92 lines
2.3 KiB
C++
92 lines
2.3 KiB
C++
#pragma once
|
|
|
|
#include <cstdint>
|
|
#include <iterator>
|
|
#include <ranges>
|
|
#include <algorithm>
|
|
|
|
namespace clice::index {
|
|
|
|
/// When serialize index to binary, we will transform all pointer to offset
|
|
/// to base address. And data only will be deserialized when it is accessed.
|
|
struct Relative {
|
|
const void* base = nullptr;
|
|
const void* data = nullptr;
|
|
|
|
bool operator== (const Relative& other) const = default;
|
|
};
|
|
|
|
template <typename T>
|
|
class LazyArray : Relative {
|
|
public:
|
|
LazyArray(const void* base, const void* data, std::uint32_t size, std::uint32_t stride) :
|
|
Relative{base, data}, size(size), stride(stride) {}
|
|
|
|
using difference_type = std::ptrdiff_t;
|
|
using value_type = T;
|
|
|
|
class Iterator : Relative {
|
|
public:
|
|
Iterator(const void* base, const void* data, std::size_t stride) :
|
|
Relative{base, data}, stride(stride) {}
|
|
|
|
using difference_type = std::ptrdiff_t;
|
|
using value_type = T;
|
|
|
|
Iterator() = default;
|
|
|
|
Iterator(const Iterator&) = default;
|
|
|
|
decltype(auto) operator* () const {
|
|
if constexpr(std::derived_from<T, Relative>) {
|
|
return T{base, data};
|
|
} else {
|
|
return *static_cast<const T*>(data);
|
|
}
|
|
}
|
|
|
|
Iterator& operator++ () {
|
|
data = static_cast<const char*>(data) + stride;
|
|
return *this;
|
|
}
|
|
|
|
Iterator operator++ (int) {
|
|
++*this;
|
|
}
|
|
|
|
bool operator== (const Iterator& other) const = default;
|
|
|
|
private:
|
|
std::uint32_t stride;
|
|
};
|
|
|
|
Iterator begin() const {
|
|
return Iterator(base, data, stride);
|
|
}
|
|
|
|
Iterator end() const {
|
|
return Iterator(base, static_cast<const char*>(data) + size * stride, stride);
|
|
}
|
|
|
|
uint32_t length() const {
|
|
return size;
|
|
}
|
|
|
|
decltype(auto) operator[] (uint32_t index) const {
|
|
const void* data = static_cast<const char*>(this->data) + index * stride;
|
|
if constexpr(std::derived_from<T, Relative>) {
|
|
return T{base, data};
|
|
} else {
|
|
return *static_cast<const T*>(data);
|
|
}
|
|
}
|
|
|
|
bool operator== (const LazyArray& other) const = default;
|
|
|
|
private:
|
|
std::uint32_t size;
|
|
std::uint32_t stride;
|
|
};
|
|
|
|
} // namespace clice::index
|