Actualizacion de los headers del nodo

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

diff --git a/src/btree.cpp b/src/btree.cpp
index 1ad006de4d029cfa203e2a47b522ad6193460a39..5df88a2dc4b6156afa1e39f14f1fc148c1a9770e 100644 (file)
--- a/src/btree.cpp
+++ b/src/btree.cpp
@@ -1,12 +1,12 @@
 
 #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;
 
-
-       fp = fopen (name, "wb");
+       fp = fopen (name.c_str(), "wb");
        if (!fp) {
                /* TODO : mandar una exception ? */
                return;
@@ -17,11 +17,17 @@ BTree::BTree (const char *name, unsigned int block_size, bool create_new_file)
        
        /* Inicializo el header */
        header.block_size = block_size;
-       write_tree_header ();
+       WriteFileHeader ();
 
        /* Creo el primer bloque vacio */
        node = new uchar[block_size];
-       write_block (node, 0);
+       ReadNodoHeader (node, &nh);
+       nh.level = 0;
+       nh.free_space = block_size - sizeof (BTreeNodeHeader);
+       nh.item_count = 0;
+       WriteNodoHeader (node, &nh);
+       WriteBlock (node, 0);
+
        delete [] node;
 }
 
@@ -30,18 +36,115 @@ BTree::~BTree ()
        fclose (fp);
 }
 
-void BTree::write_tree_header ()
+void BTree::WriteFileHeader ()
 {
        fseek (fp, 0L, SEEK_SET);
-       fwrite (&header, 1, sizeof (BTreeHeader), fp);
+       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 (BTreeHeader), SEEK_SET);
+       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)
+{
+       AddKeyR (&k, 0);
+}
+
+Clave* BTree::AddKeyR (const Clave *k, uint node_num)
+{
+       Clave *kout = NULL;
+       std::list<BTreeData> node_keys;
+
+       /* Leo el nodo raiz para empezar a agregar */
+       uchar *node = ReadBlock (node_num);
+       BTreeNodeHeader node_header;
+       ReadNodoHeader (node, &node_header);
+
+       node_keys = ReadKeys (node, node_header);
+       
+       if (node_header.free_space >= k->Size ()) {
+               /* TODO : Insertar ordenado */
+               /* Siempre se agrega en una hoja */
+               node_keys.push_back (BTreeLeafData (k->Clone ()));
+
+               WriteKeys (node, node_header, node_keys);
+               WriteNodoHeader (node, &node_header);
+               WriteBlock (node, node_num);
+               delete [] node;
+       } 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;
+       }
+
+       return kout;
+}
+
+void BTree::DelKey (const Clave &k) {}
+
+void BTree::ReadNodoHeader (uchar *node, BTreeNodeHeader *header)
+{
+       memcpy (header, node, sizeof (BTreeNodeHeader));
+}
+
+void BTree::WriteNodoHeader (uchar *node, BTreeNodeHeader *header)
+{
+       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(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? */
+}