<?php

function copyIfUnique( $relPathOffset, $source, $destination, &$checksumArray ) {
    foreach ( scandir( $source ) as $name ) {
        if ( $name === '.' || $name === '..' ) {
            continue;
        }
        $file = $source . DIRECTORY_SEPARATOR . $name;
        if ( is_dir( $file ) ) {
            copyIfUnique( $relPathOffset, $file, $destination, $checksumArray );
        } else {
            $checksum = md5_file( $file );
            if ( ! isset( $checksumArray[$checksum] ) ) {
                $checksumArray[$checksum] = 1;
                $relDir = trim( substr( dirname( $file ), $relPathOffset ), '\\/' );
                if ( ! file_exists( $relDir ) ) {
                    mkdir( $relDir, 0777, true );
                }
                copy( $file, $destination . DIRECTORY_SEPARATOR . $relDir . $name );
            }
        }
    }
}

function loadChecksums( $directory, &$checksumArray ) {
    foreach ( scandir( $directory ) as $name ) {
        if ( $name === '.' || $name === '..' ) {
            continue;
        }
        $file = $directory . DIRECTORY_SEPARATOR . $name;
        if ( is_dir( $file ) ) {
            loadChecksums( $file, $checksumArray );
        } else {
            $checksum = md5_file( $file );
            if ( ! isset( $checksumArray[$checksum] ) ) {
                $checksumArray[$checksum] = 1;
            }
        }
    }
}

$checksumArray = array();
loadChecksums( '/mappa/ahova/masolja/a/fajlokat', $checksumArray );
copyIfUnique( strlen( '/mappa/utvonala/ahol/vannak' ), '/mappa/utvonala/ahol/vannak', '/mappa/ahova/masolja/a/fajlokat', $checksumArray );

?>