SimplePie_IRI::remove_dot_segments

			// A: If the input buffer begins with a prefix of "../" or "./", then remove that prefix from the input buffer; otherwise,
			if (strpos($input, '../') === 0)
			{
				$input = substr($input, 3);
			}
			elseif (strpos($input, './') === 0)
			{
				$input = substr($input, 2);
			}
			// B: if the input buffer begins with a prefix of "/./" or "/.", where "." is a complete path segment, then replace that prefix with "/" in the input buffer; otherwise,
			elseif (strpos($input, '/./') === 0)
			{
				$input = substr($input, 2);
			}
			elseif ($input === '/.')
			{
				$input = '/';
			}
			// C: if the input buffer begins with a prefix of "/../" or "/..", where ".." is a complete path segment, then replace that prefix with "/" in the input buffer and remove the last segment and its preceding "/" (if any) from the output buffer; otherwise,
			elseif (strpos($input, '/../') === 0)
			{
				$input = substr($input, 3);
				$output = substr_replace($output, '', strrpos($output, '/'));
			}
			elseif ($input === '/..')
			{
				$input = '/';
				$output = substr_replace($output, '', strrpos($output, '/'));
			}
			// D: if the input buffer consists only of "." or "..", then remove that from the input buffer; otherwise,
			elseif ($input === '.' || $input === '..')
			{
				$input = '';
			}
			// E: move the first path segment in the input buffer to the end of the output buffer, including the initial "/" character (if any) and any subsequent characters up to, but not including, the next "/" character or the end of the input buffer
			elseif (($pos = strpos($input, '/', 1)) !== false)
			{
				$output .= substr($input, 0, $pos);
				$input = substr_replace($input, '', 0, $pos);
			}
			else
			{
				$output .= $input;
				$input = '';
			}
		}
		return $output . $input;
	}

	/**
	 * Replace invalid character with percent encoding
	 *
	 * @param string $string Input string