增加哈希表模块，加速账户ID查找，更新文档

hash.c

@@ -0,0 +1,91 @@
+#include <stdio.h>
+#include "bank.h"
+
+extern STACCOUNT g_astAccounts[];
+extern int g_iAccCount;
+
+HashEntry g_hashTable[HASH_SIZE];
+
+static int HashFunc(int id)
+{
+    return id % HASH_SIZE;
+}
+
+void InitHashTable()
+{
+    int i;
+    for (i = 0; i < HASH_SIZE; i++) {
+        g_hashTable[i].id = -1;
+        g_hashTable[i].index = -1;
+    }
+}
+
+int HashInsert(int id, int index)
+{
+    int pos = HashFunc(id);
+    int first_tombstone = -1;
+    int i;
+    for (i = 0; i < HASH_SIZE; i++) {
+        int probe = (pos + i) % HASH_SIZE;
+        if (g_hashTable[probe].id == id) {
+            g_hashTable[probe].index = index;
+            return 0;
+        }
+        if (g_hashTable[probe].id == -1) {
+            if (first_tombstone != -1) {
+                probe = first_tombstone;
+            }
+            g_hashTable[probe].id = id;
+            g_hashTable[probe].index = index;
+            return 0;
+        }
+        if (g_hashTable[probe].id == -2 && first_tombstone == -1) {
+            first_tombstone = probe;
+        }
+    }
+    return -1;
+}
+
+int HashSearch(int id)
+{
+    int pos = HashFunc(id);
+    int i;
+    for (i = 0; i < HASH_SIZE; i++) {
+        int probe = (pos + i) % HASH_SIZE;
+        if (g_hashTable[probe].id == id) {
+            return g_hashTable[probe].index;
+        }
+        if (g_hashTable[probe].id == -1) {
+            return -1;
+        }
+    }
+    return -1;
+}
+
+void HashDelete(int id)
+{
+    int pos = HashFunc(id);
+    int i;
+    for (i = 0; i < HASH_SIZE; i++) {
+        int probe = (pos + i) % HASH_SIZE;
+        if (g_hashTable[probe].id == -1) {
+            return;
+        }
+        if (g_hashTable[probe].id == id) {
+            g_hashTable[probe].id = -2;
+            g_hashTable[probe].index = -1;
+            return;
+        }
+    }
+}
+
+void RebuildHashTable()
+{
+    int i;
+    InitHashTable();
+    for (i = 0; i < g_iAccCount; i++) {
+        if (g_astAccounts[i].id != 0) {
+            HashInsert(g_astAccounts[i].id, i);
+        }
+    }
+}