src/PelTiff.php
public static function isValid(PelDataWindow $d)
    {
        /* First check that we have enough data. */
        if ($d->getSize() < 8) {
            return false;
        }

        /* Byte order */
        if ($d->strcmp(0, 'II')) {
            $d->setByteOrder(PelConvert::LITTLE_ENDIAN);
        } elseif ($d->strcmp(0, 'MM')) {
            Pel::debug('Found Motorola byte order');
            $d->setByteOrder(PelConvert::BIG_ENDIAN);
        } else {
            return false;
        }

        /* Verify the TIFF header */
        return $d->getShort(2) == self::TIFF_HEADER;
    }
public static function isValid(PelDataWindow $d)
    {
        /* First check that we have enough data. */
        if ($d->getSize() < 8) {
            return false;
        }

        /* Byte order */
        if ($d->strcmp(0, 'II')) {
            $d->setByteOrder(PelConvert::LITTLE_ENDIAN);
        } elseif ($d->strcmp(0, 'MM')) {
            Pel::debug('Found Motorola byte order');
            $d->setByteOrder(PelConvert::BIG_ENDIAN);
        } else {
            return false;
        }

        /* Verify the TIFF header */
        return $d->getShort(2) == self::TIFF_HEADER;
    }
public static function isValid ( PelDataWindow $ d ) { /* First check that we have enough data. */ if ( $ d -> getSize ( ) < 8 ) { return false ; } /* Byte order */ if ( $ d -> strcmp ( 0 , 'II' ) ) { $ d -> setByteOrder ( PelConvert :: LITTLE_ENDIAN ) ; } elseif ( $ d -> strcmp ( 0 , 'MM' ) ) { Pel :: debug ( 'Found Motorola byte order' ) ; $ d -> setByteOrder ( PelConvert :: BIG_ENDIAN ) ; } else { return false ; } /* Verify the TIFF header */ return $ d -> getShort ( 2 ) == self :: TIFF_HEADER ; }
Check if data is valid TIFF data.

This will read just enough data from the data window to determine
if the data could be a valid TIFF data. This means that the
check is more like a heuristic than a rigorous check.

@param PelDataWindow $d
the bytes that will be examined.

@return boolean true if the data looks like valid TIFF data,
false otherwise.

@see PelJpeg::isValid()
Check if data is valid TIFF data .