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https://github.com/openvswitch/ovs
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aad29cd1a1
We had these functions scattered around the source tree anyway. packets.h is a good place to centralize them. I do plan to introduce some additional callers.
72 lines
1.7 KiB
C
72 lines
1.7 KiB
C
/*
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* Copyright (c) 2011 Nicira Networks.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <config.h>
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#include <inttypes.h>
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#include <limits.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include "random.h"
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#include "util.h"
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static void
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check_log_2_floor(uint32_t x, int n)
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{
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if (log_2_floor(x) != n) {
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fprintf(stderr, "log_2_floor(%"PRIu32") is %d but should be %d\n",
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x, log_2_floor(x), n);
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abort();
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}
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}
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static void
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check_ctz(uint32_t x, int n)
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{
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if (ctz(x) != n) {
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fprintf(stderr, "ctz(%"PRIu32") is %d but should be %d\n",
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x, ctz(x), n);
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abort();
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}
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}
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int
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main(void)
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{
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int n;
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for (n = 0; n < 32; n++) {
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/* Check minimum x such that f(x) == n. */
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check_log_2_floor(1 << n, n);
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check_ctz(1 << n, n);
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/* Check maximum x such that f(x) == n. */
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check_log_2_floor((1 << n) | ((1 << n) - 1), n);
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check_ctz(UINT32_MAX << n, n);
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/* Check a random value in the middle. */
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check_log_2_floor((random_uint32() & ((1 << n) - 1)) | (1 << n), n);
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check_ctz((random_uint32() | 1) << n, n);
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}
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/* Check ctz(0).
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* (log_2_floor(0) is undefined.) */
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check_ctz(0, 32);
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return 0;
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}
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