~drizzle-trunk/drizzle/development

/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-

 *  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:

 *

 *  Copyright (C) 2008 Sun Microsystems, Inc.

 *

 *  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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

 */

#ifndef DRIZZLED_FUNCTION_FUNC_H

#define DRIZZLED_FUNCTION_FUNC_H

/// TODO: Rename this file - func.h is stupid.

#include <drizzled/item.h>

#include <drizzled/sql_list.h>

#include <drizzled/item/bin_string.h>

#include "drizzled/current_session.h"

namespace drizzled

{

class Item_func :public Item_result_field

{

  Session &_session;

protected:

  Item **args, *tmp_arg[2];

  /*

    Allowed numbers of columns in result (usually 1, which means scalar value)

    0 means get this number from first argument

  */

  uint32_t allowed_arg_cols;

public:

  using Item::split_sum_func;

  uint32_t arg_count;

  table_map used_tables_cache, not_null_tables_cache;

  bool const_item_cache;

  enum Functype { UNKNOWN_FUNC,EQ_FUNC,EQUAL_FUNC,NE_FUNC,LT_FUNC,LE_FUNC,

                  GE_FUNC,GT_FUNC,

                  LIKE_FUNC,ISNULL_FUNC,ISNOTNULL_FUNC,

                  COND_AND_FUNC, COND_OR_FUNC, COND_XOR_FUNC,

                  BETWEEN, IN_FUNC, MULT_EQUAL_FUNC,

                  INTERVAL_FUNC, ISNOTNULLTEST_FUNC,

                  NOT_FUNC, NOT_ALL_FUNC,

                  NOW_FUNC, TRIG_COND_FUNC,

                  SUSERVAR_FUNC, GUSERVAR_FUNC, COLLATE_FUNC,

                  EXTRACT_FUNC, CHAR_TYPECAST_FUNC, FUNC_SP,

                  NEG_FUNC };

  enum optimize_type { OPTIMIZE_NONE,OPTIMIZE_KEY,OPTIMIZE_OP, OPTIMIZE_NULL,

                       OPTIMIZE_EQUAL };

  enum Type type() const { return FUNC_ITEM; }

  virtual enum Functype functype() const   { return UNKNOWN_FUNC; }

  virtual ~Item_func() {}

  Item_func(void):

    _session(*current_session),

    allowed_arg_cols(1), arg_count(0),

    const_item_cache(false)

  {

    with_sum_func= 0;

    collation.set(DERIVATION_SYSCONST);

  }

  Item_func(Item *a):

    _session(*current_session),

    allowed_arg_cols(1), arg_count(1),

    const_item_cache(false)

  {

    args= tmp_arg;

    args[0]= a;

    with_sum_func= a->with_sum_func;

    collation.set(DERIVATION_SYSCONST);

  }

  Item_func(Item *a,Item *b):

    _session(*current_session),

    allowed_arg_cols(1), arg_count(2),

    const_item_cache(false)

  {

    args= tmp_arg;

    args[0]= a; args[1]= b;

    with_sum_func= a->with_sum_func || b->with_sum_func;

    collation.set(DERIVATION_SYSCONST);

  }

  Item_func(Item *a,Item *b,Item *c):

    _session(*current_session),

    allowed_arg_cols(1),

    const_item_cache(false)

  {

    arg_count= 0;

    if ((args= (Item**) memory::sql_alloc(sizeof(Item*)*3)))

    {

      arg_count= 3;

      args[0]= a; args[1]= b; args[2]= c;

      with_sum_func= a->with_sum_func || b->with_sum_func || c->with_sum_func;

    }

    collation.set(DERIVATION_SYSCONST);

  }

  Item_func(Item *a,Item *b,Item *c,Item *d):

    _session(*current_session),

    allowed_arg_cols(1),

    const_item_cache(false)

  {

    arg_count= 0;

    if ((args= (Item**) memory::sql_alloc(sizeof(Item*)*4)))

    {

      arg_count= 4;

      args[0]= a; args[1]= b; args[2]= c; args[3]= d;

      with_sum_func= a->with_sum_func || b->with_sum_func ||

        c->with_sum_func || d->with_sum_func;

    }

    collation.set(DERIVATION_SYSCONST);

  }

  Item_func(Item *a,Item *b,Item *c,Item *d,Item* e):

    _session(*current_session),

    allowed_arg_cols(1),

    const_item_cache(false)

  {

    arg_count= 5;

    if ((args= (Item**) memory::sql_alloc(sizeof(Item*)*5)))

    {

      args[0]= a; args[1]= b; args[2]= c; args[3]= d; args[4]= e;

      with_sum_func= a->with_sum_func || b->with_sum_func ||

        c->with_sum_func || d->with_sum_func || e->with_sum_func ;

    }

    collation.set(DERIVATION_SYSCONST);

  }

  Item_func(List<Item> &list);

  // Constructor used for Item_cond_and/or (see Item comment)

  Item_func(Session *session, Item_func *item);

  bool fix_fields(Session *, Item **ref);

  void fix_after_pullout(Select_Lex *new_parent, Item **ref);

  table_map used_tables() const;

  table_map not_null_tables() const;

  void update_used_tables();

  bool eq(const Item *item, bool binary_cmp) const;

  virtual optimize_type select_optimize() const { return OPTIMIZE_NONE; }

  virtual bool have_rev_func() const { return 0; }

  virtual Item *key_item() const { return args[0]; }

  /*

    This method is used for debug purposes to print the name of an

    item to the debug log. The second use of this method is as

    a helper function of print(), where it is applicable.

    To suit both goals it should return a meaningful,

    distinguishable and sintactically correct string.  This method

    should not be used for runtime type identification, use enum

    {Sum}Functype and Item_func::functype()/Item_sum::sum_func()

    instead.

  */

  virtual const char *func_name() const { return NULL; }

  virtual bool const_item() const { return const_item_cache; }

  Item **arguments() const { return args; }

  void set_arguments(List<Item> &list);

  uint32_t argument_count() const { return arg_count; }

  void remove_arguments() { arg_count=0; }

  /**

   * Check if the UDF supports the number of arguments passed in

   * @param number of args

   */

  virtual bool check_argument_count(int) { return true ; }

  virtual void split_sum_func(Session *session, Item **ref_pointer_array,

                              List<Item> &fields);

  virtual void print(String *str, enum_query_type query_type);

  void print_op(String *str, enum_query_type query_type);

  void print_args(String *str, uint32_t from, enum_query_type query_type);

  virtual void fix_num_length_and_dec();

  void count_only_length();

  void count_real_length();

  void count_decimal_length();

  bool get_arg0_date(type::Time *ltime, uint32_t fuzzy_date);

  bool get_arg0_time(type::Time *ltime);

  bool is_null();

  virtual bool deterministic() const

  {

    return false;

  }

  void signal_divide_by_null();

  virtual Field *tmp_table_field() { return result_field; }

  virtual Field *tmp_table_field(Table *t_arg);

  Item *get_tmp_table_item(Session *session);

  type::Decimal *val_decimal(type::Decimal *);

  bool agg_arg_collations(DTCollation &c, Item **items, uint32_t nitems,

                          uint32_t flags);

  bool agg_arg_collations_for_comparison(DTCollation &c,

                                         Item **items, uint32_t nitems,

                                         uint32_t flags);

  bool agg_arg_charsets(DTCollation &c, Item **items, uint32_t nitems,

                        uint32_t flags, int item_sep);

  bool walk(Item_processor processor, bool walk_subquery, unsigned char *arg);

  Item *transform(Item_transformer transformer, unsigned char *arg);

  Item* compile(Item_analyzer analyzer, unsigned char **arg_p,

                Item_transformer transformer, unsigned char *arg_t);

  void traverse_cond(Cond_traverser traverser,

                     void * arg, traverse_order order);

  double fix_result(double value);

  Session &getSession()

  {

    return _session;

  }

  Session *getSessionPtr()

  {

    return &_session;

  }

};

} /* namespace drizzled */

#endif /* DRIZZLED_FUNCTION_FUNC_H */