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A Java Bitcoin library

There is a newer version: 0.17-beta1

/*
 * Copyright 2014-2016 the libsecp256k1 contributors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.bitcoin;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.lang.SecurityException;

/**
 * This class holds the context reference used in native methods to handle ECDSA operations.
 */
public class Secp256k1Context {

    private static final boolean enabled; // true if the library is loaded
    private static final long context; // ref to pointer to context obj

    private static final Logger log = LoggerFactory.getLogger(Secp256k1Context.class);

    static { // static initializer
        boolean isEnabled = true;
        long contextRef = -1;
        try {
            System.loadLibrary("secp256k1");
            contextRef = secp256k1_init_context();
        } catch (UnsatisfiedLinkError | SecurityException e) {
            log.debug(e.toString());
            isEnabled = false;
        }
        enabled = isEnabled;
        context = contextRef;
    }

    /**
     * @return true if enabled
     */
    public static boolean isEnabled() {
        return enabled;
    }

    /**
     * @return context reference
     */
    public static long getContext() {
        if (!enabled)
            return -1; // sanity check
        return context;
    }

    private static native long secp256k1_init_context();
}