commit 0a6dc40104010537d473ac8f613c51545e214ebc
author Dmitri Plotnikov <dplotnikov@google.com> Fri Jan 19 14:33:20 2024 -0800
committer Dmitri Plotnikov <dplotnikov@google.com> Thu Oct 31 11:55:22 2024 -0700
tree 9f1586f968219e4a1ec7ef4895dcfaadc2f4d913
parent fc8ace08bb2b9f764b9e56fb105609fc20421f4e

A uint64 array wrapper for optimized allocation and copying

Bug: 315052795
Bug: 357697495
Test: atest libbattery_test; atest FrameworksCoreTests
Flag: EXEMPT bugfix
Change-Id: I3c09c438131b3f67ef04436667e589d1d86aff71

libs/battery/LongArrayMultiStateCounter.h

diff --git a/libs/battery/LongArrayMultiStateCounter.h b/libs/battery/LongArrayMultiStateCounter.h
index f3439f6..e00c968 100644
--- a/libs/battery/LongArrayMultiStateCounter.h
+++ b/libs/battery/LongArrayMultiStateCounter.h
@@ -23,7 +23,66 @@
 namespace android {
 namespace battery {
 
-typedef MultiStateCounter<std::vector<uint64_t>> LongArrayMultiStateCounter;
+/**
+ * Wrapper for an array of uint64's.
+ */
+class Uint64Array {
+  protected:
+    size_t mSize;
+
+  public:
+    Uint64Array() : Uint64Array(0) {}
+
+    Uint64Array(size_t size) : mSize(size) {}
+
+    virtual ~Uint64Array() {}
+
+    size_t size() const { return mSize; }
+
+    /**
+     * Returns the wrapped array.
+     *
+     * Nullable! Null should be interpreted the same as an array of zeros
+     */
+    virtual const uint64_t *data() const { return nullptr; }
+
+    friend std::ostream &operator<<(std::ostream &os, const Uint64Array &v);
+
+    // Test API
+    bool operator==(const Uint64Array &other) const;
+};
+
+/**
+ * Mutable version of Uint64Array.
+ */
+class Uint64ArrayRW: public Uint64Array {
+    uint64_t* mData;
+
+public:
+    Uint64ArrayRW() : Uint64ArrayRW(0) {}
+
+    Uint64ArrayRW(size_t size) : Uint64Array(size), mData(nullptr) {}
+
+    Uint64ArrayRW(const Uint64Array &copy);
+
+    // Need an explicit copy constructor. In the initialization context C++ does not understand that
+    // a Uint64ArrayRW is a Uint64Array.
+    Uint64ArrayRW(const Uint64ArrayRW &copy) : Uint64ArrayRW((const Uint64Array &) copy) {}
+
+    // Test API
+    Uint64ArrayRW(std::initializer_list<uint64_t> init);
+
+    ~Uint64ArrayRW() override { delete[] mData; }
+
+    const uint64_t *data() const override { return mData; }
+
+    // NonNull. Will initialize the wrapped array if it is null.
+    uint64_t *dataRW();
+
+    Uint64ArrayRW &operator=(const Uint64Array &t);
+};
+
+typedef MultiStateCounter<Uint64ArrayRW, Uint64Array> LongArrayMultiStateCounter;
 
 } // namespace battery
 } // namespace android