diff options
Diffstat (limited to 'libtommath/bn_mp_is_square.c')
| -rw-r--r-- | libtommath/bn_mp_is_square.c | 158 |
1 files changed, 71 insertions, 87 deletions
diff --git a/libtommath/bn_mp_is_square.c b/libtommath/bn_mp_is_square.c index dd08d58..69e77a2 100644 --- a/libtommath/bn_mp_is_square.c +++ b/libtommath/bn_mp_is_square.c @@ -1,109 +1,93 @@ -#include <tommath_private.h> +#include "tommath_private.h" #ifdef BN_MP_IS_SQUARE_C -/* LibTomMath, multiple-precision integer library -- Tom St Denis - * - * LibTomMath is a library that provides multiple-precision - * integer arithmetic as well as number theoretic functionality. - * - * The library was designed directly after the MPI library by - * Michael Fromberger but has been written from scratch with - * additional optimizations in place. - * - * The library is free for all purposes without any express - * guarantee it works. - * - * Tom St Denis, tstdenis82@gmail.com, http://libtom.org - */ +/* LibTomMath, multiple-precision integer library -- Tom St Denis */ +/* SPDX-License-Identifier: Unlicense */ /* Check if remainders are possible squares - fast exclude non-squares */ static const char rem_128[128] = { - 0, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, - 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, - 1, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, - 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, - 0, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, - 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, - 1, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, - 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1 + 0, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, + 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, + 1, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, + 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, + 0, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, + 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, + 1, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, + 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1 }; static const char rem_105[105] = { - 0, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, - 0, 0, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, - 0, 1, 1, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 1, 1, - 1, 0, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, - 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, - 1, 1, 1, 1, 0, 1, 0, 1, 1, 0, 0, 1, 1, 1, 1, - 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1 + 0, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, + 0, 0, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, + 0, 1, 1, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 1, 1, + 1, 0, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, + 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, + 1, 1, 1, 1, 0, 1, 0, 1, 1, 0, 0, 1, 1, 1, 1, + 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1 }; /* Store non-zero to ret if arg is square, and zero if not */ -int mp_is_square(mp_int *arg,int *ret) +mp_err mp_is_square(const mp_int *arg, mp_bool *ret) { - int res; - mp_digit c; - mp_int t; - unsigned long r; + mp_err err; + mp_digit c; + mp_int t; + unsigned long r; - /* Default to Non-square :) */ - *ret = MP_NO; + /* Default to Non-square :) */ + *ret = MP_NO; - if (arg->sign == MP_NEG) { - return MP_VAL; - } + if (arg->sign == MP_NEG) { + return MP_VAL; + } - /* digits used? (TSD) */ - if (arg->used == 0) { - return MP_OKAY; - } + if (MP_IS_ZERO(arg)) { + return MP_OKAY; + } - /* First check mod 128 (suppose that DIGIT_BIT is at least 7) */ - if (rem_128[127 & DIGIT(arg,0)] == 1) { - return MP_OKAY; - } + /* First check mod 128 (suppose that MP_DIGIT_BIT is at least 7) */ + if (rem_128[127u & arg->dp[0]] == (char)1) { + return MP_OKAY; + } - /* Next check mod 105 (3*5*7) */ - if ((res = mp_mod_d(arg,105,&c)) != MP_OKAY) { - return res; - } - if (rem_105[c] == 1) { - return MP_OKAY; - } + /* Next check mod 105 (3*5*7) */ + if ((err = mp_mod_d(arg, 105uL, &c)) != MP_OKAY) { + return err; + } + if (rem_105[c] == (char)1) { + return MP_OKAY; + } - if ((res = mp_init_set_int(&t,11L*13L*17L*19L*23L*29L*31L)) != MP_OKAY) { - return res; - } - if ((res = mp_mod(arg,&t,&t)) != MP_OKAY) { - goto ERR; - } - r = mp_get_int(&t); - /* Check for other prime modules, note it's not an ERROR but we must - * free "t" so the easiest way is to goto ERR. We know that res - * is already equal to MP_OKAY from the mp_mod call - */ - if (((1L<<(r%11)) & 0x5C4L) != 0L) goto ERR; - if (((1L<<(r%13)) & 0x9E4L) != 0L) goto ERR; - if (((1L<<(r%17)) & 0x5CE8L) != 0L) goto ERR; - if (((1L<<(r%19)) & 0x4F50CL) != 0L) goto ERR; - if (((1L<<(r%23)) & 0x7ACCA0L) != 0L) goto ERR; - if (((1L<<(r%29)) & 0xC2EDD0CL) != 0L) goto ERR; - if (((1L<<(r%31)) & 0x6DE2B848L) != 0L) goto ERR; + if ((err = mp_init_u32(&t, 11u*13u*17u*19u*23u*29u*31u)) != MP_OKAY) { + return err; + } + if ((err = mp_mod(arg, &t, &t)) != MP_OKAY) { + goto LBL_ERR; + } + r = mp_get_u32(&t); + /* Check for other prime modules, note it's not an ERROR but we must + * free "t" so the easiest way is to goto LBL_ERR. We know that err + * is already equal to MP_OKAY from the mp_mod call + */ + if (((1uL<<(r%11uL)) & 0x5C4uL) != 0uL) goto LBL_ERR; + if (((1uL<<(r%13uL)) & 0x9E4uL) != 0uL) goto LBL_ERR; + if (((1uL<<(r%17uL)) & 0x5CE8uL) != 0uL) goto LBL_ERR; + if (((1uL<<(r%19uL)) & 0x4F50CuL) != 0uL) goto LBL_ERR; + if (((1uL<<(r%23uL)) & 0x7ACCA0uL) != 0uL) goto LBL_ERR; + if (((1uL<<(r%29uL)) & 0xC2EDD0CuL) != 0uL) goto LBL_ERR; + if (((1uL<<(r%31uL)) & 0x6DE2B848uL) != 0uL) goto LBL_ERR; - /* Final check - is sqr(sqrt(arg)) == arg ? */ - if ((res = mp_sqrt(arg,&t)) != MP_OKAY) { - goto ERR; - } - if ((res = mp_sqr(&t,&t)) != MP_OKAY) { - goto ERR; - } + /* Final check - is sqr(sqrt(arg)) == arg ? */ + if ((err = mp_sqrt(arg, &t)) != MP_OKAY) { + goto LBL_ERR; + } + if ((err = mp_sqr(&t, &t)) != MP_OKAY) { + goto LBL_ERR; + } - *ret = (mp_cmp_mag(&t,arg) == MP_EQ) ? MP_YES : MP_NO; -ERR:mp_clear(&t); - return res; + *ret = (mp_cmp_mag(&t, arg) == MP_EQ) ? MP_YES : MP_NO; +LBL_ERR: + mp_clear(&t); + return err; } #endif - -/* ref: $Format:%D$ */ -/* git commit: $Format:%H$ */ -/* commit time: $Format:%ai$ */ |