function find($fl, $val, $field, $fieldLen)
{
$Len=156;
$numFields=100000;
if(!($f = fopen($fl, "rb")))die();
flock ($f,LOCK_SH);
$buf='';
for($s=0; $s<$numFields; ++$s)
{
fseek($f, $s*$Len+$field, SEEK_SET);
$buf=fread($f, $fieldLen);
if(strcmp($buf, $val)==0)
{
flock ($f,LOCK_UN);
fclose($f);
return true;
}
}
flock ($f,LOCK_UN);
fclose($f);
return false;
}

function DbFindRecord($fl, $login, $recordLen, $numRecords)
{
global $dbLastFind;
if(!($f = fopen($fl, "rb")))die();
flock ($f,LOCK_SH);
$low = 0; $mid=0; $midval=''; $ind=0; $c=0;
$high = $numRecords-1;
while($low <= $high)
{
$mid = (int)($low + (($high - $low) / 2));
$ind = (int)($mid*$recordLen);
fseek($f, $ind, SEEK_SET);
$midVal = fread( $f, 2);
$c=strcmp($midVal, $login);
if ( $c < 0)
{$low = $mid + 1;}
else if ($c > 0)
{$high = $mid - 1;}
else
{
flock ($f,LOCK_UN);
fclose($f);
$dbLastFind=$ind;
return $ind;
}
}
$dbLastFind=$ind;
flock ($f,LOCK_UN);
fclose($f);
return -1;
}