2 * Copyright (c) 2008-2011 Apple Inc. All rights reserved.
4 * @APPLE_APACHE_LICENSE_HEADER_START@
6 * Licensed under the Apache License, Version 2.0 (the "License");
7 * you may not use this file except in compliance with the License.
8 * You may obtain a copy of the License at
10 * http://www.apache.org/licenses/LICENSE-2.0
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
18 * @APPLE_APACHE_LICENSE_HEADER_END@
22 * IMPORTANT: This header file describes INTERNAL interfaces to libdispatch
23 * which are subject to change in future releases of Mac OS X. Any applications
24 * relying on these interfaces WILL break.
27 #ifndef __DISPATCH_SHIMS_TIME__
28 #define __DISPATCH_SHIMS_TIME__
30 #ifndef __DISPATCH_INDIRECT__
31 #error "Please #include <dispatch/dispatch.h> instead of this file directly."
34 uint64_t _dispatch_get_nanoseconds(void);
36 #if defined(__i386__) || defined(__x86_64__) || !HAVE_MACH_ABSOLUTE_TIME
37 // x86 currently implements mach time in nanoseconds
38 // this is NOT likely to change
39 #define _dispatch_time_mach2nano(x) ({x;})
40 #define _dispatch_time_nano2mach(x) ({x;})
42 typedef struct _dispatch_host_time_data_s
{
46 } _dispatch_host_time_data_s
;
47 extern _dispatch_host_time_data_s _dispatch_host_time_data
;
48 void _dispatch_get_host_time_init(void *context
);
50 static inline uint64_t
51 _dispatch_time_mach2nano(uint64_t machtime
)
53 _dispatch_host_time_data_s
*const data
= &_dispatch_host_time_data
;
54 dispatch_once_f(&data
->pred
, NULL
, _dispatch_get_host_time_init
);
56 return machtime
* data
->frac
;
60 _dispatch_time_nano2mach(int64_t nsec
)
62 _dispatch_host_time_data_s
*const data
= &_dispatch_host_time_data
;
63 dispatch_once_f(&data
->pred
, NULL
, _dispatch_get_host_time_init
);
65 if (slowpath(_dispatch_host_time_data
.ratio_1_to_1
)) {
69 long double big_tmp
= nsec
;
71 // Divide by tbi.numer/tbi.denom to convert nsec to Mach absolute time
72 big_tmp
/= data
->frac
;
74 // Clamp to a 64bit signed int
75 if (slowpath(big_tmp
> INT64_MAX
)) {
78 if (slowpath(big_tmp
< INT64_MIN
)) {
85 static inline uint64_t
86 _dispatch_absolute_time(void)
88 #if !HAVE_MACH_ABSOLUTE_TIME
92 #if HAVE_DECL_CLOCK_UPTIME
93 ret
= clock_gettime(CLOCK_UPTIME
, &ts
);
94 #elif HAVE_DECL_CLOCK_MONOTONIC
95 ret
= clock_gettime(CLOCK_MONOTONIC
, &ts
);
97 #error "clock_gettime: no supported absolute time clock"
99 (void)dispatch_assume_zero(ret
);
101 /* XXXRW: Some kind of overflow detection needed? */
102 return (ts
.tv_sec
* NSEC_PER_SEC
+ ts
.tv_nsec
);
104 return mach_absolute_time();