From 52d9e098f15ad0ca70f11b4549f3d55f55a22a83 Mon Sep 17 00:00:00 2001 From: Ricardo Markiewicz Date: Thu, 15 Sep 2005 02:03:48 +0000 Subject: [PATCH] Split de nodos --- src/btree.cpp | 126 ++++++++++++++++++++++++++++++++++++++++++----- src/btree.h | 3 +- src/btree_data.h | 1 + 3 files changed, 118 insertions(+), 12 deletions(-) diff --git a/src/btree.cpp b/src/btree.cpp index fc0a5e9..81b2fc9 100644 --- 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 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 new_node_keys; + std::list 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::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; } diff --git a/src/btree.h b/src/btree.h index 06a6941..14ef604 100644 --- a/src/btree.h +++ b/src/btree.h @@ -93,12 +93,13 @@ class BTree { void DelKey (const Clave &k); private: - Clave* AddKeyR (const Clave *k, uint node_num); + Clave* AddKeyR (const Clave *k, uint node_num, uint &left_child, uint &right_child); void WriteFileHeader (); void WriteBlock (uchar *block, uint num); uchar *ReadBlock (uint num); + uchar *NewBlock (uint &num); void ReadNodoHeader (uchar *node, BTreeNodeHeader *header); void WriteNodoHeader (uchar *node, BTreeNodeHeader *header); diff --git a/src/btree_data.h b/src/btree_data.h index c1d4261..44a3a77 100644 --- a/src/btree_data.h +++ b/src/btree_data.h @@ -17,6 +17,7 @@ class BTreeData { virtual uint Size (); virtual uchar *ToArray (); + Clave* getClave () { return clave; } bool operator < (const BTreeData &data) const; virtual operator std::string () const { -- 2.43.0