#ifndef ITEM_STRFUNC_INCLUDED
#define ITEM_STRFUNC_INCLUDED

/* Copyright (c) 2000, 2020, 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, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */


/* This file defines all string functions */
#include "crypt_genhash_impl.h"

class MY_LOCALE;

class Item_str_func :public Item_func
{
protected:
  /**
     Sets the result value of the function an empty string, using the current
     character set. No memory is allocated.
     @retval A pointer to the str_value member.
   */
  String *make_empty_result() {
    str_value.set("", 0, collation.collation);
    return &str_value; 
  }
public:
  Item_str_func() :Item_func() { decimals=NOT_FIXED_DEC; }
  Item_str_func(Item *a) :Item_func(a) {decimals=NOT_FIXED_DEC; }
  Item_str_func(Item *a,Item *b) :Item_func(a,b) { decimals=NOT_FIXED_DEC; }
  Item_str_func(Item *a,Item *b,Item *c) :Item_func(a,b,c) { decimals=NOT_FIXED_DEC; }
  Item_str_func(Item *a,Item *b,Item *c,Item *d) :Item_func(a,b,c,d) {decimals=NOT_FIXED_DEC; }
  Item_str_func(Item *a,Item *b,Item *c,Item *d, Item* e) :Item_func(a,b,c,d,e) {decimals=NOT_FIXED_DEC; }
  Item_str_func(List<Item> &list) :Item_func(list) {decimals=NOT_FIXED_DEC; }
  longlong val_int();
  double val_real();
  my_decimal *val_decimal(my_decimal *);
  bool get_date(MYSQL_TIME *ltime, uint fuzzydate)
  {
    return get_date_from_string(ltime, fuzzydate);
  }
  bool get_time(MYSQL_TIME *ltime)
  {
    return get_time_from_string(ltime);
  }
  enum Item_result result_type () const { return STRING_RESULT; }
  void left_right_max_length();
  bool fix_fields(THD *thd, Item **ref);
  String *val_str_from_val_str_ascii(String *str, String *str2);
};



/*
  Functions that return values with ASCII repertoire
*/
class Item_str_ascii_func :public Item_str_func
{
  String ascii_buf;
public:
  Item_str_ascii_func() :Item_str_func()
  { collation.set_repertoire(MY_REPERTOIRE_ASCII); }
  Item_str_ascii_func(Item *a) :Item_str_func(a)
  { collation.set_repertoire(MY_REPERTOIRE_ASCII); }
  Item_str_ascii_func(Item *a,Item *b) :Item_str_func(a,b)
  { collation.set_repertoire(MY_REPERTOIRE_ASCII); }
  Item_str_ascii_func(Item *a,Item *b,Item *c) :Item_str_func(a,b,c)
  { collation.set_repertoire(MY_REPERTOIRE_ASCII); }
  String *val_str(String *str)
  {
    return val_str_from_val_str_ascii(str, &ascii_buf);
  }
  virtual String *val_str_ascii(String *)= 0;
};


class Item_func_md5 :public Item_str_ascii_func
{
  String tmp_value;
public:
  Item_func_md5(Item *a) :Item_str_ascii_func(a) {}
  String *val_str_ascii(String *);
  void fix_length_and_dec();
  const char *func_name() const { return "md5"; }
};


class Item_func_sha :public Item_str_ascii_func
{
public:
  Item_func_sha(Item *a) :Item_str_ascii_func(a) {}
  String *val_str_ascii(String *);    
  void fix_length_and_dec();      
  const char *func_name() const { return "sha"; }	
};

class Item_func_sha2 :public Item_str_ascii_func
{
public:
  Item_func_sha2(Item *a, Item *b) :Item_str_ascii_func(a, b) {}
  String *val_str_ascii(String *);
  void fix_length_and_dec();
  const char *func_name() const { return "sha2"; }
};

class Item_func_to_base64 :public Item_str_ascii_func
{
  String tmp_value;
public:
  Item_func_to_base64(Item *a) :Item_str_ascii_func(a) {}
  String *val_str_ascii(String *);
  void fix_length_and_dec();
  const char *func_name() const { return "to_base64"; }
};

class Item_func_from_base64 :public Item_str_func
{
  String tmp_value;
public:
  Item_func_from_base64(Item *a) :Item_str_func(a) {}
  String *val_str(String *);
  void fix_length_and_dec();
  const char *func_name() const { return "from_base64"; }
};


class Item_func_aes_encrypt :public Item_str_func
{
public:
  Item_func_aes_encrypt(Item *a, Item *b) :Item_str_func(a,b) {}
  Item_func_aes_encrypt(Item *a, Item *b, Item *c) :Item_str_func(a, b, c) {}
  String *val_str(String *);
  void fix_length_and_dec();
  const char *func_name() const { return "aes_encrypt"; }
};

class Item_func_aes_decrypt :public Item_str_func	
{
public:
  Item_func_aes_decrypt(Item *a, Item *b) :Item_str_func(a,b) {}
  Item_func_aes_decrypt(Item *a, Item *b, Item *c) :Item_str_func(a, b, c) {}
  String *val_str(String *);
  void fix_length_and_dec();
  const char *func_name() const { return "aes_decrypt"; }
};


class Item_func_random_bytes : public Item_str_func
{
  /** limitation from the SSL library */
  static const longlong MAX_RANDOM_BYTES_BUFFER;
public:
  Item_func_random_bytes(Item *a) : Item_str_func(a)
  {}

  void fix_length_and_dec();
  String *val_str(String *a);

  const char *func_name() const
  {
    return "random_bytes";
  }

};

class Item_func_concat :public Item_str_func
{
  String tmp_value;
public:
  Item_func_concat(List<Item> &list)
      : Item_str_func(list), tmp_value("", 0, collation.collation) {}
  Item_func_concat(Item *a, Item *b)
      : Item_str_func(a, b), tmp_value("", 0, collation.collation) {}
  String *val_str(String *);
  void fix_length_and_dec();
  const char *func_name() const { return "concat"; }
};

class Item_func_concat_ws :public Item_str_func
{
  String tmp_value;
public:
  Item_func_concat_ws(List<Item> &list)
      : Item_str_func(list), tmp_value("", 0, collation.collation) {}
  String *val_str(String *);
  void fix_length_and_dec();
  const char *func_name() const { return "concat_ws"; }
  table_map not_null_tables() const { return 0; }
};

class Item_func_reverse :public Item_str_func
{
  String tmp_value;
public:
  Item_func_reverse(Item *a) :Item_str_func(a) {}
  String *val_str(String *);
  void fix_length_and_dec();
  const char *func_name() const { return "reverse"; }
};


class Item_func_replace :public Item_str_func
{
  String tmp_value,tmp_value2;
  /** Holds result in case we need to allocate our own result buffer.*/
  String tmp_value_res;
public:
  Item_func_replace(Item *org,Item *find,Item *replace)
    :Item_str_func(org,find,replace) {}
  String *val_str(String *);
  void fix_length_and_dec();
  const char *func_name() const { return "replace"; }
};


class Item_func_insert :public Item_str_func
{
  String tmp_value;
  /** Holds result in case we need to allocate our own result buffer.*/
  String tmp_value_res;
public:
  Item_func_insert(Item *org,Item *start,Item *length,Item *new_str)
    :Item_str_func(org,start,length,new_str) {}
  String *val_str(String *);
  void fix_length_and_dec();
  const char *func_name() const { return "insert"; }
};


class Item_str_conv :public Item_str_func
{
protected:
  uint multiply;
  my_charset_conv_case converter;
  String tmp_value;
public:
  Item_str_conv(Item *item) :Item_str_func(item) {}
  String *val_str(String *);
};


class Item_func_lcase :public Item_str_conv
{
public:
  Item_func_lcase(Item *item) :Item_str_conv(item) {}
  const char *func_name() const { return "lcase"; }
  void fix_length_and_dec();
};

class Item_func_ucase :public Item_str_conv
{
public:
  Item_func_ucase(Item *item) :Item_str_conv(item) {}
  const char *func_name() const { return "ucase"; }
  void fix_length_and_dec();
};


class Item_func_left :public Item_str_func
{
  String tmp_value;
public:
  Item_func_left(Item *a,Item *b) :Item_str_func(a,b) {}
  String *val_str(String *);
  void fix_length_and_dec();
  const char *func_name() const { return "left"; }
};


class Item_func_right :public Item_str_func
{
  String tmp_value;
public:
  Item_func_right(Item *a,Item *b) :Item_str_func(a,b) {}
  String *val_str(String *);
  void fix_length_and_dec();
  const char *func_name() const { return "right"; }
};


class Item_func_substr :public Item_str_func
{
  String tmp_value;
public:
  Item_func_substr(Item *a,Item *b) :Item_str_func(a,b) {}
  Item_func_substr(Item *a,Item *b,Item *c) :Item_str_func(a,b,c) {}
  String *val_str(String *);
  void fix_length_and_dec();
  const char *func_name() const { return "substr"; }
};


class Item_func_substr_index :public Item_str_func
{
  String tmp_value;
public:
  Item_func_substr_index(Item *a,Item *b,Item *c) :Item_str_func(a,b,c) {}
  String *val_str(String *);
  void fix_length_and_dec();
  const char *func_name() const { return "substring_index"; }
};


class Item_func_trim :public Item_str_func
{
protected:
  String tmp_value;
  String remove;
public:
  Item_func_trim(Item *a,Item *b) :Item_str_func(a,b) {}
  Item_func_trim(Item *a) :Item_str_func(a) {}
  String *val_str(String *);
  void fix_length_and_dec();
  const char *func_name() const { return "trim"; }
  virtual void print(String *str, enum_query_type query_type);
  virtual const char *mode_name() const { return "both"; }
};


class Item_func_ltrim :public Item_func_trim
{
public:
  Item_func_ltrim(Item *a,Item *b) :Item_func_trim(a,b) {}
  Item_func_ltrim(Item *a) :Item_func_trim(a) {}
  String *val_str(String *);
  const char *func_name() const { return "ltrim"; }
  const char *mode_name() const { return "leading"; }
};


class Item_func_rtrim :public Item_func_trim
{
public:
  Item_func_rtrim(Item *a,Item *b) :Item_func_trim(a,b) {}
  Item_func_rtrim(Item *a) :Item_func_trim(a) {}
  String *val_str(String *);
  const char *func_name() const { return "rtrim"; }
  const char *mode_name() const { return "trailing"; }
};


/*
  Item_func_password -- new (4.1.1) PASSWORD() function implementation.
  Returns strcat('*', octet2hex(sha1(sha1(password)))). '*' stands for new
  password format, sha1(sha1(password) is so-called hash_stage2 value.
  Length of returned string is always 41 byte. To find out how entire
  authentication procedure works, see comments in password.c.
*/

class Item_func_password :public Item_str_ascii_func
{
  char m_hashed_password_buffer[CRYPT_MAX_PASSWORD_SIZE + 1];
  unsigned int m_hashed_password_buffer_len;
  bool m_recalculate_password;
public:
  Item_func_password(Item *a) : Item_str_ascii_func(a)
  {
    m_hashed_password_buffer_len= 0;
    m_recalculate_password= false;
  }
  String *val_str_ascii(String *str);
  void fix_length_and_dec();
  const char *func_name() const { return "password"; }
  static char *create_password_hash_buffer(THD *thd, const char *password,
                                           size_t pass_len);
};


/*
  Item_func_old_password -- PASSWORD() implementation used in MySQL 3.21 - 4.0
  compatibility mode. This item is created in sql_yacc.yy when
  'old_passwords' session variable is set, and to handle OLD_PASSWORD()
  function.
*/

class Item_func_old_password :public Item_str_ascii_func
{
  char tmp_value[SCRAMBLED_PASSWORD_CHAR_LENGTH_323+1];
public:
  Item_func_old_password(Item *a) :Item_str_ascii_func(a) {}
  String *val_str_ascii(String *str);
  void fix_length_and_dec()
  {
    fix_length_and_charset(SCRAMBLED_PASSWORD_CHAR_LENGTH_323, default_charset());
  } 
  const char *func_name() const { return "old_password"; }
  static char *alloc(THD *thd, const char *password, size_t pass_len);
};


class Item_func_des_encrypt :public Item_str_func
{
  String tmp_value,tmp_arg;
public:
  Item_func_des_encrypt(Item *a) :Item_str_func(a) {}
  Item_func_des_encrypt(Item *a, Item *b): Item_str_func(a,b) {}
  String *val_str(String *);
  void fix_length_and_dec()
  {
    maybe_null=1;
    /* 9 = MAX ((8- (arg_len % 8)) + 1) */
    max_length = args[0]->max_length + 9;
  }
  const char *func_name() const { return "des_encrypt"; }
};

class Item_func_des_decrypt :public Item_str_func
{
  String tmp_value;
public:
  Item_func_des_decrypt(Item *a) :Item_str_func(a) {}
  Item_func_des_decrypt(Item *a, Item *b): Item_str_func(a,b) {}
  String *val_str(String *);
  void fix_length_and_dec()
  {
    maybe_null=1;
    /* 9 = MAX ((8- (arg_len % 8)) + 1) */
    max_length= args[0]->max_length;
    if (max_length >= 9U)
      max_length-= 9U;
  }
  const char *func_name() const { return "des_decrypt"; }
};

class Item_func_encrypt :public Item_str_func
{
  String tmp_value;

  /* Encapsulate common constructor actions */
  void constructor_helper()
  {
    collation.set(&my_charset_bin);
  }
public:
  Item_func_encrypt(Item *a) :Item_str_func(a)
  {
    constructor_helper();
  }
  Item_func_encrypt(Item *a, Item *b): Item_str_func(a,b)
  {
    constructor_helper();
  }
  String *val_str(String *);
  void fix_length_and_dec() { maybe_null=1; max_length = 13; }
  const char *func_name() const { return "encrypt"; }
};

#include "sql_crypt.h"


class Item_func_encode :public Item_str_func
{
private:
  /** Whether the PRNG has already been seeded. */
  bool seeded;
  /** Holds result in case we need to allocate our own result buffer.*/
  String tmp_value_res;
protected:
  SQL_CRYPT sql_crypt;
public:
  Item_func_encode(Item *a, Item *seed):
    Item_str_func(a, seed) {}
  String *val_str(String *);
  void fix_length_and_dec();
  const char *func_name() const { return "encode"; }
protected:
  virtual void crypto_transform(String *);
private:
  /** Provide a seed for the PRNG sequence. */
  bool seed();
};


class Item_func_decode :public Item_func_encode
{
public:
  Item_func_decode(Item *a, Item *seed): Item_func_encode(a, seed) {}
  const char *func_name() const { return "decode"; }
protected:
  void crypto_transform(String *);
};


class Item_func_sysconst :public Item_str_func
{
public:
  Item_func_sysconst()
  { collation.set(system_charset_info,DERIVATION_SYSCONST); }
  Item *safe_charset_converter(const CHARSET_INFO *tocs);
  /*
    Used to create correct Item name in new converted item in
    safe_charset_converter, return string representation of this function
    call
  */
  virtual const Name_string fully_qualified_func_name() const = 0;
};


class Item_func_database :public Item_func_sysconst
{
public:
  Item_func_database() :Item_func_sysconst() {}
  String *val_str(String *);
  void fix_length_and_dec()
  {
    max_length= MAX_FIELD_NAME * system_charset_info->mbmaxlen;
    maybe_null=1;
  }
  const char *func_name() const { return "database"; }
  const Name_string fully_qualified_func_name() const
  { return NAME_STRING("database()"); }
};


class Item_func_user :public Item_func_sysconst
{
protected:
  bool init (const char *user, const char *host);

public:
  Item_func_user()
  {
    str_value.set("", 0, system_charset_info);
  }
  String *val_str(String *)
  {
    DBUG_ASSERT(fixed == 1);
    return (null_value ? 0 : &str_value);
  }
  bool fix_fields(THD *thd, Item **ref);
  void fix_length_and_dec()
  {
    max_length= (USERNAME_LENGTH +
                 (HOSTNAME_LENGTH + 1) * SYSTEM_CHARSET_MBMAXLEN);
  }
  const char *func_name() const { return "user"; }
  const Name_string fully_qualified_func_name() const
  { return NAME_STRING("user()"); }
  type_conversion_status save_in_field(Field *field, bool no_conversions)
  {
    return save_str_value_in_field(field, &str_value);
  }
};


class Item_func_current_user :public Item_func_user
{
  Name_resolution_context *context;

public:
  Item_func_current_user(Name_resolution_context *context_arg)
    : context(context_arg) {}
  bool fix_fields(THD *thd, Item **ref);
  const char *func_name() const { return "current_user"; }
  const Name_string fully_qualified_func_name() const
  { return NAME_STRING("current_user()"); }
};


class Item_func_soundex :public Item_str_func
{
  String tmp_value;
public:
  Item_func_soundex(Item *a) :Item_str_func(a) {}
  String *val_str(String *);
  void fix_length_and_dec();
  const char *func_name() const { return "soundex"; }
};


class Item_func_elt :public Item_str_func
{
public:
  Item_func_elt(List<Item> &list) :Item_str_func(list) {}
  double val_real();
  longlong val_int();
  String *val_str(String *str);
  void fix_length_and_dec();
  const char *func_name() const { return "elt"; }
};


class Item_func_make_set :public Item_str_func
{
  Item *item;
  String tmp_str;

public:
  Item_func_make_set(Item *a,List<Item> &list) :Item_str_func(list),item(a) {}
  String *val_str(String *str);
  bool fix_fields(THD *thd, Item **ref)
  {
    DBUG_ASSERT(fixed == 0);
    bool res= ((!item->fixed && item->fix_fields(thd, &item)) ||
               item->check_cols(1) ||
               Item_func::fix_fields(thd, ref));
    maybe_null|= item->maybe_null;
    return res;
  }
  void split_sum_func(THD *thd, Ref_ptr_array ref_pointer_array,
                      List<Item> &fields);
  void fix_length_and_dec();
  void update_used_tables();
  const char *func_name() const { return "make_set"; }

  bool walk(Item_processor processor, bool walk_subquery, uchar *arg)
  {
    return item->walk(processor, walk_subquery, arg) ||
      Item_str_func::walk(processor, walk_subquery, arg);
  }
  Item *transform(Item_transformer transformer, uchar *arg);
  virtual void print(String *str, enum_query_type query_type);
};


class Item_func_format :public Item_str_ascii_func
{
  String tmp_str;
  MY_LOCALE *locale;
public:
  Item_func_format(Item *org, Item *dec): Item_str_ascii_func(org, dec) {}
  Item_func_format(Item *org, Item *dec, Item *lang):
  Item_str_ascii_func(org, dec, lang) {}
  
  MY_LOCALE *get_locale(Item *item);
  String *val_str_ascii(String *);
  void fix_length_and_dec();
  const char *func_name() const { return "format"; }
  virtual void print(String *str, enum_query_type query_type);
};


class Item_func_char :public Item_str_func
{
public:
  Item_func_char(List<Item> &list) :Item_str_func(list)
  { collation.set(&my_charset_bin); }
  Item_func_char(List<Item> &list, const CHARSET_INFO *cs) :
  Item_str_func(list)
  { collation.set(cs); }  
  String *val_str(String *);
  void fix_length_and_dec() 
  {
    max_length= arg_count * 4;
  }
  const char *func_name() const { return "char"; }
};


class Item_func_repeat :public Item_str_func
{
  String tmp_value;
public:
  Item_func_repeat(Item *arg1,Item *arg2) :Item_str_func(arg1,arg2) {}
  String *val_str(String *);
  void fix_length_and_dec();
  const char *func_name() const { return "repeat"; }
};


class Item_func_space :public Item_str_func
{
public:
  Item_func_space(Item *arg1):Item_str_func(arg1) {}
  String *val_str(String *);
  void fix_length_and_dec();
  const char *func_name() const { return "space"; }
};


class Item_func_rpad :public Item_str_func
{
  String tmp_value, rpad_str;
public:
  Item_func_rpad(Item *arg1,Item *arg2,Item *arg3)
    :Item_str_func(arg1,arg2,arg3) {}
  String *val_str(String *);
  void fix_length_and_dec();
  const char *func_name() const { return "rpad"; }
};


class Item_func_lpad :public Item_str_func
{
  String tmp_value, lpad_str;
public:
  Item_func_lpad(Item *arg1,Item *arg2,Item *arg3)
    :Item_str_func(arg1,arg2,arg3) {}
  String *val_str(String *);
  void fix_length_and_dec();
  const char *func_name() const { return "lpad"; }
};


class Item_func_conv :public Item_str_func
{
public:
  Item_func_conv(Item *a,Item *b,Item *c) :Item_str_func(a,b,c) {}
  const char *func_name() const { return "conv"; }
  String *val_str(String *);
  void fix_length_and_dec()
  {
    collation.set(default_charset());
    max_length=64;
    maybe_null= 1;
  }
};


class Item_func_hex :public Item_str_ascii_func
{
  String tmp_value;
public:
  Item_func_hex(Item *a) :Item_str_ascii_func(a) {}
  const char *func_name() const { return "hex"; }
  String *val_str_ascii(String *);
  void fix_length_and_dec()
  {
    collation.set(default_charset());
    decimals=0;
    fix_char_length(args[0]->max_length * 2);
  }
};

class Item_func_unhex :public Item_str_func
{
  String tmp_value;
public:
  Item_func_unhex(Item *a) :Item_str_func(a) 
  { 
    /* there can be bad hex strings */
    maybe_null= 1; 
  }
  const char *func_name() const { return "unhex"; }
  String *val_str(String *);
  void fix_length_and_dec()
  {
    collation.set(&my_charset_bin);
    decimals=0;
    max_length=(1+args[0]->max_length)/2;
  }
};


#ifndef DBUG_OFF
class Item_func_like_range :public Item_str_func
{
protected:
  String min_str;
  String max_str;
  const bool is_min;
public:
  Item_func_like_range(Item *a, Item *b, bool is_min_arg)
    :Item_str_func(a, b), is_min(is_min_arg)
  { maybe_null= 1; }
  String *val_str(String *);
  void fix_length_and_dec()
  {
    collation.set(args[0]->collation);
    decimals=0;
    max_length= MAX_BLOB_WIDTH;
  }
};


class Item_func_like_range_min :public Item_func_like_range
{
public:
  Item_func_like_range_min(Item *a, Item *b) 
    :Item_func_like_range(a, b, true) { }
  const char *func_name() const { return "like_range_min"; }
};


class Item_func_like_range_max :public Item_func_like_range
{
public:
  Item_func_like_range_max(Item *a, Item *b)
    :Item_func_like_range(a, b, false) { }
  const char *func_name() const { return "like_range_max"; }
};
#endif


class Item_char_typecast :public Item_str_func
{
  int cast_length;
  const CHARSET_INFO *cast_cs, *from_cs;
  bool charset_conversion;
  String tmp_value;
public:
  Item_char_typecast(Item *a, int length_arg, const CHARSET_INFO *cs_arg)
    :Item_str_func(a), cast_length(length_arg), cast_cs(cs_arg) {}
  enum Functype functype() const { return CHAR_TYPECAST_FUNC; }
  bool eq(const Item *item, bool binary_cmp) const;
  const char *func_name() const { return "cast_as_char"; }
  String *val_str(String *a);
  void fix_length_and_dec();
  virtual void print(String *str, enum_query_type query_type);
};


class Item_func_binary :public Item_str_func
{
public:
  Item_func_binary(Item *a) :Item_str_func(a) {}
  String *val_str(String *a)
  {
    DBUG_ASSERT(fixed == 1);
    String *tmp=args[0]->val_str(a);
    null_value=args[0]->null_value;
    if (tmp)
      tmp->set_charset(&my_charset_bin);
    return tmp;
  }
  void fix_length_and_dec()
  {
    collation.set(&my_charset_bin);
    max_length=args[0]->max_length;
  }
  virtual void print(String *str, enum_query_type query_type);
  const char *func_name() const { return "cast_as_binary"; }
};


class Item_load_file :public Item_str_func
{
  String tmp_value;
public:
  Item_load_file(Item *a) :Item_str_func(a) {}
  String *val_str(String *);
  const char *func_name() const { return "load_file"; }
  void fix_length_and_dec()
  {
    collation.set(&my_charset_bin, DERIVATION_COERCIBLE);
    maybe_null=1;
    max_length=MAX_BLOB_WIDTH;
  }
};


class Item_func_export_set: public Item_str_func
{
 public:
  Item_func_export_set(Item *a,Item *b,Item* c) :Item_str_func(a,b,c) {}
  Item_func_export_set(Item *a,Item *b,Item* c,Item* d) :Item_str_func(a,b,c,d) {}
  Item_func_export_set(Item *a,Item *b,Item* c,Item* d,Item* e) :Item_str_func(a,b,c,d,e) {}
  String  *val_str(String *str);
  void fix_length_and_dec();
  const char *func_name() const { return "export_set"; }
};

class Item_func_quote :public Item_str_func
{
  String tmp_value;
public:
  Item_func_quote(Item *a) :Item_str_func(a) {}
  const char *func_name() const { return "quote"; }
  String *val_str(String *);
  void fix_length_and_dec()
  {
    collation.set(args[0]->collation);
    ulong max_result_length= (ulong) args[0]->max_length * 2 +
                                  2 * collation.collation->mbmaxlen;
    max_length= std::min<ulong>(max_result_length, MAX_BLOB_WIDTH);
  }
};

class Item_func_conv_charset :public Item_str_func
{
  bool use_cached_value;
  String tmp_value;
public:
  bool safe;
  const CHARSET_INFO *conv_charset; // keep it public
  Item_func_conv_charset(Item *a, const CHARSET_INFO *cs) :Item_str_func(a) 
  { conv_charset= cs; use_cached_value= 0; safe= 0; }
  Item_func_conv_charset(Item *a, const CHARSET_INFO *cs,
                         bool cache_if_const) :Item_str_func(a)
  {
    DBUG_ASSERT(args[0]->fixed);
    conv_charset= cs;
    if (cache_if_const && args[0]->const_item())
    {
      uint errors= 0;
      String tmp, *str= args[0]->val_str(&tmp);
      if (!str || str_value.copy(str->ptr(), str->length(),
                                 str->charset(), conv_charset, &errors))
        null_value= 1;
      use_cached_value= 1;
      str_value.mark_as_const();
      safe= (errors == 0);
    }
    else
    {
      use_cached_value= 0;
      /*
        Conversion from and to "binary" is safe.
        Conversion to Unicode is safe.
        Other kind of conversions are potentially lossy.
      */
      safe= (args[0]->collation.collation == &my_charset_bin ||
             cs == &my_charset_bin ||
             (cs->state & MY_CS_UNICODE));
    }
  }
  String *val_str(String *);
  void fix_length_and_dec();
  const char *func_name() const { return "convert"; }
  virtual void print(String *str, enum_query_type query_type);
};

class Item_func_set_collation :public Item_str_func
{
public:
  Item_func_set_collation(Item *a, Item *b) :Item_str_func(a,b) {};
  String *val_str(String *);
  void fix_length_and_dec();
  bool eq(const Item *item, bool binary_cmp) const;
  const char *func_name() const { return "collate"; }
  enum Functype functype() const { return COLLATE_FUNC; }
  virtual void print(String *str, enum_query_type query_type);
  Item_field *field_for_view_update()
  {
    /* this function is transparent for view updating */
    return args[0]->field_for_view_update();
  }
};

class Item_func_charset :public Item_str_func
{
public:
  Item_func_charset(Item *a) :Item_str_func(a) {}
  String *val_str(String *);
  const char *func_name() const { return "charset"; }
  void fix_length_and_dec()
  {
     collation.set(system_charset_info);
     max_length= 64 * collation.collation->mbmaxlen; // should be enough
     maybe_null= 0;
  };
  table_map not_null_tables() const { return 0; }
};

class Item_func_collation :public Item_str_func
{
public:
  Item_func_collation(Item *a) :Item_str_func(a) {}
  String *val_str(String *);
  const char *func_name() const { return "collation"; }
  void fix_length_and_dec()
  {
     collation.set(system_charset_info);
     max_length= 64 * collation.collation->mbmaxlen; // should be enough
     maybe_null= 0;
  };
  table_map not_null_tables() const { return 0; }
};

class Item_func_weight_string :public Item_str_func
{
  String tmp_value;
  uint flags;
  uint nweights;
  uint result_length;
  Field *field;
public:
  Item_func_weight_string(Item *a, uint result_length_arg,
                          uint nweights_arg, uint flags_arg)
  :Item_str_func(a), field(NULL)
  {
    nweights= nweights_arg;
    flags= flags_arg;
    result_length= result_length_arg;
  }
  const char *func_name() const { return "weight_string"; }
  String *val_str(String *);
  void fix_length_and_dec();
};

class Item_func_crc32 :public Item_int_func
{
  String value;
public:
  Item_func_crc32(Item *a) :Item_int_func(a) { unsigned_flag= 1; }
  const char *func_name() const { return "crc32"; }
  void fix_length_and_dec() { max_length=10; }
  longlong val_int();
};

class Item_func_uncompressed_length : public Item_int_func
{
  String value;
public:
  Item_func_uncompressed_length(Item *a):Item_int_func(a){}
  const char *func_name() const{return "uncompressed_length";}
  void fix_length_and_dec() { max_length=10; }
  longlong val_int();
};

#ifdef HAVE_COMPRESS
#define ZLIB_DEPENDED_FUNCTION ;
#else
#define ZLIB_DEPENDED_FUNCTION { null_value=1; return 0; }
#endif

class Item_func_compress: public Item_str_func
{
  String buffer;
public:
  Item_func_compress(Item *a):Item_str_func(a){}
  void fix_length_and_dec(){max_length= (args[0]->max_length*120)/100+12;}
  const char *func_name() const{return "compress";}
  String *val_str(String *) ZLIB_DEPENDED_FUNCTION
};

class Item_func_uncompress: public Item_str_func
{
  String buffer;
public:
  Item_func_uncompress(Item *a): Item_str_func(a){}
  void fix_length_and_dec(){ maybe_null= 1; max_length= MAX_BLOB_WIDTH; }
  const char *func_name() const{return "uncompress";}
  String *val_str(String *) ZLIB_DEPENDED_FUNCTION
};

class Item_func_uuid: public Item_str_func
{
public:
  Item_func_uuid(): Item_str_func() {}
  void fix_length_and_dec()
  {
    collation.set(system_charset_info,
                  DERIVATION_COERCIBLE, MY_REPERTOIRE_ASCII);
    fix_char_length(UUID_LENGTH);
  }
  const char *func_name() const{ return "uuid"; }
  String *val_str(String *);
};

class Item_func_gtid_subtract: public Item_str_ascii_func
{
  String buf1, buf2;
public:
  Item_func_gtid_subtract(Item *a, Item *b) :Item_str_ascii_func(a, b) {}
  void fix_length_and_dec();
  const char *func_name() const{ return "gtid_subtract"; }
  String *val_str_ascii(String *);
};

#endif /* ITEM_STRFUNC_INCLUDED */
