1/*==============================================================================
2|
3| File Name:
4|
5| ppIO.c
6|
7| Description:
8|
9| Command line parsing and polynomial pretty printing.
10|
11| Functions:
12|
13| parse_command_line
14| write_poly
15|
16| LEGAL
17|
18| Primpoly Version 16.4 - A Program for Computing Primitive Polynomials.
19| Copyright (C) 1999-2025 by Sean Erik O'Connor. All Rights Reserved.
20|
21| This program is free software: you can redistribute it and/or modify
22| it under the terms of the GNU General Public License as published by
23| the Free Software Foundation, either version 3 of the License, or
24| (at your option) any later version.
25|
26| This program is distributed in the hope that it will be useful,
27| but WITHOUT ANY WARRANTY; without even the implied warranty of
28| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
29| GNU General Public License for more details.
30|
31| You should have received a copy of the GNU General Public License
32| along with this program. If not, see <http://www.gnu.org/licenses/>.
33|
34| The author's address is seanerikoconnor!AT!gmail!DOT!com
35| with !DOT! replaced by . and the !AT! replaced by @
36|
37==============================================================================*/
38
39/*------------------------------------------------------------------------------
40| Include Files |
41------------------------------------------------------------------------------*/
42
43#include <stdio.h> /* for printf() */
44#include <stdlib.h> /* for _MAX_PATH */
45
46#include "Primpoly.h"
47
48
49/*==============================================================================
50| parse_command_line |
51================================================================================
52
53DESCRIPTION
54
55 Parse the command line.
56
57INPUT
58 n
59 a[] (int *) Coefficients of the nth degree polynomial a(x) = a x + ...
60 n
61 + a x + a. a is stored at array location a[i],
62 1 0 i
63 0 <= i < n .
64
65 n (int) The polynomial's degree.
66
67OUTPUT
68
69 testPolynomialForPrimitivity
70
71
72EXAMPLE CALLING SEQUENCE
73
74 pp -h Prints help.
75 pp -s 2 4 Prints search statistics.
76 pp -t 2 4 x^3+x^2+1 Checks a polynomial for primitivity. No blanks, please!
77 pp -a 2 4 Lists all primitive polynomials of degree 4 modulo 2.
78 pp -c 2 4 Does a time-consuming double check on primitivity.
79
80METHOD
81
82
83
84BUGS
85
86 None.
87
88
89--------------------------------------------------------------------------------
90| Function Call |
91------------------------------------------------------------------------------*/
92
93int parse_command_line( int argc,
94 char * argv[],
95 int * testPolynomialForPrimitivity,
96 int * listAllPrimitivePolynomials,
97 int * printStatistics,
98 int * printHelp,
99 int * selfCheck,
100 int * p,
101 int * n,
102 int * testPolynomial )
103{
104
105int input_arg_index ;
106char * input_arg_string ;
107char * option_ptr ;
108
109int num_arg ;
110char * arg_string[ _MAX_PATH ] ;
111
112/* Initialize to defaults. */
113*testPolynomialForPrimitivity = NO ;
114*listAllPrimitivePolynomials = NO ;
115*printStatistics = NO ;
116*printHelp = NO ;
117*selfCheck = NO ;
118*p = 0 ;
119*n = 0 ;
120testPolynomial = (int *) 0 ;
121
122
123/*
124 * Parse the command line to get the options and their inputs.
125 */
126
127for (input_arg_index = 0, num_arg = 0 ; input_arg_index < argc ;
128 ++input_arg_index)
129{
130 /* Get next argument string. */
131 input_arg_string = argv[ input_arg_index ] ;
132
133 /* We have an option: a hyphen followed by a non-null string. */
134 if (input_arg_string[ 0 ] == '-' && input_arg_string[ 1 ] != '\0')
135 {
136 /* Scan all options. */
137 for (option_ptr = input_arg_string + 1 ; *option_ptr != '\0' ;
138 ++option_ptr)
139 {
140 switch( *option_ptr )
141 {
142 /* Test a given polynomial for primitivity. */
143 case 't':
144 *testPolynomialForPrimitivity = YES ;
145 break ;
146
147 /* List all primitive polynomials. */
148 case 'a':
149 *listAllPrimitivePolynomials = YES ;
150 break ;
151
152 /* Print statistics on program operation. */
153 case 's':
154 *printStatistics = YES ;
155 break ;
156
157 /* Print help. */
158 case 'h':
159 case 'H':
160 *printHelp = YES ;
161 break ;
162
163 /* Turn on all self-checking (slow!). */
164 case 'c':
165 *selfCheck = YES ;
166 break ;
167
168 default:
169 printf( "Cannot recognize the option %c\n", *option_ptr ) ;
170 break ;
171 }
172 }
173 }
174 else /* Not an option, but an argument. */
175 {
176 arg_string[ num_arg++ ] = input_arg_string ;
177 }
178}
179
180
181/* Assume the next two arguments are p and n. */
182if (num_arg == 3)
183{
184 *p = atoi( arg_string[ 1 ] ) ;
185 *n = atoi( arg_string[ 2 ] ) ;
186
187}
188else
189{
190 printf( "ERROR: Expecting two arguments, p and n.\n\n" ) ;
191 *printHelp = YES ;
192}
193
194return 0 ;
195
196} /* ================ end of function parse_command_line ==================== */
197
198
199/*==============================================================================
200| write_poly |
201================================================================================
202
203DESCRIPTION
204
205 Print a polynomial in a nice format. Omit terms with coefficients of zero.
206 Suppress coefficients of 1, but not the constant term. Put every
207 NUMTERMSPERLINE terms in the polynomial on a new line.
208
209INPUT
210 n
211 a[] (int *) Coefficients of the nth degree polynomial a(x) = a x + ...
212 n
213 + a x + a. a is stored at array location a[i],
214 1 0 i
215 0 <= i < n .
216
217 n (int) The polynomial's degree.
218
219OUTPUT
220
221 Standard output A pretty-printed polynomial.
222
223EXAMPLE CALLING SEQUENCE
224
225 If array a[] contains
226
227 a[0] = 1
228 a[1] = 2
229 a[2] = 0
230 a[3] = 1
231
232 and n = 3,
233
234 write_poly( a, n ) prints
235
236 x ^ 3 + 2 x + 1
237
238METHOD
239
240 Sheer hacking ingenuity (vulgarity?).
241
242BUGS
243
244 None.
245
246--------------------------------------------------------------------------------
247| Function Call |
248------------------------------------------------------------------------------*/
249
250void write_poly( int * a, int n )
251{
252
253/*------------------------------------------------------------------------------
254| Local Variables |
255------------------------------------------------------------------------------*/
256
257int
258 k, /* Loop conter. */
259 coeff, /* Coefficient a sub k. */
260 first_time_through = YES, /* = NO after printing the first coefficient. */
261 num_terms = 0 ; /* Number of terms printed so far. */
262
263/*------------------------------------------------------------------------------
264| Function Body |
265------------------------------------------------------------------------------*/
266
267for (k = n ; k >= 0 ; --k)
268{
269
270 /*
271 k
272 Print the term a x if a is nonzero.
273 k k
274 */
275
276 if ( (coeff = a[ k ]) != 0)
277 {
278
279 /* After the first time thorough, print leading plus signs "+" to
280 separate the terms of the polynomial. */
281
282 if (!first_time_through)
283
284 printf( " + " ) ;
285
286 first_time_through = NO ;
287
288 /* Always print the constant term a but print terms of higher degree
289 0
290 only if a is not 1.
291 k */
292
293 if ( (coeff != 1) || (k == 0) )
294
295 printf( "%d", coeff ) ;
296
297
298 /* k 1 0
299 Print the term x. Exceptions: print x, not x, omit x */
300
301 if (k > 1)
302
303 printf( " x ^ %d", k ) ;
304
305 else if (k == 1)
306
307 printf( " x" ) ;
308
309 /* Start a new line. */
310
311 if (++num_terms % NUMTERMSPERLINE == 0)
312
313 printf( "\n" ) ;
314
315 } /* end if coeff > 0 */
316
317} /* end for */
318
319printf( "\n" ) ;
320
321return ;
322
323} /* ======================= end of function write_poly ===================== */
