<?php
namespace JBBCode;
/**
* This Tokenizer is used while constructing the parse tree. The tokenizer
* handles splitting the input into brackets and miscellaneous text. The
* parser is then built as a FSM ontop of these possible inputs.
*
* @author jbowens
*/
class Tokenizer
{
/** @var integer[] the positions of tokens found during parsing */
protected $tokens = array();
/** @var integer the number of the current token */
protected $i = -1;
/**
* Constructs a tokenizer from the given string. The string will be tokenized
* upon construction.
*
* @param string $str the string to tokenize
*/
public function __construct($str)
{
$strLen = strlen($str);
$position = 0;
while ($position < $strLen) {
$offset = strcspn($str, '[]', $position);
//Have we hit a single ']' or '['?
if ($offset == 0) {
$this->tokens[] = $str[$position];
$position++;
} else {
$this->tokens[] = substr($str, $position, $offset);
$position += $offset;
}
}
}
/**
* Returns true if there is another token in the token stream.
* @return boolean
*/
public function hasNext()
{
return isset($this->tokens[$this->i + 1]);
}
/**
* Advances the token stream to the next token and returns the new token.
* @return null|string
*/
public function next()
{
if (!$this->hasNext()) {
return null;
} else {
return $this->tokens[++$this->i];
}
}
/**
* Retrieves the current token.
* @return null|string
*/
public function current()
{
if ($this->i < 0) {
return null;
} else {
return $this->tokens[$this->i];
}
}
/**
* Moves the token stream back a token.
*/
public function stepBack()
{
if ($this->i > -1) {
$this->i--;
}
}
/**
* Restarts the tokenizer, returning to the beginning of the token stream.
*/
public function restart()
{
$this->i = -1;
}
/**
* toString method that returns the entire string from the current index on.
* @return string
*/
public function toString()
{
return implode('', array_slice($this->tokens, $this->i + 1));
}
}