<?php
/**
* The string tokenizer class allows an application to break a string into tokens.
*
* @author Azeem Michael
* @example The following is one example of the use of the tokenizer. The code:
* <code>
* <?php
* $str = "this is:@\t\n a test!";
* $delim = " !@:'\t\n\0"; // remove these chars
* $st = new StringTokenizer($str, $delim);
* echo 'Total tokens: '.$st->countTokens().'<br/>';
* while ($st->hasMoreTokens()) {
* echo $st->nextToken() . '<br/>';
* }
* prints the following output:
* Total tokens: 4
* this
* is
* a
* test
* ?>
* </code>
*/
class StringTokenizer {
/** @var string
*/
private $string;
/** @var string
*/
private $token;
/** @var string
*/
private $delim;
/**
* Constructs a string tokenizer for the specified string.
* @param string $str String to tokenize
* @param string $delim The set of delimiters (the characters that separate tokens)
* specified at creation time, default to " \n\r\t\0"
*/
public function __construct($str, $delim=" \n\r\t\0") {
$this->string = $str;
$this->delim = $delim;
$this->token = strtok($str, $delim);
}
/**
* Destructor to prevent memory leaks
*/
public function __destruct() {
unset($this);
}
/**
* Calculates the number of times that this tokenizer's nextToken method can
* be called before it generates an exception
* @return int - number of tokens
*/
public function countTokens() {
$counter = 0;
while($this->hasMoreTokens()) {
$counter++;
$this->nextToken();
}
$this->token = strtok($this->string, $this->delim);
return $counter;
}
/**
* Tests if there are more tokens available from this tokenizer's string. It
* does not move the internal pointer in any way. To move the internal pointer
* to the next element call nextToken()
* @return boolean - true if has more tokens, false otherwise
*/
public function hasMoreTokens() {
return ($this->token !== false);
}
/**
* Returns the next token from this string tokenizer and advances the internal
* pointer by one.
* @return string - next element in the tokenized string
*/
public function nextToken() {
$hold = $this->token; //hold current pointer value
$this->token = strtok($this->delim); //increment pointer
return $hold; //return current pointer value
}
}
?>
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