~drizzle-trunk/drizzle/development

/* Copyright (C) 2000-2001, 2003-2006 MySQL AB

   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; version 2 of the License.

   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, write to the Free Software

   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */

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

#ifdef USE_PRAGMA_INTERFACE

#pragma interface

#endif

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 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 int64_t (*Udf_func_int64_t)(UDF_INIT *, UDF_ARGS *, uchar *,

                                      uchar *);

typedef struct st_udf_func

{

  LEX_STRING name;

  Item_result returns;

  Item_udftype type;

  Udf_func_any func;

  Udf_func_init func_init;

  Udf_func_deinit func_deinit;

  Udf_func_clear func_clear;

  Udf_func_add func_add;

  void *data;

} 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(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;

  }

  int64_t val_int(bool *null_value)

  {

    is_null= 0;

    if (get_arguments())

    {

      *null_value=1;

      return 0LL;

    }

    Udf_func_int64_t func= (Udf_func_int64_t) u_d->func;

    int64_t tmp=func(&initid, &f_args, &is_null, &error);

    if (is_null || error)

    {

      *null_value=1;

      return 0LL;

    }

    *null_value=0;

    return tmp;

  }

  my_decimal *val_decimal(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(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= (bool) (is_null || error);

  }

  String *val_str(String *str,String *save_str);

};

void udf_init(void),udf_free(void);

udf_func *find_udf(const char *name, uint len=0);

void free_udf(udf_func *udf);

int mysql_create_function(THD *thd,udf_func *udf);