1 files changed, 67 insertions, 0 deletions
diff --git a/media/libstagefright/wifi-display/TimeSeries.cpp b/media/libstagefright/wifi-display/TimeSeries.cpp
new file mode 100644
index 0000000..d882d98
--- /dev/null
+++ b/media/libstagefright/wifi-display/TimeSeries.cpp
@@ -0,0 +1,67 @@
+/*
+ * Copyright 2012, 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.
+ */
+
+#include "TimeSeries.h"
+
+#include <math.h>
+#include <string.h>
+
+namespace android {
+
+TimeSeries::TimeSeries()
+    : mCount(0),
+      mSum(0.0) {
+}
+
+void TimeSeries::add(double val) {
+    if (mCount < kHistorySize) {
+        mValues[mCount++] = val;
+        mSum += val;
+    } else {
+        mSum -= mValues[0];
+        memmove(&mValues[0], &mValues[1], (kHistorySize - 1) * sizeof(double));
+        mValues[kHistorySize - 1] = val;
+        mSum += val;
+    }
+}
+
+double TimeSeries::mean() const {
+    if (mCount < 1) {
+        return 0.0;
+    }
+
+    return mSum / mCount;
+}
+
+double TimeSeries::sdev() const {
+    if (mCount < 1) {
+        return 0.0;
+    }
+
+    double m = mean();
+
+    double sum = 0.0;
+    for (size_t i = 0; i < mCount; ++i) {
+        double tmp = mValues[i] - m;
+        tmp *= tmp;
+
+        sum += tmp;
+    }
+
+    return sqrt(sum / mCount);
+}
+
+}  // namespace android