/*

 * lftp - file transfer program

 *

 * Copyright (c) 1996-2012 by Alexander V. Lukyanov (lav@yars.free.net)

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 3 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program.  If not, see <http://www.gnu.org/licenses/>.

 */

#ifndef KEYVALUE_H

#define KEYVALUE_H

#include "xstring.h"

class StringMangler

{

   typedef const char *(*mangle_t)(const char *);

   mangle_t mangle;

public:

   const char *operator()(const char *s) { return mangle?mangle(s):s; }

   StringMangler(mangle_t m=0) { mangle=m; }

};

class KeyValueDB

{

public:

   class Pair

   {

   public:

      xstring_c key;

      xstring_c value;

      Pair *next;

      Pair(const char *k,const char *v)

	 : key(k), value(v), next(0) {}

      virtual ~Pair() {}

      int KeyCompare(const char *s) const

	 {

	    return strcmp(s,key);

	 }

      void SetValue(const char *v) { value.set(v); }

   };

protected:

   void Purge(Pair **p)

      {

	 Pair *to_free=*p;

	 if(current==to_free)

	    current=to_free->next;

	 *p=to_free->next;

	 delete to_free;

      }

   Pair **LookupPair(const char *key) const;

   void AddPair(Pair *p)

      {

	 p->next=chain;

	 chain=p;

      }

   virtual Pair *NewPair(const char *id,const char *value)

      {

	 return new Pair(id,value);

      }

   int Lock(int fd,int type);

   Pair *chain;

   Pair *current;

public:

   void Add(const char *id,const char *value);

   void Remove(const char *id);

   const char *Lookup(const char *id) const;

   void Empty()

      {

	 while(chain)

	    Purge(&chain);

      }

   int Write(int fd);

   int Read(int fd);

   void Sort();

   char *Format(StringMangler m=0); // returns formatted contents (malloc'ed)

   void Rewind()

      {

	 current=chain;

      }

   const char *CurrentKey() const

      {

	 if(!current)

	    return 0;

	 return current->key;

      }

   const char *CurrentValue() const

      {

	 if(!current)

	    return 0;

	 return current->value;

      }

   bool Next()

      {

	 if(current==0)

	    return false;

	 current=current->next;

	 return current!=0;

      }

   KeyValueDB()

      {

	 chain=0;

	 current=0;

      }

   virtual ~KeyValueDB()

      {

	 Empty();

      }

   static int KeyCompare(const Pair *a,const Pair *b)

      {

	 return strcmp(a->key,b->key);

      }

   static int VKeyCompare(const void *a,const void *b);

};

#endif //KEYVALUE_H