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   1 /* -*-c-*-
   2  *
   3  * $Id: maurer.h,v 1.3 2004/04/08 01:36:15 mdw Exp $
   4  *
   5  * Maurer's universal statistical test
   6  *
   7  * (c) 2000 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Catacomb.
  13  *
  14  * Catacomb is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU Library General Public License as
  16  * published by the Free Software Foundation; either version 2 of the
  17  * License, or (at your option) any later version.
  18  *
  19  * Catacomb is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU Library General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Library General Public
  25  * License along with Catacomb; if not, write to the Free
  26  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  27  * MA 02111-1307, USA.
  28  */
  29
  30 #ifndef CATACOMB_MAURER_H
  31 #define CATACOMB_MAURER_H
  32
  33 #ifdef __cplusplus
  34   extern "C" {
  35 #endif
  36
  37 /*----- Header files ------------------------------------------------------*/
  38
  39 #include <mLib/bits.h>
  40
  41 /*----- Data structures ---------------------------------------------------*/
  42
  43 typedef struct maurer_ctx {
  44   unsigned l;                           /* Chunk size, in bits */
  45   uint32 a;                             /* Bitscanner accumulator */
  46   unsigned b;                           /* Number of bits in accumulator */
  47   unsigned long n;                      /* Number of chunks read so far */
  48   double x;                             /* Statistic value */
  49   unsigned long *t;                     /* Offset table */
  50 } maurer_ctx;
  51
  52 /*----- Functions provided ------------------------------------------------*/
  53
  54 /* --- @maurer_init@ --- *
  55  *
  56  * Arguments:   @maurer_ctx *m@ = pointer to a context to initialize
  57  *              @unsigned l@ = number of bits to take at a time
  58  *
  59  * Returns:     Minimum recommended amount of data to test.
  60  *
  61  * Use:         Initializes a Maurer testing context.  Note that @l@ values
  62  *              larger than 16 are not supported, and values less than 6 can
  63  *              give bizarre results.
  64  */
  65
  66 extern unsigned long maurer_init(maurer_ctx */*m*/, unsigned /*l*/);
  67
  68 /* --- @maurer_test@ --- *
  69  *
  70  * Arguments:   @maurer_ctx *m@ = pointer to a Maurer testing context
  71  *              @const void *buf@ = pointer to a buffer of data
  72  *              @size_t sz@ = size of the buffer
  73  *
  74  * Returns:     ---
  75  *
  76  * Use:         Scans a buffer of data and updates the testing context.
  77  */
  78
  79 extern void maurer_test(maurer_ctx */*m*/,
  80                         const void */*buf*/, size_t /*sz*/);
  81
  82 /* --- @maurer_done@ --- *
  83  *
  84  * Arguments:   @maurer_ctx *m@ = pointer to a Maurer testing context
  85  *
  86  * Returns:     The statistic %$Z_u = (X_u - \mu)/\sigma$%, which should be
  87  *              normally distributed with a mean of 0 and variance of 1.
  88  *
  89  * Use:         Returns the result of Maurer's universal statistical test.
  90  *              Also frees the memory allocated during initialization.
  91  *
  92  *              If insufficient data was received, the value @HUGE_VAL@ is
  93  *              returned.
  94  */
  95
  96 extern double maurer_done(maurer_ctx */*m*/);
  97
  98 /* --- @maurer@ --- *
  99  *
 100  * Arguments:   @const octet *p@ = pointer to a buffer of data
 101  *              @size_t sz@ = size of the buffer
 102  *              @unsigned l@ = number of bits to take at a time
 103  *
 104  * Returns:     The statistic %$Z_u$%.
 105  *
 106  * Use:         Simple interface to Maurer's universal statistical test.  For
 107  *              large %$l$% you should use the more complicated restartable
 108  *              interface.
 109  */
 110
 111 extern double maurer(const octet */*p*/, size_t /*sz*/, unsigned /*l*/);
 112
 113 /*----- That's all, folks -------------------------------------------------*/
 114
 115 #ifdef __cplusplus
 116   }
 117 #endif
 118
 119 #endif