static function geoPHP::detectFormat in geoPHP 8

Same name and namespace in other branches

1. 7 geoPHP/geoPHP.inc \geoPHP::detectFormat()

2 calls to geoPHP::detectFormat()

geoPHP::load in geoPHP/geoPHP.inc

test_detection in geoPHP/tests/test.php

File

geoPHP/geoPHP.inc, line 224

Class

geoPHP

Code

static function detectFormat(&$input) {
  $mem = fopen('php://memory', 'r+');
  fwrite($mem, $input, 11);

  // Write 11 bytes - we can detect the vast majority of formats in the first 11 bytes
  fseek($mem, 0);
  $bytes = unpack("c*", fread($mem, 11));

  // If bytes is empty, then we were passed empty input
  if (empty($bytes)) {
    return FALSE;
  }

  // First char is a tab, space or carriage-return. trim it and try again
  if ($bytes[1] == 9 || $bytes[1] == 10 || $bytes[1] == 32) {
    return geoPHP::detectFormat(ltrim($input));
  }

  // Detect WKB or EWKB -- first byte is 1 (little endian indicator)
  if ($bytes[1] == 1) {

    // If SRID byte is TRUE (1), it's EWKB
    if ($bytes[5]) {
      return 'ewkb';
    }
    else {
      return 'wkb';
    }
  }

  // Detect HEX encoded WKB or EWKB (PostGIS format) -- first byte is 48, second byte is 49 (hex '01' => first-byte = 1)
  if ($bytes[1] == 48 && $bytes[2] == 49) {

    // The shortest possible WKB string (LINESTRING EMPTY) is 18 hex-chars (9 encoded bytes) long
    // This differentiates it from a geohash, which is always shorter than 18 characters.
    if (strlen($input) >= 18) {

      //@@TODO: Differentiate between EWKB and WKB -- check hex-char 10 or 11 (SRID bool indicator at encoded byte 5)
      return 'ewkb:1';
    }
  }

  // Detect GeoJSON - first char starts with {
  if ($bytes[1] == 123) {
    return 'json';
  }

  // Detect EWKT - first char is S
  if ($bytes[1] == 83) {
    return 'ewkt';
  }

  // Detect WKT - first char starts with P (80), L (76), M (77), or G (71)
  $wkt_chars = array(
    80,
    76,
    77,
    71,
  );
  if (in_array($bytes[1], $wkt_chars)) {
    return 'wkt';
  }

  // Detect XML -- first char is <
  if ($bytes[1] == 60) {

    // grab the first 256 characters
    $string = substr($input, 0, 256);
    if (strpos($string, '<kml') !== FALSE) {
      return 'kml';
    }
    if (strpos($string, '<coordinate') !== FALSE) {
      return 'kml';
    }
    if (strpos($string, '<gpx') !== FALSE) {
      return 'gpx';
    }
    if (strpos($string, '<georss') !== FALSE) {
      return 'georss';
    }
    if (strpos($string, '<rss') !== FALSE) {
      return 'georss';
    }
    if (strpos($string, '<feed') !== FALSE) {
      return 'georss';
    }
  }

  // We need an 8 byte string for geohash and unpacked WKB / WKT
  fseek($mem, 0);
  $string = trim(fread($mem, 8));

  // Detect geohash - geohash ONLY contains lowercase chars and numerics
  preg_match('/[a-z0-9]+/', $string, $matches);
  if ($matches[0] == $string) {
    return 'geohash';
  }

  // What do you get when you cross an elephant with a rhino?
  // http://youtu.be/RCBn5J83Poc
  return FALSE;
}