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js_minify_helper.php
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Sat, Jan 31, 6:51 PM

js_minify_helper.php
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<?php
/**
* PHP implementation of Douglas Crockford's JSMin.
*
* This is a direct port of jsmin.c to PHP with a few PHP performance tweaks and
* modifications to preserve some comments (see below). Also, rather than using
* stdin/stdout, JsMinifyHelper->minify() accepts a string as input and returns
* another string as output.
*
* Comments containing IE conditional compilation are preserved, as are multi-line
* comments that begin with "/*!" (for documentation purposes). In the latter case
* newlines are inserted around the comment to enhance readability.
*
* Permission is hereby granted to use this version of the library under the
* same terms as jsmin.c, which has the following license:
*
* --
* Copyright (c) 2002 Douglas Crockford (www.crockford.com)
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
* of the Software, and to permit persons to whom the Software is furnished to do
* so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* The Software shall be used for Good, not Evil.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
* --
*
* @package JSMin
* @author Ryan Grove <ryan@wonko.com> (PHP port)
* @author Steve Clay <steve@mrclay.org> (modifications + cleanup)
* @author Andrea Giammarchi <http://www.3site.eu> (spaceBeforeRegExp)
* @author Alexander Obuhovich <aik.bold@gmail.com> (PHP4,In-Portal compatibility)
* @copyright 2002 Douglas Crockford <douglas@crockford.com> (jsmin.c)
* @copyright 2008 Ryan Grove <ryan@wonko.com> (PHP port)
* @license http://opensource.org/licenses/mit-license.php MIT License
* @link http://code.google.com/p/jsmin-php/
*/
defined('FULL_PATH') or die('restricted access!');
class JsMinifyHelper extends kHelper {
const ORD_LF = 10;
const ORD_SPACE = 32;
const ACTION_KEEP_A = 1;
const ACTION_DELETE_A = 2;
const ACTION_DELETE_A_B = 3;
protected $a = "\n";
protected $b = '';
protected $input = '';
protected $inputIndex = 0;
protected $inputLength = 0;
protected $lookAhead = null;
protected $output = '';
/**
* Perform minification, return result
*
* @param string $input
* @return string
*/
public function minify($input)
{
$this->input = str_replace("\r\n", "\n", $input);
$this->inputLength = strlen($this->input);
if ($this->output !== '') { // min already run
return $this->output;
}
$this->action(self::ACTION_DELETE_A_B);
while ($this->a !== null) {
// determine next command
$command = self::ACTION_KEEP_A; // default
if ($this->a === ' ') {
if (! $this->isAlphaNum($this->b)) {
$command = self::ACTION_DELETE_A;
}
} elseif ($this->a === "\n") {
if ($this->b === ' ') {
$command = self::ACTION_DELETE_A_B;
} elseif (false === strpos('{[(+-', $this->b)
&& ! $this->isAlphaNum($this->b)) {
$command = self::ACTION_DELETE_A;
}
} elseif (! $this->isAlphaNum($this->a)) {
if ($this->b === ' '
|| ($this->b === "\n"
&& (false === strpos('}])+-"\'', $this->a)))) {
$command = self::ACTION_DELETE_A_B;
}
}
$this->action($command);
}
$this->output = trim($this->output);
return $this->output;
}
/**
* ACTION_KEEP_A = Output A. Copy B to A. Get the next B.
* ACTION_DELETE_A = Copy B to A. Get the next B.
* ACTION_DELETE_A_B = Get the next B.
*
* @param int $command
* @return void
* @access protected
*/
protected function action($command)
{
switch ($command) {
case self::ACTION_KEEP_A:
$this->output .= $this->a;
// fallthrough
case self::ACTION_DELETE_A:
$this->a = $this->b;
if ($this->a === "'" || $this->a === '"') { // string literal
$str = $this->a; // in case needed for exception
while (true) {
$this->output .= $this->a;
$this->a = $this->get();
if ($this->a === $this->b) { // end quote
break;
}
if (ord($this->a) <= self::ORD_LF) {
throw new Exception('Unterminated String: ' . var_export($str, true));
}
$str .= $this->a;
if ($this->a === '\\') {
$this->output .= $this->a;
$this->a = $this->get();
$str .= $this->a;
}
}
}
// fallthrough
case self::ACTION_DELETE_A_B:
$this->b = $this->next();
if ($this->b === '/' && $this->isRegexpLiteral()) { // RegExp literal
$this->output .= $this->a . $this->b;
$pattern = '/'; // in case needed for exception
while (true) {
$this->a = $this->get();
$pattern .= $this->a;
if ($this->a === '/') { // end pattern
break; // while (true)
} elseif ($this->a === '\\') {
$this->output .= $this->a;
$this->a = $this->get();
$pattern .= $this->a;
} elseif (ord($this->a) <= self::ORD_LF) {
throw new Exception('Unterminated RegExp: '. var_export($pattern, true));
}
$this->output .= $this->a;
}
$this->b = $this->next();
}
// end case ACTION_DELETE_A_B
}
}
protected function isRegexpLiteral()
{
if (false !== strpos("\n{;(,=:[!&|?", $this->a)) { // we aren't dividing
return true;
}
if (' ' === $this->a) {
$length = strlen($this->output);
if ($length < 2) { // weird edge case
return true;
}
// you can't divide a keyword
if (preg_match('/(?:case|else|in|return|typeof)$/', $this->output, $m)) {
if ($this->output === $m[0]) { // odd but could happen
return true;
}
// make sure it's a keyword, not end of an identifier
$charBeforeKeyword = substr($this->output, $length - strlen($m[0]) - 1, 1);
if (! $this->isAlphaNum($charBeforeKeyword)) {
return true;
}
}
}
return false;
}
/**
* Get next char. Convert ctrl char to space.
*/
protected function get()
{
$c = $this->lookAhead;
$this->lookAhead = null;
if ($c === null) {
if ($this->inputIndex < $this->inputLength) {
$c = $this->input[$this->inputIndex];
$this->inputIndex += 1;
} else {
return null;
}
}
if ($c === "\r" || $c === "\n") {
return "\n";
}
if (ord($c) < self::ORD_SPACE) { // control char
return ' ';
}
return $c;
}
/**
* Get next char. If is ctrl character, translate to a space or newline.
*/
protected function peek()
{
$this->lookAhead = $this->get();
return $this->lookAhead;
}
/**
* Is $c a letter, digit, underscore, dollar sign, escape, or non-ASCII?
*
* @param string $c
* @return bool
* @access protected
*/
protected function isAlphaNum($c)
{
return (preg_match('/^[0-9a-zA-Z_\\$\\\\]$/', $c) || ord($c) > 126);
}
protected function singleLineComment()
{
$comment = '';
while (true) {
$get = $this->get();
$comment .= $get;
if (ord($get) <= self::ORD_LF) { // EOL reached
// if IE conditional comment
if (preg_match('/^\\/@(?:cc_on|if|elif|else|end)\\b/', $comment)) {
return "/{$comment}";
}
return $get;
}
}
return '';
}
protected function multipleLineComment()
{
$this->get();
$comment = '';
while (true) {
$get = $this->get();
if ($get === '*') {
if ($this->peek() === '/') { // end of comment reached
$this->get();
// if comment preserved by YUI Compressor
if (0 === strpos($comment, '!')) {
return "\n/*" . substr($comment, 1) . "*/\n";
}
// if IE conditional comment
if (preg_match('/^@(?:cc_on|if|elif|else|end)\\b/', $comment)) {
return "/*{$comment}*/";
}
return ' ';
}
} elseif ($get === null) {
throw new Exception('Unterminated Comment: ' . var_export('/*' . $comment, true));
}
$comment .= $get;
}
return '';
}
/**
* Get the next character, skipping over comments.
* Some comments may be preserved.
*/
protected function next()
{
$get = $this->get();
if ($get !== '/') {
return $get;
}
switch ($this->peek()) {
case '/': return $this->singleLineComment();
case '*': return $this->multipleLineComment();
default: return $get;
}
}
}

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