<?php
/**
 * JSMin.php - modified PHP implementation of Douglas Crockford's JSMin.
 *
 * <code>
 * $minifiedJs = JSMin::minify($js);
 * </code>
 *
 * This is a modified port of jsmin.c. Improvements:
 *
 * Does not choke on some regexp literals containing quote characters. E.g. /'/
 *
 * Spaces are preserved after some add/sub operators, so they are not mistakenly
 * converted to post-inc/dec. E.g. a + ++b -> a+ ++b
 *
 * Preserves multi-line comments that begin with /*!
 *
 * PHP 5 or higher is required.
 *
 * 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)
 * @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/
 */

class JSMin {
 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 = '';
 protected $lastByteOut = '';
 protected $keptComment = '';

 /**
 * Minify Javascript.
 *
 * @param string $js Javascript to be minified
 *
 * @return string
 */
 public static function minify($js)
 {
 $jsmin = new JSMin($js);
 return $jsmin->min();
 }

 /**
 * @param string $input
 */
 public function __construct($input)
 {
 $this->input = $input;
 }

 /**
 * Perform minification, return result
 *
 * @return string
 */
 public function min()
 {
 if ($this->output !== '') { // min already run
 return $this->output;
 }

 $mbIntEnc = null;
 if (function_exists('mb_strlen') && ((int)ini_get('mbstring.func_overload') & 2)) {
 $mbIntEnc = mb_internal_encoding();
 mb_internal_encoding('8bit');
 }
 $this->input = str_replace("\r\n", "\n", $this->input);
 $this->inputLength = strlen($this->input);

 $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->lastByteOut === '+' || $this->lastByteOut === '-')
 && ($this->b === $this->lastByteOut)) {
 // Don't delete this space. If we do, the addition/subtraction
 // could be parsed as a post-increment
 } elseif (! $this->isAlphaNum($this->b)) {
 $command = self::ACTION_DELETE_A;
 }
 } elseif ($this->a === "\n") {
 if ($this->b === ' ') {
 $command = self::ACTION_DELETE_A_B;

 // in case of mbstring.func_overload & 2, must check for null b,
 // otherwise mb_strpos will give WARNING
 } elseif ($this->b === null
 || (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);

 if ($mbIntEnc !== null) {
 mb_internal_encoding($mbIntEnc);
 }
 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 $command
 * @throws JSMin_UnterminatedRegExpException|JSMin_UnterminatedStringException
 */
 protected function action($command)
 {
 // make sure we don't compress "a + ++b" to "a+++b", etc.
 if ($command === self::ACTION_DELETE_A_B
 && $this->b === ' '
 && ($this->a === '+' || $this->a === '-')) {
 // Note: we're at an addition/substraction operator; the inputIndex
 // will certainly be a valid index
 if ($this->input[$this->inputIndex] === $this->a) {
 // This is "+ +" or "- -". Don't delete the space.
 $command = self::ACTION_KEEP_A;
 }
 }

 switch ($command) {
 case self::ACTION_KEEP_A: // 1
 $this->output .= $this->a;

 if ($this->keptComment) {
 $this->output = rtrim($this->output, "\n");
 $this->output .= $this->keptComment;
 $this->keptComment = '';
 }

 $this->lastByteOut = $this->a;

 // fallthrough intentional
 case self::ACTION_DELETE_A: // 2
 $this->a = $this->b;
 if ($this->a === "'" || $this->a === '"') { // string literal
 $str = $this->a; // in case needed for exception
 for(;;) {
 $this->output .= $this->a;
 $this->lastByteOut = $this->a;

 $this->a = $this->get();
 if ($this->a === $this->b) { // end quote
 break;
 }
 if ($this->isEOF($this->a)) {
 throw new JSMin_UnterminatedStringException(
 "JSMin: Unterminated String at byte {$this->inputIndex}: {$str}");
 }
 $str .= $this->a;
 if ($this->a === '\\') {
 $this->output .= $this->a;
 $this->lastByteOut = $this->a;

 $this->a = $this->get();
 $str .= $this->a;
 }
 }
 }

 // fallthrough intentional
 case self::ACTION_DELETE_A_B: // 3
 $this->b = $this->next();
 if ($this->b === '/' && $this->isRegexpLiteral()) {
 $this->output .= $this->a . $this->b;
 $pattern = '/'; // keep entire pattern in case we need to report it in the exception
 for(;;) {
 $this->a = $this->get();
 $pattern .= $this->a;
 if ($this->a === '[') {
 for(;;) {
 $this->output .= $this->a;
 $this->a = $this->get();
 $pattern .= $this->a;
 if ($this->a === ']') {
 break;
 }
 if ($this->a === '\\') {
 $this->output .= $this->a;
 $this->a = $this->get();
 $pattern .= $this->a;
 }
 if ($this->isEOF($this->a)) {
 throw new JSMin_UnterminatedRegExpException(
 "JSMin: Unterminated set in RegExp at byte "
 . $this->inputIndex .": {$pattern}");
 }
 }
 }

 if ($this->a === '/') { // end pattern
 break; // while (true)
 } elseif ($this->a === '\\') {
 $this->output .= $this->a;
 $this->a = $this->get();
 $pattern .= $this->a;
 } elseif ($this->isEOF($this->a)) {
 throw new JSMin_UnterminatedRegExpException(
 "JSMin: Unterminated RegExp at byte {$this->inputIndex}: {$pattern}");
 }
 $this->output .= $this->a;
 $this->lastByteOut = $this->a;
 }
 $this->b = $this->next();
 }
 // end case ACTION_DELETE_A_B
 }
 }

 /**
 * @return bool
 */
 protected function isRegexpLiteral()
 {
 if (false !== strpos("(,=:[!&|?+-~*{;", $this->a)) {
 // we obviously aren't dividing
 return true;
 }
 if ($this->a === ' ' || $this->a === "\n") {
 $length = strlen($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;
 }

 /**
 * Return the next character from stdin. Watch out for lookahead. If the character is a control character,
 * translate it to a space or linefeed.
 *
 * @return string
 */
 protected function get()
 {
 $c = $this->lookAhead;
 $this->lookAhead = null;
 if ($c === null) {
 // getc(stdin)
 if ($this->inputIndex < $this->inputLength) {
 $c = $this->input[$this->inputIndex];
 $this->inputIndex += 1;
 } else {
 $c = null;
 }
 }
 if (ord($c) >= self::ORD_SPACE || $c === "\n" || $c === null) {
 return $c;
 }
 if ($c === "\r") {
 return "\n";
 }
 return ' ';
 }

 /**
 * Does $a indicate end of input?
 *
 * @param string $a
 * @return bool
 */
 protected function isEOF($a)
 {
 return ord($a) <= self::ORD_LF;
 }

 /**
 * Get next char (without getting it). If is ctrl character, translate to a space or newline.
 *
 * @return string
 */
 protected function peek()
 {
 $this->lookAhead = $this->get();
 return $this->lookAhead;
 }

 /**
 * Return true if the character is a letter, digit, underscore, dollar sign, or non-ASCII character.
 *
 * @param string $c
 *
 * @return bool
 */
 protected function isAlphaNum($c)
 {
 return (preg_match('/^[a-z0-9A-Z_\\$\\\\]$/', $c) || ord($c) > 126);
 }

 /**
 * Consume a single line comment from input (possibly retaining it)
 */
 protected function consumeSingleLineComment()
 {
 $comment = '';
 while (true) {
 $get = $this->get();
 $comment .= $get;
 if (ord($get) <= self::ORD_LF) { // end of line reached
 // if IE conditional comment
 if (preg_match('/^\\/@(?:cc_on|if|elif|else|end)\\b/', $comment)) {
 $this->keptComment .= "/{$comment}";
 }
 return;
 }
 }
 }

 /**
 * Consume a multiple line comment from input (possibly retaining it)
 *
 * @throws JSMin_UnterminatedCommentException
 */
 protected function consumeMultipleLineComment()
 {
 $this->get();
 $comment = '';
 for(;;) {
 $get = $this->get();
 if ($get === '*') {
 if ($this->peek() === '/') { // end of comment reached
 $this->get();
 if (0 === strpos($comment, '!')) {
 // preserved by YUI Compressor
 if (!$this->keptComment) {
 // don't prepend a newline if two comments right after one another
 $this->keptComment = "\n";
 }
 $this->keptComment .= "/*!" . substr($comment, 1) . "*/\n";
 } else if (preg_match('/^@(?:cc_on|if|elif|else|end)\\b/', $comment)) {
 // IE conditional
 $this->keptComment .= "/*{$comment}*/";
 }
 return;
 }
 } elseif ($get === null) {
 throw new JSMin_UnterminatedCommentException(
 "JSMin: Unterminated comment at byte {$this->inputIndex}: /*{$comment}");
 }
 $comment .= $get;
 }
 }

 /**
 * Get the next character, skipping over comments. Some comments may be preserved.
 *
 * @return string
 */
 protected function next()
 {
 $get = $this->get();
 if ($get === '/') {
 switch ($this->peek()) {
 case '/':
 $this->consumeSingleLineComment();
 $get = "\n";
 break;
 case '*':
 $this->consumeMultipleLineComment();
 $get = ' ';
 break;
 }
 }
 return $get;
 }
}

class JSMin_UnterminatedStringException extends Exception {}
class JSMin_UnterminatedCommentException extends Exception {}
class JSMin_UnterminatedRegExpException extends Exception {}