Add OS X support.

Author: habnabit

configure.ac

@@ -53,7 +53,11 @@ AC_TYPE_UINT32_T
 AC_CHECK_TYPE([struct timespec], [], [AC_MSG_ERROR([missing struct timespec])], [[#include <time.h>]])
 
 # Checks for functions.
-AC_CHECK_FUNCS([clock_gettime], [], [AC_MSG_ERROR([missing clock_gettime])])
+AC_CHECK_FUNCS([clock_gettime], [AC_DEFINE([HAVE_CLOCK_GETTIME])], [
+    AC_CHECK_FUNCS([host_get_clock_service],
+                   [AC_DEFINE([HAVE_HOST_GET_CLOCK_SERVICE])],
+                   [AC_MSG_ERROR([no clock_gettime or host_get_clock_service])])
+])
 
 # Checks for compiler flags.
 CCHECKFLAGS="-Wno-error"

libcurvecpr/lib/util.c

@@ -8,6 +8,11 @@
 
 #include <sodium/randombytes.h>
 
+#ifdef HAVE_HOST_GET_CLOCK_SERVICE
+#include <mach/clock.h>
+#include <mach/mach.h>
+#endif
+
 /* XXX: Current implementation is limited to n < 2^55. */
 long long curvecpr_util_random_mod_n (long long n)
 {
@@ -29,9 +34,19 @@ long long curvecpr_util_random_mod_n (long long n)
 /* XXX: Nanosecond granularity limits users to 1 terabyte per second. */
 long long curvecpr_util_nanoseconds (void)
 {
+#if defined(HAVE_CLOCK_GETTIME)
     struct timespec t;
     if (clock_gettime(CLOCK_REALTIME, &t) != 0)
         return -1;
+#elif defined(HAVE_HOST_GET_CLOCK_SERVICE)
+    clock_serv_t clock;
+    mach_timespec_t t;
+    host_get_clock_service(mach_host_self(), CALENDAR_CLOCK, &clock);
+    clock_get_time(clock, &t);
+    mach_port_deallocate(mach_task_self(), clock);
+#else
+    #error "no function for getting microseconds"
+#endif
 
     return t.tv_sec * 1000000000LL + t.tv_nsec;
 }