FD.io VPP  v16.12-rc0-308-g931be3a
Vector Packet Processing
random_buffer.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:
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7  * http://www.apache.org/licenses/LICENSE-2.0
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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
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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_clib_random_buffer_h
39 #define included_clib_random_buffer_h
40 
41 #include <vppinfra/clib.h>
42 #include <vppinfra/random_isaac.h>
43 
44 typedef struct
45 {
46  /* Two parallel ISAAC contexts for speed. */
47  isaac_t ctx[2];
48 
49  /* Random buffer. */
51 
52  /* Cache up to 1 word worth of bytes for random data
53  less than one word at a time. */
55 
56  union
57  {
58  u8 cached_bytes[sizeof (uword)];
60  };
61 }
63 
64 always_inline void
66 {
67  vec_free (b->buffer);
68 }
69 
70 /* Fill random buffer. */
72 
73 /* Initialize random buffer. */
75 
76 /* Returns word aligned random data, possibly filling buffer. */
77 always_inline void *
79 {
80  uword n_words, i, l;
81 
82  l = b->n_cached_bytes;
83  if (n_bytes <= l)
84  {
85  b->n_cached_bytes = l - n_bytes;
86  return &b->cached_bytes[l];
87  }
88 
89  n_words = n_bytes / sizeof (uword);
90  if (n_bytes % sizeof (uword))
91  n_words++;
92 
93  /* Enough random words left? */
94  if (PREDICT_FALSE (n_words > vec_len (b->buffer)))
95  clib_random_buffer_fill (b, n_words);
96 
97  i = vec_len (b->buffer) - n_words;
98  _vec_len (b->buffer) = i;
99 
100  if (n_bytes < sizeof (uword))
101  {
102  b->cached_word = b->buffer[i];
103  b->n_cached_bytes = sizeof (uword) - n_bytes;
104  return b->cached_bytes;
105  }
106  else
107  return b->buffer + i;
108 }
109 
110 #endif /* included_clib_random_buffer_h */
111 
112 /*
113  * fd.io coding-style-patch-verification: ON
114  *
115  * Local Variables:
116  * eval: (c-set-style "gnu")
117  * End:
118  */
u8 cached_bytes[sizeof(uword)]
Definition: random_buffer.h:58
sll srl srl sll sra u16x4 i
Definition: vector_sse2.h:343
static void * clib_random_buffer_get_data(clib_random_buffer_t *b, uword n_bytes)
Definition: random_buffer.h:78
void clib_random_buffer_init(clib_random_buffer_t *b, uword seed)
Definition: random_buffer.c:62
#define always_inline
Definition: clib.h:84
#define PREDICT_FALSE(x)
Definition: clib.h:97
static void clib_random_buffer_free(clib_random_buffer_t *b)
Definition: random_buffer.h:65
#define vec_free(V)
Free vector&#39;s memory (no header).
Definition: vec.h:300
void clib_random_buffer_fill(clib_random_buffer_t *b, uword n_words)
Definition: random_buffer.c:42
u64 uword
Definition: types.h:112
#define vec_len(v)
Number of elements in vector (rvalue-only, NULL tolerant)
unsigned char u8
Definition: types.h:56