key-flags.c, key-pack.c, key-pass.c: Don't use the `key.h' machinery.

[u/mdw/catacomb] / maurer.h

/* -*-c-*-
 *
 * $Id: maurer.h,v 1.3 2004/04/08 01:36:15 mdw Exp $
 *
 * Maurer's universal statistical test
 *
 * (c) 2000 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------*
 *
 * This file is part of Catacomb.
 *
 * Catacomb is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Library General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * Catacomb 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 Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with Catacomb; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

#ifndef CATACOMB_MAURER_H
#define CATACOMB_MAURER_H

#ifdef __cplusplus
  extern "C" {
#endif

/*----- Header files ------------------------------------------------------*/

#include <mLib/bits.h>

/*----- Data structures ---------------------------------------------------*/

typedef struct maurer_ctx {
  unsigned l;				/* Chunk size, in bits */
  uint32 a;				/* Bitscanner accumulator */
  unsigned b;				/* Number of bits in accumulator */
  unsigned long n;			/* Number of chunks read so far */
  double x;				/* Statistic value */
  unsigned long *t;			/* Offset table */
} maurer_ctx;

/*----- Functions provided ------------------------------------------------*/

/* --- @maurer_init@ --- *
 *
 * Arguments:	@maurer_ctx *m@ = pointer to a context to initialize
 *		@unsigned l@ = number of bits to take at a time
 *
 * Returns:	Minimum recommended amount of data to test.
 *
 * Use:		Initializes a Maurer testing context.  Note that @l@ values
 *		larger than 16 are not supported, and values less than 6 can
 *		give bizarre results.
 */

extern unsigned long maurer_init(maurer_ctx */*m*/, unsigned /*l*/);

/* --- @maurer_test@ --- *
 *
 * Arguments:	@maurer_ctx *m@ = pointer to a Maurer testing context
 *		@const void *buf@ = pointer to a buffer of data
 *		@size_t sz@ = size of the buffer
 *
 * Returns:	---
 *
 * Use:		Scans a buffer of data and updates the testing context.
 */

extern void maurer_test(maurer_ctx */*m*/,
			const void */*buf*/, size_t /*sz*/);

/* --- @maurer_done@ --- *
 *
 * Arguments:	@maurer_ctx *m@ = pointer to a Maurer testing context
 *
 * Returns:	The statistic %$Z_u = (X_u - \mu)/\sigma$%, which should be
 *		normally distributed with a mean of 0 and variance of 1.
 *
 * Use:		Returns the result of Maurer's universal statistical test.
 *		Also frees the memory allocated during initialization.
 *
 *		If insufficient data was received, the value @HUGE_VAL@ is
 *		returned.
 */

extern double maurer_done(maurer_ctx */*m*/);

/* --- @maurer@ --- *
 *
 * Arguments:	@const octet *p@ = pointer to a buffer of data
 *		@size_t sz@ = size of the buffer
 *		@unsigned l@ = number of bits to take at a time
 *
 * Returns:	The statistic %$Z_u$%.
 *
 * Use:		Simple interface to Maurer's universal statistical test.  For
 *		large %$l$% you should use the more complicated restartable
 *		interface.
 */

extern double maurer(const octet */*p*/, size_t /*sz*/, unsigned /*l*/);

/*----- That's all, folks -------------------------------------------------*/

#ifdef __cplusplus
  }
#endif

#endif