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[api] Added php decoder used on the web site

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Alex Zolotarev 2013-05-07 16:23:25 +03:00 • committed by Alex Zolotarev
parent c94dd547f4
commit fae8616ab9
1 changed files with 106 additions and 0 deletions
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api/src/php/mwm_api.php Normal file
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<?php
// @TODO add tests
// Returns array(lat, lon, zoom) or empty array in the case of error
function DecodeGe0LatLonZoom($latLonZoom)
{
$MAPSWITHME_MAX_POINT_BYTES = 10;
$MAPSWITHME_MAX_COORD_BITS = $MAPSWITHME_MAX_POINT_BYTES * 3;
$FAILED = array();
$base64ReverseArray = GetBase64ReverseArray();
$zoom = $base64ReverseArray[ord($latLonZoom[0])];
if ($zoom > 63)
return $FAILED;
$zoom = $zoom / 4. + 4.;
$latLonStr = substr($latLonZoom, 1);
$latLonBytes = strlen($latLonStr);
$lat = 0;
$lon = 0;
for($i = 0, $shift = $MAPSWITHME_MAX_COORD_BITS - 3; $i < $latLonBytes; $i++, $shift -= 3)
{
$a = $base64ReverseArray[ord($latLonStr[$i])];
$lat1 = ((($a >> 5) & 1) << 2 |
(($a >> 3) & 1) << 1 |
(($a >> 1) & 1));
$lon1 = ((($a >> 4) & 1) << 2 |
(($a >> 2) & 1) << 1 |
($a & 1));
$lat |= $lat1 << $shift;
$lon |= $lon1 << $shift;
}
$middleOfSquare = 1 << (3 * ($MAPSWITHME_MAX_POINT_BYTES - $latLonBytes) - 1);
$lat += $middleOfSquare;
$lon += $middleOfSquare;
$lat = round($lat / ((1 << $MAPSWITHME_MAX_COORD_BITS) - 1) * 180.0 - 90.0, 5);
$lon = round($lon / (1 << $MAPSWITHME_MAX_COORD_BITS) * 360.0 - 180.0, 5);
if ($lat <= -90.0 || $lat >= 90.0)
return $FAILED;
if ($lon <= -180.0 || $lon >= 180.0)
return $FAILED;
return array($lat, $lon, $zoom);
}
// Returns decoded name
function DecodeGe0Name($name)
{
return str_replace('_', ' ', rawurldecode($name));
}
// Returns empty array in the case of error.
// In the good case, returns array(lat, lon, zoom) or array(lat, lon, zoom, name)
function DecodeGe0Url($url)
{
$MAPSWITHME_ZOOM_POSITION = 6;
$NAME_POSITON_IN_URL = 17;
$FAILED = array();
if (strlen($url) < 16 || strpos($url, "ge0://") != 0)
return $FAILED;
$base64ReverseArray = GetBase64ReverseArray();
$latLonZoom = DecodeGe0LatLonZoom(substr($url, 6, 10));
if (empty($latLonZoom))
return $FAILED;
if (strlen($url) < $NAME_POSITON_IN_URL)
return $latLonZoom;
$name = DecodeGe0Name(substr($url, $NAME_POSITON_IN_URL));
array_push($latLonZoom, $name);
return $latLonZoom;
}
// Internal helper function
function GetBase64ReverseArray()
{
static $base64Alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
$base64ReverseArray = array();
// fill array with 255's
array_pad($base64ReverseArray, 256, 255);
for ($i = 0; $i < 64; $i++)
{
$c = $base64Alphabet[$i];
$base64ReverseArray[ord($c)] = $i;
}
return $base64ReverseArray;
}
//////////////////////////////////////
// Tests are below
//print_r(DecodeGe0Url("ge0://B4srhdHVVt/Some_Name"));
//print_r(DecodeGe0Url("ge0://AwAAAAAAAA/%d0%9c%d0%b8%d0%bd%d1%81%d0%ba_%d1%83%d0%bb._%d0%9b%d0%b5%d0%bd%d0%b8%d0%bd%d0%b0_9"));
?>