29 lines
680 B
C
29 lines
680 B
C
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#include "pseudorand.h"
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#include <assert.h>
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#include <ccan/err/err.h>
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#include <ccan/isaac/isaac64.h>
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#include <ccan/likely/likely.h>
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#include <openssl/err.h>
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#include <openssl/rand.h>
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#include <stdbool.h>
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static struct isaac64_ctx isaac64;
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static bool pseudorand_initted = false;
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uint64_t pseudorand(uint64_t max)
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{
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if (unlikely(!pseudorand_initted)) {
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unsigned char seedbuf[16];
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/* PRNG */
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if (RAND_bytes(seedbuf, sizeof(seedbuf)) != 1)
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errx(1, "Could not seed PRNG: %s",
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ERR_error_string(ERR_get_error(), NULL));
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isaac64_init(&isaac64, seedbuf, sizeof(seedbuf));
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pseudorand_initted = true;
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}
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assert(max);
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return isaac64_next_uint(&isaac64, max);
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}
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