map

UC Library Extensions UnderC comes with a pocket implementation of the standard C++ libraries, wh

// map
// a 'pocket' implementation of std::map
// UnderC Development Project, 2001.
#ifndef __MAP_H
#define __MAP_H
#include <list>

namespace std {

template <class K, class T>
class map
{
 struct Node {
   T second;
   Node *m_left, *m_right;
   K first;
 };
 typedef Node *PNode;
 typedef list<PNode> NodeStack;

 PNode m_root;
 int m_size;

public:
    class iterator {
	  PNode m_node;
	  NodeStack* m_stack;
	public:
	  iterator(PNode pe)
            : m_node(pe),m_stack(NULL)
          { }
	  iterator()
            : m_node(NULL),m_stack(NULL)
          { }

      iterator(const iterator& it)
      {
            m_node = it.m_node;
            m_stack = it.m_stack;
      }

      ~iterator()
      { 
           //if (m_stack) delete m_stack;
      }

      bool operator == (const iterator& it) const
      { return m_node == it.m_node; }

      bool operator != (const iterator& it) const
      { return m_node != it.m_node; }

      void cursor(PNode pe)       { m_node = pe; }
      PNode cursor()  const       { return m_node; }

      void alloc_stack()
      {
	   m_stack = new NodeStack();
      }

      void go_down(PNode p)
      {
            m_stack->push_back(m_node);
            m_node = p;
      }

      void next()
      {
            if (m_node->m_left)  go_down(m_node->m_left);     else
            if (m_node->m_right) go_down(m_node->m_right);
            else { // this is a leaf
               while (m_stack->size() > 0) { // so for all nodes in this branch
                 PNode old_node = m_node;
                 m_node = m_stack->back();
                 m_stack->pop_back();
                 // try to visit the right nodes
                 if (m_node->m_right && m_node->m_right != old_node) {
                   go_down(m_node->m_right);
                   return; 
                 } 
              }
            }
      }

      void prior(){  }

     Node& operator*()  const 
     { 
          return *m_node;
     }

     Node *operator->() const 
     { 
          return m_node;
     }

     void operator++()
     {
          next();
     }

     void operator--()
     { prior(); }

     void operator++(int)
     { next(); }

     void operator--(int)
     { prior(); }

    };

   iterator begin() {
     iterator ii (m_root);
     ii.alloc_stack();
     ii.next();
     return ii;
   }

   iterator end() { return iterator(m_root); }



  int  size() const { return m_size; }

 PNode _alloc(const K& key, const T& val) {
   PNode p = new Node;
   p->first = key;
   p->second = val;
   p->m_left = NULL;
   p->m_right = NULL;
   m_size++;
   return p;
 }


 PNode _find(const K& key, PNode p) const {
  if (p == NULL) return NULL;
  if (key == p->first) return p;
  if (key < p->first) return _find(key,p->m_left);
             else     return _find(key,p->m_right);
 }

 PNode _insert(const K& key, const T& val, PNode p) {
   if (key == p->first) { p->second = val; return p; }
   else
   if (key < p->first) {
        if (p->m_left == NULL) return p->m_left = _alloc(key,val); 
                     else  return  _insert(key,val,p->m_left);
   } else {
        if (p->m_right == NULL) return p->m_right = _alloc(key,val);
                     else  return  _insert(key,val,p->m_right);
   }
 }

 iterator insert(const K& key, const T& val) {
    return iterator(_insert(key,val,m_root));
 }

 iterator find(const K& key) {
   return iterator(_find(key,m_root));
 }

 T& operator[] (const K& key) {
   PNode p = _find(key,m_root);
   T val = 0;   // '0' shd be T() !!
   if (p == NULL) p = _insert(key,val,m_root); 
   return p->second;
 }

 map() {
   m_size = -1;
   K key = 0;
   T val = 0;
   m_root = _alloc(key,val);
 }

};

// vs 1.0.0 A fast specialization of map<string,int>
#ifdef __UNDERC__
template <>
 class map<string,int>
{
  void *m_map;

  struct StrPair {
     string first;
     int second;
  };

  public:
 class iterator {
	  void *m_iter;
	public:
	  iterator(void* ip)
          : m_iter(ip)
      { }

	  iterator()
          : m_iter(NULL)
      { }

      iterator(const iterator& it)
      {
          m_iter = it.m_iter;
      }

      ~iterator()
      { 
           //if (m_stack) delete m_stack;
      }

      bool operator == (const iterator& it) const
      { return _map_iter_equal(m_iter,it.m_iter); }

      bool operator != (const iterator& it) const
      { return ! _map_iter_equal(m_iter,it.m_iter); }

      void next()
      { _map_iter_next(m_iter,0);  }

      void prior() {}

      StrPair& operator*()  const 
      { 
          static StrPair node;
          _map_iter_fetch(m_iter,&node);
          return node;
      }

      StrPair* operator->() const 
      { 
          static StrPair node;
          _map_iter_fetch(m_iter,&node);
          return &node;
      }

     void operator++()
     {
          next();
     }

     void operator--()
     { prior(); }

     void operator++(int)
     { next(); }

     void operator--(int)
     { prior(); }

    };

  iterator begin() {
      return iterator(_map_iter_ep(m_map,0));
  }

 iterator end() { 
     return iterator(_map_iter_ep(m_map,1));
 }

 /*
  iterator insert(const string& key, int val) {
    return iterator(_insert(key,val,m_root));
 }
*/
 iterator find(const string& key) {
   return iterator(_map_iter_find(m_map,&key));
 }

   map() {
     m_map = _map_create();
   }
   ~map() { _map_destroy(m_map); }

   int size() { return _map_size(m_map); }
  
   int& operator[] (const string& key) {
     int *pi = _map_find(&key,m_map);
     if (pi == NULL) return *_map_insert(&key,0,m_map); 
     else return *pi;
  }
 };
#endif

} // namespace std

#endif