/**
* <p>Reads version information from one of its two locations within the QR Code.</p>
*
* @return {@link Version} encapsulating the QR Code's version
* @throws FormatException if both version information locations cannot be parsed as
* the valid encoding of version information
*/
function readVersion()
{
if ($this->parsedVersion != null) {
return $this->parsedVersion;
}
$dimension = $this->bitMatrix->getHeight();
$provisionalVersion = ($dimension - 17) / 4;
if ($provisionalVersion <= 6) {
return Version::getVersionForNumber($provisionalVersion);
}
// Read top-right version info: 3 wide by 6 tall
$versionBits = 0;
$ijMin = $dimension - 11;
for ($j = 5; $j >= 0; $j--) {
for ($i = $dimension - 9; $i >= $ijMin; $i--) {
$versionBits = $this->copyBit($i, $j, $versionBits);
}
}
$theParsedVersion = Version::decodeVersionInformation($versionBits);
if ($theParsedVersion != null && $theParsedVersion->getDimensionForVersion() == $dimension) {
$this->parsedVersion = $theParsedVersion;
return $theParsedVersion;
}
// Hmm, failed. Try bottom left: 6 wide by 3 tall
$versionBits = 0;
for ($i = 5; $i >= 0; $i--) {
for ($j = $dimension - 9; $j >= $ijMin; $j--) {
$versionBits = $this->copyBit($i, $j, $versionBits);
}
}
$theParsedVersion = Version::decodeVersionInformation($versionBits);
if ($theParsedVersion != null && $theParsedVersion->getDimensionForVersion() == $dimension) {
$this->parsedVersion = $theParsedVersion;
return $theParsedVersion;
}
throw FormatException::getFormatInstance();
}
