57 lines
1.4 KiB
C
57 lines
1.4 KiB
C
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/*
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* Copyright (c) 2017 Lev Walkin <vlm@lionet.info>.
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* All rights reserved.
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* Redistribution and modifications are permitted subject to BSD license.
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*/
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#include <asn_internal.h>
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#include <asn_random_fill.h>
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#include <constr_TYPE.h>
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int
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asn_random_fill(const struct asn_TYPE_descriptor_s *td, void **struct_ptr,
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size_t length) {
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if(td && td->op->random_fill) {
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asn_random_fill_result_t res =
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td->op->random_fill(td, struct_ptr, 0, length);
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return (res.code == ARFILL_OK) ? 0 : -1;
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} else {
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return -1;
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}
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}
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static uintmax_t
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asn__intmax_range(intmax_t lb, intmax_t ub) {
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assert(lb <= ub);
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if((ub < 0) == (lb < 0)) {
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return ub - lb;
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} else if(lb < 0) {
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return 1 + ((uintmax_t)ub + (uintmax_t)-(lb + 1));
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} else {
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assert(!"Unreachable");
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return 0;
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}
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}
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intmax_t
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asn_random_between(intmax_t lb, intmax_t rb) {
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if(lb == rb) {
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return lb;
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} else {
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const uintmax_t intmax_max = ((~(uintmax_t)0) >> 1);
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uintmax_t range = asn__intmax_range(lb, rb);
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uintmax_t value = 0;
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uintmax_t got_entropy = 0;
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assert(RAND_MAX > 0xffffff); /* Seen 7ffffffd! */
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assert(range < intmax_max);
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for(; got_entropy < range;) {
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got_entropy = (got_entropy << 24) | 0xffffff;
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value = (value << 24) | (random() % 0xffffff);
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}
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return lb + (intmax_t)(value % (range + 1));
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}
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}
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