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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: maurer.h,v 1.3 2004/04/08 01:36:15 mdw Exp $ |
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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 | |
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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 | |
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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 | |
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52 | /*----- Functions provided ------------------------------------------------*/ |
53 | |
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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 | |
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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 | * |
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104 | * Returns: The statistic %$Z_u$%. |
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105 | * |
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106 | * Use: Simple interface to Maurer's universal statistical test. For |
107 | * large %$l$% you should use the more complicated restartable |
108 | * interface. |
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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 |