| 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 |