helper.php

<?php
$KMPERMILE = "1.609344"; // must be a string or locale may turn this into a comma!

$modes = array ("F" => "Flight", "T" => "Train", "S" => "Ship", "R" => "Road trip");
$modeOperators = array ("F" => "airline", "T" => "railway", "S" => "shipping company", "R" => "road transport company");

//
// End with JSON-formatted data, localized message and a successful status
//
function json_success($data) {
  $data["status"] = 1;
  $data["message"] = _($data["message"]);
  die(json_encode($data));
}

//
// Abort with a JSON-formatted localized error message
//
function json_error($msg, $detail='') {
  die (json_encode(array("status" => 0, "message" => _($msg) . ' ' . $detail)));
}

//
// Return a quoted string or NULL if empty
//
function null_if_empty($str) {
  return($str == "" ? "NULL" : "'" . mysql_real_escape_string($str) . "'");
}

//
// Standard formatting of airport data
// Input: row: associative array containing iata, icao
// Output: " code : apid : x : y : timezone : dstrule "
//
function format_apdata($row) {
  return sprintf ("%s:%s:%s:%s:%s:%s", format_apcode($row), $row["apid"], $row["x"], $row["y"], $row["timezone"], $row["dst"]);
}

//
// Standard formatting of airport codes
// row: associative array containing iata, icao
//
function format_apcode($row) {
  return format_apcode2($row["iata"], $row["icao"]);
}

function format_apcode2($iata, $icao) {
  $code = $iata;
  if(! $code || $code == "N/A") {
    $code = $icao;
    if(! $code) {
      $code = "Priv";
    }
  }
  return $code;
}

//
// Standard formatting of airport names
// row: associative array containing name, city, country/code and iata/icao
//
function format_airport($row) {
  $name = $row["name"];
  $city = $row["city"];
  $country = $row["country"];
  if(array_key_exists("code", $row)) {
    $country = $code; // hack for DAFIF
  }
  $iata = format_apcode($row);

  // Foobar-Foobar Intl into Foobar Intl
  // Foo-bar-Foo Bar Intl into Foo Bar Intl
  if(strncasecmp(strtr($name, "-", " "), strtr($city, "-", " "), strlen($city)) == 0) {
    $city = "";
  } else {
    $city = $city . "-";
  }
  if(strlen($city . $name . $country) > 40) {
    $name = trim(substr($city . $name, 0, 39 - strlen($country))) . ".";
    $city = "";
  }

  return $city . $name . " (" . $iata . "), " . $country;
}

//
// Standard formatting of airline names
// row: associative array containing name, iata, icao and (optionally) mode
//
function format_airline($row) {
  $mode = $row["mode"];
  if($mode && $mode != "F") {
    // Not an airline
    return $row["name"];
  } else {
    return $row["name"] . " (" . format_alcode($row["iata"], $row["icao"], $row["mode"]) . ")";
  }
}

function format_alcode($iata, $icao, $mode) {
  if($mode && $mode != "F") return "";
  if($iata && $iata != "") {
    return $iata;
  } else {
    if($icao && $icao != "") {
      return $icao;
    } else {
      return "Priv";
    }
  }
}  

// Calculate (distance, duration) between two airport IDs
function gcDistance($db, $src_apid, $dst_apid) {
  // Special case: loop flight to/from same airport
  if($src_apid == $dst_apid) {
    $dist = 0;
  } else {
    $sql = "SELECT x,y FROM airports WHERE apid=$src_apid OR apid=$dst_apid";

    // Handle both OO and procedural-style database handles, depending on what type we've got.
    if(get_class($db) == "PDO") {
      $sth = $db->prepare($sql);
      $sth->execute();
      if($sth->rowCount() != 2) return array(null, null);
      $coord1 = $sth->fetch();
      $lon1 = $coord1["x"];
      $lat1 = $coord1["y"];
      $coord2 = $sth->fetch();
      $lon2 = $coord2["x"];
      $lat2 = $coord2["y"];
    } else {
      $rs = mysql_query($sql, $db);
      if(mysql_num_rows($rs) != 2) return array(null, null);
      $row = mysql_fetch_assoc($rs);
      $lon1 = $row["x"];
      $lat1 = $row["y"];
      $row = mysql_fetch_assoc($rs);
      $lon2 = $row["x"];
      $lat2 = $row["y"];
    }

    $pi = 3.1415926;
    $rad = doubleval($pi/180.0);
    $lon1 = doubleval($lon1)*$rad; $lat1 = doubleval($lat1)*$rad;
    $lon2 = doubleval($lon2)*$rad; $lat2 = doubleval($lat2)*$rad;
    
    $theta = $lon2 - $lon1;
    $dist = acos(sin($lat1) * sin($lat2) + cos($lat1) * cos($lat2) * cos($theta));
    if ($dist < 0) { $dist += $pi; }
    $dist = floor($dist * 6371.2 * 0.621);
  }
  $duration = gcDuration($dist);
  return array($dist, $duration);
}

function gcDuration($dist) {
  $rawtime = floor(30 + ($dist / 500) * 60);
  return sprintf("%02d:%02d",  floor($rawtime/60), $rawtime % 60);
}

/**
 * Convert a filename (relative to the document root) to a relative URL with a date-based version string appended.
 * @param $filename string Relative filename (e.g. "/js/foo.js")
 * @return string Relative filename with version (e.g. "/js/foo.js?version=20120102")
 * @throws Exception Invalid input
 */
function fileUrlWithDate($filename) {
  if($filename === null || empty($filename) || strlen($filename) < 1) {
    throw new Exception("fileUrlWithDate requires a valid filename.");
  }
  # Make sure there is a leading slash.
  if(substr($filename, 0, 1) != '/') {
    $filename = '/' . $filename;
  }

  $docroot = getenv("DOCUMENT_ROOT");
  $full_path = $docroot . $filename;

  if(!file_exists($full_path)) {
    throw new Exception("$full_path does not exist; can't get URL with date.");
  }
  $mtime = filemtime($full_path);
  $datestamp = gmdate("Ymd", $mtime);
  return $filename . '?version=' . $datestamp;
}

// Hack to record X-Y and Y-X flights as same in DB
function orderAirports($src_apid, $dst_apid) {
  if($src_apid > $dst_apid) {
    return array($dst_apid, $src_apid, "Y");
  } else {
    return array($src_apid, $dst_apid, "N");
  }
}

?>