git.distorted.org.uk Git - u/mdw/catacomb/blob - rand/maurer.h

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