: sprintf("[%'#10s]", 'monkey');
  //   returns 3: '[####monkey]'
  //   example 4: sprintf("%d", 123456789012345);
  //   returns 4: '123456789012345'
  //   example 5: sprintf('%-03s', 'E');
  //   returns 5: 'E00'

  var regex = /%%|%(\d+\$)?([-+\'#0 ]*)(\*\d+\$|\*|\d+)?(\.(\*\d+\$|\*|\d+))?([scboxXuideEfFgG])/g;
  var a = arguments;
  var i = 0;
  var format = a[i++];

  // pad()
  var pad = function (str, len, chr, leftJustify) {
    if (!chr) {
      chr = ' ';
    }
    var padding = (str.length >= len) ? '' : new Array(1 + len - str.length >>> 0)
      .join(chr);
    return leftJustify ? str + padding : padding + str;
  };

  // justify()
  var justify = function (value, prefix, leftJustify, minWidth, zeroPad, customPadChar) {
    var diff = minWidth - value.length;
    if (diff > 0) {
      if (leftJustify || !zeroPad) {
        value = pad(value, minWidth, customPadChar, leftJustify);
      } else {
        value = value.slice(0, prefix.length) + pad('', diff, '0', true) + value.slice(prefix.length);
      }
    }
    return value;
  };

  // formatBaseX()
  var formatBaseX = function (value, base, prefix, leftJustify, minWidth, precision, zeroPad) {
    // Note: casts negative numbers to positive ones
    var number = value >>> 0;
    prefix = prefix && number && {
      '2': '0b',
      '8': '0',
      '16': '0x'
    }[base] || '';
    value = prefix + pad(number.toString(base), precision || 0, '0', false);
    return justify(value, prefix, leftJustify, minWidth, zeroPad);
  };

  // formatString()
  var formatString = function (value, leftJustify, minWidth, precision, zeroPad, customPadChar) {
    if (precision != null) {
      value = value.slice(0, precision);
    }
    return justify(value, '', leftJustify, minWidth, zeroPad, customPadChar);
  };

  // doFormat()
  var doFormat = function (substring, valueIndex, flags, minWidth, _, precision, type) {
    var number, prefix, method, textTransform, value;

    if (substring === '%%') {
      return '%';
    }

    // parse flags
    var leftJustify = false;
    var positivePrefix = '';
    var zeroPad = false;
    var prefixBaseX = false;
    var customPadChar = ' ';
    var flagsl = flags.length;
    for (var j = 0; flags && j < flagsl; j++) {
      switch (flags.charAt(j)) {
      case ' ':
        positivePrefix = ' ';
        break;
      case '+':
        positivePrefix = '+';
        break;
      case '-':
        leftJustify = true;
        break;
      case "'":
        customPadChar = flags.charAt(j + 1);
        break;
      case '0':
        zeroPad = true;
        customPadChar = '0';
        break;
      case '#':
        prefixBaseX = true;
        break;
      }
    }

    // parameters may be null, undefined, empty-string or real valued
    // we want to ignore null, undefined and empty-string values
    if (!minWidth) {
      minWidth = 0;
    } else if (minWidth === '*') {
      minWidth = +a[i++];
    } else if (minWidth.charAt(0) == '*') {
      minWidth = +a[minWidth.slice(1, -1)];
    } else {
      minWidth = +minWidth;
    }

    // Note: undocumented perl feature:
    if (minWidth < 0) {
      minWidth = -minWidth;
      leftJustify = true;
    }

    if (!isFinite(minWidth)) {
      throw new Error('sprintf: (minimum-)width must be finite');
    }

    if (!precision) {
      precision = 'fFeE'.indexOf(type) > -1 ? 6 : (type === 'd') ? 0 : undefined;
    } else if (precision === '*') {
      precision = +a[i++];
    } else if (precision.charAt(0) == '*') {
      precision = +a[precision.slice(1, -1)];
    } else {
      precision = +precision;
    }

    // grab value using valueIndex if required?
    value = valueIndex ? a[valueIndex.slice(0, -1)] : a[i++];

    switch (type) {
    case 's':
      return formatString(String(value), leftJustify, minWidth, precision, zeroPad, customPadChar);
    case 'c':
      return formatString(String.fromCharCode(+value), leftJustify, minWidth, precision, zeroPad);
    case 'b':
      return formatBaseX(value, 2, prefixBaseX, leftJustify, minWidth, precision, zeroPad);
    case 'o':
      return formatBaseX(value, 8, prefixBaseX, leftJustify, minWidth, precision, zeroPad);
    case 'x':
      return formatBaseX(value, 16, prefixBaseX, leftJustify, minWidth, precision, zeroPad);
    case 'X':
      return formatBaseX(value, 16, prefixBaseX, leftJustify, minWidth, precision, zeroPad)
        .toUpperCase();
    case 'u':
      return formatBaseX(value, 10, prefixBaseX, leftJustify, minWidth, precision, zeroPad);
    case 'i':
    case 'd':
      number = +value || 0;
      // Plain Math.round doesn't just truncate
      number = Math.round(number - number % 1);
      prefix = number < 0 ? '-' : positivePrefix;
      value = prefix + pad(String(Math.abs(number)), precision, '0', false);
      return justify(value, prefix, leftJustify, minWidth, zeroPad);
    case 'e':
    case 'E':
    case 'f': // Should handle locales (as per setlocale)
    case 'F':
    case 'g':
    case 'G':
      number = +value;
      prefix = number < 0 ? '-' : positivePrefix;
      method = ['toExponential', 'toFixed', 'toPrecision']['efg'.indexOf(type.toLowerCase())];
      textTransform = ['toString', 'toUpperCase']['eEfFgG'.indexOf(type) % 2];
      value = prefix + Math.abs(number)[method](precision);
      return justify(value, prefix, leftJustify, minWidth, zeroPad)[textTransform]();
    default:
      return substring;
    }
  };

  return format.replace(regex, doFormat);
}