/**
* Transform the supplied data.
*
* This method may transform only part of the supplied data. The return
* value includes information about how much data was actually consumed. The
* transform can be forced to consume all data by passing a boolean true as
* the $isEnd argument.
*
* The $context argument will initially be null, but any value assigned to
* this variable will persist until the stream transformation is complete.
* It can be used as a place to store state, such as a buffer.
*
* It is guaranteed that this method will be called with $isEnd = true once,
* and only once, at the end of the stream transformation.
*
* @param string $data The data to transform.
* @param mixed &$context An arbitrary context value.
* @param boolean $isEnd True if all supplied data must be transformed.
*
* @return tuple<string,integer,mixed> A 3-tuple of the transformed data, the number of bytes consumed, and any resulting error.
*/
public function transform($data, &$context, $isEnd = false)
{
if ($isEnd) {
list($output, $consumed, $error) = parent::transform(preg_replace('{[^[:alnum:]+/=]+}', '', $data), $context, true);
if (null !== $error) {
return array('', 0, new InvalidEncodedDataException('base64mime', $error->data()));
}
return array($output, strlen($data), $error);
}
$chunks = preg_split('{([^[:alnum:]+/=]+)}', $data, -1, PREG_SPLIT_OFFSET_CAPTURE);
$numChunks = count($chunks);
$buffer = '';
$output = '';
$lastFullyConsumed = -1;
$consumed = 0;
for ($i = 0; $i < $numChunks; $i++) {
$buffer .= $chunks[$i][0];
list($thisOutput, $consumed, $error) = parent::transform($buffer, $context);
$output .= $thisOutput;
if ($consumed === strlen($buffer)) {
$buffer = '';
$lastFullyConsumed = $i;
} else {
$buffer = substr($buffer, $consumed);
}
}
if ($lastFullyConsumed > -1) {
if ($lastFullyConsumed < $numChunks - 1) {
$consumed = $chunks[$lastFullyConsumed + 1][1];
} else {
$consumed = $chunks[$lastFullyConsumed][1] + strlen($chunks[$lastFullyConsumed][0]);
}
}
return array($output, $consumed, null);
}
/**
* Construct a new base64 codec.
*
* @param TransformInterface|null $encodeTransform The encode transform to use.
* @param TransformInterface|null $decodeTransform The decode transform to use.
*/
public function __construct(TransformInterface $encodeTransform = null, TransformInterface $decodeTransform = null)
{
if (null === $encodeTransform) {
$encodeTransform = Base64EncodeTransform::instance();
}
if (null === $decodeTransform) {
$decodeTransform = Base64DecodeTransform::instance();
}
parent::__construct($encodeTransform, $decodeTransform);
}
/**
* Create the transform.
*
* @return TransformInterface The data transform.
*/
protected function createTransform()
{
return Base64DecodeTransform::instance();
}
