Add MultiStateCounter

This native object is used to track values per-state. For example,
if the state changes from 0 to 1 between two updateValue calls,
the delta between the values is distributed to the states 0 and 1
in accordance with the time spent in those states.

Bug: 197162116
Test: atest libbattery_test

Change-Id: Ie304db5c93f4aa9676d12d0a8ab53b6867b24fff

1 files changed, 54 insertions, 0 deletions

diff --git a/libs/battery/LongArrayMultiStateCounterTest.cpp b/libs/battery/LongArrayMultiStateCounterTest.cpp
new file mode 100644
index 0000000000..24cb437eaa
--- /dev/null
+++ b/libs/battery/LongArrayMultiStateCounterTest.cpp
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ * Android BPF library - public API
+ *
+ * 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 <gtest/gtest.h>
+#include "LongArrayMultiStateCounter.h"
+
+namespace android {
+namespace battery {
+
+class LongArrayMultiStateCounterTest : public testing::Test {};
+
+TEST_F(LongArrayMultiStateCounterTest, stateChange) {
+    LongArrayMultiStateCounter testCounter(2, 0, std::vector<uint64_t>(4), 1000);
+    testCounter.setState(1, 2000);
+    testCounter.updateValue(std::vector<uint64_t>({100, 200, 300, 400}), 3000);
+
+    // Time was split in half between the two states, so the counts will be split 50:50 too
+    EXPECT_EQ(std::vector<uint64_t>({50, 100, 150, 200}), testCounter.getCount(0));
+    EXPECT_EQ(std::vector<uint64_t>({50, 100, 150, 200}), testCounter.getCount(1));
+}
+
+TEST_F(LongArrayMultiStateCounterTest, accumulation) {
+    LongArrayMultiStateCounter testCounter(2, 0, std::vector<uint64_t>(4), 1000);
+    testCounter.setState(1, 2000);
+    testCounter.updateValue(std::vector<uint64_t>({100, 200, 300, 400}), 3000);
+    testCounter.setState(0, 4000);
+    testCounter.updateValue(std::vector<uint64_t>({200, 300, 400, 500}), 8000);
+
+    // The first delta is split 50:50:
+    //   0: {50, 100, 150, 200}
+    //   1: {50, 100, 150, 200}
+    // The second delta is split 4:1
+    //   0: {80, 80, 80, 80}
+    //   1: {20, 20, 20, 20}
+    EXPECT_EQ(std::vector<uint64_t>({130, 180, 230, 280}), testCounter.getCount(0));
+    EXPECT_EQ(std::vector<uint64_t>({70, 120, 170, 220}), testCounter.getCount(1));
+}
+
+} // namespace battery
+} // namespace android