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Diffstat (limited to 'contrib/bind9/lib/isc/lfsr.c')
| -rw-r--r-- | contrib/bind9/lib/isc/lfsr.c | 161 |
1 files changed, 0 insertions, 161 deletions
diff --git a/contrib/bind9/lib/isc/lfsr.c b/contrib/bind9/lib/isc/lfsr.c deleted file mode 100644 index 61f9386..0000000 --- a/contrib/bind9/lib/isc/lfsr.c +++ /dev/null @@ -1,161 +0,0 @@ -/* - * Copyright (C) 2004, 2005 Internet Systems Consortium, Inc. ("ISC") - * Copyright (C) 1999-2002 Internet Software Consortium. - * - * Permission to use, copy, modify, and distribute this software for any - * purpose with or without fee is hereby granted, provided that the above - * copyright notice and this permission notice appear in all copies. - * - * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH - * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY - * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, - * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM - * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE - * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR - * PERFORMANCE OF THIS SOFTWARE. - */ - -/* $Id: lfsr.c,v 1.14.18.4 2005/10/14 01:28:29 marka Exp $ */ - -/*! \file */ - -#include <config.h> - -#include <stddef.h> -#include <stdlib.h> - -#include <isc/assertions.h> -#include <isc/lfsr.h> -#include <isc/util.h> - -#define VALID_LFSR(x) (x != NULL) - -void -isc_lfsr_init(isc_lfsr_t *lfsr, isc_uint32_t state, unsigned int bits, - isc_uint32_t tap, unsigned int count, - isc_lfsrreseed_t reseed, void *arg) -{ - REQUIRE(VALID_LFSR(lfsr)); - REQUIRE(8 <= bits && bits <= 32); - REQUIRE(tap != 0); - - lfsr->state = state; - lfsr->bits = bits; - lfsr->tap = tap; - lfsr->count = count; - lfsr->reseed = reseed; - lfsr->arg = arg; - - if (count == 0 && reseed != NULL) - reseed(lfsr, arg); - if (lfsr->state == 0) - lfsr->state = 0xffffffffU >> (32 - lfsr->bits); -} - -/*! - * Return the next state of the lfsr. - */ -static inline isc_uint32_t -lfsr_generate(isc_lfsr_t *lfsr) -{ - - /* - * If the previous state is zero, we must fill it with something - * here, or we will begin to generate an extremely predictable output. - * - * First, give the reseed function a crack at it. If the state is - * still 0, set it to all ones. - */ - if (lfsr->state == 0) { - if (lfsr->reseed != NULL) - lfsr->reseed(lfsr, lfsr->arg); - if (lfsr->state == 0) - lfsr->state = 0xffffffffU >> (32 - lfsr->bits); - } - - if (lfsr->state & 0x01) { - lfsr->state = (lfsr->state >> 1) ^ lfsr->tap; - return (1); - } else { - lfsr->state >>= 1; - return (0); - } -} - -void -isc_lfsr_generate(isc_lfsr_t *lfsr, void *data, unsigned int count) -{ - unsigned char *p; - unsigned int bit; - unsigned int byte; - - REQUIRE(VALID_LFSR(lfsr)); - REQUIRE(data != NULL); - REQUIRE(count > 0); - - p = data; - byte = count; - - while (byte--) { - *p = 0; - for (bit = 0; bit < 7; bit++) { - *p |= lfsr_generate(lfsr); - *p <<= 1; - } - *p |= lfsr_generate(lfsr); - p++; - } - - if (lfsr->count != 0 && lfsr->reseed != NULL) { - if (lfsr->count <= count * 8) - lfsr->reseed(lfsr, lfsr->arg); - else - lfsr->count -= (count * 8); - } -} - -static inline isc_uint32_t -lfsr_skipgenerate(isc_lfsr_t *lfsr, unsigned int skip) -{ - while (skip--) - (void)lfsr_generate(lfsr); - - (void)lfsr_generate(lfsr); - - return (lfsr->state); -} - -/* - * Skip "skip" states in "lfsr". - */ -void -isc_lfsr_skip(isc_lfsr_t *lfsr, unsigned int skip) -{ - REQUIRE(VALID_LFSR(lfsr)); - - while (skip--) - (void)lfsr_generate(lfsr); -} - -/* - * Skip states in lfsr1 and lfsr2 using the other's current state. - * Return the final state of lfsr1 ^ lfsr2. - */ -isc_uint32_t -isc_lfsr_generate32(isc_lfsr_t *lfsr1, isc_lfsr_t *lfsr2) -{ - isc_uint32_t state1, state2; - isc_uint32_t skip1, skip2; - - REQUIRE(VALID_LFSR(lfsr1)); - REQUIRE(VALID_LFSR(lfsr2)); - - skip1 = lfsr1->state & 0x01; - skip2 = lfsr2->state & 0x01; - - /* cross-skip. */ - state1 = lfsr_skipgenerate(lfsr1, skip2); - state2 = lfsr_skipgenerate(lfsr2, skip1); - - return (state1 ^ state2); -} |
