3 * $Id: mpscan.c,v 1.3 2000/07/29 17:03:31 mdw Exp $
5 * Sequential bit scan of multiprecision integers
7 * (c) 1999 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of Catacomb.
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.
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.
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,
30 /*----- Revision history --------------------------------------------------*
33 * Revision 1.3 2000/07/29 17:03:31 mdw
34 * Add support for left-to-right bitscanning, for use in modular
37 * Revision 1.2 1999/11/13 01:55:10 mdw
38 * Fixed so that they compile. Minor interface changes.
40 * Revision 1.1 1999/09/03 08:41:12 mdw
45 /*----- Header files ------------------------------------------------------*/
49 /*----- Right-to-left scanning --------------------------------------------*/
51 /* --- @mpscan_initx@ --- *
53 * Arguments: @mpscan *m@ = pointer to bitscanner structure
54 * @const mpw *v, *vl@ = vector of words to scan
58 * Use: Initializes a bitscanner from a low-level vector-and-length
59 * representation of an integer. Initially no bit is ready; you
60 * must call @mpscan_step@ before anything useful will come
64 void mpscan_initx(mpscan
*m
, const mpw
*v
, const mpw
*vl
)
66 MPSCAN_INITX(m
, v
, vl
);
69 /* --- @mpscan_step@ --- *
71 * Arguments: @mpscan *m@ = pointer to bitscanner
73 * Returns: Nonzero if there is another bit to read.
75 * Use: Steps on to the next bit in the integer. The macro version
76 * evaluates its argument multiple times.
79 int mpscan_step(mpscan
*m
) { return (MPSCAN_STEP(m
)); }
81 /* --- @mpscan_bit@ --- *
83 * Arguments: @const mpscan *m@ = pointer to bitscanner
85 * Returns: The value of the current bit.
87 * Use: Reads the value of the current bit looked at by a
91 int mpscan_bit(const mpscan
*m
) { return (MPSCAN_BIT(m
)); }
93 /*----- Left-to right-scanning --------------------------------------------*/
95 /* --- @mpscan_rinitx@ --- *
97 * Arguments: @mpscan *m@ = pointer to bitscanner structure
98 * @const mpw *v, *vl@ = vector of words to scan
102 * Use: Initializes a reverse bitscanner from a low-level
103 * vector-and-length representation of an integer. Initially no
104 * bit is ready; you must call @mpscan_rstep@ before anything
105 * useful will come out.
108 void mpscan_rinitx(mpscan
*m
, const mpw
*v
, const mpw
*vl
)
110 MPSCAN_RINITX(m
, v
, vl
);
113 /* --- @mpscan_rstep@ --- *
115 * Arguments: @mpscan *m@ = pointer to bitscanner
117 * Returns: Nonzero if there is another bit to read.
119 * Use: Steps on to the next bit in the integer. The macro version
120 * evaluates its argument multiple times.
123 int mpscan_rstep(mpscan
*m
) { return (MPSCAN_RSTEP(m
)); }
125 /* --- @mpscan_rbit@ --- *
127 * Arguments: @const mpscan *m@ = pointer to bitscanner
129 * Returns: The value of the current bit.
131 * Use: Reads the value of the current bit looked at by a
132 * reverse bitscanner.
135 int mpscan_rbit(const mpscan
*m
) { return (MPSCAN_RBIT(m
)); }
137 /*----- That's all, folks -------------------------------------------------*/