intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 81 insertions, 0 deletions

diff --git a/library/cpp/containers/ring_buffer/ring_buffer.h b/library/cpp/containers/ring_buffer/ring_buffer.h
new file mode 100644
index 0000000000..41220dcf6b
--- /dev/null
+++ b/library/cpp/containers/ring_buffer/ring_buffer.h
@@ -0,0 +1,81 @@
+#pragma once
+
+#include <util/generic/vector.h>
+#include <util/system/yassert.h>
+
+template <typename T>
+class TSimpleRingBuffer {
+public:
+    TSimpleRingBuffer(size_t maxSize)
+        : MaxSize(maxSize)
+    {
+        Items.reserve(MaxSize);
+    }
+
+    TSimpleRingBuffer(const TSimpleRingBuffer&) = default;
+    TSimpleRingBuffer(TSimpleRingBuffer&&) = default;
+
+    TSimpleRingBuffer& operator=(const TSimpleRingBuffer&) = default;
+    TSimpleRingBuffer& operator=(TSimpleRingBuffer&&) = default;
+
+    // First available item
+    size_t FirstIndex() const {
+        return Begin;
+    }
+
+    size_t AvailSize() const {
+        return Items.size();
+    }
+
+    // Total number of items inserted
+    size_t TotalSize() const {
+        return FirstIndex() + AvailSize();
+    }
+
+    bool IsAvail(size_t index) const {
+        return index >= FirstIndex() && index < TotalSize();
+    }
+
+    const T& operator[](size_t index) const {
+        Y_ASSERT(IsAvail(index));
+        return Items[RealIndex(index)];
+    }
+
+    T& operator[](size_t index) {
+        Y_ASSERT(IsAvail(index));
+        return Items[RealIndex(index)];
+    }
+
+    void PushBack(const T& t) {
+        if (Items.size() < MaxSize) {
+            Items.push_back(t);
+        } else {
+            Items[RealIndex(Begin)] = t;
+            Begin += 1;
+        }
+    }
+
+    void Clear() {
+        Items.clear();
+        Begin = 0;
+    }
+
+private:
+    size_t RealIndex(size_t index) const {
+        return index % MaxSize;
+    }
+
+private:
+    size_t MaxSize;
+    size_t Begin = 0;
+    TVector<T> Items;
+};
+
+template <typename T, size_t maxSize>
+class TStaticRingBuffer: public TSimpleRingBuffer<T> {
+public:
+    TStaticRingBuffer()
+        : TSimpleRingBuffer<T>(maxSize)
+    {
+    }
+};