Split de nodos

[z.facultad/75.52/treemulator.git] / src / btree.cpp

diff --git a/src/btree.cpp b/src/btree.cpp
index fc0a5e926f27973bb60c2c82619d4f4d8551e0a4..81b2fc98bbd40424974e893d4d316badb52d3026 100644 (file)
--- a/src/btree.cpp
+++ b/src/btree.cpp
@@ -50,14 +50,21 @@ void BTree::WriteBlock (uchar *block, uint num)
 
 void BTree::AddKey (const Clave &k)
 {
-       AddKeyR (&k, 0);
+       uint left, right;
+       Clave *kout = AddKeyR (&k, 0, left, right);
+
+       if (kout) {
+               std::cout << "Raiz fue spliteada!!" << std::endl;
+       }
 }
 
-Clave* BTree::AddKeyR (const Clave *k, uint node_num)
+Clave* BTree::AddKeyR (const Clave *k, uint node_num, uint &left_child, uint &right_child)
 {
        Clave *kout = NULL;
        std::list<BTreeData> node_keys;
 
+       BTreeLeafData data (k->Clone ());
+
        /* Leo el nodo raiz para empezar a agregar */
        uchar *node = ReadBlock (node_num);
        BTreeNodeHeader node_header;
@@ -72,7 +79,6 @@ Clave* BTree::AddKeyR (const Clave *k, uint node_num)
 
 
        /* Estoy en una hoja, veo si lo puedo agregar */
-       BTreeLeafData data (k->Clone ());
 
        if (node_header.free_space > data.Size ()) {
                /* TODO : Insertar ordenado */
@@ -86,6 +92,7 @@ Clave* BTree::AddKeyR (const Clave *k, uint node_num)
                        if (data < datait)
                                /* Me pase, lo agrego aca! */
                                break;
+                       it++;
                }
                node_keys.insert (it, data);
                WriteKeys (node, node_header, node_keys);
@@ -94,13 +101,85 @@ Clave* BTree::AddKeyR (const Clave *k, uint node_num)
 
                PrintNode (node_num);
        } else {
-               /* Split */
-               /* Lo que debe pasar :
-                *  1) Separar N/2 claves en "nodo"
-                *  2) Separar N/2-1 claves en un nuevo nodo
-                *  3) kout = clave del medio y mandarla al padre
-                */
-               std::cout << "SPLIT" << std::endl;
+               std::cout << "=============== SPLIT ================" << std::endl;
+               /* Split : Creo e inicializo el nuevo nodo */
+               std::list<BTreeData> new_node_keys;
+               std::list<BTreeData> old_node_keys;
+               BTreeNodeHeader new_node_header;
+               uint new_node_num;
+               uchar *new_node = NewBlock (new_node_num);
+               ReadNodoHeader (new_node, &new_node_header);
+
+               node_keys = ReadKeys (node, node_header);
+               new_node_keys = ReadKeys (new_node, new_node_header);
+
+               /* Agrego la clave en la lista que ya tengo de manera ordenada */
+               std::list<BTreeData>::iterator it = node_keys.begin ();
+
+               while (it != node_keys.end ()) {
+                       BTreeData datait;
+                       datait = (*it);
+                       if (data < datait)
+                               /* Me pase, lo agrego aca! */
+                               break;
+                       it++;
+               }
+               if (it != node_keys.end ())
+                       node_keys.insert (it, data);
+               else
+                       node_keys.push_back (data);
+
+               /* Tengo que guardar claves hasta ocupar nodo size/2 en cada nodo
+                * y subir la clave del medio */
+               node_header.item_count = 0;
+               node_header.free_space = header.block_size - sizeof (BTreeNodeHeader);
+
+               uint total_size = 0;
+               it = node_keys.begin ();
+               while (it != node_keys.end ()) {
+                       BTreeData datait;
+                       datait = (*it);
+                       total_size += datait.Size ();
+                       it++;
+                       /* Hack : Si me quedo con todas las claves, en el caso de ser
+                        * del mismo tama#o se desbalancea. Hay que ver que efecto 
+                        * puede tener en el caso de claves de long. variable
+                        */
+                       if (it == node_keys.end ())
+                               total_size -= datait.Size ();
+               }
+
+               it = node_keys.begin ();
+               uint used = 0;
+               while (used < total_size/2) {
+                       BTreeData d = (*it);
+                       std::cout << used << "   " << total_size << std::endl;
+                       old_node_keys.push_back (d);
+                       used += d.Size ();
+                       it++;
+               }
+               kout = (*it++).getClave (); // Esta se retorna al "padre" para que se la agregue
+               while (it != node_keys.end ()) {
+                       BTreeData d = (*it);
+                       new_node_keys.push_back (d);
+                       it++;
+               }
+       
+               /* Guardo */
+               WriteKeys (node, node_header, old_node_keys);
+               WriteNodoHeader (node, &node_header);
+               WriteBlock (node, node_num);
+               WriteKeys (new_node, new_node_header, new_node_keys);
+               WriteNodoHeader (new_node, &new_node_header);
+               WriteBlock (new_node, new_node_num);
+
+               PrintNode (node_num);
+               PrintNode (new_node_num);
+
+               /* Paso los hijos */
+               left_child = node_num;
+               right_child = new_node_num;
+               delete [] new_node;
                delete [] node;
        }
 
@@ -187,8 +266,33 @@ void BTree::PrintNode (uint num)
        std::cout << "Free  : " << node_header.free_space << " (" << (header.block_size - sizeof (BTreeNodeHeader)) << ")" << std::endl;
        while (it != node_keys.end ()) {
                std::string s = (*it);
-               std::cout << "(" << s << ") "; 
+               std::cout << "(" << s << ") ";
+               it++;
        }
        std::cout << std::endl;
+
+       delete [] node;
+}
+
+uchar *BTree::NewBlock (uint &num)
+{
+       long filelen;
+       uchar *node;
+       BTreeNodeHeader nh;
+
+       fseek (fp, 0, SEEK_END);
+       filelen = ftell (fp);
+
+       num = (filelen - sizeof (BTreeFileHeader))/header.block_size;
+
+       node = new uchar[header.block_size];
+       ReadNodoHeader (node, &nh);
+       nh.level = 0;
+       nh.free_space = header.block_size - sizeof (BTreeNodeHeader);
+       nh.item_count = 0;
+       WriteNodoHeader (node, &nh);
+       WriteBlock (node, 0);
+
+       return node;
 }