function normalize_ipv6addr($v6addr)
{
if (strlen($v6addr) == 0) {
return null;
}
$v6str = expand_ipv6addr($v6addr);
// suppress prefix zero
$v6a = explode(":", $v6str);
foreach ($v6a as &$tmp) {
$tmp = preg_replace("/^[0]+/", "", $tmp);
if (strlen($tmp) == 0) {
$tmp = "0";
}
}
$v6str = implode(":", $v6a);
// replace first zero as "::"
$replace_flag = 1;
$found_zero = 0;
$v6a = explode(":", $v6str);
foreach ($v6a as &$tmp) {
if (strcmp($tmp, "0") == 0) {
if ($replace_flag) {
$tmp = "z";
$found_zero++;
}
} else {
if ($found_zero) {
$replace_flag = 0;
}
}
}
unset($tmp);
$v6str = implode(":", $v6a);
if ($found_zero > 1) {
$v6str = preg_replace("/(:?z:?)+/", "::", $v6str);
} else {
$v6str = preg_replace("/(z)+/", "0", $v6str);
}
return $v6str;
}
function get_ipv6network($v6addr, $mask)
{
if (strlen($v6addr) == 0) {
return null;
}
$v6str = expand_ipv6addr($v6addr);
// compute by 16bits
$v6a = explode(":", $v6str);
foreach ($v6a as &$tmp) {
if ($mask >= 16) {
$mask -= 16;
} else {
if ($mask != 0) {
$bmask = 0xffff;
$bmask <<= 16 - $mask;
$tmp = sprintf("%x", intval($tmp, 16) & $bmask);
$mask = 0;
} else {
$tmp = 0;
}
}
}
unset($tmp);
$v6str = implode(":", $v6a);
$v6str = normalize_ipv6addr($v6str);
return $v6str;
}
