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1 | /* -*-c-*- |
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2 | * |
3 | * Maurer's universal statistical test |
4 | * |
5 | * (c) 2000 Straylight/Edgeware |
6 | */ |
7 | |
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8 | /*----- Licensing notice --------------------------------------------------* |
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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. |
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16 | * |
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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. |
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21 | * |
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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 | |
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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 | |
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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 | |
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50 | /*----- Functions provided ------------------------------------------------*/ |
51 | |
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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 | |
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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 | * |
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102 | * Returns: The statistic %$Z_u$%. |
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103 | * |
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104 | * Use: Simple interface to Maurer's universal statistical test. For |
105 | * large %$l$% you should use the more complicated restartable |
106 | * interface. |
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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 |