/*

 * Copyright (c) 2008-2012 Zmanda, Inc.  All Rights Reserved.

 * Copyright (c) 2013-2016 Carbonite, Inc.  All Rights Reserved.

 *

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

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2

 * of the License, or (at your option) any later version.

 *

 * This program 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

 * for more details.

 *

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

 * with this program; if not, write to the Free Software Foundation, Inc.,

 * 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA

 *

 * Contact information: Carbonite Inc., 756 N Pastoria Ave

 * Sunnyvale, CA 94086, USA, or: http://www.zmanda.com

 */

#ifndef SIMPLEPRNG_H

#define	SIMPLEPRNG_H

#include "amanda.h"

/* A very simple, thread-safe PRNG.  This is intended for use in generating

 * reproducable bytestreams for testing purposes.  It is *not*

 * cryptographically secure! */

typedef struct {

    guint32 val;

    guint64 count;

} simpleprng_state_t;

/* Initialize and seed the PRNG

 *

 * @param state: pointer to PRNG state

 * @param seed: initial value

 */

void simpleprng_seed(

    simpleprng_state_t *state,

    guint32 seed);

/* Get a seed that will reproduce the PRNG's current state

 *

 * @param state: pointer to PRNG state

 * @returns: seed;

 */

guint32 simpleprng_get_seed(

    simpleprng_state_t *state);

/* Get a random guint32

 *

 * @param state: pointer to PRNG state

 * @returns: random integer

 */

guint32 simpleprng_rand(

    simpleprng_state_t *state);

/* Get a random byte

 *

 * @param state: pointer to PRNG state

 * @returns: random integer

 */

/* use the high-order bytes, as they're "more random" */

#define simpleprng_rand_byte(state) \

    ((guint8)(simpleprng_rand((state)) >> 24))

/* Fill the given buffer with a sequence of bytes

 *

 * @param state: pointer to PRNG state

 * @param buf: buffer to fill

 * @param len: number of bytes to write

 */

void simpleprng_fill_buffer(

    simpleprng_state_t *state,

    gpointer buf,

    size_t len);

/* Verify that a buffer matches the values from the PRNG.

 *

 * @param state: pointer to PRNG state

 * @param buf: buffer to verify

 * @param len: number of bytes to verify

 * @returns: true if all bytes match

 */

gboolean simpleprng_verify_buffer(

    simpleprng_state_t *state,

    gpointer buf,

    size_t len);

#endif	/* SIMPLEPRNG_H */