}

/**

 * \brief

 *   Detect if a point in a buffer is at a newline.

 *

 * \internal

 *   Used by school_crawl_csv_parse().

 * \param $data

 *   The buffer

 * \param $len

 *   Number of bytes in buffer.

 * \param $i

 *   The location within the buffer.

 * \param $eof

 *   The end of the buffer is the end of the file.

 * \return

 *   The location of the next character after the EOL sequence or

 *   FALSE if there is no EOL.

 */

function _school_crawl_csv_parse_eol($data, $len, $i = 0, $eof = FALSE)

{

  if ($len <= $i)

    return $eof ? $i : FALSE;

  if ($data[$i] == "\n")

    return $i + 1;

  if ($data[$i] == "\r" && $len > $i + 1 && $data[$i + 1] == "\n")

      return $i + 2;

  return FALSE;

}

/**

 * \brief

 *   Read a line of CSV and return it as an array.

 *

 * \param $data

 *   CSV data to parse. Parsed data shall be deleted.

 * \param $options

 *   An array with any number of the following optional arguments

 *   which have the documented defaults:

 *   - delimiter (','): The character which delimits fields.

 *   - eof (FALSE): Whether there will be no more data coming.

 *     Normally, if the $data ends without a newline this function

 *     will assume that it cannot assume that there is an implicit

 *     newline. Some improper files don't have the extra newline at

 *     their end and thus this is needed to support them.

 * \return

 *   An array with an entry for each line in the CSV file where each

 *   line's entry is an array of the items in that row. An empty array

 *   will be returned in the case that there is insufficient data to

 *   read a line (or insufficient data to tell if the line is

 *   complete, see $options['eof']).

 */

function school_crawl_csv_parse(&$data, array $options = array())

{

  $options += array(

    'delimiter' => ',',

    'eof' => FALSE,

  );

  $ret = array();

  $i = 0;

  $last_line_i = $i;

  $strlen_data = strlen($data);

  while ($i < $strlen_data)

    {

	$row = array();

	$quote = FALSE;

	$entry = '';

	while ($quote

	       || (_school_crawl_csv_parse_eol($data, $strlen_data, $i, $options['eof']) === FALSE))

	  {

	    /*

	     * There are two ways to read data. One within the

	     * doublequoted entry and the other outside of that.

	     */

	    if ($quote)

	      switch ($data[$i])

		{

		case '"':

		  /*

		   * This is either a lone quote or the terminating

		   * quote. It is a terminating quote if the next

		   * character is EOL or non-quote.

		   */

		  if ($strlen_data > $i + 1 && $data[$i + 1] != '"'

		      || _school_crawl_csv_parse_eol($data, $strlen_data, $i + 1, $options['eof']) !== FALSE)

		    {

		      $quote = FALSE;

		      /*

		       * can't fall-through for this case, eat the

		       * doublequote.

		       */

		      break;

		    }

		  else

		    {

		      /*

		       * We got `""' inside of a doublequoted string,

		       * which is CSV's way of escaping a

		       * doublequote. Thus, eat one of the two

		       * doublequotes.

		       */

		      $i ++;

		      /*

		       * or we don't yet have enough data... The outer

		       * loop also will break on its own in this case...

		       */

		      if ($strlen_data <= $i)

			break;

		      /* fall-through to append doublequote */

		    }

		default:

		  $entry .= $data[$i];

		}

	    else /* if ($quote) */

	      switch ($data[$i])

		{

		case '"':

		  /**

		   * \todo

		   *   Decide if we want to parse ``a,b"c",d'' as

		   *   ["a", "b\"c\"", "d"] or (current) ["a", "bc",

		   *   "d"].

		   */

		  $quote = TRUE;

		  break;

		case $options['delimiter']:

		  $row[] = $entry;

		  $entry = '';

		  break;

		default:

		  $entry .= $data[$i];

		}

	    $i ++;

	    if ($i >= $strlen_data)

	      break;

	  }

	/* Ignore read row because if we encountered end of buffer */

	if (($next_i = _school_crawl_csv_parse_eol($data, $strlen_data, $i, $options['eof'])) === FALSE)

	  break;

	$i = $next_i;

	$last_line_i = $i;

	$row[] = $entry;

	$ret[] = $row;

    }

  if (!empty($last_line_i))

    {

      $data = substr($data, $last_line_i);

      if ($data === FALSE)

	$data = '';

    }

  return $ret;

}