From 01cb78a763e0d8ea31feb6f5754cd99718cbe075 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <slouken@libsdl.org>
Date: Fri, 25 Mar 2011 14:45:04 -0700
Subject: [PATCH] Added high resolution timing API:
 SDL_GetPerformanceCounter(), SDL_GetPerformanceFrequency()

---
 include/SDL_timer.h              | 10 +++++++++
 src/timer/beos/SDL_systimer.c    | 12 +++++++++++
 src/timer/dummy/SDL_systimer.c   | 12 +++++++++++
 src/timer/nds/SDL_systimer.c     | 12 +++++++++++
 src/timer/unix/SDL_systimer.c    | 36 ++++++++++++++++++++++++++++++++
 src/timer/wince/SDL_systimer.c   | 12 +++++++++++
 src/timer/windows/SDL_systimer.c | 22 +++++++++++++++++++
 test/testtimer.c                 | 12 ++++++++++-
 8 files changed, 127 insertions(+), 1 deletion(-)

diff --git a/include/SDL_timer.h b/include/SDL_timer.h
index 9b7ad837b..37e07551d 100644
--- a/include/SDL_timer.h
+++ b/include/SDL_timer.h
@@ -47,6 +47,16 @@ extern "C" {
  */
 extern DECLSPEC Uint32 SDLCALL SDL_GetTicks(void);
 
+/**
+ * \brief Get the current value of the high resolution counter
+ */
+extern DECLSPEC Uint64 SDLCALL SDL_GetPerformanceCounter(void);
+
+/**
+ * \brief Get the count per second of the high resolution counter
+ */
+extern DECLSPEC Uint64 SDLCALL SDL_GetPerformanceFrequency(void);
+
 /**
  * \brief Wait a specified number of milliseconds before returning.
  */
diff --git a/src/timer/beos/SDL_systimer.c b/src/timer/beos/SDL_systimer.c
index af30f4ed2..4809cce48 100644
--- a/src/timer/beos/SDL_systimer.c
+++ b/src/timer/beos/SDL_systimer.c
@@ -42,6 +42,18 @@ SDL_GetTicks(void)
     return ((system_time() - start) / 1000);
 }
 
+Uint64
+SDL_GetPerformanceCounter(void)
+{
+    return system_time();
+}
+
+Uint64
+SDL_GetPerformanceFrequency(void)
+{
+    return 1000000;
+}
+
 void
 SDL_Delay(Uint32 ms)
 {
diff --git a/src/timer/dummy/SDL_systimer.c b/src/timer/dummy/SDL_systimer.c
index f6cf50cb6..bfe798c03 100644
--- a/src/timer/dummy/SDL_systimer.c
+++ b/src/timer/dummy/SDL_systimer.c
@@ -37,6 +37,18 @@ SDL_GetTicks(void)
     return 0;
 }
 
+Uint64
+SDL_GetPerformanceCounter(void)
+{
+    return SDL_GetTicks();
+}
+
+Uint64
+SDL_GetPerformanceFrequency(void)
+{
+    return 1000;
+}
+
 void
 SDL_Delay(Uint32 ms)
 {
diff --git a/src/timer/nds/SDL_systimer.c b/src/timer/nds/SDL_systimer.c
index 8eb453ba9..8b9cfdc9c 100644
--- a/src/timer/nds/SDL_systimer.c
+++ b/src/timer/nds/SDL_systimer.c
@@ -52,6 +52,18 @@ SDL_GetTicks(void)
     return timer_ticks;
 }
 
+Uint64
+SDL_GetPerformanceCounter(void)
+{
+    return SDL_GetTicks();
+}
+
+Uint64
+SDL_GetPerformanceFrequency(void)
+{
+    return 1000;
+}
+
 void
 SDL_Delay(Uint32 ms)
 {
diff --git a/src/timer/unix/SDL_systimer.c b/src/timer/unix/SDL_systimer.c
index 48bc85049..ba40284a3 100644
--- a/src/timer/unix/SDL_systimer.c
+++ b/src/timer/unix/SDL_systimer.c
@@ -64,6 +64,7 @@ SDL_GetTicks(void)
 #if HAVE_CLOCK_GETTIME
     Uint32 ticks;
     struct timespec now;
+
     clock_gettime(CLOCK_MONOTONIC, &now);
     ticks =
         (now.tv_sec - start.tv_sec) * 1000 + (now.tv_nsec -
@@ -72,6 +73,7 @@ SDL_GetTicks(void)
 #else
     Uint32 ticks;
     struct timeval now;
+
     gettimeofday(&now, NULL);
     ticks =
         (now.tv_sec - start.tv_sec) * 1000 + (now.tv_usec -
@@ -80,6 +82,40 @@ SDL_GetTicks(void)
 #endif
 }
 
+Uint64
+SDL_GetPerformanceCounter(void)
+{
+#if HAVE_CLOCK_GETTIME
+    Uint64 ticks;
+    struct timespec now;
+
+    clock_gettime(CLOCK_MONOTONIC, &now);
+    ticks = now.tv_sec;
+    ticks *= 1000000000;
+    ticks += now.tv_nsec;
+    return (ticks);
+#else
+    Uint64 ticks;
+    struct timeval now;
+
+    gettimeofday(&now, NULL);
+    ticks = now.tv_sec;
+    ticks *= 1000000;
+    ticks += now.tv_usec;
+    return (ticks);
+#endif
+}
+
+Uint64
+SDL_GetPerformanceFrequency(void)
+{
+#if HAVE_CLOCK_GETTIME
+    return 1000000000;
+#else
+    return 1000000;
+#endif
+}
+
 void
 SDL_Delay(Uint32 ms)
 {
diff --git a/src/timer/wince/SDL_systimer.c b/src/timer/wince/SDL_systimer.c
index 35aa46557..33160bbbb 100644
--- a/src/timer/wince/SDL_systimer.c
+++ b/src/timer/wince/SDL_systimer.c
@@ -87,6 +87,18 @@ SDL_GetTicks()
     return ((Uint32) wce_rel_ticks());
 }
 
+Uint64
+SDL_GetPerformanceCounter(void)
+{
+    return SDL_GetTicks();
+}
+
+Uint64
+SDL_GetPerformanceFrequency(void)
+{
+    return 1000;
+}
+
 /* Give up approx. givem milliseconds to the OS. */
 void
 SDL_Delay(Uint32 ms)
diff --git a/src/timer/windows/SDL_systimer.c b/src/timer/windows/SDL_systimer.c
index df22ad22b..0f4d8f331 100644
--- a/src/timer/windows/SDL_systimer.c
+++ b/src/timer/windows/SDL_systimer.c
@@ -99,6 +99,28 @@ SDL_GetTicks(void)
     return (ticks);
 }
 
+Uint64
+SDL_GetPerformanceCounter(void)
+{
+    LARGE_INTEGER counter;
+
+    if (!QueryPerformanceCounter(&counter)) {
+        return SDL_GetTicks();
+    }
+    return counter.QuadPart;
+}
+
+Uint64
+SDL_GetPerformanceFrequency(void)
+{
+    LARGE_INTEGER frequency;
+
+    if (!QueryPerformanceFrequency(&frequency)) {
+        return 1000;
+    }
+    return frequency.QuadPart;
+}
+
 void
 SDL_Delay(Uint32 ms)
 {
diff --git a/test/testtimer.c b/test/testtimer.c
index f58efbbda..c2d1573ab 100644
--- a/test/testtimer.c
+++ b/test/testtimer.c
@@ -29,8 +29,9 @@ callback(Uint32 interval, void *param)
 int
 main(int argc, char *argv[])
 {
-    int desired;
+    int i, desired;
     SDL_TimerID t1, t2, t3;
+    Uint64 start, now;
 
     if (SDL_Init(SDL_INIT_TIMER) < 0) {
         fprintf(stderr, "Couldn't initialize SDL: %s\n", SDL_GetError());
@@ -85,6 +86,15 @@ main(int argc, char *argv[])
     SDL_RemoveTimer(t2);
     SDL_RemoveTimer(t3);
 
+    start = SDL_GetPerformanceCounter();
+    for (i = 0; i < 1000000; ++i) {
+        ticktock(0);
+    }
+    now = SDL_GetPerformanceCounter();
+    printf("1 million iterations of ticktock took %f ms\n", (double)((now - start)*1000) / SDL_GetPerformanceFrequency());
+
     SDL_Quit();
     return (0);
 }
+
+/* vi: set ts=4 sw=4 expandtab: */