Split de nodos

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

diff --git a/src/btree.cpp b/src/btree.cpp
index 50a78016fa05554a203184c8bfa9be486ed1729b..81b2fc98bbd40424974e893d4d316badb52d3026 100644 (file)
--- a/src/btree.cpp
+++ b/src/btree.cpp
@@ -1,12 +1,12 @@
 
 #include "btree.h"
 
 
 #include "btree.h"
 

-BTree::BTree (const char *name, unsigned int block_size, bool create_new_file)
+BTree::BTree (const std::string &name, unsigned int block_size, bool create_new_file)

 {
        uchar *node;
        BTreeNodeHeader nh;
 
 {
        uchar *node;
        BTreeNodeHeader nh;
 

-       fp = fopen (name, "wb");
+       fp = fopen (name.c_str(), "wb+");

        if (!fp) {
                /* TODO : mandar una exception ? */
                return;
        if (!fp) {
                /* TODO : mandar una exception ? */
                return;


@@ -17,7 +17,7 @@ BTree::BTree (const char *name, unsigned int block_size, bool create_new_file)
        
        /* Inicializo el header */
        header.block_size = block_size;
        
        /* Inicializo el header */
        header.block_size = block_size;

-       write_tree_header ();
+       WriteFileHeader ();

 
        /* Creo el primer bloque vacio */
        node = new uchar[block_size];
 
        /* Creo el primer bloque vacio */
        node = new uchar[block_size];


@@ -26,7 +26,7 @@ BTree::BTree (const char *name, unsigned int block_size, bool create_new_file)
        nh.free_space = block_size - sizeof (BTreeNodeHeader);
        nh.item_count = 0;
        WriteNodoHeader (node, &nh);
        nh.free_space = block_size - sizeof (BTreeNodeHeader);
        nh.item_count = 0;
        WriteNodoHeader (node, &nh);

-       write_block (node, 0);
+       WriteBlock (node, 0);

 
        delete [] node;
 }
 
        delete [] node;
 }


@@ -36,20 +36,157 @@ BTree::~BTree ()
        fclose (fp);
 }
 
        fclose (fp);
 }
 

-void BTree::write_tree_header ()
+void BTree::WriteFileHeader ()

 {
        fseek (fp, 0L, SEEK_SET);
        fwrite (&header, 1, sizeof (BTreeFileHeader), fp);
 }
 
 {
        fseek (fp, 0L, SEEK_SET);
        fwrite (&header, 1, sizeof (BTreeFileHeader), fp);
 }
 

-void BTree::write_block (uchar *block, uint num)
+void BTree::WriteBlock (uchar *block, uint num)

 {
        fseek (fp, num*header.block_size + sizeof (BTreeFileHeader), SEEK_SET);
        fwrite (block, 1, header.block_size, fp);
 }
 
 {
        fseek (fp, num*header.block_size + sizeof (BTreeFileHeader), SEEK_SET);
        fwrite (block, 1, header.block_size, fp);
 }
 

-void BTree::AddKey () {}
-void BTree::DelKey () {}
+void BTree::AddKey (const Clave &k)
+{
+       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, 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;
+       ReadNodoHeader (node, &node_header);
+
+       if (node_header.level != 0) {
+               /* No estoy en una hoja, asi que tengo que buscar
+                * para donde moverme para agregar la clave
+                */
+               /* TODO :) */
+       }
+
+
+       /* Estoy en una hoja, veo si lo puedo agregar */
+
+       if (node_header.free_space > data.Size ()) {
+               /* TODO : Insertar ordenado */
+               BTreeData datait;
+
+               node_keys = ReadKeys (node, node_header);
+               std::list<BTreeData>::iterator it = node_keys.begin ();
+
+               while (it != node_keys.end ()) {
+                       datait = (*it);
+                       if (data < datait)
+                               /* Me pase, lo agrego aca! */
+                               break;
+                       it++;
+               }
+               node_keys.insert (it, data);
+               WriteKeys (node, node_header, node_keys);
+               WriteNodoHeader (node, &node_header);
+               WriteBlock (node, node_num);
+
+               PrintNode (node_num);
+       } else {
+               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;
+       }
+
+       return kout;
+}
+
+void BTree::DelKey (const Clave &k) {}

 
 void BTree::ReadNodoHeader (uchar *node, BTreeNodeHeader *header)
 {
 
 void BTree::ReadNodoHeader (uchar *node, BTreeNodeHeader *header)
 {


@@ -61,3 +198,101 @@ void BTree::WriteNodoHeader (uchar *node, BTreeNodeHeader *header)
        memcpy (node, header, sizeof (BTreeNodeHeader));
 }
 
        memcpy (node, header, sizeof (BTreeNodeHeader));
 }
 

+uchar *BTree::ReadBlock (uint num)
+{
+       uchar *out = new uchar[header.block_size];
+
+       fseek (fp, num*header.block_size + sizeof (BTreeFileHeader), SEEK_SET); 
+       fread (out, 1, header.block_size, fp);
+
+       return out;
+}
+
+std::list<BTreeData> BTree::ReadKeys (uchar *node, BTreeNodeHeader &node_header)
+{
+       std::list<BTreeData> keys;
+       node += sizeof (BTreeNodeHeader);
+
+       for (uint i=0; i<node_header.item_count; i++) {
+               /* TODO : El tipo de clave deberia ser usado 
+                * dependiendo de algun dato en el header del
+                * arbol
+                */
+               /* TODO : Detectar si estoy en una hoja */
+               BTreeData data;
+               if (node_header.level == 0)
+                       data = BTreeLeafData (node);
+               else
+                       data = BTreeData (node);
+               node += data.Size ();
+               keys.push_back (data);
+       }
+
+       return keys;
+}
+
+void BTree::WriteKeys (uchar *node, BTreeNodeHeader &node_header, std::list<BTreeData> &keys)
+{
+       std::list<BTreeData>::iterator it = keys.begin ();
+
+       node += sizeof (BTreeNodeHeader);
+
+       node_header.item_count = 0;
+       node_header.free_space = header.block_size - sizeof (BTreeNodeHeader);
+
+       while (it != keys.end ()) {
+               BTreeData d = (*it);
+               memcpy (node, d.ToArray(), d.Size ());
+               node += d.Size ();
+               node_header.free_space -= d.Size ();
+               node_header.item_count++;
+               it++;
+       }
+
+       /* TODO : incrementar node_header.item_count aca o fuera de este metodo? */
+}
+               
+void BTree::PrintNode (uint num)
+{
+       uchar *node = ReadBlock (num);
+       BTreeNodeHeader node_header;
+       ReadNodoHeader (node, &node_header);
+               
+       std::list<BTreeData> node_keys = ReadKeys (node, node_header);
+       std::list<BTreeData>::iterator it = node_keys.begin ();
+
+       std::cout << "Nodo  : " << num << std::endl;
+       std::cout << "Items : " << node_header.item_count << std::endl;
+       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 << ") ";
+               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;
+}
+