From: Ricardo Markiewicz <rmarkie@fi.uba.ar>
Date: Mon, 12 Sep 2005 04:36:26 +0000 (+0000)
Subject: Manejo de headers de nodos del arbol
X-Git-Tag: 1_0-pre1~159
X-Git-Url: https://git.llucax.com/z.facultad/75.52/treemulator.git/commitdiff_plain/fbf727a8d5f7eb87843eb17720eb66e51ba1707a?ds=sidebyside

Manejo de headers de nodos del arbol
---

diff --git a/src/btree.cpp b/src/btree.cpp
index 1ad006d..50a7801 100644
--- a/src/btree.cpp
+++ b/src/btree.cpp
@@ -4,7 +4,7 @@
 BTree::BTree (const char *name, unsigned int block_size, bool create_new_file)
 {
 	uchar *node;
-
+	BTreeNodeHeader nh;
 
 	fp = fopen (name, "wb");
 	if (!fp) {
@@ -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];
+	ReadNodoHeader (node, &nh);
+	nh.level = 0;
+	nh.free_space = block_size - sizeof (BTreeNodeHeader);
+	nh.item_count = 0;
+	WriteNodoHeader (node, &nh);
 	write_block (node, 0);
+
 	delete [] node;
 }
 
@@ -33,15 +39,25 @@ BTree::~BTree ()
 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)
 {
-	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::ReadNodoHeader (uchar *node, BTreeNodeHeader *header)
+{
+	memcpy (header, node, sizeof (BTreeNodeHeader));
+}
+
+void BTree::WriteNodoHeader (uchar *node, BTreeNodeHeader *header)
+{
+	memcpy (node, header, sizeof (BTreeNodeHeader));
+}
+
diff --git a/src/btree.h b/src/btree.h
index cacd29b..0ed4fbd 100644
--- a/src/btree.h
+++ b/src/btree.h
@@ -51,7 +51,7 @@ typedef unsigned char uchar;
 
 /** Encabezado del archivo BTree */
 typedef struct _btree_file_ {
-	unsigned int block_size;
+	uint block_size;
 } BTreeFileHeader;
 
 /** Encabezado de un bloque */
@@ -71,7 +71,7 @@ typedef struct _btree_header_ {
 
 	/** Cantidad de elementos en el nodo */
 	unsigned int item_count;
-} BTreeHeader;
+} BTreeNodeHeader;
 
 /** Crea un nuevo arbol B
  *
@@ -90,6 +90,8 @@ class BTree {
 	private:
 		void write_tree_header ();
 		void write_block (uchar *block, uint num);
+		void ReadNodoHeader (uchar *node, BTreeNodeHeader *header);
+		void WriteNodoHeader (uchar *node, BTreeNodeHeader *header);
 
 		std::string filename;
 		BTreeFileHeader header;