| /* |
| * Copyright (C) 2019 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. |
| */ |
| |
| #ifndef AUDIO_UTILS_HISTOGRAM_H |
| #define AUDIO_UTILS_HISTOGRAM_H |
| |
| #include <memory> |
| #include <sstream> |
| #include <vector> |
| |
| namespace android::audio_utils { |
| |
| class Histogram { |
| public: |
| /** |
| * Construct a histogram. |
| * @param numBinsInRange number of bins to create |
| * @param binWidth width of each bin. Must be positive. |
| */ |
| Histogram(int32_t numBinsInRange, int32_t binWidth) |
| : mBinWidth(binWidth) |
| , mBins(numBinsInRange + kExtraBins) |
| , mLastItemNumbers(mBins.size()) |
| { |
| assert(binWidth > 0); |
| } |
| |
| /** |
| * Add another item to the histogram. |
| * The value will be divided by the binWidth to determine the bin index. |
| * @param value |
| */ |
| void add(int32_t value) { |
| int32_t binIndex = (value + mBinWidth) / mBinWidth; |
| binIndex = std::max(binIndex, 0); // put values below range in bottom bin |
| binIndex = std::min(binIndex, (int32_t)mBins.size() - 1); |
| // put values below range in top bin |
| mBins[binIndex]++; |
| mLastItemNumbers[binIndex] = mItemCount++; |
| } |
| |
| /** |
| * Reset all counters to zero. |
| */ |
| void clear() { |
| std::fill(mBins.begin(), mBins.end(), 0); |
| std::fill(mLastItemNumbers.begin(), mLastItemNumbers.end(), 0); |
| mItemCount = 0; |
| } |
| |
| /** |
| * @return original number of bins passed to the constructor |
| */ |
| int32_t getNumBinsInRange() const { |
| return mBins.size() - kExtraBins; |
| } |
| |
| /** |
| * @return number of items below the lowest bin |
| */ |
| uint64_t getCountBelowRange() const { |
| return mBins[0]; |
| } |
| |
| /** |
| * @param binIndex between 0 and numBins-1 |
| * @return number of items for the given bin index |
| */ |
| uint64_t getCount(int32_t binIndex) const { |
| if (binIndex < 0 || binIndex >= getNumBinsInRange()) { |
| return 0; |
| } |
| return mBins[binIndex + 1]; |
| } |
| |
| /** |
| * @return total number of items added |
| */ |
| uint64_t getCount() const { |
| return mItemCount; |
| } |
| |
| /** |
| * This can be used to determine whether outlying bins were incremented |
| * early or late in the process. |
| * @param binIndex between 0 and numBins-1 |
| * @return number of the last item added to this bin |
| */ |
| uint64_t getLastItemNumber(int32_t binIndex) const { |
| if (binIndex < 0 || binIndex >= getNumBinsInRange()) { |
| return 0; |
| } |
| return mLastItemNumbers[binIndex + 1]; |
| } |
| |
| /** |
| * @return number of items above the highest bin |
| */ |
| uint64_t getCountAboveRange() const { |
| return mBins[mBins.size() - 1]; |
| } |
| |
| /** |
| * Dump the bins in CSV format, which can be easily imported into a spreadsheet. |
| * @return string bins in CSV format |
| */ |
| std::string dump() const { |
| std::stringstream result; |
| uint64_t count = getCountBelowRange(); |
| if (count > 0) { |
| result << "below range = " << count << std::endl; |
| } |
| result << "index, start, count, last" << std::endl; |
| for (size_t i = 1; i < mBins.size() - 1; i++) { |
| if (mBins[i] > 0) { |
| size_t properIndex = i - 1; |
| result << properIndex; |
| result << ", "<< (properIndex * mBinWidth); |
| result << ", " << mBins[i]; |
| result << ", " << mLastItemNumbers[i]; |
| result << std::endl; |
| } |
| } |
| count = getCountAboveRange(); |
| if (count > 0) { |
| result << "above range = " << count << std::endl; |
| } |
| return result.str(); |
| } |
| |
| private: |
| static constexpr int kExtraBins = 2; // for out of range values |
| const int32_t mBinWidth; |
| int64_t mItemCount = 0; |
| std::vector<uint64_t> mBins; // count of the number of items in the range of this bin |
| std::vector<uint64_t> mLastItemNumbers; // number of the last item added this bin |
| }; |
| |
| } // namespace |
| #endif //AUDIO_UTILS_HISTOGRAM_H |