<?php
/**
 * Buffer class for a string.
 * Will fix issues with sockets that don't care about linebreaks.
 * Can also be used for all kinds of purpose.
 * @author jpt
 * @package Misc
 */
class Misc_Buffer {

	/**
	 * Bufferstring - contains all the data.
	 * @var string
	 */
	protected $buffer;

	/**
	 * Linebreak to use for pulling lines out of the buffer.
	 * @var string
	 */
	protected $linebreak;

	/**
	 * Default constructor. Sets a default linebreak and initializes the buffer.
	 * @param $linebreak
	 * @return void
	 */
	public function __construct($linebreak = "") {
		$this->buffer = "";
		$this->linebreak = $linebreak;
	}

	/**
	 * Prunes empty lines out of the buffer.
	 * @return void
	 */
	protected function pruneEmptyLines() {
			//no need to do this when there are no linebreaks.
		if($this->linebreak === "") return;
		if(strpos($this->buffer, $this->linebreak) === FALSE) return;
		$hasLinebreakAtEnd = (substr($this->buffer, (-1) * strlen($this->linebreak)) === $this->linebreak) ? TRUE : FALSE;
		$lines = explode($this->linebreak, $this->buffer);
		foreach($lines AS $key=>$line) {
			$line = str_replace($this->linebreak, "", $line);
			$line = trim($line);
			if($line === "") unset($lines[$key]);
		}
		$this->buffer = implode($this->linebreak, $lines);
		if($hasLinebreakAtEnd === TRUE) $this->buffer .= $this->linebreak;
	}

	/**
	 * Appends data to the buffer.
	 * @param string $data
	 * @return void
	 */
	public function addData($data) {
		$this->buffer .= $data;
		$this->pruneEmptyLines();
	}

	/**
	 * Returns the next line in the buffer and removes it from the buffer.
	 * @return string
	 * @throws Exception_GeneralException
	 */
	public function getNextLine() {
		if($this->linebreak === "") throw new Exception_GeneralException("Cannot return a line - no linebreak is set!", 1290964174);
		if(!$this->hasLines()) return "";
		list($line) = explode($this->linebreak, $this->buffer);
		$this->buffer = str_replace($line.$this->linebreak, "", $this->buffer);
		$line = trim($line);
		$result = ($line !== "") ? $line.$this->linebreak : "";
		return $result;
	}

	/**
	 * Returns the length of the buffer.
	 * @return int
	 */
	public function getBufferLength() {
		return strlen($this->buffer);
	}

	/**
	 * Returns the next $length chars from the buffer or throws an exception if this cannot be done.
	 * @throws Exception_GeneralException
	 * @return string
	 */
	public function getNextChars($length) {
		if(strlen($this->buffer) < $length) throw new Exception_GeneralException("Cannot return ".$length." chars, there are only ".strlen($this->buffer)." chars left!", 1292780386);
		$data = substr($this->buffer, 0, $length);
		$this->buffer = substr($this->buffer, $length);
		return $data;
	}

	/**
	 * Checks whether the buffer contains more lines to process.
	 * @return boolean
	 * @throws Exception_GeneralException
	 */
	public function hasLines() {
		if($this->linebreak === "") throw new Exception_GeneralException("Cannot tell whether the buffer has lines - no linebreak set!", 1290964243);
		return (trim(strstr($this->buffer, $this->linebreak, TRUE)) !== "") ? TRUE : FALSE;
	}

	/**
	 * Returns TRUE when there is data in the buffer.
	 * @return boolean
	 */
	public function hasData() {
		return (strlen($this->buffer) > 0) ? TRUE : FALSE;
	}

	/**
	 * Returns the full buffer contents.
	 * Also truncates the buffer.
	 * @return string
	 */
	public function getAllBufferContents() {
		$return = $this->buffer;
		$this->buffer = "";
		return $return;
	}

}
?>