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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: mpscan.c,v 1.4 2004/04/08 01:36:15 mdw Exp $ |
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4 | * |
5 | * Sequential bit scan of multiprecision integers |
6 | * |
7 | * (c) 1999 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 | /*----- Header files ------------------------------------------------------*/ |
31 | |
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32 | #include "mpscan.h" |
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33 | |
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34 | /*----- Right-to-left scanning --------------------------------------------*/ |
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35 | |
36 | /* --- @mpscan_initx@ --- * |
37 | * |
38 | * Arguments: @mpscan *m@ = pointer to bitscanner structure |
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39 | * @const mpw *v, *vl@ = vector of words to scan |
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40 | * |
41 | * Returns: --- |
42 | * |
43 | * Use: Initializes a bitscanner from a low-level vector-and-length |
44 | * representation of an integer. Initially no bit is ready; you |
45 | * must call @mpscan_step@ before anything useful will come |
46 | * out. |
47 | */ |
48 | |
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49 | void mpscan_initx(mpscan *m, const mpw *v, const mpw *vl) |
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50 | { |
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51 | MPSCAN_INITX(m, v, vl); |
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52 | } |
53 | |
54 | /* --- @mpscan_step@ --- * |
55 | * |
56 | * Arguments: @mpscan *m@ = pointer to bitscanner |
57 | * |
58 | * Returns: Nonzero if there is another bit to read. |
59 | * |
60 | * Use: Steps on to the next bit in the integer. The macro version |
61 | * evaluates its argument multiple times. |
62 | */ |
63 | |
64 | int mpscan_step(mpscan *m) { return (MPSCAN_STEP(m)); } |
65 | |
66 | /* --- @mpscan_bit@ --- * |
67 | * |
68 | * Arguments: @const mpscan *m@ = pointer to bitscanner |
69 | * |
70 | * Returns: The value of the current bit. |
71 | * |
72 | * Use: Reads the value of the current bit looked at by a |
73 | * bitscanner. |
74 | */ |
75 | |
76 | int mpscan_bit(const mpscan *m) { return (MPSCAN_BIT(m)); } |
77 | |
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78 | /*----- Left-to right-scanning --------------------------------------------*/ |
79 | |
80 | /* --- @mpscan_rinitx@ --- * |
81 | * |
82 | * Arguments: @mpscan *m@ = pointer to bitscanner structure |
83 | * @const mpw *v, *vl@ = vector of words to scan |
84 | * |
85 | * Returns: --- |
86 | * |
87 | * Use: Initializes a reverse bitscanner from a low-level |
88 | * vector-and-length representation of an integer. Initially no |
89 | * bit is ready; you must call @mpscan_rstep@ before anything |
90 | * useful will come out. |
91 | */ |
92 | |
93 | void mpscan_rinitx(mpscan *m, const mpw *v, const mpw *vl) |
94 | { |
95 | MPSCAN_RINITX(m, v, vl); |
96 | } |
97 | |
98 | /* --- @mpscan_rstep@ --- * |
99 | * |
100 | * Arguments: @mpscan *m@ = pointer to bitscanner |
101 | * |
102 | * Returns: Nonzero if there is another bit to read. |
103 | * |
104 | * Use: Steps on to the next bit in the integer. The macro version |
105 | * evaluates its argument multiple times. |
106 | */ |
107 | |
108 | int mpscan_rstep(mpscan *m) { return (MPSCAN_RSTEP(m)); } |
109 | |
110 | /* --- @mpscan_rbit@ --- * |
111 | * |
112 | * Arguments: @const mpscan *m@ = pointer to bitscanner |
113 | * |
114 | * Returns: The value of the current bit. |
115 | * |
116 | * Use: Reads the value of the current bit looked at by a |
117 | * reverse bitscanner. |
118 | */ |
119 | |
120 | int mpscan_rbit(const mpscan *m) { return (MPSCAN_RBIT(m)); } |
121 | |
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122 | /*----- That's all, folks -------------------------------------------------*/ |