FD.io VPP  v19.08.3-2-gbabecb413
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:
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_clib_random_buffer_h
39 #define included_clib_random_buffer_h
40 
41 #include <vppinfra/clib.h>
42 #include <vppinfra/random_isaac.h>
43 #include <vppinfra/warnings.h>
44 
45 /* *INDENT-OFF* */
46 WARN_OFF(array-bounds)
47 /* *INDENT-ON* */
48 
49 typedef struct
50 {
51  /* Two parallel ISAAC contexts for speed. */
53 
54  /* Random buffer. */
56 
57  /* Cache up to 1 word worth of bytes for random data
58  less than one word at a time. */
60 
61  union
62  {
63  u8 cached_bytes[sizeof (uword)];
65  };
66 }
68 
69 always_inline void
71 {
72  vec_free (b->buffer);
73 }
74 
75 /* Fill random buffer. */
77 
78 /* Initialize random buffer. */
80 
81 /* Returns word aligned random data, possibly filling buffer. */
82 always_inline void *
84 {
85  uword n_words, i, l;
86 
87  l = b->n_cached_bytes;
88  if (n_bytes <= l)
89  {
90  b->n_cached_bytes = l - n_bytes;
91  return &b->cached_bytes[l];
92  }
93 
94  n_words = n_bytes / sizeof (uword);
95  if (n_bytes % sizeof (uword))
96  n_words++;
97 
98  /* Enough random words left? */
99  if (PREDICT_FALSE (n_words > vec_len (b->buffer)))
100  clib_random_buffer_fill (b, n_words);
101 
102  i = vec_len (b->buffer) - n_words;
103  _vec_len (b->buffer) = i;
104 
105  if (n_bytes < sizeof (uword))
106  {
107  b->cached_word = b->buffer[i];
108  b->n_cached_bytes = sizeof (uword) - n_bytes;
109  return b->cached_bytes;
110  }
111  else
112  return b->buffer + i;
113 }
114 
115 /* *INDENT-OFF* */
116 WARN_ON(array-bounds)
117 /* *INDENT-ON* */
118 
119 #endif /* included_clib_random_buffer_h */
120 
121 /*
122  * fd.io coding-style-patch-verification: ON
123  *
124  * Local Variables:
125  * eval: (c-set-style "gnu")
126  * End:
127  */
u8 cached_bytes[sizeof(uword)]
Definition: random_buffer.h:63
static void * clib_random_buffer_get_data(clib_random_buffer_t *b, uword n_bytes)
Definition: random_buffer.h:83
int i
unsigned char u8
Definition: types.h:56
void clib_random_buffer_init(clib_random_buffer_t *b, uword seed)
Definition: random_buffer.c:62
#define always_inline
Definition: clib.h:99
#define WARN_ON(x)
Definition: warnings.h:81
long ctx[MAX_CONNS]
Definition: main.c:144
#define PREDICT_FALSE(x)
Definition: clib.h:112
static void clib_random_buffer_free(clib_random_buffer_t *b)
Definition: random_buffer.h:70
#define vec_free(V)
Free vector&#39;s memory (no header).
Definition: vec.h:341
#define WARN_OFF(x)
Definition: warnings.h:80
void clib_random_buffer_fill(clib_random_buffer_t *b, uword n_words)
Definition: random_buffer.c:42
#define vec_len(v)
Number of elements in vector (rvalue-only, NULL tolerant)
u64 uword
Definition: types.h:112