blob: f3f443209024b9e8ffacf521ac13457ca03f3d55 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
|
// bits.h
/* Copyright 2012 10gen Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
// figure out if we're on a 64 or 32 bit system
#if defined(__x86_64__) || defined(__amd64__) || defined(_WIN64) || defined(__aarch64__) || defined(__powerpc64__)
#define MONGO_PLATFORM_64
#elif defined(__i386__) || defined(_WIN32) || defined(__arm__)
#define MONGO_PLATFORM_32
#else
#error "unknown platform"
#endif
namespace mongo {
// defined here so can test on linux
inline int mongo_firstBitSet( unsigned long long v ) {
if ( v == 0 )
return 0;
for ( int i = 0; i<8; i++ ) {
unsigned long long x = ( v >> ( 8 * i ) ) & 0xFF;
if ( x == 0 )
continue;
for ( int j = 0; j < 8; j++ ) {
if ( ( x >> j ) & 0x1 )
return ( i * 8 ) + j + 1;
}
}
return 0;
}
}
#if defined(__linux__)
#define firstBitSet ffsll
#define MONGO_SYSTEM_FFS 1
#elif defined(__MACH__) && defined(MONGO_PLATFORM_64)
#define firstBitSet ffsl
#define MONGO_SYSTEM_FFS 1
#else
#define firstBitSet mongo::mongo_firstBitSet
#endif
|
