php - 去除php代码中的多余空格

<?php
class Test{
    public function test(){
        $tmplContent = file_get_contents('./test.php');
        $tmplContent = str_replace('?><?php','',$tmplContent);
        echo $this->stripWhitespace($tmplContent);
    }

    /**
     * 去除代码中的空白和注释
     * @param string $content 代码内容
     * @return string
     */
    private static function stripWhitespace($content) {
        $stripStr   = '';
        //分析php源码
        $tokens     = token_get_all($content);
        $last_space = false;
        for ($i = 0, $j = count($tokens); $i < $j; $i++) {
            if (is_string($tokens[$i])) {
                $last_space = false;
                $stripStr  .= $tokens[$i];
            } else {
                switch ($tokens[$i][0]) {
                    //过滤各种PHP注释
                    case T_COMMENT:
                    case T_DOC_COMMENT:
                        break;
                        //过滤空格
                    case T_WHITESPACE:
                        if (!$last_space) {
                            $stripStr  .= ' ';
                            $last_space = true;
                        }
                        break;
                    case T_START_HEREDOC:
                        $stripStr .= "<<<DOCLABEL\n";
                        break;
                    case T_END_HEREDOC:
                        $stripStr .= "DOCLABEL;\n";
                        for($k = $i+1; $k < $j; $k++) {
                            if(is_string($tokens[$k]) && $tokens[$k] == ';') {
                                $i = $k;
                                break;
                            } else if($tokens[$k][0] == T_CLOSE_TAG) {
                                break;
                            }
                        }
                        break;
                    default:
                        $last_space = false;
                        $stripStr  .= $tokens[$i][1];
                }
            }
        }
        return $stripStr;
    }
}