PHP文件去掉PHP注释空格的函数分析(PHP代码压缩)

function strip_whitespace($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;
                default:
                    $last_space = false;
                    $stripStr .= $tokens[$i][1];
            }
        }
    }
    return $stripStr;
}

$str = strip_whitespace('<?php'.$str);