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   1 /* -*-c-*-
   2  *
   3  * $Id: maurer.h,v 1.2 2000/08/11 21:34:59 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 /*----- Revision history --------------------------------------------------*
  31  *
  32  * $Log: maurer.h,v $
  33  * Revision 1.2  2000/08/11 21:34:59  mdw
  34  * New restartable interface to Maurer testing.
  35  *
  36  * Revision 1.1  2000/06/17 11:29:49  mdw
  37  * Maurer's universal statistical test.
  38  *
  39  */
  40
  41 #ifndef CATACOMB_MAURER_H
  42 #define CATACOMB_MAURER_H
  43
  44 #ifdef __cplusplus
  45   extern "C" {
  46 #endif
  47
  48 /*----- Header files ------------------------------------------------------*/
  49
  50 #include <mLib/bits.h>
  51
  52 /*----- Data structures ---------------------------------------------------*/
  53
  54 typedef struct maurer_ctx {
  55   unsigned l;                           /* Chunk size, in bits */
  56   uint32 a;                             /* Bitscanner accumulator */
  57   unsigned b;                           /* Number of bits in accumulator */
  58   unsigned long n;                      /* Number of chunks read so far */
  59   double x;                             /* Statistic value */
  60   unsigned long *t;                     /* Offset table */
  61 } maurer_ctx;
  62
  63 /*----- Functions provided ------------------------------------------------*/
  64
  65 /* --- @maurer_init@ --- *
  66  *
  67  * Arguments:   @maurer_ctx *m@ = pointer to a context to initialize
  68  *              @unsigned l@ = number of bits to take at a time
  69  *
  70  * Returns:     Minimum recommended amount of data to test.
  71  *
  72  * Use:         Initializes a Maurer testing context.  Note that @l@ values
  73  *              larger than 16 are not supported, and values less than 6 can
  74  *              give bizarre results.
  75  */
  76
  77 extern unsigned long maurer_init(maurer_ctx */*m*/, unsigned /*l*/);
  78
  79 /* --- @maurer_test@ --- *
  80  *
  81  * Arguments:   @maurer_ctx *m@ = pointer to a Maurer testing context
  82  *              @const void *buf@ = pointer to a buffer of data
  83  *              @size_t sz@ = size of the buffer
  84  *
  85  * Returns:     ---
  86  *
  87  * Use:         Scans a buffer of data and updates the testing context.
  88  */
  89
  90 extern void maurer_test(maurer_ctx */*m*/,
  91                         const void */*buf*/, size_t /*sz*/);
  92
  93 /* --- @maurer_done@ --- *
  94  *
  95  * Arguments:   @maurer_ctx *m@ = pointer to a Maurer testing context
  96  *
  97  * Returns:     The statistic %$Z_u = (X_u - \mu)/\sigma$%, which should be
  98  *              normally distributed with a mean of 0 and variance of 1.
  99  *
 100  * Use:         Returns the result of Maurer's universal statistical test.
 101  *              Also frees the memory allocated during initialization.
 102  *
 103  *              If insufficient data was received, the value @HUGE_VAL@ is
 104  *              returned.
 105  */
 106
 107 extern double maurer_done(maurer_ctx */*m*/);
 108
 109 /* --- @maurer@ --- *
 110  *
 111  * Arguments:   @const octet *p@ = pointer to a buffer of data
 112  *              @size_t sz@ = size of the buffer
 113  *              @unsigned l@ = number of bits to take at a time
 114  *
 115  * Returns:     The statistic %$Z_u$%.
 116  *
 117  * Use:         Simple interface to Maurer's universal statistical test.  For
 118  *              large %$l$% you should use the more complicated restartable
 119  *              interface.
 120  */
 121
 122 extern double maurer(const octet */*p*/, size_t /*sz*/, unsigned /*l*/);
 123
 124 /*----- That's all, folks -------------------------------------------------*/
 125
 126 #ifdef __cplusplus
 127   }
 128 #endif
 129
 130 #endif