auto import from //depot/cupcake/@135843

1 files changed, 240 insertions, 0 deletions

diff --git a/libs/utils/Timers.cpp b/libs/utils/Timers.cpp
new file mode 100644
index 0000000..2abc811
--- /dev/null
+++ b/libs/utils/Timers.cpp
@@ -0,0 +1,240 @@
+/*
+ * Copyright (C) 2005 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+//
+// Timer functions.
+//
+#include <utils/Timers.h>
+#include <utils/ported.h>     // may need usleep
+#include <utils/Log.h>
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <time.h>
+#include <errno.h>
+
+#ifdef HAVE_WIN32_THREADS
+#include <windows.h>
+#endif
+
+nsecs_t systemTime(int clock)
+{
+#if defined(HAVE_POSIX_CLOCKS)
+    static const clockid_t clocks[] = {
+            CLOCK_REALTIME,
+            CLOCK_MONOTONIC,
+            CLOCK_PROCESS_CPUTIME_ID,
+            CLOCK_THREAD_CPUTIME_ID
+    };
+    struct timespec t;
+    t.tv_sec = t.tv_nsec = 0;
+    clock_gettime(clocks[clock], &t);
+    return nsecs_t(t.tv_sec)*1000000000LL + t.tv_nsec;
+#else
+    // we don't support the clocks here.
+    struct timeval t;
+    t.tv_sec = t.tv_usec = 0;
+    gettimeofday(&t, NULL);
+    return nsecs_t(t.tv_sec)*1000000000LL + nsecs_t(t.tv_usec)*1000LL;
+#endif
+}
+
+//#define MONITOR_USLEEP
+
+/*
+ * Sleep long enough that we'll wake up "interval" milliseconds after
+ * the previous snooze.
+ *
+ * The "nextTick" argument is updated on each call, and should be passed
+ * in every time.  Set its fields to zero on the first call.
+ *
+ * Returns the #of intervals we have overslept, which will be zero if we're
+ * on time.  [Currently just returns 0 or 1.]
+ */
+int sleepForInterval(long interval, struct timeval* pNextTick)
+{
+    struct timeval now;
+    long long timeBeforeNext;
+    long sleepTime = 0;
+    bool overSlept = false;
+    //int usleepBias = 0;
+
+#ifdef USLEEP_BIAS
+    /*
+     * Linux likes to add 9000ms or so.
+     * [not using this for now]
+     */
+    //usleepBias = USLEEP_BIAS;
+#endif
+
+    gettimeofday(&now, NULL);
+
+    if (pNextTick->tv_sec == 0) {
+        /* special-case for first time through */
+        *pNextTick = now;
+        sleepTime = interval;
+        android::DurationTimer::addToTimeval(pNextTick, interval);
+    } else {
+        /*
+         * Compute how much time there is before the next tick.  If this
+         * value is negative, we've run over.  If we've run over a little
+         * bit we can shorten the next frame to keep the pace steady, but
+         * if we've dramatically overshot we need to re-sync.
+         */
+        timeBeforeNext = android::DurationTimer::subtractTimevals(pNextTick, &now);
+        //printf("TOP: now=%ld.%ld next=%ld.%ld diff=%ld\n",
+        //    now.tv_sec, now.tv_usec, pNextTick->tv_sec, pNextTick->tv_usec,
+        //    (long) timeBeforeNext);
+        if (timeBeforeNext < -interval) {
+            /* way over */
+            overSlept = true;
+            sleepTime = 0;
+            *pNextTick = now;
+        } else if (timeBeforeNext <= 0) {
+            /* slightly over, keep the pace steady */
+            overSlept = true;
+            sleepTime = 0;
+        } else if (timeBeforeNext <= interval) {
+            /* right on schedule */
+            sleepTime = timeBeforeNext;
+        } else if (timeBeforeNext > interval && timeBeforeNext <= 2*interval) {
+            /* sleep call returned early; do a longer sleep this time */
+            sleepTime = timeBeforeNext;
+        } else if (timeBeforeNext > interval) {
+            /* we went back in time -- somebody updated system clock? */
+            /* (could also be a *seriously* broken usleep()) */
+            LOG(LOG_DEBUG, "",
+                " Impossible: timeBeforeNext = %ld\n", (long)timeBeforeNext);
+            sleepTime = 0;
+            *pNextTick = now;
+        }
+        android::DurationTimer::addToTimeval(pNextTick, interval);
+    }
+    //printf(" Before sleep: now=%ld.%ld next=%ld.%ld sleepTime=%ld\n",
+    //    now.tv_sec, now.tv_usec, pNextTick->tv_sec, pNextTick->tv_usec,
+    //    sleepTime);
+
+    /*
+     * Sleep for the designated period of time.
+     *
+     * Linux tends to sleep for longer than requested, often by 17-18ms.
+     * MinGW tends to sleep for less than requested, by as much as 14ms,
+     * but occasionally oversleeps for 40+ms (looks like some external
+     * factors plus round-off on a 64Hz clock).  Cygwin is pretty steady.
+     *
+     * If you start the MinGW version, and then launch the Cygwin version,
+     * the MinGW clock becomes more erratic.  Not entirely sure why.
+     *
+     * (There's a lot of stuff here; it's really just a usleep() call with
+     * a bunch of instrumentation.)
+     */
+    if (sleepTime > 0) {
+#if defined(MONITOR_USLEEP)
+        struct timeval before, after;
+        long long actual;
+
+        gettimeofday(&before, NULL);
+        usleep((long) sleepTime);
+        gettimeofday(&after, NULL);
+
+        /* check usleep() accuracy; default Linux threads are pretty sloppy */
+        actual = android::DurationTimer::subtractTimevals(&after, &before);
+        if ((long) actual < sleepTime - 14000 /*(sleepTime/10)*/ ||
+            (long) actual > sleepTime + 20000 /*(sleepTime/10)*/)
+        {
+            LOG(LOG_DEBUG, "", " Odd usleep: req=%ld, actual=%ld\n", sleepTime,
+                (long) actual);
+        }
+#else
+#ifdef HAVE_WIN32_THREADS
+        Sleep( sleepTime/1000 );
+#else        
+        usleep((long) sleepTime);
+#endif        
+#endif
+    }
+
+    //printf("slept %d\n", sleepTime);
+
+    if (overSlept)
+        return 1;       // close enough
+    else
+        return 0;
+}
+
+
+/*
+ * ===========================================================================
+ *      DurationTimer
+ * ===========================================================================
+ */
+
+using namespace android;
+
+// Start the timer.
+void DurationTimer::start(void)
+{
+    gettimeofday(&mStartWhen, NULL);
+}
+
+// Stop the timer.
+void DurationTimer::stop(void)
+{
+    gettimeofday(&mStopWhen, NULL);
+}
+
+// Get the duration in microseconds.
+long long DurationTimer::durationUsecs(void) const
+{
+    return (long) subtractTimevals(&mStopWhen, &mStartWhen);
+}
+
+// Subtract two timevals.  Returns the difference (ptv1-ptv2) in
+// microseconds.
+/*static*/ long long DurationTimer::subtractTimevals(const struct timeval* ptv1,
+    const struct timeval* ptv2)
+{
+    long long stop  = ((long long) ptv1->tv_sec) * 1000000LL +
+                      ((long long) ptv1->tv_usec);
+    long long start = ((long long) ptv2->tv_sec) * 1000000LL +
+                      ((long long) ptv2->tv_usec);
+    return stop - start;
+}
+
+// Add the specified amount of time to the timeval.
+/*static*/ void DurationTimer::addToTimeval(struct timeval* ptv, long usec)
+{
+    if (usec < 0) {
+        LOG(LOG_WARN, "", "Negative values not supported in addToTimeval\n");
+        return;
+    }
+
+    // normalize tv_usec if necessary
+    if (ptv->tv_usec >= 1000000) {
+        ptv->tv_sec += ptv->tv_usec / 1000000;
+        ptv->tv_usec %= 1000000;
+    }
+
+    ptv->tv_usec += usec % 1000000;
+    if (ptv->tv_usec >= 1000000) {
+        ptv->tv_usec -= 1000000;
+        ptv->tv_sec++;
+    }
+    ptv->tv_sec += usec / 1000000;
+}
+