php一些公用函数的集合

　　/*获得客户端ip地址*/
functiongetIP(){
if(getenv(HTTP_CLIENT_IP)&&strcasecmp(getenv(HTTP_CLIENT_IP),unknown)){
$ip=getenv(HTTP_CLIENT_IP);
}
elseif(getenv(HTTP_X_FORWARDED_FOR)&&strcasecmp(getenv(HTTP_X_FORWARDED_FOR),unknown)){
$ip=getenv(HTTP_X_FORWARDED_FOR);
}
elseif(getenv(REMOTE_ADDR)&&strcasecmp(getenv(REMOTE_ADDR),unknown)){
$ip=getenv(REMOTE_ADDR);
}
elseif(isset($_SERVER[REMOTE_ADDR])&&$_SERVER[REMOTE_ADDR]&&strcasecmp($_SERVER[REMOTE_ADDR],unknown)){
$ip=$_SERVER[REMOTE_ADDR];
}
else{
$ip=unknown;
}

return($ip);
}

/*验证IP地址函数*/
functioncheckIP($ip){
returnpreg_match((2[0-4]\d25[0-5][01]?\d\d?)\.){3}(2[0-4]\d25[0-5][01]?\d\d?);
}

/*用户输入内容过滤函数*/
functiongetStr($str){
$tmpstr=trim($str);
$tmpstr=strip_tags($tmpstr);
$tmpstr=htmlspecialchars($tmpstr);

/*加入字符转义*/
$tmpstr=addslashes($tmpstr);

return$tmpstr;
}

/*容量大小计算函数*/
functionsizecount($filesize){
if($filesize>=1073741824){
$filesize=round($filesize/1073741824*100)/100.G;
}elseif($filesize>=1048576){
$filesize=round($filesize/1048576*100)/100.M;
}elseif($filesize>=1024){
$filesize=round($filesize/1024*100)/100.K;
}else{
$filesize=$filesize.bytes;
}
return$filesize;
}

/*简单防SQL注入函数*/
functiongetSQL($feild){
$tmpfeild=mysql_escape_string($feild);

return$tmpfeild;
}
/*$num必须为英文字符或数字0-9*/
functiongetNums($num){
return(ctype_alnum($num));
}

/*$char必须为英文字符*/
functiongetChar($char){
return(ctype_alpha($char));
}
/*匹配qq(5-12)位*/
functiongetQQ($qq){
returnpreg_match(/^\b[0-9]{5,12}\b/,$qq);
}
/*匹配电子邮件地址*/
functiongetEmail($email){
returnstrlen($email)>6&&preg_match(/^\w+@(\w+\.)+[com][cn]$/,$email);
//preg_match(/^[\w\-\.]+@[\w\-\.]+(\.\w+)+$/,$email);
}

/*生成email连接*/
functionemailconv($email,$tolink=1){
$email=str_replace(array(@,.),array(@,.),$email);
return$tolink?<ahref=mailto:.$email.>.$email.</a>:$email;
}

/*检查ip是否被允许访问*/
functionipaccess($ip,$accesslist){
returnpreg_match(/^(.str_replace(array(\r\n,),array(,),preg_quote($accesslist,/)).)/,$ip);
}

/*若标题过长，此函数可显示前几个字符，剩余字符用...代替*/
functioncutstr($string,$length){
if(strlen($string)>$length){
for($i=0;$i<$length-3;$i++){
/*返回字符的序数值*/
$strcut.=ord($string[$i])>127?$string[$i].$string[++$i]:$string[$i];
}
return$strcut....;
}else{
return$string;
}
}