| 1 |
//$Header: /cvsroot/esrg/sfesrg/esrgnxpj/sfnthcgi0304/subfunc_gcd.c,v 1.5 2003/07/01 03:46:58 dtashley Exp $
|
| 2 |
//
|
| 3 |
//********************************************************************************
|
| 4 |
//Copyright (C) 2003 David T. Ashley
|
| 5 |
//********************************************************************************
|
| 6 |
//This program or source file is free software; you can redistribute it and/or
|
| 7 |
//modify it under the terms of the GNU General Public License as published by
|
| 8 |
//the Free Software Foundation; either version 2 of the License, or (at your
|
| 9 |
//option) any later version.
|
| 10 |
//
|
| 11 |
//This program or source file is distributed in the hope that it will
|
| 12 |
//be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
|
| 13 |
//MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
| 14 |
//GNU General Public License for more details.
|
| 15 |
//
|
| 16 |
//You may have received a copy of the GNU General Public License
|
| 17 |
//along with this program; if not, write to the Free Software
|
| 18 |
//Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
| 19 |
//
|
| 20 |
//This module is the GCD subfunction of a general-purpose CGI-BIN program to support
|
| 21 |
//number theory demonstration applications.
|
| 22 |
//
|
| 23 |
//INPUT PARAMETERS
|
| 24 |
//----------------
|
| 25 |
//The subfunction accepts two parameters, the integers whose GCD is to be
|
| 26 |
//calculated. There is substantial tolerance for invalid characters.
|
| 27 |
//Naturally, the integers should be positive.
|
| 28 |
//
|
| 29 |
//OUTPUT RESULTS
|
| 30 |
//--------------
|
| 31 |
//The notation below gives the outputs of the program. In some cases, [i] notation
|
| 32 |
//is used to indicate line numbers.
|
| 33 |
//
|
| 34 |
//[01] An overall success or failure code for the operation. Valid responses
|
| 35 |
// are:
|
| 36 |
// S : Success.
|
| 37 |
// EP1A : The first integer could not be parsed, which means it is ill-formatted.
|
| 38 |
// EP1B : The first integer was zero or negative.
|
| 39 |
// EP2A : The second integer could not be parsed, which means it is ill-formatted.
|
| 40 |
// EP2B : The second integer was zero or negative.
|
| 41 |
// EQ : Other or unspecified error.
|
| 42 |
//
|
| 43 |
//[02] The fully normalized first integer entered. This means it has been
|
| 44 |
// stripped of all weird characters, etc. This can be used by the
|
| 45 |
// PHP script to repopulate the form boxes.
|
| 46 |
//[03] The fully normalized second integer entered.
|
| 47 |
//
|
| 48 |
//In the event that the status code indicates error, no further lines
|
| 49 |
//will be written.
|
| 50 |
//
|
| 51 |
//[04] The round number of the application of Euclid's algorithm, starting
|
| 52 |
// at "1".
|
| 53 |
//[05] "a".
|
| 54 |
//[06] "b".
|
| 55 |
//[07] a div b.
|
| 56 |
//[08] a mod b.
|
| 57 |
//[09] ... repeating sequence, starting back at [4] and repeating until a
|
| 58 |
// zero remainder.
|
| 59 |
//[..] The GCD of the two integers. This will be positive and
|
| 60 |
// contain no commas or extraneous characters.
|
| 61 |
//[..] "S", indicating success.
|
| 62 |
//
|
| 63 |
//Note that as per the definition above, any valid non-error output from
|
| 64 |
//this program will contain a number of lines which is a multiple of 5.
|
| 65 |
//
|
| 66 |
//The return value (exit code) from this subfunction is always 0.
|
| 67 |
//
|
| 68 |
|
| 69 |
#define MODULE_SUBFUNC_GCD
|
| 70 |
|
| 71 |
#include <assert.h>
|
| 72 |
#include <ctype.h>
|
| 73 |
#include <stddef.h>
|
| 74 |
#include <stdio.h>
|
| 75 |
#include <stdlib.h>
|
| 76 |
#include <string.h>
|
| 77 |
#include <time.h>
|
| 78 |
|
| 79 |
#include <gmp.h>
|
| 80 |
|
| 81 |
#include "auxfuncs.h"
|
| 82 |
#include "subfunc_gcd.h"
|
| 83 |
|
| 84 |
int SUBFUNC_GCD_main(int argc, char *argv[])
|
| 85 |
{
|
| 86 |
//Normalized first and second parameters (the integers).
|
| 87 |
char *arg1;
|
| 88 |
char *arg2;
|
| 89 |
|
| 90 |
//GMP types to maintain the algorithm.
|
| 91 |
int round;
|
| 92 |
mpz_t alg_a, alg_b, alg_adivb, alg_amodb;
|
| 93 |
|
| 94 |
//There must be an acceptable number of command-line arguments.
|
| 95 |
if (argc != 4)
|
| 96 |
{
|
| 97 |
printf("EQ\n0\n0\n");
|
| 98 |
return(0);
|
| 99 |
}
|
| 100 |
|
| 101 |
//Copy the command-line arguments to a safe place where we can manipulate them.
|
| 102 |
//Leave 2 characters of space in case we assign a "0".
|
| 103 |
arg1 = (char *)malloc((AUXFUNCS_size_t_max(1, strlen(argv[2])) + 1) * sizeof(char));
|
| 104 |
arg2 = (char *)malloc((AUXFUNCS_size_t_max(1, strlen(argv[3])) + 1) * sizeof(char));
|
| 105 |
if ((arg1 == NULL) || (arg2 == NULL))
|
| 106 |
{
|
| 107 |
printf("EQ\n%s\n%s\n", argv[2], argv[3]);
|
| 108 |
exit(0);
|
| 109 |
}
|
| 110 |
strcpy(arg1, argv[2]);
|
| 111 |
strcpy(arg2, argv[3]);
|
| 112 |
|
| 113 |
//Strip all of the non-digit trash out of the arguments.
|
| 114 |
AUXFUNCS_remove_non_digits(arg1);
|
| 115 |
AUXFUNCS_remove_non_digits(arg2);
|
| 116 |
|
| 117 |
//Remove all leading zeros from both arguments.
|
| 118 |
AUXFUNCS_remove_leading_zeros(arg1);
|
| 119 |
AUXFUNCS_remove_leading_zeros(arg2);
|
| 120 |
|
| 121 |
//If either argument is zero length, fill it in with 0.
|
| 122 |
if (!strlen(arg1))
|
| 123 |
strcpy(arg1, "0");
|
| 124 |
if (!strlen(arg2))
|
| 125 |
strcpy(arg2, "0");
|
| 126 |
|
| 127 |
//If either argument exceeds 1000 digits, abort.
|
| 128 |
if ((strlen(arg1)>1000) || (strlen(arg2) > 1000))
|
| 129 |
{
|
| 130 |
printf("EQ\n0\n0\n");
|
| 131 |
return(0);
|
| 132 |
}
|
| 133 |
|
| 134 |
//If either argument is zero, abort.
|
| 135 |
if (!strcmp(arg1, "0"))
|
| 136 |
{
|
| 137 |
printf("EP1B\n0\n0\n");
|
| 138 |
return(0);
|
| 139 |
}
|
| 140 |
if (!strcmp(arg2, "0"))
|
| 141 |
{
|
| 142 |
printf("EP2B\n0\n0\n");
|
| 143 |
return(0);
|
| 144 |
}
|
| 145 |
|
| 146 |
//Initialize all of the GMP variables.
|
| 147 |
mpz_init(alg_a);
|
| 148 |
mpz_init(alg_b);
|
| 149 |
mpz_init(alg_adivb);
|
| 150 |
mpz_init(alg_amodb);
|
| 151 |
|
| 152 |
//Assign a and b to initial values.
|
| 153 |
mpz_set_str(alg_a, arg1, 10);
|
| 154 |
mpz_set_str(alg_b, arg2, 10);
|
| 155 |
|
| 156 |
//We assume at this point that we will be successful. Output
|
| 157 |
//the header stuff.
|
| 158 |
printf("S\n");
|
| 159 |
mpz_out_str(stdout, 10, alg_a);
|
| 160 |
printf("\n");
|
| 161 |
mpz_out_str(stdout, 10, alg_b);
|
| 162 |
printf("\n");
|
| 163 |
|
| 164 |
//We require as an initial condition that a >= b. Make
|
| 165 |
//that happen.
|
| 166 |
if (mpz_cmp(alg_a, alg_b) < 0)
|
| 167 |
{
|
| 168 |
mpz_swap(alg_a, alg_b);
|
| 169 |
}
|
| 170 |
|
| 171 |
//To make the algorithm cleaner, we preload for the first
|
| 172 |
//assignment.
|
| 173 |
mpz_set(alg_amodb, alg_b);
|
| 174 |
mpz_set(alg_b, alg_a);
|
| 175 |
|
| 176 |
//Now begin the algorithm proper.
|
| 177 |
round = 0;
|
| 178 |
do
|
| 179 |
{
|
| 180 |
//We are at next round.
|
| 181 |
round++;
|
| 182 |
|
| 183 |
//Values for this round inherited from the last one.
|
| 184 |
mpz_set(alg_a, alg_b);
|
| 185 |
mpz_set(alg_b, alg_amodb);
|
| 186 |
|
| 187 |
//Calculate the quotient and remainder.
|
| 188 |
mpz_fdiv_qr(alg_adivb, alg_amodb, alg_a, alg_b);
|
| 189 |
|
| 190 |
//Output all the data from the round.
|
| 191 |
printf("%d\n", round);
|
| 192 |
mpz_out_str(stdout, 10, alg_a);
|
| 193 |
printf("\n");
|
| 194 |
mpz_out_str(stdout, 10, alg_b);
|
| 195 |
printf("\n");
|
| 196 |
mpz_out_str(stdout, 10, alg_adivb);
|
| 197 |
printf("\n");
|
| 198 |
mpz_out_str(stdout, 10, alg_amodb);
|
| 199 |
printf("\n");
|
| 200 |
}
|
| 201 |
while((round < 2000) && (mpz_sgn(alg_amodb) > 0));
|
| 202 |
|
| 203 |
//The GCD canonically will be the last non-zero remainder.
|
| 204 |
mpz_out_str(stdout, 10, alg_b);
|
| 205 |
printf("\n");
|
| 206 |
|
| 207 |
//Finally, we output the trailing "S".
|
| 208 |
printf("S\n");
|
| 209 |
|
| 210 |
return(0);
|
| 211 |
}
|
| 212 |
|
| 213 |
//********************************************************************************
|
| 214 |
// $Log: subfunc_gcd.c,v $
|
| 215 |
// Revision 1.5 2003/07/01 03:46:58 dtashley
|
| 216 |
// Edits towards working continued fraction best rational approximation
|
| 217 |
// functionality.
|
| 218 |
//
|
| 219 |
// Revision 1.4 2003/04/17 20:02:05 dtashley
|
| 220 |
// License text for the GPL added. All source files are now under the GPL,
|
| 221 |
// after some discussion on the GMP list.
|
| 222 |
//
|
| 223 |
// Revision 1.3 2003/04/14 23:27:01 dtashley
|
| 224 |
// Subfunction GMP_PROB_PRIME finished.
|
| 225 |
//
|
| 226 |
// Revision 1.2 2003/04/14 02:55:25 dtashley
|
| 227 |
// Final edits on GCD.
|
| 228 |
//
|
| 229 |
// Revision 1.1 2003/04/13 23:46:06 dtashley
|
| 230 |
// Initial checkin.
|
| 231 |
//********************************************************************************
|
| 232 |
// End of SUBFUNC_GCD.C.
|
| 233 |
//********************************************************************************
|
Parent Directory
| 
Revision Log