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/*                Centre for Speech Technology Research                  */
/*                     University of Edinburgh, UK                       */
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/*************************************************************************/
/*                   Author :  Paul Taylor                               */
/*                   Date   :  January 1995                              */
/*-----------------------------------------------------------------------*/
/*              Key/Value list template class                            */
/*                                                                       */
/*=======================================================================*/
#ifndef __EST_TKVL_H__
#define __EST_TKVL_H__

#include <cmath>

using namespace std;

#include "EST_TList.h"
#include "instantiate/EST_TKVLI.h"
#include "EST_TIterator.h"

class EST_String;


/** Templated Key-Value Item. Serves as the items in the list of the
EST_TKVL class.  */
template<class K, class V> class EST_TKVI {
 public:
    K k;
    V v;

    inline bool operator==(const EST_TKVI<K,V> &i){
	return( (i.k == k) && (i.v == v) );
    }

    friend  ostream& operator << (ostream& s, EST_TKVI<K,V> const &i)
        {  return s << i.k << "\t" << i.v << "\n"; }
};


/** Templated Key-Value list. Objects of type EST_TKVL contain lists which
are accessed by a key of type {\bf K}, which returns a value of type
{\bf V}. */
template<class K, class V> class EST_TKVL {
 private:
    EST_Litem *find_pair_key(const K &key) const;
    EST_Litem *find_pair_val(const V &val) const;
 public:
    /**@name Constructor functions */
    //@{
    /// default constructor
    EST_TKVL() {;}
    /// copy constructor
    EST_TKVL(const EST_TKVL<K, V> &kv);
    //@}

    /// default value, returned when there is no such entry.
    static V *default_val;

    /// default value, returned when there is no such entry.
    static K *default_key;

    /// Linked list of key-val pairs. Don't use
    /// this as it will be made private in the future
    EST_TList< EST_TKVI<K,V> > list;	

    /// number of key value pairs in list
    const int length() const {return list.length();} 

    /// Return First key value pair in list
    EST_Litem * head() const {return list.head();};

    /// Empty list.
    void clear();
    
    /**@name Access functions.
     */
    //@{
    /// return value according to key (const)
    const V &val(const K &rkey, bool m=0) const;
    /// return value according to key (non-const)
    V &val(const K &rkey, bool m=0);
    /// return value according to ptr
    const V &val(EST_Litem *ptr, bool m=0) const;     
    /// return value according to ptr
    V &val(EST_Litem *ptr, bool m=0);     
    /// value or default 
    const V &val_def(const K &rkey, const V &def) const;

    /// find key, reference by ptr 
    const K &key(EST_Litem *ptr, int m=1) const;
    /// find key, reference by ptr 
    K &key(EST_Litem *ptr, int m=1);

    /// return first matching key, referenced by val
    const K &key(const V &v, int m=1) const;

    /** change key-val pair. If no corresponding entry is present, add
      to end of list.
      */
    int change_val(const K &rkey,const V &rval); 
    /** change key-val pair. If no corresponding entry is present, add
      to end of list.*/
    int change_val(EST_Litem *ptr,const V &rval); // change key-val pair.
    /// change name of key pair.
    int change_key(EST_Litem *ptr,const K &rkey);

    /// add key-val pair to list
    int add_item(const K &rkey,const V &rval, int no_search = 0);

    /// remove key and val pair from list
    int remove_item(const K &rkey, int quiet = 0);

    //@}
    
    /// Returns true if key is present.
    const int present(const K &rkey) const;

    /// apply function to each pair
    void map(void (*func)(K&, V&));
    
    friend ostream& operator << (ostream& s, EST_TKVL<K,V> const &l)
    {EST_Litem *p; 
        for (p = l.list.head(); p ; p = p->next()) 
            s << l.list(p).k << "\t" << l.list(p).v << endl; 
        return s;
    } 
    
    /// full copy of KV list.
    EST_TKVL<K, V> & operator =  (const EST_TKVL<K,V> &kv);
    /// add kv after existing list.
    EST_TKVL<K, V> & operator += (const EST_TKVL<K,V> &kv); 
    /// make new concatenated list
    EST_TKVL<K, V>   operator +  (const EST_TKVL<K,V> &kv); 

  // Iteration support

protected:
  struct IPointer {  EST_Litem *p; };

  void point_to_first(IPointer &ip) const { ip.p = list.head(); }
  void move_pointer_forwards(IPointer &ip) const { ip.p = ip.p->next(); }
  bool points_to_something(const IPointer &ip) const { return ip.p != NULL; }
  EST_TKVI<K, V> &points_at(const IPointer &ip) { return list(ip.p); }

  friend class EST_TIterator< EST_TKVL<K, V>, IPointer, EST_TKVI<K, V> >;
  friend class EST_TStructIterator< EST_TKVL<K, V>, IPointer, EST_TKVI<K, V> >;
  friend class EST_TRwIterator< EST_TKVL<K, V>, IPointer, EST_TKVI<K, V> >;
  friend class EST_TRwStructIterator< EST_TKVL<K, V>, IPointer, EST_TKVI<K, V> >;

public:
  typedef EST_TKVI<K, V> Entry;
  typedef EST_TStructIterator< EST_TKVL<K, V>, IPointer, Entry> Entries;
  typedef EST_TRwStructIterator< EST_TKVL<K, V>, IPointer, Entry> RwEntries;

  // Iteration support

protected:
  struct IPointer_k {  EST_Litem *p; };

  void point_to_first(IPointer_k &ip) const { ip.p = list.head(); }
  void move_pointer_forwards(IPointer_k &ip) const { ip.p = ip.p->next(); }
  bool points_to_something(const IPointer_k &ip) const { return ip.p != NULL; }
  K &points_at(const IPointer_k &ip) { return list(ip.p).k; }

  friend class EST_TIterator< EST_TKVL<K, V>, IPointer_k, K >;
  friend class EST_TRwIterator< EST_TKVL<K, V>, IPointer_k, K >;

public:
  typedef K KeyEntry;
  typedef EST_TIterator< EST_TKVL<K, V>, IPointer_k, KeyEntry> KeyEntries;
  typedef EST_TRwIterator< EST_TKVL<K, V>, IPointer_k, KeyEntry> KeyRwEntries;

};

#endif				// __KVL_H__