From bafb629b6afb3ad899a53ebb4a976340a1165b1a Mon Sep 17 00:00:00 2001
From: Kacper Donat <kadet1090@gmail.com>
Date: Fri, 14 Dec 2018 22:32:02 +0100
Subject: [PATCH] optimizing

---
 index.c   | 38 ++++++++++++++++++++++++++++++++++++++
 index.h   |  2 ++
 openidx.c |  8 ++++++++
 3 files changed, 48 insertions(+)

diff --git a/index.c b/index.c
index e602be7..1a1fa27 100644
--- a/index.c
+++ b/index.c
@@ -672,3 +672,41 @@ void btree_flush(btree_t* tree)
     file_flush(tree->file);
     file_flush(tree->main->file);
 }
+
+void _btree_optimize_page(btree_t* tree, tape_t* tmp, page_t page)
+{
+    if (!page) return;
+
+    btree_node_t  node;
+    btree_entry_t *entry;
+    record_t      record;
+    _btree_load_node(&node, tree, page);
+
+    for (int i = 0; i < node.header.entries; i++) {
+        entry = btree_get_entry(&node, i);
+        _btree_optimize_page(tree, tmp, entry->left);
+
+        tape_read(tree->main, entry->location, &record, sizeof(record_t));
+        entry->location = tape_append(tmp, &record, sizeof(record_t));
+    }
+    _btree_write_node(&node, tree, node.page);
+
+    _btree_optimize_page(tree, tmp, entry->right);
+}
+
+void btree_optimize(btree_t *tree)
+{
+    char tmp[PATH_MAX + 4], old[PATH_MAX];
+    strcpy(old, tree->main->file->filename);
+    sprintf(tmp, "%s.tmp", old);
+
+    tape_t *temp = tape_open(tmp, "wb+");
+    _btree_optimize_page(tree, temp, tree->header.root);
+    tape_close(temp);
+    tape_close(tree->main);
+
+    remove(old);
+    rename(tmp, old);
+
+    tree->main = tape_open(old, "rb+");
+}
diff --git a/index.h b/index.h
index 1ee7fe1..5e61868 100644
--- a/index.h
+++ b/index.h
@@ -70,6 +70,8 @@ typedef struct {
 int btree_init(btree_t *tree, char* filename, size_t d);
 int btree_open(btree_t *tree, char* filename);
 
+void btree_optimize(btree_t *tree);
+
 page_t btree_insert(btree_t *tree, record_t record);
 page_t btree_remove(btree_t *tree, record_key_t key);
 bool   btree_update(btree_t *tree, record_key_t key, record_t record);
diff --git a/openidx.c b/openidx.c
index 5514184..2aca95b 100644
--- a/openidx.c
+++ b/openidx.c
@@ -68,6 +68,7 @@ result_t update_command(const char* command, char* args);
 result_t verbosity_command(const char* command, char* args);
 result_t iostat_command(const char* command, char* args);
 result_t flush_command(const char* command, char* args);
+result_t optimize_command(const char* command, char* args);
 
 static command_t commands[] = {
     { "help", "Prints out help", help_command },
@@ -83,6 +84,7 @@ static command_t commands[] = {
     { "iostat", "Prints IO counts", iostat_command },
     { "flush", "Fluhshes index into disk", flush_command },
     { "verbosity", "Changes the verbosity", verbosity_command },
+    { "optimize", "Optimizes the index", optimize_command },
 };
 
 result_t exit_command(const char* command, char* args)
@@ -102,6 +104,12 @@ result_t flush_command(const char* command, char* args)
     return RESULT_OK;
 }
 
+result_t optimize_command(const char* command, char* args)
+{
+    btree_optimize(&tree);
+    return RESULT_OK;
+}
+
 result_t verbosity_command(const char* command, char* args)
 {
     verbosity_t v;