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/**

 * @test

 * @bug 4856966

 * @summary Test the Signature.update(ByteBuffer) method

 * @author Andreas Sterbenz

 * @library ..

 * @key randomness

 */

import java.util.*;

import java.nio.*;

import java.security.*;

public class ByteBuffers extends PKCS11Test {

    public static void main(String[] args) throws Exception {

        main(new ByteBuffers());

    }

    public void main(Provider p) throws Exception {

        Random random = new Random();

        int n = 10 * 1024;

        byte[] t = new byte[n];

        random.nextBytes(t);

        KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA", p);

        kpg.initialize(512);

        KeyPair kp = kpg.generateKeyPair();

        Signature sig = Signature.getInstance("MD5withRSA", p);

        sig.initSign(kp.getPrivate());

        sig.update(t);

        byte[] signature = sig.sign();

        sig.initVerify(kp.getPublic());

        // test 1: ByteBuffer with an accessible backing array

        ByteBuffer b1 = ByteBuffer.allocate(n + 256);

        b1.position(random.nextInt(256));

        b1.limit(b1.position() + n);

        ByteBuffer b2 = b1.slice();

        b2.put(t);

        b2.clear();

        verify(sig, signature, b2, random);

        // test 2: direct ByteBuffer

        ByteBuffer b3 = ByteBuffer.allocateDirect(t.length);

        b3.put(t);

        b3.clear();

        verify(sig, signature, b3, random);

        // test 3: ByteBuffer without an accessible backing array

        b2.clear();

        ByteBuffer b4 = b2.asReadOnlyBuffer();

        verify(sig, signature, b4, random);

        System.out.println("All tests passed");

    }

    private static void verify(Signature sig, byte[] signature, ByteBuffer b, Random random) throws Exception {

        int lim = b.limit();

        b.limit(random.nextInt(lim));

        sig.update(b);

        if (b.hasRemaining()) {

            throw new Exception("Buffer not consumed");

        }

        b.limit(lim);

        sig.update(b);

        if (b.hasRemaining()) {

            throw new Exception("Buffer not consumed");

        }

        if (sig.verify(signature) == false) {

            throw new Exception("Signature did not verify");

        }

    }

}