<?php

/**
 * Validates an integer.
 * @note While this class was modeled off the CSS definition, no currently
 *       allowed CSS uses this type.  The properties that do are: widows,
 *       orphans, z-index, counter-increment, counter-reset.  Some of the
 *       HTML attributes, however, find use for a non-negative version of this.
 */
class HTMLPurifier_AttrDef_Integer extends HTMLPurifier_AttrDef {
	
	/**
	 * Whether or not negative values are allowed.
	 * @type bool
	 */
	protected $negative = true;
	
	/**
	 * Whether or not zero is allowed.
	 * @type bool
	 */
	protected $zero = true;
	
	/**
	 * Whether or not positive values are allowed.
	 * @type bool
	 */
	protected $positive = true;
	
	/**
	 *
	 * @param $negative Bool
	 *        	indicating whether or not negative values are allowed
	 * @param $zero Bool
	 *        	indicating whether or not zero is allowed
	 * @param $positive Bool
	 *        	indicating whether or not positive values are allowed
	 */
	public function __construct($negative = true, $zero = true, $positive = true) {
		$this->negative = $negative;
		$this->zero = $zero;
		$this->positive = $positive;
	}
	
	/**
	 *
	 * @param string $integer        	
	 * @param HTMLPurifier_Config $config        	
	 * @param HTMLPurifier_Context $context        	
	 * @return bool|string
	 */
	public function validate($integer, $config, $context) {
		$integer = $this->parseCDATA ( $integer );
		if ($integer === '') {
			return false;
		}
		
		// we could possibly simply typecast it to integer, but there are
		// certain fringe cases that must not return an integer.
		
		// clip leading sign
		if ($this->negative && $integer [0] === '-') {
			$digits = substr ( $integer, 1 );
			if ($digits === '0') {
				$integer = '0';
			} // rm minus sign for zero
		} elseif ($this->positive && $integer [0] === '+') {
			$digits = $integer = substr ( $integer, 1 ); // rm unnecessary plus
		} else {
			$digits = $integer;
		}
		
		// test if it's numeric
		if (! ctype_digit ( $digits )) {
			return false;
		}
		
		// perform scope tests
		if (! $this->zero && $integer == 0) {
			return false;
		}
		if (! $this->positive && $integer > 0) {
			return false;
		}
		if (! $this->negative && $integer < 0) {
			return false;
		}
		
		return $integer;
	}
}

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