2 * Copyright (c) 2015 Cisco and/or its affiliates.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at:
7 * http://www.apache.org/licenses/LICENSE-2.0
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
16 Copyright (c) 2005 Eliot Dresselhaus
18 Permission is hereby granted, free of charge, to any person obtaining
19 a copy of this software and associated documentation files (the
20 "Software"), to deal in the Software without restriction, including
21 without limitation the rights to use, copy, modify, merge, publish,
22 distribute, sublicense, and/or sell copies of the Software, and to
23 permit persons to whom the Software is furnished to do so, subject to
24 the following conditions:
26 The above copyright notice and this permission notice shall be
27 included in all copies or substantial portions of the Software.
29 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
30 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
31 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
32 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
33 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
34 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
35 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
38 #ifndef included_phash_h
39 #define included_phash_h
41 #include <vppinfra/hash.h> /* for Bob's mixing functions */
45 /* Maybe either pointer to vector or inline word. */
48 /* Hash code (A, B). */
52 /* Table indexed by B. */
55 /* Vector of key indices with this same value of B. */
58 /* hash=a^tabb[b].val_b */
61 /* High watermark of who has visited this map node. */
66 phash_tabb_free (phash_tabb_t * b)
69 b->val_b = b->water_b = 0;
74 /* b that currently occupies this hash */
77 /* Queue position of parent that could use this hash. */
80 /* What to change parent tab[b] to use this hash. */
83 /* Original value of tab[b]. */
89 u8 a_bits, b_bits, s_bits, a_shift;
94 /* Seed value for hash mixer. */
99 /* Key functions want 64 bit keys.
100 Use hash_mix64 rather than hash_mix32. */
101 #define PHASH_FLAG_MIX64 (1 << 0)
102 #define PHASH_FLAG_MIX32 (0 << 0)
104 /* When b_bits is large enough (>= 12) we scramble. */
105 #define PHASH_FLAG_USE_SCRAMBLE (1 << 1)
107 /* Slow mode gives smaller tables but at the expense of more run time. */
108 #define PHASH_FLAG_SLOW_MODE (0 << 2)
109 #define PHASH_FLAG_FAST_MODE (1 << 2)
111 /* Generate minimal perfect hash instead of perfect hash. */
112 #define PHASH_FLAG_NON_MINIMAL (0 << 3)
113 #define PHASH_FLAG_MINIMAL (1 << 3)
115 /* vec_len (keys) for minimal hash;
116 1 << s_bits for non-minimal hash. */
119 /* Vector of keys. */
122 /* Used by callbacks to identify keys. */
125 /* Key comparison callback. */
126 int (*key_is_equal) (void *private, uword key1, uword key2);
128 /* Callback to reduce single key -> hash seeds. */
129 void (*key_seed1) (void *private, uword key, void *seed);
131 /* Callback to reduce two key2 -> hash seeds. */
132 void (*key_seed2) (void *private, uword key1, uword key2, void *seed);
134 /* Stuff used to compute perfect hash. */
137 /* Stuff indexed by B. */
140 /* Table of B ordered by number of keys in tabb[b]. */
143 /* Unique key (or ~0 if none) for a given hash
144 H = A ^ scramble[tab[B].val_b]. */
147 /* Stuff indexed by q. */
151 u32 n_seed_trials, n_perfect_calls;
155 phash_main_free_working_memory (phash_main_t * pm)
160 vec_free (pm->tabb_sort);
161 if (!(pm->flags & PHASH_FLAG_USE_SCRAMBLE))
162 vec_free (pm->scramble);
166 phash_main_free (phash_main_t * pm)
168 phash_main_free_working_memory (pm);
171 clib_memset (pm, 0, sizeof (pm[0]));
174 /* Slow hash computation for general keys. */
175 uword phash_hash_slow (phash_main_t * pm, uword key);
177 /* Main routine to compute perfect hash. */
178 clib_error_t *phash_find_perfect_hash (phash_main_t * pm);
180 /* Validates that hash is indeed perfect. */
181 clib_error_t *phash_validate (phash_main_t * pm);
184 int phash_test_main (unformat_input_t * input);
186 #endif /* included_phash_h */
189 * fd.io coding-style-patch-verification: ON
192 * eval: (c-set-style "gnu")