gistfile1.php

<?php
function endc( $array ) { return end( $array ); }

$file = fopen('bitstampUSD.csv', 'r');
$firstTime = 0;
$periods = array(
//    "min5" => 300, // 5 minutes
//    "min30" => 1800, // 30 minutes
//    "hour1" => 3600, // 1 hour
//    "hour6" => 21600, // 6 hour
//    "hour12" => 43200, // 12 hour
    "day1" => 86400, // 24 hour
);
$data = array();
$first = fgetcsv($file);
foreach($periods as $periodName => $period){
    $data[$periodName] = array(
        array(
          "time"    => $first[0] - ($first[0] % $period),
          "date"    => date("Y/m/d H:i:s",$first[0] - ($first[0] % $period)),
          "open"    => $first[1],
          "close"    => $first[1],
          "min"     => $first[1],
          "max"     => $first[1],
          "volume"     => $first[2] * $first[1],
          "volume_btc"     => $first[2],
        )
    );
}

while (($line = fgetcsv($file)) !== FALSE) {
    foreach($periods as $periodName => $period){
        $last = &$data[$periodName][count($data[$periodName])-1];
        if($line[0] > ($last["time"] + $period)){
            $data[$periodName][] = array(
                "time"    => $line[0] - ($line[0] % $period),
                "date"    => date("Y/m/d H:i:s",$line[0] - ($line[0] % $period)),
                "open"    => $line[1],
                "close"    => $line[1],
                "min"     => $line[1],
                "max"     => $line[1],
                "volume"  => $line[2] * $line[1],
                "volume_btc"  => $line[2],
            );
        }else{
            $last["close"] = $line[1];
            $last["volume"] += $line[2] * $line[1];
            $last["volume_btc"] += $line[2];
            if($line[1] < $last["min"]){
                $last["min"] = $line[1];
            }elseif($line[1] > $last["max"]){
                $last["max"] = $line[1];
            }
        }
    }
}
fclose($file);