--- /dev/null
+//===-- vector_test.cc ------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "vector.h"
+
+#include "gtest/gtest.h"
+
+TEST(ScudoVectorTest, Basic) {
+ scudo::Vector<int> V;
+ EXPECT_EQ(V.size(), 0U);
+ V.push_back(42);
+ EXPECT_EQ(V.size(), 1U);
+ EXPECT_EQ(V[0], 42);
+ V.push_back(43);
+ EXPECT_EQ(V.size(), 2U);
+ EXPECT_EQ(V[0], 42);
+ EXPECT_EQ(V[1], 43);
+}
+
+TEST(ScudoVectorTest, Stride) {
+ scudo::Vector<int> V;
+ for (int i = 0; i < 1000; i++) {
+ V.push_back(i);
+ EXPECT_EQ(V.size(), i + 1U);
+ EXPECT_EQ(V[i], i);
+ }
+ for (int i = 0; i < 1000; i++)
+ EXPECT_EQ(V[i], i);
+}
+
+TEST(ScudoVectorTest, ResizeReduction) {
+ scudo::Vector<int> V;
+ V.push_back(0);
+ V.push_back(0);
+ EXPECT_EQ(V.size(), 2U);
+ V.resize(1);
+ EXPECT_EQ(V.size(), 1U);
+}
--- /dev/null
+//===-- vector.h ------------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SCUDO_VECTOR_H_
+#define SCUDO_VECTOR_H_
+
+#include "common.h"
+
+#include <string.h>
+
+namespace scudo {
+
+// A low-level vector based on map. May incur a significant memory overhead for
+// small vectors. The current implementation supports only POD types.
+template <typename T> class VectorNoCtor {
+public:
+ void init(uptr InitialCapacity) {
+ CapacityBytes = 0;
+ Size = 0;
+ Data = nullptr;
+ reserve(InitialCapacity);
+ }
+ void destroy() {
+ if (Data)
+ unmap(Data, CapacityBytes);
+ }
+ T &operator[](uptr I) {
+ DCHECK_LT(I, Size);
+ return Data[I];
+ }
+ const T &operator[](uptr I) const {
+ DCHECK_LT(I, Size);
+ return Data[I];
+ }
+ void push_back(const T &Element) {
+ DCHECK_LE(Size, capacity());
+ if (Size == capacity()) {
+ const uptr NewCapacity = roundUpToPowerOfTwo(Size + 1);
+ reallocate(NewCapacity);
+ }
+ memcpy(&Data[Size++], &Element, sizeof(T));
+ }
+ T &back() {
+ DCHECK_GT(Size, 0);
+ return Data[Size - 1];
+ }
+ void pop_back() {
+ DCHECK_GT(Size, 0);
+ Size--;
+ }
+ uptr size() const { return Size; }
+ const T *data() const { return Data; }
+ T *data() { return Data; }
+ uptr capacity() const { return CapacityBytes / sizeof(T); }
+ void reserve(uptr NewSize) {
+ // Never downsize internal buffer.
+ if (NewSize > capacity())
+ reallocate(NewSize);
+ }
+ void resize(uptr NewSize) {
+ if (NewSize > Size) {
+ reserve(NewSize);
+ memset(&Data[Size], 0, sizeof(T) * (NewSize - Size));
+ }
+ Size = NewSize;
+ }
+
+ void clear() { Size = 0; }
+ bool empty() const { return size() == 0; }
+
+ const T *begin() const { return data(); }
+ T *begin() { return data(); }
+ const T *end() const { return data() + size(); }
+ T *end() { return data() + size(); }
+
+private:
+ void reallocate(uptr NewCapacity) {
+ DCHECK_GT(NewCapacity, 0);
+ DCHECK_LE(Size, NewCapacity);
+ const uptr NewCapacityBytes =
+ roundUpTo(NewCapacity * sizeof(T), getPageSizeCached());
+ T *NewData = (T *)map(nullptr, NewCapacityBytes, "scudo:vector");
+ if (Data) {
+ memcpy(NewData, Data, Size * sizeof(T));
+ unmap(Data, CapacityBytes);
+ }
+ Data = NewData;
+ CapacityBytes = NewCapacityBytes;
+ }
+
+ T *Data;
+ uptr CapacityBytes;
+ uptr Size;
+};
+
+template <typename T> class Vector : public VectorNoCtor<T> {
+public:
+ Vector() { VectorNoCtor<T>::init(1); }
+ explicit Vector(uptr Count) {
+ VectorNoCtor<T>::init(Count);
+ this->resize(Count);
+ }
+ ~Vector() { VectorNoCtor<T>::destroy(); }
+ // Disallow copies and moves.
+ Vector(const Vector &) = delete;
+ Vector &operator=(const Vector &) = delete;
+ Vector(Vector &&) = delete;
+ Vector &operator=(Vector &&) = delete;
+};
+
+} // namespace scudo
+
+#endif // SCUDO_VECTOR_H_