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<?php
/**
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @file
*/
/**
* An iterator which works exactly like:
*
* foreach ( explode( $delim, $s ) as $element ) {
* ...
* }
*
* Except it doesn't use 193 byte per element
*/
class ExplodeIterator implements Iterator {
// The subject string
private $subject, $subjectLength;
// The delimiter
private $delim, $delimLength;
// The position of the start of the line
private $curPos;
// The position after the end of the next delimiter
private $endPos;
/** @var string|false The current token */
private $current;
/**
* Construct a DelimIterator
* @param string $delim
* @param string $subject
*/
public function __construct( $delim, $subject ) {
$this->subject = $subject;
$this->delim = $delim;
// Micro-optimisation (theoretical)
$this->subjectLength = strlen( $subject );
$this->delimLength = strlen( $delim );
$this->rewind();
}
public function rewind() {
$this->curPos = 0;
$this->endPos = strpos( $this->subject, $this->delim );
$this->refreshCurrent();
}
public function refreshCurrent() {
if ( $this->curPos === false ) {
$this->current = false;
} elseif ( $this->curPos >= $this->subjectLength ) {
$this->current = '';
} elseif ( $this->endPos === false ) {
$this->current = substr( $this->subject, $this->curPos );
} else {
$this->current = substr( $this->subject, $this->curPos, $this->endPos - $this->curPos );
}
}
public function current() {
return $this->current;
}
/**
* @return int|bool Current position or boolean false if invalid
*/
public function key() {
return $this->curPos;
}
/**
* @return string
*/
public function next() {
if ( $this->endPos === false ) {
$this->curPos = false;
} else {
$this->curPos = $this->endPos + $this->delimLength;
if ( $this->curPos >= $this->subjectLength ) {
$this->endPos = false;
} else {
$this->endPos = strpos( $this->subject, $this->delim, $this->curPos );
}
}
$this->refreshCurrent();
return $this->current;
}
/**
* @return bool
*/
public function valid() {
return $this->curPos !== false;
}
}
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