<?php

/**
 * PHPExcel_Shared_String
 *
 * Copyright (c) 2006 - 2015 PHPExcel
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * @category   PHPExcel
 * @package    PHPExcel_Shared
 * @copyright  Copyright (c) 2006 - 2015 PHPExcel (http://www.codeplex.com/PHPExcel)
 * @license    http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt    LGPL
 * @version    ##VERSION##, ##DATE##
 */
class PHPExcel_Shared_String
{
  /**
   * Constants
   */
  /**
   * Regular Expressions
   */
  // Fraction
  const STRING_REGEXP_FRACTION = '(-?)(\d+)\s+(\d+\/\d+)';
  
  /**
   * Control characters array
   *
   * @var string[]
   */
  private static $controlCharacters = array ();
  
  /**
   * SYLK Characters array
   *
   * $var array
   */
  private static $SYLKCharacters = array ();
  
  /**
   * Decimal separator
   *
   * @var string
   */
  private static $decimalSeparator;
  
  /**
   * Thousands separator
   *
   * @var string
   */
  private static $thousandsSeparator;
  
  /**
   * Currency code
   *
   * @var string
   */
  private static $currencyCode;
  
  /**
   * Is mbstring extension avalable?
   *
   * @var boolean
   */
  private static $isMbstringEnabled;
  
  /**
   * Is iconv extension avalable?
   *
   * @var boolean
   */
  private static $isIconvEnabled;
  
  /**
   * Build control characters array
   */
  private static function buildControlCharacters()
  {
    for($i = 0; $i <= 31; ++ $i)
    {
      if ($i != 9 && $i != 10 && $i != 13)
      {
        $find = '_x' . sprintf ( '%04s', strtoupper ( dechex ( $i ) ) ) . '_';
        $replace = chr ( $i );
        self::$controlCharacters [$find] = $replace;
      }
    }
  }
  
  /**
   * Build SYLK characters array
   */
  private static function buildSYLKCharacters()
  {
    self::$SYLKCharacters = array (
        "\x1B 0" => chr ( 0 ),
        "\x1B 1" => chr ( 1 ),
        "\x1B 2" => chr ( 2 ),
        "\x1B 3" => chr ( 3 ),
        "\x1B 4" => chr ( 4 ),
        "\x1B 5" => chr ( 5 ),
        "\x1B 6" => chr ( 6 ),
        "\x1B 7" => chr ( 7 ),
        "\x1B 8" => chr ( 8 ),
        "\x1B 9" => chr ( 9 ),
        "\x1B :" => chr ( 10 ),
        "\x1B ;" => chr ( 11 ),
        "\x1B <" => chr ( 12 ),
        "\x1B :" => chr ( 13 ),
        "\x1B >" => chr ( 14 ),
        "\x1B ?" => chr ( 15 ),
        "\x1B!0" => chr ( 16 ),
        "\x1B!1" => chr ( 17 ),
        "\x1B!2" => chr ( 18 ),
        "\x1B!3" => chr ( 19 ),
        "\x1B!4" => chr ( 20 ),
        "\x1B!5" => chr ( 21 ),
        "\x1B!6" => chr ( 22 ),
        "\x1B!7" => chr ( 23 ),
        "\x1B!8" => chr ( 24 ),
        "\x1B!9" => chr ( 25 ),
        "\x1B!:" => chr ( 26 ),
        "\x1B!;" => chr ( 27 ),
        "\x1B!<" => chr ( 28 ),
        "\x1B!=" => chr ( 29 ),
        "\x1B!>" => chr ( 30 ),
        "\x1B!?" => chr ( 31 ),
        "\x1B'?" => chr ( 127 ),
        "\x1B(0" => '€', // 128 in CP1252
        "\x1B(2" => '‚', // 130 in CP1252
        "\x1B(3" => 'ƒ', // 131 in CP1252
        "\x1B(4" => '„', // 132 in CP1252
        "\x1B(5" => '…', // 133 in CP1252
        "\x1B(6" => '†', // 134 in CP1252
        "\x1B(7" => '‡', // 135 in CP1252
        "\x1B(8" => 'ˆ', // 136 in CP1252
        "\x1B(9" => '‰', // 137 in CP1252
        "\x1B(:" => 'Š', // 138 in CP1252
        "\x1B(;" => '‹', // 139 in CP1252
        "\x1BNj" => 'Œ', // 140 in CP1252
        "\x1B(>" => 'Ž', // 142 in CP1252
        "\x1B)1" => '‘', // 145 in CP1252
        "\x1B)2" => '’', // 146 in CP1252
        "\x1B)3" => '“', // 147 in CP1252
        "\x1B)4" => '”', // 148 in CP1252
        "\x1B)5" => '•', // 149 in CP1252
        "\x1B)6" => '–', // 150 in CP1252
        "\x1B)7" => '—', // 151 in CP1252
        "\x1B)8" => '˜', // 152 in CP1252
        "\x1B)9" => '™', // 153 in CP1252
        "\x1B):" => 'š', // 154 in CP1252
        "\x1B);" => '›', // 155 in CP1252
        "\x1BNz" => 'œ', // 156 in CP1252
        "\x1B)>" => 'ž', // 158 in CP1252
        "\x1B)?" => 'Ÿ', // 159 in CP1252
        "\x1B*0" => ' ', // 160 in CP1252
        "\x1BN!" => '¡', // 161 in CP1252
        "\x1BN\"" => '¢', // 162 in CP1252
        "\x1BN#" => '£', // 163 in CP1252
        "\x1BN(" => '¤', // 164 in CP1252
        "\x1BN%" => '¥', // 165 in CP1252
        "\x1B*6" => '¦', // 166 in CP1252
        "\x1BN'" => '§', // 167 in CP1252
        "\x1BNH " => '¨', // 168 in CP1252
        "\x1BNS" => '©', // 169 in CP1252
        "\x1BNc" => 'ª', // 170 in CP1252
        "\x1BN+" => '«', // 171 in CP1252
        "\x1B*<" => '¬', // 172 in CP1252
        "\x1B*=" => '­', // 173 in CP1252
        "\x1BNR" => '®', // 174 in CP1252
        "\x1B*?" => '¯', // 175 in CP1252
        "\x1BN0" => '°', // 176 in CP1252
        "\x1BN1" => '±', // 177 in CP1252
        "\x1BN2" => '²', // 178 in CP1252
        "\x1BN3" => '³', // 179 in CP1252
        "\x1BNB " => '´', // 180 in CP1252
        "\x1BN5" => 'µ', // 181 in CP1252
        "\x1BN6" => '¶', // 182 in CP1252
        "\x1BN7" => '·', // 183 in CP1252
        "\x1B+8" => '¸', // 184 in CP1252
        "\x1BNQ" => '¹', // 185 in CP1252
        "\x1BNk" => 'º', // 186 in CP1252
        "\x1BN;" => '»', // 187 in CP1252
        "\x1BN<" => '¼', // 188 in CP1252
        "\x1BN=" => '½', // 189 in CP1252
        "\x1BN>" => '¾', // 190 in CP1252
        "\x1BN?" => '¿', // 191 in CP1252
        "\x1BNAA" => 'À', // 192 in CP1252
        "\x1BNBA" => 'Á', // 193 in CP1252
        "\x1BNCA" => 'Â', // 194 in CP1252
        "\x1BNDA" => 'Ã', // 195 in CP1252
        "\x1BNHA" => 'Ä', // 196 in CP1252
        "\x1BNJA" => 'Å', // 197 in CP1252
        "\x1BNa" => 'Æ', // 198 in CP1252
        "\x1BNKC" => 'Ç', // 199 in CP1252
        "\x1BNAE" => 'È', // 200 in CP1252
        "\x1BNBE" => 'É', // 201 in CP1252
        "\x1BNCE" => 'Ê', // 202 in CP1252
        "\x1BNHE" => 'Ë', // 203 in CP1252
        "\x1BNAI" => 'Ì', // 204 in CP1252
        "\x1BNBI" => 'Í', // 205 in CP1252
        "\x1BNCI" => 'Î', // 206 in CP1252
        "\x1BNHI" => 'Ï', // 207 in CP1252
        "\x1BNb" => 'Ð', // 208 in CP1252
        "\x1BNDN" => 'Ñ', // 209 in CP1252
        "\x1BNAO" => 'Ò', // 210 in CP1252
        "\x1BNBO" => 'Ó', // 211 in CP1252
        "\x1BNCO" => 'Ô', // 212 in CP1252
        "\x1BNDO" => 'Õ', // 213 in CP1252
        "\x1BNHO" => 'Ö', // 214 in CP1252
        "\x1B-7" => '×', // 215 in CP1252
        "\x1BNi" => 'Ø', // 216 in CP1252
        "\x1BNAU" => 'Ù', // 217 in CP1252
        "\x1BNBU" => 'Ú', // 218 in CP1252
        "\x1BNCU" => 'Û', // 219 in CP1252
        "\x1BNHU" => 'Ü', // 220 in CP1252
        "\x1B-=" => 'Ý', // 221 in CP1252
        "\x1BNl" => 'Þ', // 222 in CP1252
        "\x1BN{" => 'ß', // 223 in CP1252
        "\x1BNAa" => 'à', // 224 in CP1252
        "\x1BNBa" => 'á', // 225 in CP1252
        "\x1BNCa" => 'â', // 226 in CP1252
        "\x1BNDa" => 'ã', // 227 in CP1252
        "\x1BNHa" => 'ä', // 228 in CP1252
        "\x1BNJa" => 'å', // 229 in CP1252
        "\x1BNq" => 'æ', // 230 in CP1252
        "\x1BNKc" => 'ç', // 231 in CP1252
        "\x1BNAe" => 'è', // 232 in CP1252
        "\x1BNBe" => 'é', // 233 in CP1252
        "\x1BNCe" => 'ê', // 234 in CP1252
        "\x1BNHe" => 'ë', // 235 in CP1252
        "\x1BNAi" => 'ì', // 236 in CP1252
        "\x1BNBi" => 'í', // 237 in CP1252
        "\x1BNCi" => 'î', // 238 in CP1252
        "\x1BNHi" => 'ï', // 239 in CP1252
        "\x1BNs" => 'ð', // 240 in CP1252
        "\x1BNDn" => 'ñ', // 241 in CP1252
        "\x1BNAo" => 'ò', // 242 in CP1252
        "\x1BNBo" => 'ó', // 243 in CP1252
        "\x1BNCo" => 'ô', // 244 in CP1252
        "\x1BNDo" => 'õ', // 245 in CP1252
        "\x1BNHo" => 'ö', // 246 in CP1252
        "\x1B/7" => '÷', // 247 in CP1252
        "\x1BNy" => 'ø', // 248 in CP1252
        "\x1BNAu" => 'ù', // 249 in CP1252
        "\x1BNBu" => 'ú', // 250 in CP1252
        "\x1BNCu" => 'û', // 251 in CP1252
        "\x1BNHu" => 'ü', // 252 in CP1252
        "\x1B/=" => 'ý', // 253 in CP1252
        "\x1BN|" => 'þ', // 254 in CP1252
        "\x1BNHy" => 'ÿ' 
    ) // 255 in CP1252
;
  }
  
  /**
   * Get whether mbstring extension is available
   *
   * @return boolean
   */
  public static function getIsMbstringEnabled()
  {
    if (isset ( self::$isMbstringEnabled ))
    {
      return self::$isMbstringEnabled;
    }
    
    self::$isMbstringEnabled = function_exists ( 'mb_convert_encoding' ) ? true : false;
    
    return self::$isMbstringEnabled;
  }
  
  /**
   * Get whether iconv extension is available
   *
   * @return boolean
   */
  public static function getIsIconvEnabled()
  {
    if (isset ( self::$isIconvEnabled ))
    {
      return self::$isIconvEnabled;
    }
    
    // Fail if iconv doesn't exist
    if (! function_exists ( 'iconv' ))
    {
      self::$isIconvEnabled = false;
      return false;
    }
    
    // Sometimes iconv is not working, and e.g. iconv('UTF-8', 'UTF-16LE', 'x') just returns false,
    if (! @iconv ( 'UTF-8', 'UTF-16LE', 'x' ))
    {
      self::$isIconvEnabled = false;
      return false;
    }
    
    // Sometimes iconv_substr('A', 0, 1, 'UTF-8') just returns false in PHP 5.2.0
    // we cannot use iconv in that case either (http://bugs.php.net/bug.php?id=37773)
    if (! @iconv_substr ( 'A', 0, 1, 'UTF-8' ))
    {
      self::$isIconvEnabled = false;
      return false;
    }
    
    // CUSTOM: IBM AIX iconv() does not work
    if (defined ( 'PHP_OS' ) && @stristr ( PHP_OS, 'AIX' ) && defined ( 'ICONV_IMPL' ) && (@strcasecmp ( ICONV_IMPL, 'unknown' ) == 0) && defined ( 'ICONV_VERSION' ) && (@strcasecmp ( ICONV_VERSION, 'unknown' ) == 0))
    {
      self::$isIconvEnabled = false;
      return false;
    }
    
    // If we reach here no problems were detected with iconv
    self::$isIconvEnabled = true;
    return true;
  }
  public static function buildCharacterSets()
  {
    if (empty ( self::$controlCharacters ))
    {
      self::buildControlCharacters ();
    }
    if (empty ( self::$SYLKCharacters ))
    {
      self::buildSYLKCharacters ();
    }
  }
  
  /**
   * Convert from OpenXML escaped control character to PHP control character
   *
   * Excel 2007 team:
   * ----------------
   * That's correct, control characters are stored directly in the shared-strings table.
   * We do encode characters that cannot be represented in XML using the following escape sequence:
   * _xHHHH_ where H represents a hexadecimal character in the character's value...
   * So you could end up with something like _x0008_ in a string (either in a cell value (<v>)
   * element or in the shared string <t> element.
   *
   * @param string $value
   *          Value to unescape
   * @return string
   */
  public static function ControlCharacterOOXML2PHP($value = '')
  {
    return str_replace ( array_keys ( self::$controlCharacters ), array_values ( self::$controlCharacters ), $value );
  }
  
  /**
   * Convert from PHP control character to OpenXML escaped control character
   *
   * Excel 2007 team:
   * ----------------
   * That's correct, control characters are stored directly in the shared-strings table.
   * We do encode characters that cannot be represented in XML using the following escape sequence:
   * _xHHHH_ where H represents a hexadecimal character in the character's value...
   * So you could end up with something like _x0008_ in a string (either in a cell value (<v>)
   * element or in the shared string <t> element.
   *
   * @param string $value
   *          Value to escape
   * @return string
   */
  public static function ControlCharacterPHP2OOXML($value = '')
  {
    return str_replace ( array_values ( self::$controlCharacters ), array_keys ( self::$controlCharacters ), $value );
  }
  
  /**
   * Try to sanitize UTF8, stripping invalid byte sequences.
   * Not perfect. Does not surrogate characters.
   *
   * @param string $value          
   * @return string
   */
  public static function SanitizeUTF8($value)
  {
    if (self::getIsIconvEnabled ())
    {
      $value = @iconv ( 'UTF-8', 'UTF-8', $value );
      return $value;
    }
    
    if (self::getIsMbstringEnabled ())
    {
      $value = mb_convert_encoding ( $value, 'UTF-8', 'UTF-8' );
      return $value;
    }
    
    // else, no conversion
    return $value;
  }
  
  /**
   * Check if a string contains UTF8 data
   *
   * @param string $value          
   * @return boolean
   */
  public static function IsUTF8($value = '')
  {
    return $value === '' || preg_match ( '/^./su', $value ) === 1;
  }
  
  /**
   * Formats a numeric value as a string for output in various output writers forcing
   * point as decimal separator in case locale is other than English.
   *
   * @param mixed $value          
   * @return string
   */
  public static function FormatNumber($value)
  {
    if (is_float ( $value ))
    {
      return str_replace ( ',', '.', $value );
    }
    return ( string ) $value;
  }
  
  /**
   * Converts a UTF-8 string into BIFF8 Unicode string data (8-bit string length)
   * Writes the string using uncompressed notation, no rich text, no Asian phonetics
   * If mbstring extension is not available, ASCII is assumed, and compressed notation is used
   * although this will give wrong results for non-ASCII strings
   * see OpenOffice.org's Documentation of the Microsoft Excel File Format, sect. 2.5.3
   *
   * @param string $value
   *          UTF-8 encoded string
   * @param mixed[] $arrcRuns
   *          Details of rich text runs in $value
   * @return string
   */
  public static function UTF8toBIFF8UnicodeShort($value, $arrcRuns = array())
  {
    // character count
    $ln = self::CountCharacters ( $value, 'UTF-8' );
    // option flags
    if (empty ( $arrcRuns ))
    {
      $opt = (self::getIsIconvEnabled () || self::getIsMbstringEnabled ()) ? 0x0001 : 0x0000;
      $data = pack ( 'CC', $ln, $opt );
      // characters
      $data .= self::ConvertEncoding ( $value, 'UTF-16LE', 'UTF-8' );
    }
    else
    {
      $data = pack ( 'vC', $ln, 0x09 );
      $data .= pack ( 'v', count ( $arrcRuns ) );
      // characters
      $data .= self::ConvertEncoding ( $value, 'UTF-16LE', 'UTF-8' );
      foreach ( $arrcRuns as $cRun )
      {
        $data .= pack ( 'v', $cRun ['strlen'] );
        $data .= pack ( 'v', $cRun ['fontidx'] );
      }
    }
    return $data;
  }
  
  /**
   * Converts a UTF-8 string into BIFF8 Unicode string data (16-bit string length)
   * Writes the string using uncompressed notation, no rich text, no Asian phonetics
   * If mbstring extension is not available, ASCII is assumed, and compressed notation is used
   * although this will give wrong results for non-ASCII strings
   * see OpenOffice.org's Documentation of the Microsoft Excel File Format, sect. 2.5.3
   *
   * @param string $value
   *          UTF-8 encoded string
   * @return string
   */
  public static function UTF8toBIFF8UnicodeLong($value)
  {
    // character count
    $ln = self::CountCharacters ( $value, 'UTF-8' );
    
    // option flags
    $opt = (self::getIsIconvEnabled () || self::getIsMbstringEnabled ()) ? 0x0001 : 0x0000;
    
    // characters
    $chars = self::ConvertEncoding ( $value, 'UTF-16LE', 'UTF-8' );
    
    $data = pack ( 'vC', $ln, $opt ) . $chars;
    return $data;
  }
  
  /**
   * Convert string from one encoding to another.
   * First try mbstring, then iconv, finally strlen
   *
   * @param string $value          
   * @param string $to
   *          Encoding to convert to, e.g. 'UTF-8'
   * @param string $from
   *          Encoding to convert from, e.g. 'UTF-16LE'
   * @return string
   */
  public static function ConvertEncoding($value, $to, $from)
  {
    if (self::getIsIconvEnabled ())
    {
      return iconv ( $from, $to, $value );
    }
    
    if (self::getIsMbstringEnabled ())
    {
      return mb_convert_encoding ( $value, $to, $from );
    }
    
    if ($from == 'UTF-16LE')
    {
      return self::utf16_decode ( $value, false );
    }
    elseif ($from == 'UTF-16BE')
    {
      return self::utf16_decode ( $value );
    }
    // else, no conversion
    return $value;
  }
  
  /**
   * Decode UTF-16 encoded strings.
   *
   * Can handle both BOM'ed data and un-BOM'ed data.
   * Assumes Big-Endian byte order if no BOM is available.
   * This function was taken from http://php.net/manual/en/function.utf8-decode.php
   * and $bom_be parameter added.
   *
   * @param string $str
   *          UTF-16 encoded data to decode.
   * @return string UTF-8 / ISO encoded data.
   * @access public
   * @version 0.2 / 2010-05-13
   * @author Rasmus Andersson {@link http://rasmusandersson.se/}
   * @author vadik56
   */
  public static function utf16_decode($str, $bom_be = true)
  {
    if (strlen ( $str ) < 2)
    {
      return $str;
    }
    $c0 = ord ( $str {0} );
    $c1 = ord ( $str {1} );
    if ($c0 == 0xfe && $c1 == 0xff)
    {
      $str = substr ( $str, 2 );
    }
    elseif ($c0 == 0xff && $c1 == 0xfe)
    {
      $str = substr ( $str, 2 );
      $bom_be = false;
    }
    $len = strlen ( $str );
    $newstr = '';
    for($i = 0; $i < $len; $i += 2)
    {
      if ($bom_be)
      {
        $val = ord ( $str {$i} ) << 4;
        $val += ord ( $str {$i + 1} );
      }
      else
      {
        $val = ord ( $str {$i + 1} ) << 4;
        $val += ord ( $str {$i} );
      }
      $newstr .= ($val == 0x228) ? "\n" : chr ( $val );
    }
    return $newstr;
  }
  
  /**
   * Get character count.
   * First try mbstring, then iconv, finally strlen
   *
   * @param string $value          
   * @param string $enc
   *          Encoding
   * @return int Character count
   */
  public static function CountCharacters($value, $enc = 'UTF-8')
  {
    if (self::getIsMbstringEnabled ())
    {
      return mb_strlen ( $value, $enc );
    }
    
    if (self::getIsIconvEnabled ())
    {
      return iconv_strlen ( $value, $enc );
    }
    
    // else strlen
    return strlen ( $value );
  }
  
  /**
   * Get a substring of a UTF-8 encoded string.
   * First try mbstring, then iconv, finally strlen
   *
   * @param string $pValue
   *          UTF-8 encoded string
   * @param int $pStart
   *          Start offset
   * @param int $pLength
   *          Maximum number of characters in substring
   * @return string
   */
  public static function Substring($pValue = '', $pStart = 0, $pLength = 0)
  {
    if (self::getIsMbstringEnabled ())
    {
      return mb_substr ( $pValue, $pStart, $pLength, 'UTF-8' );
    }
    
    if (self::getIsIconvEnabled ())
    {
      return iconv_substr ( $pValue, $pStart, $pLength, 'UTF-8' );
    }
    
    // else substr
    return substr ( $pValue, $pStart, $pLength );
  }
  
  /**
   * Convert a UTF-8 encoded string to upper case
   *
   * @param string $pValue
   *          UTF-8 encoded string
   * @return string
   */
  public static function StrToUpper($pValue = '')
  {
    if (function_exists ( 'mb_convert_case' ))
    {
      return mb_convert_case ( $pValue, MB_CASE_UPPER, "UTF-8" );
    }
    return strtoupper ( $pValue );
  }
  
  /**
   * Convert a UTF-8 encoded string to lower case
   *
   * @param string $pValue
   *          UTF-8 encoded string
   * @return string
   */
  public static function StrToLower($pValue = '')
  {
    if (function_exists ( 'mb_convert_case' ))
    {
      return mb_convert_case ( $pValue, MB_CASE_LOWER, "UTF-8" );
    }
    return strtolower ( $pValue );
  }
  
  /**
   * Convert a UTF-8 encoded string to title/proper case
   * (uppercase every first character in each word, lower case all other characters)
   *
   * @param string $pValue
   *          UTF-8 encoded string
   * @return string
   */
  public static function StrToTitle($pValue = '')
  {
    if (function_exists ( 'mb_convert_case' ))
    {
      return mb_convert_case ( $pValue, MB_CASE_TITLE, "UTF-8" );
    }
    return ucwords ( $pValue );
  }
  public static function mb_is_upper($char)
  {
    return mb_strtolower ( $char, "UTF-8" ) != $char;
  }
  public static function mb_str_split($string)
  {
    // Split at all position not after the start: ^
    // and not before the end: $
    return preg_split ( '/(?<!^)(?!$)/u', $string );
  }
  
  /**
   * Reverse the case of a string, so that all uppercase characters become lowercase
   * and all lowercase characters become uppercase
   *
   * @param string $pValue
   *          UTF-8 encoded string
   * @return string
   */
  public static function StrCaseReverse($pValue = '')
  {
    if (self::getIsMbstringEnabled ())
    {
      $characters = self::mb_str_split ( $pValue );
      foreach ( $characters as &$character )
      {
        if (self::mb_is_upper ( $character ))
        {
          $character = mb_strtolower ( $character, 'UTF-8' );
        }
        else
        {
          $character = mb_strtoupper ( $character, 'UTF-8' );
        }
      }
      return implode ( '', $characters );
    }
    return strtolower ( $pValue ) ^ strtoupper ( $pValue ) ^ $pValue;
  }
  
  /**
   * Identify whether a string contains a fractional numeric value,
   * and convert it to a numeric if it is
   *
   * @param
   *          string &$operand string value to test
   * @return boolean
   */
  public static function convertToNumberIfFraction(&$operand)
  {
    if (preg_match ( '/^' . self::STRING_REGEXP_FRACTION . '$/i', $operand, $match ))
    {
      $sign = ($match [1] == '-') ? '-' : '+';
      $fractionFormula = '=' . $sign . $match [2] . $sign . $match [3];
      $operand = PHPExcel_Calculation::getInstance ()->_calculateFormulaValue ( $fractionFormula );
      return true;
    }
    return false;
  } // function convertToNumberIfFraction()
  
  /**
   * Get the decimal separator.
   * If it has not yet been set explicitly, try to obtain number
   * formatting information from locale.
   *
   * @return string
   */
  public static function getDecimalSeparator()
  {
    if (! isset ( self::$decimalSeparator ))
    {
      $localeconv = localeconv ();
      self::$decimalSeparator = ($localeconv ['decimal_point'] != '') ? $localeconv ['decimal_point'] : $localeconv ['mon_decimal_point'];
      
      if (self::$decimalSeparator == '')
      {
        // Default to .
        self::$decimalSeparator = '.';
      }
    }
    return self::$decimalSeparator;
  }
  
  /**
   * Set the decimal separator.
   * Only used by PHPExcel_Style_NumberFormat::toFormattedString()
   * to format output by PHPExcel_Writer_HTML and PHPExcel_Writer_PDF
   *
   * @param string $pValue
   *          Character for decimal separator
   */
  public static function setDecimalSeparator($pValue = '.')
  {
    self::$decimalSeparator = $pValue;
  }
  
  /**
   * Get the thousands separator.
   * If it has not yet been set explicitly, try to obtain number
   * formatting information from locale.
   *
   * @return string
   */
  public static function getThousandsSeparator()
  {
    if (! isset ( self::$thousandsSeparator ))
    {
      $localeconv = localeconv ();
      self::$thousandsSeparator = ($localeconv ['thousands_sep'] != '') ? $localeconv ['thousands_sep'] : $localeconv ['mon_thousands_sep'];
      
      if (self::$thousandsSeparator == '')
      {
        // Default to .
        self::$thousandsSeparator = ',';
      }
    }
    return self::$thousandsSeparator;
  }
  
  /**
   * Set the thousands separator.
   * Only used by PHPExcel_Style_NumberFormat::toFormattedString()
   * to format output by PHPExcel_Writer_HTML and PHPExcel_Writer_PDF
   *
   * @param string $pValue
   *          Character for thousands separator
   */
  public static function setThousandsSeparator($pValue = ',')
  {
    self::$thousandsSeparator = $pValue;
  }
  
  /**
   * Get the currency code.
   * If it has not yet been set explicitly, try to obtain the
   * symbol information from locale.
   *
   * @return string
   */
  public static function getCurrencyCode()
  {
    if (! isset ( self::$currencyCode ))
    {
      $localeconv = localeconv ();
      self::$currencyCode = ($localeconv ['currency_symbol'] != '') ? $localeconv ['currency_symbol'] : $localeconv ['int_curr_symbol'];
      
      if (self::$currencyCode == '')
      {
        // Default to $
        self::$currencyCode = '$';
      }
    }
    return self::$currencyCode;
  }
  
  /**
   * Set the currency code.
   * Only used by PHPExcel_Style_NumberFormat::toFormattedString()
   * to format output by PHPExcel_Writer_HTML and PHPExcel_Writer_PDF
   *
   * @param string $pValue
   *          Character for currency code
   */
  public static function setCurrencyCode($pValue = '$')
  {
    self::$currencyCode = $pValue;
  }
  
  /**
   * Convert SYLK encoded string to UTF-8
   *
   * @param string $pValue          
   * @return string UTF-8 encoded string
   */
  public static function SYLKtoUTF8($pValue = '')
  {
    // If there is no escape character in the string there is nothing to do
    if (strpos ( $pValue, '' ) === false)
    {
      return $pValue;
    }
    
    foreach ( self::$SYLKCharacters as $k => $v )
    {
      $pValue = str_replace ( $k, $v, $pValue );
    }
    
    return $pValue;
  }
  
  /**
   * Retrieve any leading numeric part of a string, or return the full string if no leading numeric
   * (handles basic integer or float, but not exponent or non decimal)
   *
   * @param string $value          
   * @return mixed string or only the leading numeric part of the string
   */
  public static function testStringAsNumeric($value)
  {
    if (is_numeric ( $value ))
    {
      return $value;
    }
    $v = floatval ( $value );
    return (is_numeric ( substr ( $value, 0, strlen ( $v ) ) )) ? $v : $value;
  }
}
