[babl/sse-conversions-2013] Use clock_gettime for babl_ticks if available

[Daniel Sabo <daniels src gnome org>]

commit e4d0837384bcf39eea8b099aec222e2b30d0578c
Author: Daniel Sabo <DanielSabo gmail com>
Date:   Fri Apr 5 20:14:04 2013 -0700

    Use clock_gettime for babl_ticks if available

 babl/Makefile.am |    1 +
 babl/babl-util.c |   30 ++++++++++++++++++++++++
 configure.ac     |   66 ++++++++++++++++++++++++++++++++++++++++++++---------
 3 files changed, 85 insertions(+), 12 deletions(-)
---
diff --git a/babl/Makefile.am b/babl/Makefile.am
index 976b1e0..89636c0 100644
--- a/babl/Makefile.am
+++ b/babl/Makefile.am
@@ -85,6 +85,7 @@ libbabl_ BABL_API_VERSION@_la_LIBADD=\
 
 libbabl_ BABL_API_VERSION@_la_LDFLAGS=                 \
        ${no_undefined} $(MATH_LIB)     \
+       $(CLOCK_GETTIME_LIBS) \
        -version-info $(BABL_LIBRARY_VERSION)
 
 # GObject Introspection
diff --git a/babl/babl-util.c b/babl/babl-util.c
index 40ddfa2..504977c 100644
--- a/babl/babl-util.c
+++ b/babl/babl-util.c
@@ -23,6 +23,34 @@
 #include <sys/time.h>
 #include <time.h>
 
+#ifdef HAVE_CLOCK_GETTIME
+struct timespec start_time;
+
+static void
+init_ticks (void)
+{
+  static int done = 0;
+
+  if (done)
+    return;
+  done = 1;
+  clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &start_time);
+}
+
+long
+babl_ticks (void)
+{
+  struct timespec measure_time;
+  init_ticks ();
+  clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &measure_time);
+
+  long long delta_t = (measure_time.tv_sec - start_time.tv_sec) * 1000000000 + (measure_time.tv_nsec - 
start_time.tv_nsec);
+
+  return (delta_t + 999) / 1000;
+}
+
+#else
+
 static struct timeval start_time;
 
 #define usecs(time)    ((time.tv_sec - start_time.tv_sec) * 1000000 + time.tv_usec)
@@ -47,6 +75,8 @@ babl_ticks (void)
   return usecs (measure_time) - usecs (start_time);
 }
 
+#endif HAVE_CLOCK_GETTIME
+
 long
 babl_process_cost (long ticks_start,
                    long ticks_end)
diff --git a/configure.ac b/configure.ac
index 4954e38..28abf22 100644
--- a/configure.ac
+++ b/configure.ac
@@ -278,6 +278,30 @@ AC_SUBST(MATH_LIB)
 AM_CONDITIONAL(OS_WIN32, test "$os_win32" = "yes")
 AM_CONDITIONAL(OS_UNIX, test "$os_win32" != "yes")
 
+############################
+# Check for clock_gettime
+############################
+
+if test "x$os_win32" != xyes; then
+  have_clock_gettime_save_LIBS="$LIBS"
+  LIBS="$LIBS -lrt"
+  AC_MSG_CHECKING([for clock_gettime])
+  AC_RUN_IFELSE(
+    [AC_LANG_PROGRAM(
+      [[#include <time.h>]],
+      [[struct timespec t; clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &t);]])],
+    [have_clock_gettime=yes],
+    [have_clock_gettime=no])
+  AC_MSG_RESULT($have_clock_gettime)
+  if test "x$have_clock_gettime" = xyes; then
+    CLOCK_GETTIME_LIBS="-lrt"
+    AC_DEFINE(HAVE_CLOCK_GETTIME, 1, [Define to 1 if clock_gettime is available.])
+  fi
+  LIBS="$have_clock_gettime_save_LIBS"
+fi
+
+AC_SUBST(CLOCK_GETTIME_LIBS)
+#AM_CONDITIONAL(HAVE_CLOCK_GETTIME, test "x$have_clock_gettime" = "xyes")
 
 dnl ===========================================================================
 
@@ -294,6 +318,10 @@ AC_ARG_ENABLE(sse,
   [  --enable-sse            enable SSE support (default=auto)],,
   enable_sse=$enable_mmx)
 
+AC_ARG_ENABLE(sse2,
+  [  --enable-sse2            enable SSE2 support (default=auto)],,
+  enable_sse2=$enable_sse)
+
 if test "x$enable_mmx" = xyes; then
   BABL_DETECT_CFLAGS(MMX_EXTRA_CFLAGS, '-mmmx')
   SSE_EXTRA_CFLAGS=
@@ -329,21 +357,24 @@ if test "x$enable_mmx" = xyes; then
         AC_MSG_WARN([The assembler does not support the SSE command set.])
       )
       
-      BABL_DETECT_CFLAGS(sse2_flag, '-msse2')
-      SSE2_EXTRA_CFLAGS="$SSE_EXTRA_CFLAGS $sse2_flag"
+      
+      if test "x$enable_sse2" = xyes; then
+        BABL_DETECT_CFLAGS(sse2_flag, '-msse2')
+        SSE2_EXTRA_CFLAGS="$SSE_EXTRA_CFLAGS $sse2_flag"
 
-      AC_MSG_CHECKING(whether we can compile SSE2 code)
+        AC_MSG_CHECKING(whether we can compile SSE2 code)
 
-      CFLAGS="$CFLAGS $sse2_flag"
+        CFLAGS="$CFLAGS $sse2_flag"
 
-      AC_COMPILE_IFELSE([AC_LANG_PROGRAM(,[asm ("punpckhwd %xmm0,%xmm1");])],
-        AC_DEFINE(USE_SSE2, 1, [Define to 1 if SSE2 assembly is available.])
-        AC_MSG_RESULT(yes)
-      ,
-        enable_sse2=no
-        AC_MSG_RESULT(no)
-        AC_MSG_WARN([The assembler does not support the SSE2 command set.])
-      )
+        AC_COMPILE_IFELSE([AC_LANG_PROGRAM(,[asm ("punpckhwd %xmm0,%xmm1");])],
+          AC_DEFINE(USE_SSE2, 1, [Define to 1 if SSE2 assembly is available.])
+          AC_MSG_RESULT(yes)
+        ,
+          enable_sse2=no
+          AC_MSG_RESULT(no)
+          AC_MSG_WARN([The assembler does not support the SSE2 command set.])
+        )
+      fi
 
     fi
   ,
@@ -454,3 +485,14 @@ INSTALL
 )
 
 AC_OUTPUT
+
+dnl Print a summary of features enabled/disabled:
+AC_MSG_RESULT([
+Building Babl with prefix=$prefix
+
+Optional features:
+  SIMD: mmx: $enable_mmx
+        sse: $enable_sse
+        sse2:$enable_sse2
+  RTC: $have_clock_gettime
+]);