Java DerInputStream.peekByte方法代码示例

import sun.security.util.DerInputStream; //导入方法依赖的package包/类
/**
 * Parse (unmarshal) a kerberostime from a DER input stream.  This form
 * parsing might be used when expanding a value which is part of
 * a constructed sequence and uses explicitly tagged type.
 *
 * @exception Asn1Exception on error.
 * @param data the Der input stream value, which contains
 *             one or more marshaled value.
 * @param explicitTag tag number.
 * @param optional indicates if this data field is optional
 * @return an instance of KerberosTime.
 *
 */
public static KerberosTime parse(
        DerInputStream data, byte explicitTag, boolean optional)
        throws Asn1Exception, IOException {
    if ((optional) && (((byte)data.peekByte() & (byte)0x1F)!= explicitTag))
        return null;
    DerValue der = data.getDerValue();
    if (explicitTag != (der.getTag() & (byte)0x1F))  {
        throw new Asn1Exception(Krb5.ASN1_BAD_ID);
    }
    else {
        DerValue subDer = der.getData().getDerValue();
        Date temp = subDer.getGeneralizedTime();
        return new KerberosTime(temp.getTime(), 0);
    }
}
 

import sun.security.util.DerInputStream; //导入方法依赖的package包/类
/**
 * Parses a PKCS#7 signer info.
 *
 * <p>This constructor is used only for backwards compatibility with
 * PKCS#7 blocks that were generated using JDK1.1.x.
 *
 * @param derin the ASN.1 encoding of the signer info.
 * @param oldStyle flag indicating whether or not the given signer info
 * is encoded according to JDK1.1.x.
 */
public SignerInfo(DerInputStream derin, boolean oldStyle)
    throws IOException, ParsingException
{
    // version
    version = derin.getBigInteger();

    // issuerAndSerialNumber
    DerValue[] issuerAndSerialNumber = derin.getSequence(2);
    byte[] issuerBytes = issuerAndSerialNumber[0].toByteArray();
    issuerName = new X500Name(new DerValue(DerValue.tag_Sequence,
                                           issuerBytes));
    certificateSerialNumber = issuerAndSerialNumber[1].getBigInteger();

    // digestAlgorithmId
    DerValue tmp = derin.getDerValue();

    digestAlgorithmId = AlgorithmId.parse(tmp);

    // authenticatedAttributes
    if (oldStyle) {
        // In JDK1.1.x, the authenticatedAttributes are always present,
        // encoded as an empty Set (Set of length zero)
        derin.getSet(0);
    } else {
        // check if set of auth attributes (implicit tag) is provided
        // (auth attributes are OPTIONAL)
        if ((byte)(derin.peekByte()) == (byte)0xA0) {
            authenticatedAttributes = new PKCS9Attributes(derin);
        }
    }

    // digestEncryptionAlgorithmId - little RSA naming scheme -
    // signature == encryption...
    tmp = derin.getDerValue();

    digestEncryptionAlgorithmId = AlgorithmId.parse(tmp);

    // encryptedDigest
    encryptedDigest = derin.getOctetString();

    // unauthenticatedAttributes
    if (oldStyle) {
        // In JDK1.1.x, the unauthenticatedAttributes are always present,
        // encoded as an empty Set (Set of length zero)
        derin.getSet(0);
    } else {
        // check if set of unauth attributes (implicit tag) is provided
        // (unauth attributes are OPTIONAL)
        if (derin.available() != 0
            && (byte)(derin.peekByte()) == (byte)0xA1) {
            unauthenticatedAttributes =
                new PKCS9Attributes(derin, true);// ignore unsupported attrs
        }
    }

    // all done
    if (derin.available() != 0) {
        throw new ParsingException("extra data at the end");
    }
}