Lectura de claves desde un nodo a memoria.

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

diff --git a/src/btree.cpp b/src/btree.cpp
index 1ad006de4d029cfa203e2a47b522ad6193460a39..d1fbab3b13281de444fd20858aef443b0785935f 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;
 {
        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;


@@ -21,7 +21,13 @@ BTree::BTree (const char *name, unsigned int block_size, bool create_new_file)
 
        /* Creo el primer bloque vacio */
        node = new uchar[block_size];
 
        /* Creo el primer bloque vacio */
        node = new uchar[block_size];

+       ReadNodoHeader (node, &nh);
+       nh.level = 0;
+       nh.free_space = block_size - sizeof (BTreeNodeHeader);
+       nh.item_count = 0;
+       WriteNodoHeader (node, &nh);

        write_block (node, 0);
        write_block (node, 0);

+

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


@@ -33,15 +39,73 @@ BTree::~BTree ()
 void BTree::write_tree_header ()
 {
        fseek (fp, 0L, SEEK_SET);
 void BTree::write_tree_header ()
 {
        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::write_block (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);
 }
 
        fwrite (block, 1, header.block_size, fp);
 }
 

-void BTree::AddKey () {}
-void BTree::DelKey () {}
+void BTree::AddKey (const Clave &k)
+{
+       std::list<Clave *> node_keys;
+
+       /* Leo el nodo raiz para empezar a agregar */
+       uchar *root = ReadBlock (0);
+       BTreeNodeHeader root_header;
+       ReadNodoHeader (root, &root_header);
+
+       node_keys = ReadKeys (root, root_header);
+       std::cout << node_keys.size () << std::endl;
+       
+       if (root_header.free_space >= k.Size ()) {
+               std::cout << "Hay lugar para meter la clave" << std::endl;
+       } else {
+               std::cout << "__NO__ hay lugar para meter la clave" << std::endl;
+       }
+
+       delete [] root;
+}
+
+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<Clave *> BTree::ReadKeys (uchar *node, BTreeNodeHeader &node_header)
+{
+       std::list<Clave *> 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
+                */
+               ClaveFija *k = new ClaveFija (node);
+               node += k->Size ();
+               keys.push_back (k);
+       }
+
+       return keys;
+}