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author | Lorry <lorry@roadtrain.codethink.co.uk> | 2012-07-18 20:31:20 +0100 |
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committer | Lorry <lorry@roadtrain.codethink.co.uk> | 2012-07-18 20:31:20 +0100 |
commit | e43ad1f4ce7f1504e6f01fc8a90d5c0398013383 (patch) | |
tree | 03504d9d81336081b899c9f34cc0f66801caf67c /mozilla/security/nss/lib/freebl/mpi/utils/fact.c | |
download | nss-e43ad1f4ce7f1504e6f01fc8a90d5c0398013383.tar.gz |
Tarball conversion
Diffstat (limited to 'mozilla/security/nss/lib/freebl/mpi/utils/fact.c')
-rw-r--r-- | mozilla/security/nss/lib/freebl/mpi/utils/fact.c | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/mozilla/security/nss/lib/freebl/mpi/utils/fact.c b/mozilla/security/nss/lib/freebl/mpi/utils/fact.c new file mode 100644 index 0000000..384500e --- /dev/null +++ b/mozilla/security/nss/lib/freebl/mpi/utils/fact.c @@ -0,0 +1,115 @@ +/* + * fact.c + * + * Compute factorial of input integer + * + * ***** BEGIN LICENSE BLOCK ***** + * Version: MPL 1.1/GPL 2.0/LGPL 2.1 + * + * The contents of this file are subject to the Mozilla Public License Version + * 1.1 (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * http://www.mozilla.org/MPL/ + * + * Software distributed under the License is distributed on an "AS IS" basis, + * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License + * for the specific language governing rights and limitations under the + * License. + * + * The Original Code is the MPI Arbitrary Precision Integer Arithmetic library. + * + * The Initial Developer of the Original Code is + * Michael J. Fromberger. + * Portions created by the Initial Developer are Copyright (C) 1998 + * the Initial Developer. All Rights Reserved. + * + * Contributor(s): + * + * Alternatively, the contents of this file may be used under the terms of + * either the GNU General Public License Version 2 or later (the "GPL"), or + * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), + * in which case the provisions of the GPL or the LGPL are applicable instead + * of those above. If you wish to allow use of your version of this file only + * under the terms of either the GPL or the LGPL, and not to allow others to + * use your version of this file under the terms of the MPL, indicate your + * decision by deleting the provisions above and replace them with the notice + * and other provisions required by the GPL or the LGPL. If you do not delete + * the provisions above, a recipient may use your version of this file under + * the terms of any one of the MPL, the GPL or the LGPL. + * + * ***** END LICENSE BLOCK ***** */ +/* $Id: fact.c,v 1.3 2004/04/27 23:04:37 gerv%gerv.net Exp $ */ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include "mpi.h" + +mp_err mp_fact(mp_int *a, mp_int *b); + +int main(int argc, char *argv[]) +{ + mp_int a; + mp_err res; + + if(argc < 2) { + fprintf(stderr, "Usage: %s <number>\n", argv[0]); + return 1; + } + + mp_init(&a); + mp_read_radix(&a, argv[1], 10); + + if((res = mp_fact(&a, &a)) != MP_OKAY) { + fprintf(stderr, "%s: error: %s\n", argv[0], + mp_strerror(res)); + mp_clear(&a); + return 1; + } + + { + char *buf; + int len; + + len = mp_radix_size(&a, 10); + buf = malloc(len); + mp_todecimal(&a, buf); + + puts(buf); + + free(buf); + } + + mp_clear(&a); + return 0; +} + +mp_err mp_fact(mp_int *a, mp_int *b) +{ + mp_int ix, s; + mp_err res = MP_OKAY; + + if(mp_cmp_z(a) < 0) + return MP_UNDEF; + + mp_init(&s); + mp_add_d(&s, 1, &s); /* s = 1 */ + mp_init(&ix); + mp_add_d(&ix, 1, &ix); /* ix = 1 */ + + for(/* */; mp_cmp(&ix, a) <= 0; mp_add_d(&ix, 1, &ix)) { + if((res = mp_mul(&s, &ix, &s)) != MP_OKAY) + break; + } + + mp_clear(&ix); + + /* Copy out results if we got them */ + if(res == MP_OKAY) + mp_copy(&s, b); + + mp_clear(&s); + + return res; +} |