recurser

I recently had to write a PHP CSV parser for a project, and found the built-in fgetcsv function fairly useless for real-world CSVs (where some fields are quoted and some aren’t for example, or where escaped delimiters or quotes are present inside the field text). This function should handle :

• Lines where some fields are quoted and some aren’t
• Lines where quoted fields have ‘escaped’ quotes inside them
• Lines where non-quoted fields have ‘escaped’ delimiters inside them
• Lines where the quote is ‘escaped’ by another quote (the default behaviour for Excel CSV exports)

• Lines containing multi-byte strings

  /**
   * Split a line from a CSV file into fields. Should handle various field
   * delimiters, escape characters and enclosing quotes for fields
   *
   * @param string $line Line to split for the CSV
   * @param string $delimiter Field delimiter (defaults to ',')
   * @param string $escaper Field escaper (defaults to '\')
   * @param string $encloser Field encloser (defaults to '"')
   */
      function splitCsvLine($line, $delimiter=',', $encloser='"', $escaper='\\') {
                              
          $fields = array();               
          if (is_string($delimiter) && is_string($encloser)) :
              
              // Make sure the arguments are regex-safe 
              $reg_safe_delimiter = '\x' . dechex(ord($delimiter));
              $reg_safe_encloser = '\x' . dechex(ord($encloser));
              $reg_safe_escaper = '\x' . dechex(ord($escaper));
          
              $line = trim($line);
              
              // Replace any 'quote-escaped' quotes within fields. This is only really necessary to 
              // handle excel exports, which often escape double quotes with double quotes. 
              if ($encloser == $escaper) :
                  $line = mb_ereg_replace($reg_safe_escaper . $reg_safe_encloser, "__ESCAPED__ENCLOSER__", $line);
              endif;
              
              // Loop over the string and extract each field       
              $field_num = 0;
              while(mb_strlen($line) > 0) :
                  if(mb_substr($line, 0, 1) == $encloser) :
                  
                      // If this string starts with an encloser, look for the next (non-escaped) encloser
                      preg_match('/^' . $reg_safe_encloser . '((?:[^' . $reg_safe_encloser . 
                                  ']|(?<='.$reg_safe_escaper.')' . $reg_safe_encloser . 
                                  ')*)' . $reg_safe_encloser . $reg_safe_delimiter . 
                                  '?(.*)$/', $line, $matches);
                      $value = mb_ereg_replace($reg_safe_escaper . $reg_safe_encloser, $encloser, $matches[1]);
                      $line = trim($matches[2]);                   
                      $fields[$field_num++] = $value;
                      
                  // Otherwise, look for the next (non-escaped) delimiter
                  else :
                      preg_match('/^((?:[^' . $reg_safe_delimiter . 
                                  ']|(?<='.$reg_safe_escaper.')' . $reg_safe_delimiter . 
                                  ')*)' . $reg_safe_delimiter . 
                                  '?(.*)$/', $line, $matches);                   
                      $value = mb_ereg_replace($reg_safe_escaper . $reg_safe_delimiter, $delimiter, $matches[1]);
                      $line = trim($matches[2]);
                      $fields[$field_num++] = $value;
                  endif;
              endwhile;
         
              if ($encloser == $escaper) :
                  for ($i=0; $i<count($fields); $i++) :    
                      $fields[$i] = mb_ereg_replace("__ESCAPED__ENCLOSER__", $encloser, $fields[$i]);
                  endfor;
              endif;
          endif;
              
          return $fields;
      }