ZYM/BH-Bookstore-2023
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upd: first version of database

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This commit is contained in:
ZhuangYumin
2023-12-04 07:52:18 +00:00
parent a7e167d30d
commit 01864d5a5e
3 changed files with 223 additions and 14 deletions
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35
backend/include/drivearray.hpp
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@ -13,7 +13,7 @@
#include <stack>
#include <string>
template <class T, const int info_len = 2>
template <class T, const int info_len = 2, const int kRefreshThreshold = 100>
class DriveArray {
private:
static const int kPageSize = 4096;
@ -26,10 +26,8 @@ class DriveArray {
((info_len + 2) * sizeof(int) + kPageSize - 1) / kPageSize * kPageSize;
std::stack<int> free_mem;
int total_mem = 0;
const int kRefreshThreshold = 100;
unsigned int forced_refresh = 0;
std::mutex mtx;
void reallocate(bool include_resync = false) {
void reallocate(bool include_resync = false) noexcept {
size_t length_needed =
raw_data_begin +
(sizeofT * total_mem + kPageSize - 1) / kPageSize * kPageSize;
@ -43,7 +41,7 @@ class DriveArray {
virtual_mem = mmap(nullptr, file_length, PROT_READ | PROT_WRITE, MAP_SHARED,
file_descriptor, 0);
}
void ForceRefresh() {
void ForceRefresh() noexcept {
munmap(virtual_mem, file_length);
virtual_mem = mmap(nullptr, file_length, PROT_READ | PROT_WRITE, MAP_SHARED,
file_descriptor, 0);
@ -51,6 +49,7 @@ class DriveArray {
public:
DriveArray() = default;
inline bool IsOpen() const noexcept { return file_descriptor >= 0; }
~DriveArray() {
reallocate(true);
int stk_data_begin =
@ -65,11 +64,17 @@ class DriveArray {
}
munmap(virtual_mem, file_length);
close(file_descriptor);
file_descriptor = -1;
}
bool operator=(const DriveArray &) = delete;
DriveArray(const std::string &file_name) : file_name(file_name) {
void OpenFile(const std::string &file_name) {
if (file_name == "") return;
if (file_descriptor >= 0) {
munmap(virtual_mem, file_length);
close(file_descriptor);
file_descriptor = -1;
}
file_descriptor =
open(file_name.c_str(), O_CREAT | O_RDWR, S_IRUSR | S_IWUSR);
struct stat file_state;
@ -93,8 +98,9 @@ class DriveArray {
for (int i = 0; i < free_mem_cnt; i++) {
free_mem.push(*(p++));
}
// madvise(virtual_mem + stk_data_begin, free_mem_cnt * sizeof(int),
// MADV_FREE);
}
DriveArray(const std::string &file_name) : file_name(file_name) {
OpenFile(file_name);
}
void initialise(std::string FN = "") {
@ -102,6 +108,7 @@ class DriveArray {
if (file_descriptor >= 0) {
munmap(virtual_mem, file_length);
close(file_descriptor);
file_descriptor = -1;
}
file_descriptor =
open(file_name.c_str(), O_CREAT | O_RDWR, S_IRUSR | S_IWUSR);
@ -115,7 +122,7 @@ class DriveArray {
for (int i = 0; i < info_len; i++) *((int *)(virtual_mem) + i) = 0;
}
void get_info(int &tmp, int n) {
void get_info(int &tmp, int n) noexcept {
if (n > info_len) return;
tmp = *((int *)(virtual_mem) + n - 1);
if (++forced_refresh >= kRefreshThreshold) {
@ -124,7 +131,7 @@ class DriveArray {
}
}
void write_info(int tmp, int n) {
void write_info(int tmp, int n) noexcept {
if (n > info_len) return;
*((int *)(virtual_mem) + n - 1) = tmp;
if (++forced_refresh >= kRefreshThreshold) {
@ -133,7 +140,7 @@ class DriveArray {
}
}
int write(T &t) {
int write(T &t) noexcept {
int index = -1;
if (!free_mem.empty()) {
index = free_mem.top();
@ -144,7 +151,7 @@ class DriveArray {
return index;
}
void update(T &t, const int index) {
void update(T &t, const int index) noexcept {
reallocate();
void *data_begin = virtual_mem + raw_data_begin + sizeofT * (index - 1);
std::memmove(data_begin, &t, sizeofT);
@ -155,7 +162,7 @@ class DriveArray {
}
}
void read(T &t, const int index) {
void read(T &t, const int index) noexcept {
reallocate();
void *data_begin = virtual_mem + raw_data_begin + sizeofT * (index - 1);
std::memmove(&t, data_begin, sizeofT);
@ -166,7 +173,7 @@ class DriveArray {
}
}
void Delete(int index) { free_mem.push(index); }
void Delete(int index) noexcept { free_mem.push(index); }
};
#endif // BPT_DriveArray_HPP