/**
* Reads a token from the context
*
* @param pdf_context $c
* @return mixed
*/
protected function _readToken($c)
{
// If there is a token available
// on the stack, pop it out and
// return it.
if (count($c->stack)) {
return array_pop($c->stack);
}
// Strip away any whitespace
do {
if (!$c->ensureContent()) {
return false;
}
$c->offset += strspn($c->buffer, " \n\f\r\t", $c->offset);
} while ($c->offset >= $c->length - 1);
// Get the first character in the stream
$char = $c->buffer[$c->offset++];
switch ($char) {
case '[':
case ']':
case '(':
case ')':
// This is either an array or literal string
// delimiter, Return it
return $char;
case '<':
case '>':
// This could either be a hex string or
// dictionary delimiter. Determine the
// appropriate case and return the token
if ($c->buffer[$c->offset] == $char) {
if (!$c->ensureContent()) {
return false;
}
$c->offset++;
return $char . $char;
} else {
return $char;
}
case '%':
// This is a comment - jump over it!
$pos = $c->offset;
while (1) {
$match = preg_match("/(\r\n|\r|\n)/", $c->buffer, $m, PREG_OFFSET_CAPTURE, $pos);
if ($match === 0) {
if (!$c->increaseLength()) {
return false;
} else {
continue;
}
}
$c->offset = $m[0][1] + strlen($m[0][0]);
return $this->_readToken($c);
}
default:
// This is "another" type of token (probably
// a dictionary entry or a numeric value)
// Find the end and return it.
if (!$c->ensureContent()) {
return false;
}
while (1) {
// Determine the length of the token
$pos = strcspn($c->buffer, " %[]<>()/\n\f\r\t", $c->offset);
if ($c->offset + $pos <= $c->length - 1) {
break;
} else {
// If the script reaches this point,
// the token may span beyond the end
// of the current buffer. Therefore,
// we increase the size of the buffer
// and try again--just to be safe.
$c->increaseLength();
}
}
$result = substr($c->buffer, $c->offset - 1, $pos + 1);
$c->offset += $pos;
return $result;
}
}
