content: /*
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   * 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.
   *
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   */
  package java.security.spec;
  
  import java.math.BigInteger;
  import java.util.Arrays;
  
  /**
   * This immutable class defines an elliptic curve (EC) prime
   * finite field.
   *
   * @see ECField
   *
   * @author Valerie Peng
   *
   * @since 1.5
   */
  public class ECFieldFp implements ECField {
  
      private BigInteger p;
  
      /**
       * Creates an elliptic curve prime finite field
       * with the specified prime {@code p}.
       * @param p the prime.
       * @exception NullPointerException if {@code p} is null.
       * @exception IllegalArgumentException if {@code p}
       * is not positive.
       */
      public ECFieldFp(BigInteger p) {
          if (p.signum() != 1) {
              throw new IllegalArgumentException("p is not positive");
          }
          this.p = p;
      }
  
      /**
       * Returns the field size in bits which is size of prime p
       * for this prime finite field.
       * @return the field size in bits.
       */
      public int getFieldSize() {
          return p.bitLength();
      };
  
      /**
       * Returns the prime {@code p} of this prime finite field.
       * @return the prime.
       */
      public BigInteger getP() {
          return p;
      }
  
      /**
       * Compares this prime finite field for equality with the
       * specified object.
       * @param obj the object to be compared.
       * @return true if {@code obj} is an instance
       * of ECFieldFp and the prime value match, false otherwise.
       */
      public boolean equals(Object obj) {
          if (this == obj)  return true;
          if (obj instanceof ECFieldFp) {
              return (p.equals(((ECFieldFp)obj).p));
          }
          return false;
      }
  
      /**
       * Returns a hash code value for this prime finite field.
       * @return a hash code value.
       */
      public int hashCode() {
          return p.hashCode();
      }
  }
  