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Vector Packet Processing
sparse_vec.h
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1 /*
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:
6  *
7  * http://www.apache.org/licenses/LICENSE-2.0
8  *
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.
14  */
15 /*
16  Copyright (c) 2005 Eliot Dresselhaus
17 
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:
25 
26  The above copyright notice and this permission notice shall be
27  included in all copies or substantial portions of the Software.
28 
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.
36 */
37 
38 #ifndef included_sparse_vec_h
39 #define included_sparse_vec_h
40 
41 #include <vppinfra/vec.h>
42 #include <vppinfra/bitops.h>
43 
44 /* Sparsely indexed vectors. Basic idea taken from Hacker's delight.
45  Eliot added ranges. */
46 typedef struct
47 {
48  /* Bitmap one for each sparse index. */
50 
51  /* member_counts[i] = total number of members with j < i. */
53 
54 #define SPARSE_VEC_IS_RANGE (1 << 0)
55 #define SPARSE_VEC_IS_VALID_RANGE (1 << 1)
58 
61 {
62  return vec_header (v, sizeof (sparse_vec_header_t));
63 }
64 
65 /* Index 0 is always used to mark indices that are not valid in
66  sparse vector. For example, you look up V[0x1234] and 0x1234 is not
67  known you'll get 0 back as an index. */
68 #define SPARSE_VEC_INVALID_INDEX (0)
69 
70 always_inline void *
71 sparse_vec_new (uword elt_bytes, uword sparse_index_bits)
72 {
73  void *v;
75  word n;
76 
77  ASSERT (sparse_index_bits <= 16);
78 
79  v = _vec_resize (0,
80  /* length increment */ 8,
81  /* data bytes */ 8 * elt_bytes,
82  /* header bytes */ sizeof (h[0]),
83  /* data align */ 0);
84 
85  /* Make space for invalid entry (entry 0). */
86  _vec_len (v) = 1;
87 
88  h = sparse_vec_header (v);
89 
90  n = sparse_index_bits - min_log2 (BITS (uword));
91  if (n < 0)
92  n = 0;
93  n = 1ULL << n;
95  vec_resize (h->member_counts, n);
96 
97  return v;
98 }
99 
102  uword sparse_index,
103  uword maybe_range, u32 * insert)
104 {
106  uword i, b, d, w;
107  u8 is_member;
108 
109  h = sparse_vec_header (v);
110  i = sparse_index / BITS (h->is_member_bitmap[0]);
111  b = (uword) 1 << (uword) (sparse_index % BITS (h->is_member_bitmap[0]));
112 
113  ASSERT (i < vec_len (h->is_member_bitmap));
114  ASSERT (i < vec_len (h->member_counts));
115 
116  w = h->is_member_bitmap[i];
117  d = h->member_counts[i] + count_set_bits (w & (b - 1));
118 
119  is_member = (w & b) != 0;
120  if (maybe_range)
121  {
122  u8 r = h->range_flags[d];
123  u8 is_range, is_valid_range;
124 
125  is_range = maybe_range & (r & SPARSE_VEC_IS_RANGE);
126  is_valid_range = (r & SPARSE_VEC_IS_VALID_RANGE) != 0;
127 
128  is_member = is_range ? is_valid_range : is_member;
129  }
130 
131  if (insert)
132  {
133  *insert = !is_member;
134  if (!is_member)
135  {
136  uword j;
137  w |= b;
138  h->is_member_bitmap[i] = w;
139  for (j = i + 1; j < vec_len (h->member_counts); j++)
140  h->member_counts[j] += 1;
141  }
142 
143  return 1 + d;
144  }
145 
146  d = is_member ? d : 0;
147 
148  return is_member + d;
149 }
150 
152 sparse_vec_index (void *v, uword sparse_index)
153 {
154  return sparse_vec_index_internal (v, sparse_index,
155  /* maybe range */ 0,
156  /* insert? */ 0);
157 }
158 
159 always_inline void
161  u32 si0, u32 si1, u32 * i0_return, u32 * i1_return)
162 {
164  uword b0, b1, w0, w1, v0, v1;
165  u32 i0, i1, d0, d1;
166  u8 is_member0, is_member1;
167 
168  h = sparse_vec_header (v);
169 
170  i0 = si0 / BITS (h->is_member_bitmap[0]);
171  i1 = si1 / BITS (h->is_member_bitmap[0]);
172 
173  b0 = (uword) 1 << (uword) (si0 % BITS (h->is_member_bitmap[0]));
174  b1 = (uword) 1 << (uword) (si1 % BITS (h->is_member_bitmap[0]));
175 
176  ASSERT (i0 < vec_len (h->is_member_bitmap));
177  ASSERT (i1 < vec_len (h->is_member_bitmap));
178 
179  ASSERT (i0 < vec_len (h->member_counts));
180  ASSERT (i1 < vec_len (h->member_counts));
181 
182  w0 = h->is_member_bitmap[i0];
183  w1 = h->is_member_bitmap[i1];
184 
185  v0 = w0 & (b0 - 1);
186  v1 = w1 & (b1 - 1);
187 
188  /* Speculate that masks will have zero or one bits set. */
189  d0 = h->member_counts[i0] + (v0 != 0);
190  d1 = h->member_counts[i1] + (v1 != 0);
191 
192  /* Validate speculation. */
193  if (PREDICT_FALSE (!is_pow2 (v0) || !is_pow2 (v1)))
194  {
195  d0 += count_set_bits (v0) - (v0 != 0);
196  d1 += count_set_bits (v1) - (v1 != 0);
197  }
198 
199  is_member0 = (w0 & b0) != 0;
200  is_member1 = (w1 & b1) != 0;
201 
202  d0 = is_member0 ? d0 : 0;
203  d1 = is_member1 ? d1 : 0;
204 
205  *i0_return = is_member0 + d0;
206  *i1_return = is_member1 + d1;
207 }
208 
209 #define sparse_vec_free(v) vec_free(v)
210 
211 #define sparse_vec_elt_at_index(v,i) \
212  vec_elt_at_index ((v), sparse_vec_index ((v), (i)))
213 
214 #define sparse_vec_validate(v,i) \
215 ({ \
216  uword _i; \
217  u32 _insert; \
218  \
219  if (! (v)) \
220  (v) = sparse_vec_new (sizeof ((v)[0]), BITS (u16)); \
221  \
222  _i = sparse_vec_index_internal ((v), (i), \
223  /* maybe range */ 0, \
224  /* insert? */ &_insert); \
225  if (_insert) \
226  vec_insert_ha ((v), 1, _i, \
227  /* header size */ sizeof (sparse_vec_header_t), \
228  /* align */ 0); \
229  \
230  /* Invalid index is 0. */ \
231  ASSERT (_i > 0); \
232  \
233  (v) + _i; \
234 })
235 
236 #endif /* included_sparse_vec_h */
237 
238 /*
239  * fd.io coding-style-patch-verification: ON
240  *
241  * Local Variables:
242  * eval: (c-set-style "gnu")
243  * End:
244  */
sll srl srl sll sra u16x4 i
Definition: vector_sse2.h:343
#define SPARSE_VEC_IS_RANGE
Definition: sparse_vec.h:54
static uword min_log2(uword x)
Definition: clib.h:189
#define always_inline
Definition: clib.h:84
#define vec_resize(V, N)
Resize a vector (no header, unspecified alignment) Add N elements to end of given vector V...
Definition: vec.h:241
static void sparse_vec_index2(void *v, u32 si0, u32 si1, u32 *i0_return, u32 *i1_return)
Definition: sparse_vec.h:160
#define v
Definition: acl.c:246
#define PREDICT_FALSE(x)
Definition: clib.h:97
vec_header_t h
Definition: buffer.c:275
static sparse_vec_header_t * sparse_vec_header(void *v)
Definition: sparse_vec.h:60
static uword sparse_vec_index(void *v, uword sparse_index)
Definition: sparse_vec.h:152
#define ASSERT(truth)
unsigned int u32
Definition: types.h:88
static uword is_pow2(uword x)
Definition: clib.h:272
u64 uword
Definition: types.h:112
static uword sparse_vec_index_internal(void *v, uword sparse_index, uword maybe_range, u32 *insert)
Definition: sparse_vec.h:101
unsigned short u16
Definition: types.h:57
i64 word
Definition: types.h:111
#define vec_len(v)
Number of elements in vector (rvalue-only, NULL tolerant)
unsigned char u8
Definition: types.h:56
#define SPARSE_VEC_IS_VALID_RANGE
Definition: sparse_vec.h:55
static void * vec_header(void *v, uword header_bytes)
Find a user vector header.
Definition: vec_bootstrap.h:92
static uword count_set_bits(uword x)
Definition: bitops.h:45
uword * is_member_bitmap
Definition: sparse_vec.h:49
static void * sparse_vec_new(uword elt_bytes, uword sparse_index_bits)
Definition: sparse_vec.h:71
#define BITS(x)
Definition: clib.h:58
CLIB vectors are ubiquitous dynamically resized arrays with by user defined "headers".