3 * $Id: mpscan.h,v 1.3 1999/12/10 23:29:48 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 1999/12/10 23:29:48 mdw
34 * Change header file guard names.
36 * Revision 1.2 1999/11/13 01:55:10 mdw
37 * Fixed so that they compile. Minor interface changes.
39 * Revision 1.1 1999/09/03 08:41:12 mdw
44 #ifndef CATACOMB_MPSCAN_H
45 #define CATACOMB_MPSCAN_H
51 /*----- Header files ------------------------------------------------------*/
53 #ifndef CATACOMB_MPW_H
57 /*----- Data structures ---------------------------------------------------*/
59 typedef struct mpscan
{
60 const mpw
*v
, *vl
; /* Vector of words to scan */
61 mpw w
; /* Current word to scan */
62 int bits
; /* Number of bits left in @w@ */
65 /*----- Functions provided ------------------------------------------------*/
67 /* --- @mpscan_initx@ --- *
69 * Arguments: @mpscan *m@ = pointer to bitscanner structure
70 * @const mpw *v, *vl@ = vector of words to scan
74 * Use: Initializes a bitscanner from a low-level base-and-limit
75 * representation of an integer. Initially no bit is ready; you
76 * must call @mpscan_step@ before anything useful will come
80 #define MPSCAN_INITX(m_, v_, vl_) do { \
87 extern void mpscan_initx(mpscan */
*m*/
, const mpw */
*v*/
, const mpw */
*vl*/
);
89 /* --- @mpscan_step@ --- *
91 * Arguments: @mpscan *m@ = pointer to bitscanner
93 * Returns: Nonzero if there is another bit to read.
95 * Use: Steps on to the next bit in the integer. The macro version
96 * evaluates its argument multiple times.
99 #define MPSCAN_STEP(m) \
100 ((m)->bits ? ((m)->w >>= 1, \
102 (m)->v < (m)->vl ? ((m)->w = *(m)->v++, \
103 (m)->bits = MPW_BITS - 1, 1) : \
106 extern int mpscan_step(mpscan */
*m*/
);
108 /* --- @mpscan_bit@ --- *
110 * Arguments: @const mpscan *m@ = pointer to bitscanner
112 * Returns: The value of the current bit.
114 * Use: Reads the value of the current bit looked at by a
118 #define MPSCAN_BIT(m) ((m)->w & 1)
120 extern int mpscan_bit(const mpscan */
*m*/
);
122 /*----- That's all, folks -------------------------------------------------*/