/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

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 */

package sun.security.pkcs11;

import java.math.BigInteger;

import java.security.*;

/**

 * Collection of static utility methods.

 *

 * @author  Andreas Sterbenz

 * @since   1.5

 */

public final class P11Util {

    private static Object LOCK = new Object();

    private static volatile Provider sun, sunRsaSign, sunJce;

    private P11Util() {

        // empty

    }

    static Provider getSunProvider() {

        Provider p = sun;

        if (p == null) {

            synchronized (LOCK) {

                p = getProvider

                    (sun, "SUN", "sun.security.provider.Sun");

                sun = p;

            }

        }

        return p;

    }

    static Provider getSunRsaSignProvider() {

        Provider p = sunRsaSign;

        if (p == null) {

            synchronized (LOCK) {

                p = getProvider

                    (sunRsaSign, "SunRsaSign", "sun.security.rsa.SunRsaSign");

                sunRsaSign = p;

            }

        }

        return p;

    }

    static Provider getSunJceProvider() {

        Provider p = sunJce;

        if (p == null) {

            synchronized (LOCK) {

                p = getProvider

                    (sunJce, "SunJCE", "com.sun.crypto.provider.SunJCE");

                sunJce = p;

            }

        }

        return p;

    }

    private static Provider getProvider(Provider p, String providerName,

            String className) {

        if (p != null) {

            return p;

        }

        p = Security.getProvider(providerName);

        if (p == null) {

            try {

                p = (Provider)clazz.newInstance();

            } catch (Exception e) {

                throw new ProviderException

                        ("Could not find provider " + providerName, e);

            }

        }

        return p;

    }

    static byte[] convert(byte[] input, int offset, int len) {

        if ((offset == 0) && (len == input.length)) {

            return input;

        } else {

            byte[] t = new byte[len];

            System.arraycopy(input, offset, t, 0, len);

            return t;

        }

    }

    static byte[] subarray(byte[] b, int ofs, int len) {

        byte[] out = new byte[len];

        System.arraycopy(b, ofs, out, 0, len);

        return out;

    }

    static byte[] concat(byte[] b1, byte[] b2) {

        byte[] b = new byte[b1.length + b2.length];

        System.arraycopy(b1, 0, b, 0, b1.length);

        System.arraycopy(b2, 0, b, b1.length, b2.length);

        return b;

    }

    static long[] concat(long[] b1, long[] b2) {

        if (b1.length == 0) {

            return b2;

        }

        long[] b = new long[b1.length + b2.length];

        System.arraycopy(b1, 0, b, 0, b1.length);

        System.arraycopy(b2, 0, b, b1.length, b2.length);

        return b;

    }

    // trim leading (most significant) zeroes from the result

    static byte[] trimZeroes(byte[] b) {

        int i = 0;

        while ((i < b.length - 1) && (b[i] == 0)) {

            i++;

        }

        if (i == 0) {

            return b;

        }

        byte[] t = new byte[b.length - i];

        System.arraycopy(b, i, t, 0, t.length);

        return t;

    }

    public static byte[] getMagnitude(BigInteger bi) {

        byte[] b = bi.toByteArray();

        if ((b.length > 1) && (b[0] == 0)) {

            int n = b.length - 1;

            byte[] newarray = new byte[n];

            System.arraycopy(b, 1, newarray, 0, n);

            b = newarray;

        }

        return b;

    }

    static byte[] getBytesUTF8(String s) {

        try {

            return s.getBytes("UTF8");

        } catch (java.io.UnsupportedEncodingException e) {

            throw new RuntimeException(e);

        }

    }

    static byte[] sha1(byte[] data) {

        try {

            MessageDigest md = MessageDigest.getInstance("SHA-1");

            md.update(data);

            return md.digest();

        } catch (GeneralSecurityException e) {

            throw new ProviderException(e);

        }

    }

    private final static char[] hexDigits = "0123456789abcdef".toCharArray();

    static String toString(byte[] b) {

        if (b == null) {

            return "(null)";

        }

        StringBuffer sb = new StringBuffer(b.length * 3);

        for (int i = 0; i < b.length; i++) {

            int k = b[i] & 0xff;

            if (i != 0) {

                sb.append(':');

            }

            sb.append(hexDigits[k >>> 4]);

            sb.append(hexDigits[k & 0xf]);

        }

        return sb.toString();

    }

}