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//$Header$ |
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//******************************************************************************** |
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//Copyright (c) 2003, 2018 David T. Ashley. |
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//******************************************************************************** |
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//This file is part of "arith_large_cgi", a program that is designed to be |
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//invoked by a PHP script as part of serving a web page that performs |
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//calculations involving large integers. (A secondary compiled program is |
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//used because a compiled program can perform certain calculation-intensive |
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//tasks far more efficiently than a PHP script.) This program is provided by |
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//David T. Ashley (dashley@gmail.com) under the MIT License (reproduced |
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//immediately below). |
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//******************************************************************************** |
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//Permission is hereby granted, free of charge, to any person obtaining a copy |
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//of this software and associated documentation files (the "Software"), to deal |
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//in the Software without restriction, including without limitation the rights |
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//to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
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//copies of the Software, and to permit persons to whom the Software is |
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//furnished to do so, subject to the following conditions: |
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// |
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//The above copyright notice and this permission notice shall be included in all |
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//copies or substantial portions of the Software. |
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// |
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//THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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//IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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//FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
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//AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
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//LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
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//OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
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//SOFTWARE. |
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//******************************************************************************** |
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//This program is written exclusively to support a PHP script which must calculate and |
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//display a number of number theory results. The necessity of this script |
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//(rather than using BCMATH) comes about because SourceForge does not have |
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//bcmath installed on its PHP system. |
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// |
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//This program is meant to be called by the PHP script using the exec() |
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//call, but could also be run by hand (and in fact this method is used for testing). |
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// |
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//The first parameter after the program name is the suboperation to be performed |
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//(each CGI page probably uses a different suboperation). This program |
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//will return a non-zero exit code only if there is a missing or unrecognized |
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//suboperation. Otherwise, error reporting is controlled by the rules of the |
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//suboperation. |
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// |
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//The currently defined suboperations are: |
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// |
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// a)"help" |
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// Display information about what the program is and how to use |
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// it. |
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// b)"gcd" |
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// Calculate the gcd of two integers using Euclid's classic |
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// algorithm and also display the intermediate results. |
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// c)"gmp_prob_prime" |
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// Use Miller-Rabin to determine to high certainty whther a |
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// number is prime or composite. |
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// d)"pfact_18" |
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// Attempt to factor a number of 18 decimal digits or less into |
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// component primes. |
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// e)"cfbrap" |
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// Finds the best rational approximation to a rational number subject |
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// to constraints on the denominator and numerator using continued |
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// fraction techniques. |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <string.h> |
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#include "auxfuncs.h" |
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#include "subfunc_cfbrap.h" |
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#include "subfunc_gcd.h" |
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#include "subfunc_gmp_prob_prime.h" |
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#include "subfunc_pfact_18.h" |
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//Single function prototype needed for a forward reference. |
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static void dump_subfunction_choices(int indent); |
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//Implements the help. |
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int SUBFUNC_HELP_main(int argc, char *argv[]) |
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{ |
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int i; |
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char *help[] = |
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{ |
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"This program is a compiled 'C'-language program designed to be called from a", |
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"PHP script to assist in calculating number theory and large integer", |
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"arithmetic results. This scheme (of having a separate executable like this", |
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"one) was used with SourceForge web content because SourceForge did not have", |
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"the bcmath library compiled into PHP, and it was determined experimentally", |
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"that writing large integer arithmetic functions in PHP directly resulted in", |
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"unusably slow performance. This program makes use of the GMP library, which", |
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"gives it superior performance.", |
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"", |
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"This program can of course be invoked from a shell or from another scripting", |
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"language besides PHP. It is designed, however, for execution from a", |
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"scripting language, as you might guess from the human-unfriendly output.", |
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"", |
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"Please contact Dave Ashley (dtashley@aol.com) with any questions or", |
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"concerns.", |
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"", |
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"Dave Ashley, Detroit, Michigan, USA, April, 2003.", |
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"", |
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"The available subfunction choices (the first parameter on the command", |
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"line) are:", |
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}; |
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for (i=0; i<sizeof(help)/sizeof(help[0]); i++) |
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printf("%s\n", help[i]); |
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dump_subfunction_choices(3); |
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} |
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//Structure type used to hold the jump table of different functions |
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//to handle different subcommands. |
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struct struct_ARITH_LARGE_CGI_subcmd_jmp |
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{ |
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char *subfunc_string; |
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int (*subfunc_ptr)(int argc, char *argv[]); |
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}; |
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//The jump table. The last element is defined to have both a |
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//NULL string pointer and a NULL function pointer. |
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static struct struct_ARITH_LARGE_CGI_subcmd_jmp subcmd_jump_tbl[] = |
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{ |
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{"cfbrap", SUBFUNC_CFBRAP_main }, |
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{"gcd", SUBFUNC_GCD_main }, |
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{"gmp_prob_prime", SUBFUNC_GMP_PROB_PRIME_main }, |
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{"pfact_18", SUBFUNC_PFACT_18_main }, |
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{"help", SUBFUNC_HELP_main }, |
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{NULL, NULL } |
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}; |
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//Dumps the available choices for the subfunction code to the |
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//standard output, each indented by "indent" characters. |
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static void dump_subfunction_choices(int indent) |
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{ |
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int i, j; |
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for (i=0; subcmd_jump_tbl[i].subfunc_string != NULL; i++) |
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{ |
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for (j=0; j<indent; j++) |
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printf(" "); |
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printf("%s\n", subcmd_jump_tbl[i].subfunc_string); |
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} |
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} |
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int main(int argc, char *argv[]) |
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{ |
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int i; |
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int rv; |
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if (argc < 2) |
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{ |
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printf("Missing subfunction code. Choices are:\n"); |
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dump_subfunction_choices(3); |
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exit(4); |
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} |
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for (i=0; subcmd_jump_tbl[i].subfunc_string != NULL; i++) |
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{ |
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if (!strcmp(argv[1], subcmd_jump_tbl[i].subfunc_string)) |
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{ |
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rv = (subcmd_jump_tbl[i].subfunc_ptr)(argc, argv); |
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goto normal_return; |
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} |
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} |
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printf("Invalid subfunction code. Choices are:\n"); |
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dump_subfunction_choices(3); |
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exit(4); |
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normal_return: |
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exit(rv); |
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} |
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//******************************************************************************** |
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//End of file ARITH_LARGE_CGI.C. |
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//******************************************************************************** |