github.com/YoungNK/go-ethereum@v1.9.7/crypto/secp256k1/libsecp256k1/src/java/org/bitcoin/Secp256k1Context.java (about)

     1  /*
     2   * Copyright 2014-2016 the libsecp256k1 contributors
     3   *
     4   * Licensed under the Apache License, Version 2.0 (the "License");
     5   * you may not use this file except in compliance with the License.
     6   * You may obtain a copy of the License at
     7   *
     8   *    http://www.apache.org/licenses/LICENSE-2.0
     9   *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS,
    12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13   * See the License for the specific language governing permissions and
    14   * limitations under the License.
    15   */
    16  
    17  package org.bitcoin;
    18  
    19  /**
    20   * This class holds the context reference used in native methods 
    21   * to handle ECDSA operations.
    22   */
    23  public class Secp256k1Context {
    24    private static final boolean enabled; //true if the library is loaded
    25    private static final long context; //ref to pointer to context obj
    26  
    27    static { //static initializer
    28        boolean isEnabled = true;
    29        long contextRef = -1;
    30        try {
    31            System.loadLibrary("secp256k1");
    32            contextRef = secp256k1_init_context();
    33        } catch (UnsatisfiedLinkError e) {
    34            System.out.println("UnsatisfiedLinkError: " + e.toString());
    35            isEnabled = false;
    36        }
    37        enabled = isEnabled;
    38        context = contextRef;
    39    }
    40  
    41    public static boolean isEnabled() {
    42       return enabled;
    43    }
    44  
    45    public static long getContext() {
    46       if(!enabled) return -1; //sanity check
    47       return context;
    48    }
    49  
    50    private static native long secp256k1_init_context();
    51  }