From e76bdbd436d3c835092ea3e940a5795f19418902 Mon Sep 17 00:00:00 2001
From: ZhuangYumin <zhuangyumin@sjtu.edu.cn>
Date: Mon, 4 Dec 2023 08:14:27 +0000
Subject: [PATCH] upd: optimize database

---
 backend/include/drivearray.hpp | 40 ++++++++++++++++++----------------
 backend/include/key2index.hpp  | 16 +++++++++++---
 2 files changed, 34 insertions(+), 22 deletions(-)

diff --git a/backend/include/drivearray.hpp b/backend/include/drivearray.hpp
index 265a578..a0ae3a1 100644
--- a/backend/include/drivearray.hpp
+++ b/backend/include/drivearray.hpp
@@ -41,33 +41,35 @@ class DriveArray {
     virtual_mem = mmap(nullptr, file_length, PROT_READ | PROT_WRITE, MAP_SHARED,
                        file_descriptor, 0);
   }
-  void ForceRefresh() noexcept {
-    munmap(virtual_mem, file_length);
-    virtual_mem = mmap(nullptr, file_length, PROT_READ | PROT_WRITE, MAP_SHARED,
-                       file_descriptor, 0);
-  }
 
  public:
   DriveArray() = default;
   inline bool IsOpen() const noexcept { return file_descriptor >= 0; }
   ~DriveArray() {
-    reallocate(true);
-    int stk_data_begin =
-        raw_data_begin +
-        (sizeofT * total_mem + kPageSize - 1) / kPageSize * kPageSize;
-    *((int *)(virtual_mem) + info_len) = total_mem;
-    *((int *)(virtual_mem) + info_len + 1) = (int)free_mem.size();
-    int *p = (int *)(virtual_mem + stk_data_begin);
-    while (!free_mem.empty()) {
-      *(p++) = free_mem.top();
-      free_mem.pop();
+    if (file_descriptor >= 0) {
+      reallocate(true);
+      int stk_data_begin =
+          raw_data_begin +
+          (sizeofT * total_mem + kPageSize - 1) / kPageSize * kPageSize;
+      *((int *)(virtual_mem) + info_len) = total_mem;
+      *((int *)(virtual_mem) + info_len + 1) = (int)free_mem.size();
+      int *p = (int *)(virtual_mem + stk_data_begin);
+      while (!free_mem.empty()) {
+        *(p++) = free_mem.top();
+        free_mem.pop();
+      }
+      munmap(virtual_mem, file_length);
+      close(file_descriptor);
+      file_descriptor = -1;
     }
-    munmap(virtual_mem, file_length);
-    close(file_descriptor);
-    file_descriptor = -1;
   }
   bool operator=(const DriveArray &) = delete;
-
+  void ForceRefresh() noexcept {
+    munmap(virtual_mem, file_length);
+    virtual_mem = mmap(nullptr, file_length, PROT_READ | PROT_WRITE, MAP_SHARED,
+                       file_descriptor, 0);
+  }
+  void *RawData() noexcept { return virtual_mem; }
   void OpenFile(const std::string &file_name) {
     if (file_name == "") return;
     if (file_descriptor >= 0) {
diff --git a/backend/include/key2index.hpp b/backend/include/key2index.hpp
index 49c39e9..4e30ab2 100644
--- a/backend/include/key2index.hpp
+++ b/backend/include/key2index.hpp
@@ -57,7 +57,12 @@ class String2Index {
     mem.OpenFile(file_name);
     delete[] hash_table;
     hash_table = new int[kBucketSize];
-    for (int i = 0; i < kBucketSize; ++i) mem.get_info(hash_table[i], i + 1);
+    // std::memmove(hash_table, mem.RawData(), sizeof(int) * kBucketSize);
+    // mem.ForceRefresh();
+    for (int i = 0; i < kBucketSize; i++) {
+      hash_table[i] = *((int *)(mem.RawData()) + i);
+      if (i % 4096 == 0) mem.ForceRefresh();
+    }
   }
   String2Index(const std::string __file_name) : file_name(__file_name) {
     OpenFile(file_name);
@@ -72,8 +77,13 @@ class String2Index {
     hash_table = new int[kBucketSize]();
   }
   ~String2Index() {
-    for (int i = 0; i < kBucketSize; ++i) mem.write_info(hash_table[i], i + 1);
-    delete[] hash_table;
+    if (hash_table != nullptr) {
+      for (int i = 0; i < kBucketSize; i++) {
+        *((int *)(mem.RawData()) + i) = hash_table[i];
+        if (i % 4096 == 0) mem.ForceRefresh();
+      }
+      delete[] hash_table;
+    }
   }
   void Insert(const std::string &str, int val) noexcept {
     size_t hash_val = Hash(str);