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//===-- 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_
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