From 94584e8b20f67a342c625a674590e8bc1aad88cb Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@gmail.com>
Date: Wed, 1 Dec 2010 00:29:34 -0500
Subject: Check for platform support for times().

---
 configure.ac            | 19 +++++++++++++++++++
 libdimension/platform.c | 33 +++++++++++++++++++++++++++++++++
 libdimension/platform.h |  7 +++++++
 libdimension/timer.c    | 34 +++++++---------------------------
 4 files changed, 66 insertions(+), 27 deletions(-)

diff --git a/configure.ac b/configure.ac
index 336c996..6fbf585 100644
--- a/configure.ac
+++ b/configure.ac
@@ -125,6 +125,25 @@ AC_COMPILE_IFELSE([
    AC_MSG_RESULT([no])]
 )
 
+AC_MSG_CHECKING([for times()])
+AC_COMPILE_IFELSE([
+  AC_LANG_PROGRAM(
+    [
+      #include <sys/times.h>
+      #include <unistd.h>
+    ],
+    [
+      long clk_tck = sysconf(_SC_CLK_TCK);
+      struct tms buf;
+      clock_t real = times(&buf);
+    ]
+  )],
+  [AC_DEFINE([DMNSN_TIMES], [1])
+   AC_MSG_RESULT([yes])],
+  [AC_DEFINE([DMNSN_TIMES], [0])
+   AC_MSG_RESULT([no])]
+)
+
 AC_MSG_CHECKING([for ioctl(TIOCGWINSZ)])
 AC_COMPILE_IFELSE([
   AC_LANG_PROGRAM(
diff --git a/libdimension/platform.c b/libdimension/platform.c
index e8f090d..b506c10 100644
--- a/libdimension/platform.c
+++ b/libdimension/platform.c
@@ -36,6 +36,9 @@
 #if DMNSN_SCHED_GETAFFINITY
   #include <sched.h>       /* For sched_getaffinity() */
 #endif
+#if DMNSN_TIMES
+  #include <sys/times.h>
+#endif
 
 void
 dmnsn_backtrace(FILE *file)
@@ -96,3 +99,33 @@ dmnsn_ncpus(void)
   return 1;
 #endif
 }
+
+#if DMNSN_TIMES
+/** Clock ticks per second. */
+static long clk_tck = 0;
+#endif
+
+void
+dmnsn_get_times(dmnsn_timer *timer)
+{
+#if DMNSN_TIMES
+  /* Figure out the clock ticks per second */
+  if (!clk_tck) {
+    clk_tck = sysconf(_SC_CLK_TCK);
+    if (clk_tck == -1) {
+      dmnsn_error(DMNSN_SEVERITY_MEDIUM, "sysconf(_SC_CLK_TCK) failed.");
+      clk_tck = 1000000L;
+    }
+  }
+
+  struct tms buf;
+  clock_t real = times(&buf);
+  timer->real   = (double)real/clk_tck;
+  timer->user   = (double)buf.tms_utime/clk_tck;
+  timer->system = (double)buf.tms_stime/clk_tck;
+#else
+  timer->real   = 0.0;
+  timer->user   = 0.0;
+  timer->system = 0.0;
+#endif
+}
diff --git a/libdimension/platform.h b/libdimension/platform.h
index fbf467b..83b5c37 100644
--- a/libdimension/platform.h
+++ b/libdimension/platform.h
@@ -55,4 +55,11 @@ bool dmnsn_is_little_endian(void);
  */
 size_t dmnsn_ncpus(void);
 
+/**
+ * Calculate process times.
+ * @param[out] timer  The timer in which to store the current total process
+ *                    times.
+ */
+void dmnsn_get_times(dmnsn_timer *timer);
+
 #endif /* DIMENSION_IMPL_PLATFORM_H */
diff --git a/libdimension/timer.c b/libdimension/timer.c
index 53d7101..fa96b06 100644
--- a/libdimension/timer.c
+++ b/libdimension/timer.c
@@ -23,44 +23,24 @@
  * Performance counter.
  */
 
-#include "dimension.h"
-#include <sys/times.h>
-#include <unistd.h>
-
-/** Clock ticks per second. */
-static long clk_tck = 0;
+#include "dimension-impl.h"
 
 dmnsn_timer *
 dmnsn_new_timer(void)
 {
-  /* Figure out the clock ticks per second */
-  if (!clk_tck) {
-    clk_tck = sysconf(_SC_CLK_TCK);
-    if (clk_tck == -1) {
-      dmnsn_error(DMNSN_SEVERITY_MEDIUM, "sysconf(_SC_CLK_TCK) failed.");
-      clk_tck = 1000000L;
-    }
-  }
-
   dmnsn_timer *timer = dmnsn_malloc(sizeof(dmnsn_timer));
-
-  struct tms buf;
-  clock_t real = times(&buf);
-  timer->real   = (double)real/clk_tck;
-  timer->user   = (double)buf.tms_utime/clk_tck;
-  timer->system = (double)buf.tms_stime/clk_tck;
-
+  dmnsn_get_times(timer);
   return timer;
 }
 
 void
 dmnsn_complete_timer(dmnsn_timer *timer)
 {
-  struct tms buf;
-  clock_t real = times(&buf);
-  timer->real   = (double)real/clk_tck - timer->real;
-  timer->user   = (double)buf.tms_utime/clk_tck - timer->user;
-  timer->system = (double)buf.tms_stime/clk_tck - timer->system;
+  dmnsn_timer now;
+  dmnsn_get_times(&now);
+  timer->real   = now.real   - timer->real;
+  timer->user   = now.user   - timer->user;
+  timer->system = now.system - timer->system;
 }
 
 void
-- 
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