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package sun.security.util.math;

import java.nio.ByteBuffer;

/**

 * An interface for mutable integers modulo a prime value. This interface

 * should be used to improve performance and avoid the allocation of a large

 * number of temporary objects.

 *

 * Methods in this interface that modify the value also return the modified

 * element. This structure enables fluent expressions like:

 * a.setSum(b).setProduct(c).setDifference(d).setSquare()

 *

 */

public interface MutableIntegerModuloP extends IntegerModuloP {

    /**

     * Swap the value of this with the value of b when swap has the value 1.

     * No change is made to either element when swap has the value 0. The

     * result is undefined when swap has a value other than 0 or 1. The swap

     * parameter is an int (rather than boolean) to allow the implementation

     * to perform the swap using branch-free integer arithmetic.

     *

     * @param b the element to conditionally swap with

     * @param swap an int that determines whether to swap

     */

    void conditionalSwapWith(MutableIntegerModuloP b, int swap);

    /**

     * Set the value of this element equal to the value of the supplied

     * element. The argument is not modified.

     *

     * @param v the element whose value should be copied to this

     * @return this

     */

    MutableIntegerModuloP setValue(IntegerModuloP v);

    /**

     * Set the value equal to the little-endian unsigned integer stored at the

     * specified position in an array. The range of accepted values is

     * implementation-specific. This method also takes a byte which is

     * interpreted as an additional high-order byte of the number.

     *

     * @param v an array containing a little-endian unsigned integer

     * @param offset the starting position of the integer

     * @param length the number of bytes to read

     * @param highByte the high-order byte of the number

     * @return this

     */

    MutableIntegerModuloP setValue(byte[] v, int offset, int length,

                                   byte highByte);

    /**

     * Set the value equal to the little-endian unsigned integer stored in a

     * buffer. The range of accepted values is implementation-specific.

     * This method also takes a byte which is interpreted as an additional

     * high-order byte of the number.

     *

     * @param buf a buffer containing a little-endian unsigned integer

     * @param length the number of bytes to read

     * @param highByte the high-order byte of the number

     * @return this

     */

    MutableIntegerModuloP setValue(ByteBuffer buf, int length, byte highByte);

    /**

     * Set the value of this element equal to this * this.

     *

     * @return this

     */

    MutableIntegerModuloP setSquare();

    /**

     * Set the value of this element equal to this + b. The argument is

     * not modified.

     *

     * @param b the sumand

     * @return this

     */

    MutableIntegerModuloP setSum(IntegerModuloP b);

    /**

     * Set the value of this element equal to this - b. The argument is

     * not modified.

     *

     * @param b the subtrahend

     * @return this

     */

    MutableIntegerModuloP setDifference(IntegerModuloP b);

    /**

     * Set the value of this element equal to this * b. The argument is

     * not modified.

     *

     * @param b the multiplicand

     * @return this

     */

    MutableIntegerModuloP setProduct(IntegerModuloP b);

    /**

     * Set the value of this element equal to this * v. The argument is

     * not modified.

     *

     * @param v the small multiplicand

     * @return this

     */

    MutableIntegerModuloP setProduct(SmallValue v);

}