56 lines
1.3 KiB
C
56 lines
1.3 KiB
C
#include "tommath_private.h"
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#ifdef S_MP_RAND_JENKINS_C
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/* LibTomMath, multiple-precision integer library -- Tom St Denis */
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/* SPDX-License-Identifier: Unlicense */
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/* Bob Jenkins' http://burtleburtle.net/bob/rand/smallprng.html */
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/* Chosen for speed and a good "mix" */
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/* TODO: jenkins prng is not thread safe as of now */
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typedef struct {
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uint64_t a;
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uint64_t b;
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uint64_t c;
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uint64_t d;
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} ranctx;
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static ranctx jenkins_x;
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#define rot(x,k) (((x)<<(k))|((x)>>(64-(k))))
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static uint64_t s_rand_jenkins_val(void)
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{
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uint64_t e = jenkins_x.a - rot(jenkins_x.b, 7);
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jenkins_x.a = jenkins_x.b ^ rot(jenkins_x.c, 13);
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jenkins_x.b = jenkins_x.c + rot(jenkins_x.d, 37);
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jenkins_x.c = jenkins_x.d + e;
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jenkins_x.d = e + jenkins_x.a;
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return jenkins_x.d;
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}
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static void s_mp_rand_jenkins_init(uint64_t seed)
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{
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int i;
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jenkins_x.a = 0xF1EA5EEDuL;
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jenkins_x.b = jenkins_x.c = jenkins_x.d = seed;
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for (i = 0; i < 20; ++i) {
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(void)s_rand_jenkins_val();
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}
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}
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static mp_err s_mp_rand_jenkins(void *p, size_t n)
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{
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char *q = (char *)p;
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while (n > 0u) {
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int i;
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uint64_t x = s_rand_jenkins_val();
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for (i = 0; (i < 8) && (n > 0u); ++i, --n) {
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*q++ = (char)(x & 0xFFu);
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x >>= 8;
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}
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}
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return MP_OKAY;
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}
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#endif
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