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Diffstat (limited to 'src/core/random.c')
| -rw-r--r-- | src/core/random.c | 202 |
1 files changed, 0 insertions, 202 deletions
diff --git a/src/core/random.c b/src/core/random.c deleted file mode 100644 index 2d899f21..00000000 --- a/src/core/random.c +++ /dev/null @@ -1,202 +0,0 @@ -// -// Copyright 2018 Staysail Systems, Inc. <info@staysail.tech> -// Copyright 2018 Capitar IT Group BV <info@capitar.com> -// -// This software is supplied under the terms of the MIT License, a -// copy of which should be located in the distribution where this -// file was obtained (LICENSE.txt). A copy of the license may also be -// found online at https://opensource.org/licenses/MIT. -// - -#include "core/nng_impl.h" - -// This is ISAAC, a (reputedly) cryptographically secure PRNG that is also -// quite efficient. While the particular adjustments to fit in our code -// base are under our copyright, the actual algorithm itself, as well as -// sample implementations, are part of the public domain. See this: -// http://www.burtleburtle.net/bob/c/readable.c -// -// Our changes include making this code thread safe/reentrant, and naming -// and style changes, to fit C99. - -typedef struct { - // the rsl is the actual results, and the randcnt is the length - // of the results. - uint32_t randrsl[256]; - uint32_t randcnt; - - // lock to protect concurrent access - nni_mtx mx; - - // more or less internal state - uint32_t mm[256]; - uint32_t aa; - uint32_t bb; - uint32_t cc; -} nni_isaac_ctx; - -static void -nni_isaac(nni_isaac_ctx *ctx) -{ - ctx->cc++; // cc incremented once per 256 results - ctx->bb += ctx->cc; // then combined with bb - - for (uint32_t i = 0; i < 256; ++i) { - uint32_t x = ctx->mm[i]; - uint32_t y; - switch (i % 4) { - case 0: - ctx->aa ^= (ctx->aa << 13); - break; - case 1: - ctx->aa ^= (ctx->aa >> 6); - break; - case 2: - ctx->aa ^= (ctx->aa << 2); - break; - case 3: - ctx->aa ^= (ctx->aa >> 16); - break; - } - ctx->aa += ctx->mm[(i + 128) % 256]; - ctx->mm[i] = y = ctx->mm[(x >> 2) % 256] + ctx->aa + ctx->bb; - ctx->randrsl[i] = ctx->bb = ctx->mm[(y >> 10) % 256] + x; - - // Note that bits 2..9 are chosen from x but 10..17 are chosen - // from y. The only important thing here is that 2..9 and - // 10..17 don't overlap. 2..9 and 10..17 were then chosen - // for speed in the optimized version (rand.c) - - // See http://burtleburtle.net/bob/rand/isaac.html - // for further explanations and analysis. - } -} - -// if (flag!=0), then use the contents of randrsl[] to initialize mm[]. -#define nni_isaac_mix(a, b, c, d, e, f, g, h) \ - { \ - a ^= b << 11; \ - d += a; \ - b += c; \ - b ^= c >> 2; \ - e += b; \ - c += d; \ - c ^= d << 8; \ - f += c; \ - d += e; \ - d ^= e >> 16; \ - g += d; \ - e += f; \ - e ^= f << 10; \ - h += e; \ - f += g; \ - f ^= g >> 4; \ - a += f; \ - g += h; \ - g ^= h << 8; \ - b += g; \ - h += a; \ - h ^= a >> 9; \ - c += h; \ - a += b; \ - } - -static void -nni_isaac_randinit(nni_isaac_ctx *ctx, int flag) -{ - int i; - uint32_t a, b, c, d, e, f, g, h; - - ctx->aa = ctx->bb = ctx->cc = 0; - a = b = c = d = e = f = g = h = 0x9e3779b9; // the golden ratio - - for (i = 0; i < 4; ++i) { // scramble it - nni_isaac_mix(a, b, c, d, e, f, g, h); - } - - for (i = 0; i < 256; i += 8) { // fill in mm[] with messy stuff - if (flag) { // use all the information in the seed - a += ctx->randrsl[i]; - b += ctx->randrsl[i + 1]; - c += ctx->randrsl[i + 2]; - d += ctx->randrsl[i + 3]; - e += ctx->randrsl[i + 4]; - f += ctx->randrsl[i + 5]; - g += ctx->randrsl[i + 6]; - h += ctx->randrsl[i + 7]; - } - nni_isaac_mix(a, b, c, d, e, f, g, h); - ctx->mm[i] = a; - ctx->mm[i + 1] = b; - ctx->mm[i + 2] = c; - ctx->mm[i + 3] = d; - ctx->mm[i + 4] = e; - ctx->mm[i + 5] = f; - ctx->mm[i + 6] = g; - ctx->mm[i + 7] = h; - } - - if (flag) { - // do a second pass to make all of the seed affect all of mm - for (i = 0; i < 256; i += 8) { - a += ctx->mm[i]; - b += ctx->mm[i + 1]; - c += ctx->mm[i + 2]; - d += ctx->mm[i + 3]; - e += ctx->mm[i + 4]; - f += ctx->mm[i + 5]; - g += ctx->mm[i + 6]; - h += ctx->mm[i + 7]; - nni_isaac_mix(a, b, c, d, e, f, g, h); - ctx->mm[i] = a; - ctx->mm[i + 1] = b; - ctx->mm[i + 2] = c; - ctx->mm[i + 3] = d; - ctx->mm[i + 4] = e; - ctx->mm[i + 5] = f; - ctx->mm[i + 6] = g; - ctx->mm[i + 7] = h; - } - } - - nni_isaac(ctx); // fill in the first set of results - ctx->randcnt = 256; // prepare to use the first set of results -} - -static nni_isaac_ctx nni_random_ctx; - -int -nni_random_sys_init(void) -{ - // minimally, grab the system clock - nni_isaac_ctx *ctx = &nni_random_ctx; - - nni_mtx_init(&ctx->mx); - nni_plat_seed_prng(ctx->randrsl, sizeof(ctx->randrsl)); - nni_isaac_randinit(ctx, 1); - return (0); -} - -uint32_t -nni_random(void) -{ - uint32_t rv; - nni_isaac_ctx *ctx = &nni_random_ctx; - - nni_mtx_lock(&ctx->mx); - if (ctx->randcnt < 1) { - nni_isaac(ctx); - ctx->randcnt = 256; - } - ctx->randcnt--; - rv = ctx->randrsl[ctx->randcnt]; - nni_mtx_unlock(&ctx->mx); - - return (rv); -} - -void -nni_random_sys_fini(void) -{ - nni_mtx_fini(&nni_random_ctx.mx); -} |