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comparison bn_mp_is_square.c @ 142:d29b64170cf0 libtommath-orig

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import of libtommath 0.32
author Matt Johnston <matt@ucc.asn.au>
date Sun, 19 Dec 2004 11:33:56 +0000
parents 86e0b50a9b58
children
comparison
equal deleted inserted replaced
19:e1037a1e12e7 142:d29b64170cf0
1 #include <tommath.h>
2 #ifdef BN_MP_IS_SQUARE_C
1 /* LibTomMath, multiple-precision integer library -- Tom St Denis 3 /* LibTomMath, multiple-precision integer library -- Tom St Denis
2 * 4 *
3 * LibTomMath is a library that provides multiple-precision 5 * LibTomMath is a library that provides multiple-precision
4 * integer arithmetic as well as number theoretic functionality. 6 * integer arithmetic as well as number theoretic functionality.
5 * 7 *
10 * The library is free for all purposes without any express 12 * The library is free for all purposes without any express
11 * guarantee it works. 13 * guarantee it works.
12 * 14 *
13 * Tom St Denis, [email protected], http://math.libtomcrypt.org 15 * Tom St Denis, [email protected], http://math.libtomcrypt.org
14 */ 16 */
15 #include <tommath.h>
16 17
17 /* Check if remainders are possible squares - fast exclude non-squares */ 18 /* Check if remainders are possible squares - fast exclude non-squares */
18 static const char rem_128[128] = { 19 static const char rem_128[128] = {
19 0, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 20 0, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1,
20 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 21 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1,
67 } 68 }
68 if (rem_105[c] == 1) { 69 if (rem_105[c] == 1) {
69 return MP_OKAY; 70 return MP_OKAY;
70 } 71 }
71 72
72 /* product of primes less than 2^31 */ 73
73 if ((res = mp_init_set_int(&t,11L*13L*17L*19L*23L*29L*31L)) != MP_OKAY) { 74 if ((res = mp_init_set_int(&t,11L*13L*17L*19L*23L*29L*31L)) != MP_OKAY) {
74 return res; 75 return res;
75 } 76 }
76 if ((res = mp_mod(arg,&t,&t)) != MP_OKAY) { 77 if ((res = mp_mod(arg,&t,&t)) != MP_OKAY) {
77 goto ERR; 78 goto ERR;
99 100
100 *ret = (mp_cmp_mag(&t,arg) == MP_EQ) ? MP_YES : MP_NO; 101 *ret = (mp_cmp_mag(&t,arg) == MP_EQ) ? MP_YES : MP_NO;
101 ERR:mp_clear(&t); 102 ERR:mp_clear(&t);
102 return res; 103 return res;
103 } 104 }
105 #endif