[TeX] Introduced Telemetry Express Histogram metric Native API
- added support C++ TeX Histogram logging API
Bug: 268161449
Test: atest expresslog_test
Change-Id: I284c6ceab42208dc9432fe3887c9ac000028d072
diff --git a/libstats/expresslog/Histogram.cpp b/libstats/expresslog/Histogram.cpp
new file mode 100644
index 0000000..c90282d
--- /dev/null
+++ b/libstats/expresslog/Histogram.cpp
@@ -0,0 +1,74 @@
+//
+// Copyright (C) 2023 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 "include/Histogram.h"
+
+#define LOG_TAG "tex"
+
+#include <log/log.h>
+#include <statslog_express.h>
+#include <string.h>
+#include <utils/hash/farmhash.h>
+
+namespace android {
+namespace expresslog {
+
+Histogram::UniformOptions* Histogram::UniformOptions::create(int binCount, float minValue,
+ float exclusiveMaxValue) {
+ if (binCount < 1) {
+ ALOGE("Bin count should be positive number");
+ return nullptr;
+ }
+
+ if (exclusiveMaxValue <= minValue) {
+ ALOGE("Bins range invalid (maxValue < minValue)");
+ return nullptr;
+ }
+
+ return new UniformOptions(binCount, minValue, exclusiveMaxValue);
+}
+
+Histogram::UniformOptions::UniformOptions(int binCount, float minValue, float exclusiveMaxValue)
+ : // Implicitly add 2 for the extra undeflow & overflow bins
+ mBinCount(binCount + 2),
+ mMinValue(minValue),
+ mExclusiveMaxValue(exclusiveMaxValue),
+ mBinSize((exclusiveMaxValue - minValue) / binCount) {
+}
+
+int Histogram::UniformOptions::getBinForSample(float sample) const {
+ if (sample < mMinValue) {
+ // goes to underflow
+ return 0;
+ } else if (sample >= mExclusiveMaxValue) {
+ // goes to overflow
+ return mBinCount - 1;
+ }
+ return (int)((sample - mMinValue) / mBinSize + 1);
+}
+
+Histogram::Histogram(const char* metricName, std::shared_ptr<BinOptions> binOptions)
+ : mMetricIdHash(farmhash::Fingerprint64(metricName, strlen(metricName))),
+ mBinOptions(std::move(binOptions)) {
+}
+
+void Histogram::logSample(float sample) const {
+ const int binIndex = mBinOptions->getBinForSample(sample);
+ stats_write(EXPRESS_HISTOGRAM_SAMPLE_REPORTED, mMetricIdHash, /*count*/ 1, binIndex);
+}
+
+} // namespace expresslog
+} // namespace android