FD.io VPP  v18.07-34-g55fbdb9
Vector Packet Processing
string.c
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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) 2006 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 #include <vppinfra/string.h>
39 #include <vppinfra/error.h>
40 
41 /* Exchanges source and destination. */
42 void
43 clib_memswap (void *_a, void *_b, uword bytes)
44 {
45  uword pa = pointer_to_uword (_a);
46  uword pb = pointer_to_uword (_b);
47 
48 #define _(TYPE) \
49  if (0 == ((pa | pb) & (sizeof (TYPE) - 1))) \
50  { \
51  TYPE * a = uword_to_pointer (pa, TYPE *); \
52  TYPE * b = uword_to_pointer (pb, TYPE *); \
53  \
54  while (bytes >= 2*sizeof (TYPE)) \
55  { \
56  TYPE a0, a1, b0, b1; \
57  bytes -= 2*sizeof (TYPE); \
58  a += 2; \
59  b += 2; \
60  a0 = a[-2]; a1 = a[-1]; \
61  b0 = b[-2]; b1 = b[-1]; \
62  a[-2] = b0; a[-1] = b1; \
63  b[-2] = a0; b[-1] = a1; \
64  } \
65  pa = pointer_to_uword (a); \
66  pb = pointer_to_uword (b); \
67  }
68 
69  if (BITS (uword) == BITS (u64))
70  _(u64);
71  _(u32);
72  _(u16);
73  _(u8);
74 
75 #undef _
76 
77  ASSERT (bytes < 2);
78  if (bytes)
79  {
80  u8 *a = uword_to_pointer (pa, u8 *);
81  u8 *b = uword_to_pointer (pb, u8 *);
82  u8 a0 = a[0], b0 = b[0];
83  a[0] = b0;
84  b[0] = a0;
85  }
86 }
87 
88 /*
89  * fd.io coding-style-patch-verification: ON
90  *
91  * Local Variables:
92  * eval: (c-set-style "gnu")
93  * End:
94  */
void clib_memswap(void *_a, void *_b, uword bytes)
Definition: string.c:43
a
Definition: bitmap.h:538
unsigned long u64
Definition: types.h:89
unsigned char u8
Definition: types.h:56
unsigned int u32
Definition: types.h:88
unsigned short u16
Definition: types.h:57
#define uword_to_pointer(u, type)
Definition: types.h:136
#define ASSERT(truth)
static uword pointer_to_uword(const void *p)
Definition: types.h:131
u64 uword
Definition: types.h:112
#define BITS(x)
Definition: clib.h:58