#ifndef SQL_UDF_INCLUDED
#define SQL_UDF_INCLUDED

/* Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.

   This program is also distributed with certain software (including
   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have included with MySQL.

   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, version 2.0, for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA */


/* This file defines structures needed by udf functions */

enum Item_udftype {UDFTYPE_FUNCTION=1,UDFTYPE_AGGREGATE};

typedef void (*Udf_func_clear)(UDF_INIT *, uchar *, uchar *);
typedef void (*Udf_func_add)(UDF_INIT *, UDF_ARGS *, uchar *, uchar *);
typedef void (*Udf_func_deinit)(UDF_INIT*);
typedef my_bool (*Udf_func_init)(UDF_INIT *, UDF_ARGS *,  char *);
typedef void (*Udf_func_any)();
typedef double (*Udf_func_double)(UDF_INIT *, UDF_ARGS *, uchar *, uchar *);
typedef longlong (*Udf_func_longlong)(UDF_INIT *, UDF_ARGS *, uchar *,
                                      uchar *);

typedef struct st_udf_func
{
  LEX_STRING name;
  Item_result returns;
  Item_udftype type;
  char *dl;
  void *dlhandle;
  Udf_func_any func;
  Udf_func_init func_init;
  Udf_func_deinit func_deinit;
  Udf_func_clear func_clear;
  Udf_func_add func_add;
  ulong usage_count;
} udf_func;

class Item_result_field;

class udf_handler :public Sql_alloc
{
 protected:
  udf_func *u_d;
  String *buffers;
  UDF_ARGS f_args;
  UDF_INIT initid;
  char *num_buffer;
  uchar error, is_null;
  bool initialized;
  Item **args;

 public:
  table_map used_tables_cache;
  bool const_item_cache;
  bool not_original;
  udf_handler(udf_func *udf_arg) :u_d(udf_arg), buffers(0), error(0),
    is_null(0), initialized(0), not_original(0)
  {}
  ~udf_handler();
  const char *name() const { return u_d ? u_d->name.str : "?"; }
  Item_result result_type () const
  { return u_d	? u_d->returns : STRING_RESULT;}
  bool get_arguments();
  bool fix_fields(THD *thd, Item_result_field *item,
		  uint arg_count, Item **args);
  void cleanup();
  double val(my_bool *null_value)
  {
    is_null= 0;
    if (get_arguments())
    {
      *null_value=1;
      return 0.0;
    }
    Udf_func_double func= (Udf_func_double) u_d->func;
    double tmp=func(&initid, &f_args, &is_null, &error);
    if (is_null || error)
    {
      *null_value=1;
      return 0.0;
    }
    *null_value=0;
    return tmp;
  }
  longlong val_int(my_bool *null_value)
  {
    is_null= 0;
    if (get_arguments())
    {
      *null_value=1;
      return LL(0);
    }
    Udf_func_longlong func= (Udf_func_longlong) u_d->func;
    longlong tmp=func(&initid, &f_args, &is_null, &error);
    if (is_null || error)
    {
      *null_value=1;
      return LL(0);
    }
    *null_value=0;
    return tmp;
  }
  my_decimal *val_decimal(my_bool *null_value, my_decimal *dec_buf);
  void clear()
  {
    is_null= 0;
    Udf_func_clear func= u_d->func_clear;
    func(&initid, &is_null, &error);
  }
  void add(my_bool *null_value)
  {
    if (get_arguments())
    {
      *null_value=1;
      return;
    }
    Udf_func_add func= u_d->func_add;
    func(&initid, &f_args, &is_null, &error);
    *null_value= (my_bool) (is_null || error);
  }
  String *val_str(String *str,String *save_str);
};


#ifdef HAVE_DLOPEN
void udf_init(void),udf_free(void);
udf_func *find_udf(const char *name, uint len=0,bool mark_used=0);
void free_udf(udf_func *udf);
int mysql_create_function(THD *thd,udf_func *udf);
int mysql_drop_function(THD *thd,const LEX_STRING *name);
#endif
#endif /* SQL_UDF_INCLUDED */
