mariadb/sql/item_strfunc.cc

/* Copyright (C) 2000-2006 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 */


/**
  @file

  @brief
  This file defines all string functions

  @warning
    Some string functions don't always put and end-null on a String.
    (This shouldn't be needed)
*/

#ifdef USE_PRAGMA_IMPLEMENTATION
#pragma implementation				// gcc: Class implementation
#endif

#include "mysql_priv.h"
#include <m_ctype.h>
#include "my_md5.h"
#include "sha1.h"
#include "my_aes.h"
#include <zlib.h>
C_MODE_START
#include "../mysys/my_static.h"			// For soundex_map
C_MODE_END

String my_empty_string("",default_charset_info);


/*
  Convert an array of bytes to a hexadecimal representation.

  Used to generate a hexadecimal representation of a message digest.
*/
static void array_to_hex(char *to, const char *str, uint len)
{
  const char *str_end= str + len;
  for (; str != str_end; ++str)
  {
    *to++= _dig_vec_lower[((uchar) *str) >> 4];
    *to++= _dig_vec_lower[((uchar) *str) & 0x0F];
  }
}


bool Item_str_func::fix_fields(THD *thd, Item **ref)
{
  bool res= Item_func::fix_fields(thd, ref);
  /*
    In Item_str_func::check_well_formed_result() we may set null_value
    flag on the same condition as in test() below.
  */
  maybe_null= (maybe_null ||
               test(thd->variables.sql_mode &
                    (MODE_STRICT_TRANS_TABLES | MODE_STRICT_ALL_TABLES)));
  return res;
}


my_decimal *Item_str_func::val_decimal(my_decimal *decimal_value)
{
  DBUG_ASSERT(fixed == 1);
  char buff[64];
  String *res, tmp(buff,sizeof(buff), &my_charset_bin);
  res= val_str(&tmp);
  if (!res)
    return 0;
  (void)str2my_decimal(E_DEC_FATAL_ERROR, (char*) res->ptr(),
                       res->length(), res->charset(), decimal_value);
  return decimal_value;
}


double Item_str_func::val_real()
{
  DBUG_ASSERT(fixed == 1);
  int err_not_used;
  char *end_not_used, buff[64];
  String *res, tmp(buff,sizeof(buff), &my_charset_bin);
  res= val_str(&tmp);
  return res ? my_strntod(res->charset(), (char*) res->ptr(), res->length(),
			  &end_not_used, &err_not_used) : 0.0;
}


longlong Item_str_func::val_int()
{
  DBUG_ASSERT(fixed == 1);
  int err;
  char buff[22];
  String *res, tmp(buff,sizeof(buff), &my_charset_bin);
  res= val_str(&tmp);
  return (res ?
	  my_strntoll(res->charset(), res->ptr(), res->length(), 10, NULL,
		      &err) :
	  (longlong) 0);
}


String *Item_func_md5::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  String * sptr= args[0]->val_str(str);
  str->set_charset(&my_charset_bin);
  if (sptr)
  {
    uchar digest[16];

    null_value=0;
    MY_MD5_HASH(digest,(uchar *) sptr->ptr(), sptr->length());
    if (str->alloc(32))				// Ensure that memory is free
    {
      null_value=1;
      return 0;
    }
    array_to_hex((char *) str->ptr(), (const char*) digest, 16);
    str->length((uint) 32);
    return str;
  }
  null_value=1;
  return 0;
}


void Item_func_md5::fix_length_and_dec()
{
  max_length=32;
  /*
    The MD5() function treats its parameter as being a case sensitive. Thus
    we set binary collation on it so different instances of MD5() will be
    compared properly.
  */
  args[0]->collation.set(
      get_charset_by_csname(args[0]->collation.collation->csname,
                            MY_CS_BINSORT,MYF(0)), DERIVATION_COERCIBLE);
}


String *Item_func_sha::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  String * sptr= args[0]->val_str(str);
  str->set_charset(&my_charset_bin);
  if (sptr)  /* If we got value different from NULL */
  {
    SHA1_CONTEXT context;  /* Context used to generate SHA1 hash */
    /* Temporary buffer to store 160bit digest */
    uint8 digest[SHA1_HASH_SIZE];
    mysql_sha1_reset(&context);  /* We do not have to check for error here */
    /* No need to check error as the only case would be too long message */
    mysql_sha1_input(&context,
                     (const uchar *) sptr->ptr(), sptr->length());
    /* Ensure that memory is free and we got result */
    if (!( str->alloc(SHA1_HASH_SIZE*2) ||
           (mysql_sha1_result(&context,digest))))
    {
      array_to_hex((char *) str->ptr(), (const char*) digest, SHA1_HASH_SIZE);
      str->length((uint)  SHA1_HASH_SIZE*2);
      null_value=0;
      return str;
    }
  }
  null_value=1;
  return 0;
}

void Item_func_sha::fix_length_and_dec()
{
  max_length=SHA1_HASH_SIZE*2; // size of hex representation of hash
  /*
    The SHA() function treats its parameter as being a case sensitive. Thus
    we set binary collation on it so different instances of MD5() will be
    compared properly.
  */
  args[0]->collation.set(
      get_charset_by_csname(args[0]->collation.collation->csname,
                            MY_CS_BINSORT,MYF(0)), DERIVATION_COERCIBLE);
}


/* Implementation of AES encryption routines */

String *Item_func_aes_encrypt::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  char key_buff[80];
  String tmp_key_value(key_buff, sizeof(key_buff), system_charset_info);
  String *sptr= args[0]->val_str(str);			// String to encrypt
  String *key=  args[1]->val_str(&tmp_key_value);	// key
  int aes_length;
  if (sptr && key) // we need both arguments to be not NULL
  {
    null_value=0;
    aes_length=my_aes_get_size(sptr->length()); // Calculate result length

    if (!str_value.alloc(aes_length))		// Ensure that memory is free
    {
      // finally encrypt directly to allocated buffer.
      if (my_aes_encrypt(sptr->ptr(),sptr->length(), (char*) str_value.ptr(),
			 key->ptr(), key->length()) == aes_length)
      {
	// We got the expected result length
	str_value.length((uint) aes_length);
	return &str_value;
      }
    }
  }
  null_value=1;
  return 0;
}


void Item_func_aes_encrypt::fix_length_and_dec()
{
  max_length=my_aes_get_size(args[0]->max_length);
}


String *Item_func_aes_decrypt::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  char key_buff[80];
  String tmp_key_value(key_buff, sizeof(key_buff), system_charset_info);
  String *sptr, *key;
  DBUG_ENTER("Item_func_aes_decrypt::val_str");

  sptr= args[0]->val_str(str);			// String to decrypt
  key=  args[1]->val_str(&tmp_key_value);	// Key
  if (sptr && key)  			// Need to have both arguments not NULL
  {
    null_value=0;
    if (!str_value.alloc(sptr->length()))  // Ensure that memory is free
    {
      // finally decrypt directly to allocated buffer.
      int length;
      length=my_aes_decrypt(sptr->ptr(), sptr->length(),
			    (char*) str_value.ptr(),
                            key->ptr(), key->length());
      if (length >= 0)  // if we got correct data data
      {
        str_value.length((uint) length);
        DBUG_RETURN(&str_value);
      }
    }
  }
  // Bad parameters. No memory or bad data will all go here
  null_value=1;
  DBUG_RETURN(0);
}


void Item_func_aes_decrypt::fix_length_and_dec()
{
   max_length=args[0]->max_length;
   maybe_null= 1;
}


/**
  Concatenate args with the following premises:
  If only one arg (which is ok), return value of arg;
  Don't reallocate val_str() if not absolute necessary.
*/

String *Item_func_concat::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  String *res,*res2,*use_as_buff;
  uint i;
  bool is_const= 0;

  null_value=0;
  if (!(res=args[0]->val_str(str)))
    goto null;
  use_as_buff= &tmp_value;
  /* Item_subselect in --ps-protocol mode will state it as a non-const */
  is_const= args[0]->const_item() || !args[0]->used_tables();
  for (i=1 ; i < arg_count ; i++)
  {
    if (res->length() == 0)
    {
      if (!(res=args[i]->val_str(str)))
	goto null;
      /*
       CONCAT accumulates its result in the result of its the first
       non-empty argument. Because of this we need is_const to be 
       evaluated only for it.
      */
      is_const= args[i]->const_item() || !args[i]->used_tables();
    }
    else
    {
      if (!(res2=args[i]->val_str(use_as_buff)))
	goto null;
      if (res2->length() == 0)
	continue;
      if (res->length()+res2->length() >
	  current_thd->variables.max_allowed_packet)
      {
	push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
			    ER_WARN_ALLOWED_PACKET_OVERFLOWED,
			    ER(ER_WARN_ALLOWED_PACKET_OVERFLOWED), func_name(),
			    current_thd->variables.max_allowed_packet);
	goto null;
      }
      if (!is_const && res->alloced_length() >= res->length()+res2->length())
      {						// Use old buffer
	res->append(*res2);
      }
      else if (str->alloced_length() >= res->length()+res2->length())
      {
	if (str->ptr() == res2->ptr())
	  str->replace(0,0,*res);
	else
	{
	  str->copy(*res);
	  str->append(*res2);
	}
        res= str;
        use_as_buff= &tmp_value;
      }
      else if (res == &tmp_value)
      {
	if (res->append(*res2))			// Must be a blob
	  goto null;
      }
      else if (res2 == &tmp_value)
      {						// This can happend only 1 time
	if (tmp_value.replace(0,0,*res))
	  goto null;
	res= &tmp_value;
	use_as_buff=str;			// Put next arg here
      }
      else if (tmp_value.is_alloced() && res2->ptr() >= tmp_value.ptr() &&
	       res2->ptr() <= tmp_value.ptr() + tmp_value.alloced_length())
      {
	/*
	  This happens really seldom:
	  In this case res2 is sub string of tmp_value.  We will
	  now work in place in tmp_value to set it to res | res2
	*/
	/* Chop the last characters in tmp_value that isn't in res2 */
	tmp_value.length((uint32) (res2->ptr() - tmp_value.ptr()) +
			 res2->length());
	/* Place res2 at start of tmp_value, remove chars before res2 */
	if (tmp_value.replace(0,(uint32) (res2->ptr() - tmp_value.ptr()),
			      *res))
	  goto null;
	res= &tmp_value;
	use_as_buff=str;			// Put next arg here
      }
      else
      {						// Two big const strings
        /*
          NOTE: We should be prudent in the initial allocation unit -- the
          size of the arguments is a function of data distribution, which
          can be any. Instead of overcommitting at the first row, we grow
          the allocated amount by the factor of 2. This ensures that no
          more than 25% of memory will be overcommitted on average.
        */

        uint concat_len= res->length() + res2->length();

        if (tmp_value.alloced_length() < concat_len)
        {
          if (tmp_value.alloced_length() == 0)
          {
            if (tmp_value.alloc(concat_len))
              goto null;
          }
          else
          {
            uint new_len = max(tmp_value.alloced_length() * 2, concat_len);

            if (tmp_value.realloc(new_len))
              goto null;
          }
        }

	if (tmp_value.copy(*res) || tmp_value.append(*res2))
	  goto null;

	res= &tmp_value;
	use_as_buff=str;
      }
      is_const= 0;
    }
  }
  res->set_charset(collation.collation);
  return res;

null:
  null_value=1;
  return 0;
}


void Item_func_concat::fix_length_and_dec()
{
  ulonglong max_result_length= 0;

  if (agg_arg_charsets(collation, args, arg_count, MY_COLL_ALLOW_CONV, 1))
    return;

  for (uint i=0 ; i < arg_count ; i++)
  {
    if (args[i]->collation.collation->mbmaxlen != collation.collation->mbmaxlen)
      max_result_length+= (args[i]->max_length /
                           args[i]->collation.collation->mbmaxlen) *
                           collation.collation->mbmaxlen;
    else
      max_result_length+= args[i]->max_length;
  }

  if (max_result_length >= MAX_BLOB_WIDTH)
  {
    max_result_length= MAX_BLOB_WIDTH;
    maybe_null= 1;
  }
  max_length= (ulong) max_result_length;
}

/**
  @details
  Function des_encrypt() by tonu@spam.ee & monty
  Works only if compiled with OpenSSL library support.
  @return
    A binary string where first character is CHAR(128 | key-number).
    If one uses a string key key_number is 127.
    Encryption result is longer than original by formula:
  @code new_length= org_length + (8-(org_length % 8))+1 @endcode
*/

String *Item_func_des_encrypt::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
#ifdef HAVE_OPENSSL
  uint code= ER_WRONG_PARAMETERS_TO_PROCEDURE;
  DES_cblock ivec;
  struct st_des_keyblock keyblock;
  struct st_des_keyschedule keyschedule;
  const char *append_str="********";
  uint key_number, res_length, tail;
  String *res= args[0]->val_str(str);

  if ((null_value= args[0]->null_value))
    return 0;                                   // ENCRYPT(NULL) == NULL
  if ((res_length=res->length()) == 0)
    return &my_empty_string;

  if (arg_count == 1)
  {
    /* Protect against someone doing FLUSH DES_KEY_FILE */
    VOID(pthread_mutex_lock(&LOCK_des_key_file));
    keyschedule= des_keyschedule[key_number=des_default_key];
    VOID(pthread_mutex_unlock(&LOCK_des_key_file));
  }
  else if (args[1]->result_type() == INT_RESULT)
  {
    key_number= (uint) args[1]->val_int();
    if (key_number > 9)
      goto error;
    VOID(pthread_mutex_lock(&LOCK_des_key_file));
    keyschedule= des_keyschedule[key_number];
    VOID(pthread_mutex_unlock(&LOCK_des_key_file));
  }
  else
  {
    String *keystr=args[1]->val_str(&tmp_value);
    if (!keystr)
      goto error;
    key_number=127;				// User key string

    /* We make good 24-byte (168 bit) key from given plaintext key with MD5 */
    bzero((char*) &ivec,sizeof(ivec));
    EVP_BytesToKey(EVP_des_ede3_cbc(),EVP_md5(),NULL,
		   (uchar*) keystr->ptr(), (int) keystr->length(),
		   1, (uchar*) &keyblock,ivec);
    DES_set_key_unchecked(&keyblock.key1,&keyschedule.ks1);
    DES_set_key_unchecked(&keyblock.key2,&keyschedule.ks2);
    DES_set_key_unchecked(&keyblock.key3,&keyschedule.ks3);
  }

  /*
     The problem: DES algorithm requires original data to be in 8-bytes
     chunks. Missing bytes get filled with '*'s and result of encryption
     can be up to 8 bytes longer than original string. When decrypted,
     we do not know the size of original string :(
     We add one byte with value 0x1..0x8 as the last byte of the padded
     string marking change of string length.
  */

  tail= 8 - (res_length % 8);                   // 1..8 marking extra length
  res_length+=tail;
  tmp_arg.realloc(res_length);
  tmp_arg.length(0);
  tmp_arg.append(res->ptr(), res->length());
  code= ER_OUT_OF_RESOURCES;
  if (tmp_arg.append(append_str, tail) || tmp_value.alloc(res_length+1))
    goto error;
  tmp_arg[res_length-1]=tail;                   // save extra length
  tmp_value.realloc(res_length+1);
  tmp_value.length(res_length+1);
  tmp_value[0]=(char) (128 | key_number);
  // Real encryption
  bzero((char*) &ivec,sizeof(ivec));
  DES_ede3_cbc_encrypt((const uchar*) (tmp_arg.ptr()),
		       (uchar*) (tmp_value.ptr()+1),
		       res_length,
		       &keyschedule.ks1,
		       &keyschedule.ks2,
		       &keyschedule.ks3,
		       &ivec, TRUE);
  return &tmp_value;

error:
  push_warning_printf(current_thd,MYSQL_ERROR::WARN_LEVEL_ERROR,
                          code, ER(code),
                          "des_encrypt");
#else
  push_warning_printf(current_thd,MYSQL_ERROR::WARN_LEVEL_ERROR,
                      ER_FEATURE_DISABLED, ER(ER_FEATURE_DISABLED),
                      "des_encrypt","--with-openssl");
#endif	/* HAVE_OPENSSL */
  null_value=1;
  return 0;
}


String *Item_func_des_decrypt::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
#ifdef HAVE_OPENSSL
  uint code= ER_WRONG_PARAMETERS_TO_PROCEDURE;
  DES_cblock ivec;
  struct st_des_keyblock keyblock;
  struct st_des_keyschedule keyschedule;
  String *res= args[0]->val_str(str);
  uint length,tail;

  if ((null_value= args[0]->null_value))
    return 0;
  length= res->length();
  if (length < 9 || (length % 8) != 1 || !((*res)[0] & 128))
    return res;				// Skip decryption if not encrypted

  if (arg_count == 1)			// If automatic uncompression
  {
    uint key_number=(uint) (*res)[0] & 127;
    // Check if automatic key and that we have privilege to uncompress using it
    if (!(current_thd->security_ctx->master_access & SUPER_ACL) ||
        key_number > 9)
      goto error;

    VOID(pthread_mutex_lock(&LOCK_des_key_file));
    keyschedule= des_keyschedule[key_number];
    VOID(pthread_mutex_unlock(&LOCK_des_key_file));
  }
  else
  {
    // We make good 24-byte (168 bit) key from given plaintext key with MD5
    String *keystr=args[1]->val_str(&tmp_value);
    if (!keystr)
      goto error;

    bzero((char*) &ivec,sizeof(ivec));
    EVP_BytesToKey(EVP_des_ede3_cbc(),EVP_md5(),NULL,
		   (uchar*) keystr->ptr(),(int) keystr->length(),
		   1,(uchar*) &keyblock,ivec);
    // Here we set all 64-bit keys (56 effective) one by one
    DES_set_key_unchecked(&keyblock.key1,&keyschedule.ks1);
    DES_set_key_unchecked(&keyblock.key2,&keyschedule.ks2);
    DES_set_key_unchecked(&keyblock.key3,&keyschedule.ks3);
  }
  code= ER_OUT_OF_RESOURCES;
  if (tmp_value.alloc(length-1))
    goto error;

  bzero((char*) &ivec,sizeof(ivec));
  DES_ede3_cbc_encrypt((const uchar*) res->ptr()+1,
		       (uchar*) (tmp_value.ptr()),
		       length-1,
		       &keyschedule.ks1,
		       &keyschedule.ks2,
		       &keyschedule.ks3,
		       &ivec, FALSE);
  /* Restore old length of key */
  if ((tail=(uint) (uchar) tmp_value[length-2]) > 8)
    goto wrong_key;				     // Wrong key
  tmp_value.length(length-1-tail);
  return &tmp_value;

error:
  push_warning_printf(current_thd,MYSQL_ERROR::WARN_LEVEL_ERROR,
                          code, ER(code),
                          "des_decrypt");
wrong_key:
#else
  push_warning_printf(current_thd,MYSQL_ERROR::WARN_LEVEL_ERROR,
                      ER_FEATURE_DISABLED, ER(ER_FEATURE_DISABLED),
                      "des_decrypt","--with-openssl");
#endif	/* HAVE_OPENSSL */
  null_value=1;
  return 0;
}


/**
  concat with separator. First arg is the separator
  concat_ws takes at least two arguments.
*/

String *Item_func_concat_ws::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  char tmp_str_buff[10];
  String tmp_sep_str(tmp_str_buff, sizeof(tmp_str_buff),default_charset_info),
         *sep_str, *res, *res2,*use_as_buff;
  uint i;
  bool is_const= 0;

  null_value=0;
  if (!(sep_str= args[0]->val_str(&tmp_sep_str)))
    goto null;

  use_as_buff= &tmp_value;
  str->length(0);				// QQ; Should be removed
  res=str;

  // Skip until non-null argument is found.
  // If not, return the empty string
  for (i=1; i < arg_count; i++)
    if ((res= args[i]->val_str(str)))
    {
      is_const= args[i]->const_item() || !args[i]->used_tables();
      break;
    }

  if (i ==  arg_count)
    return &my_empty_string;

  for (i++; i < arg_count ; i++)
  {
    if (!(res2= args[i]->val_str(use_as_buff)))
      continue;					// Skip NULL

    if (res->length() + sep_str->length() + res2->length() >
	current_thd->variables.max_allowed_packet)
    {
      push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
			  ER_WARN_ALLOWED_PACKET_OVERFLOWED,
			  ER(ER_WARN_ALLOWED_PACKET_OVERFLOWED), func_name(),
			  current_thd->variables.max_allowed_packet);
      goto null;
    }
    if (!is_const && res->alloced_length() >=
	res->length() + sep_str->length() + res2->length())
    {						// Use old buffer
      res->append(*sep_str);			// res->length() > 0 always
      res->append(*res2);
    }
    else if (str->alloced_length() >=
	     res->length() + sep_str->length() + res2->length())
    {
      /* We have room in str;  We can't get any errors here */
      if (str->ptr() == res2->ptr())
      {						// This is quite uncommon!
	str->replace(0,0,*sep_str);
	str->replace(0,0,*res);
      }
      else
      {
	str->copy(*res);
	str->append(*sep_str);
	str->append(*res2);
      }
      res=str;
      use_as_buff= &tmp_value;
    }
    else if (res == &tmp_value)
    {
      if (res->append(*sep_str) || res->append(*res2))
	goto null; // Must be a blob
    }
    else if (res2 == &tmp_value)
    {						// This can happend only 1 time
      if (tmp_value.replace(0,0,*sep_str) || tmp_value.replace(0,0,*res))
	goto null;
      res= &tmp_value;
      use_as_buff=str;				// Put next arg here
    }
    else if (tmp_value.is_alloced() && res2->ptr() >= tmp_value.ptr() &&
	     res2->ptr() < tmp_value.ptr() + tmp_value.alloced_length())
    {
      /*
	This happens really seldom:
	In this case res2 is sub string of tmp_value.  We will
	now work in place in tmp_value to set it to res | sep_str | res2
      */
      /* Chop the last characters in tmp_value that isn't in res2 */
      tmp_value.length((uint32) (res2->ptr() - tmp_value.ptr()) +
		       res2->length());
      /* Place res2 at start of tmp_value, remove chars before res2 */
      if (tmp_value.replace(0,(uint32) (res2->ptr() - tmp_value.ptr()),
			    *res) ||
	  tmp_value.replace(res->length(),0, *sep_str))
	goto null;
      res= &tmp_value;
      use_as_buff=str;			// Put next arg here
    }
    else
    {						// Two big const strings
      /*
        NOTE: We should be prudent in the initial allocation unit -- the
        size of the arguments is a function of data distribution, which can
        be any. Instead of overcommitting at the first row, we grow the
        allocated amount by the factor of 2. This ensures that no more than
        25% of memory will be overcommitted on average.
      */

      uint concat_len= res->length() + sep_str->length() + res2->length();

      if (tmp_value.alloced_length() < concat_len)
      {
        if (tmp_value.alloced_length() == 0)
        {
          if (tmp_value.alloc(concat_len))
            goto null;
        }
        else
        {
          uint new_len = max(tmp_value.alloced_length() * 2, concat_len);

          if (tmp_value.realloc(new_len))
            goto null;
        }
      }

      if (tmp_value.copy(*res) ||
	  tmp_value.append(*sep_str) ||
	  tmp_value.append(*res2))
	goto null;
      res= &tmp_value;
      use_as_buff=str;
    }
  }
  res->set_charset(collation.collation);
  return res;

null:
  null_value=1;
  return 0;
}


void Item_func_concat_ws::fix_length_and_dec()
{
  ulonglong max_result_length;

  if (agg_arg_charsets(collation, args, arg_count, MY_COLL_ALLOW_CONV, 1))
    return;

  /*
     arg_count cannot be less than 2,
     it is done on parser level in sql_yacc.yy
     so, (arg_count - 2) is safe here.
  */
  max_result_length= (ulonglong) args[0]->max_length * (arg_count - 2);
  for (uint i=1 ; i < arg_count ; i++)
    max_result_length+=args[i]->max_length;

  if (max_result_length >= MAX_BLOB_WIDTH)
  {
    max_result_length= MAX_BLOB_WIDTH;
    maybe_null= 1;
  }
  max_length= (ulong) max_result_length;
}


String *Item_func_reverse::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  String *res = args[0]->val_str(str);
  char *ptr, *end, *tmp;

  if ((null_value=args[0]->null_value))
    return 0;
  /* An empty string is a special case as the string pointer may be null */
  if (!res->length())
    return &my_empty_string;
  if (tmp_value.alloced_length() < res->length() &&
      tmp_value.realloc(res->length()))
  {
    null_value= 1;
    return 0;
  }
  tmp_value.length(res->length());
  tmp_value.set_charset(res->charset());
  ptr= (char *) res->ptr();
  end= ptr + res->length();
  tmp= (char *) tmp_value.ptr() + tmp_value.length();
#ifdef USE_MB
  if (use_mb(res->charset()))
  {
    register uint32 l;
    while (ptr < end)
    {
      if ((l= my_ismbchar(res->charset(),ptr,end)))
      {
        tmp-= l;
        memcpy(tmp,ptr,l);
        ptr+= l;
      }
      else
        *--tmp= *ptr++;
    }
  }
  else
#endif /* USE_MB */
  {
    while (ptr < end)
      *--tmp= *ptr++;
  }
  return &tmp_value;
}


void Item_func_reverse::fix_length_and_dec()
{
  collation.set(args[0]->collation);
  max_length = args[0]->max_length;
}

/**
  Replace all occurences of string2 in string1 with string3.

  Don't reallocate val_str() if not needed.

  @todo
    Fix that this works with binary strings when using USE_MB 
*/

String *Item_func_replace::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  String *res,*res2,*res3;
  int offset;
  uint from_length,to_length;
  bool alloced=0;
#ifdef USE_MB
  const char *ptr,*end,*strend,*search,*search_end;
  register uint32 l;
  bool binary_cmp;
#endif

  null_value=0;
  res=args[0]->val_str(str);
  if (args[0]->null_value)
    goto null;
  res2=args[1]->val_str(&tmp_value);
  if (args[1]->null_value)
    goto null;

  res->set_charset(collation.collation);

#ifdef USE_MB
  binary_cmp = ((res->charset()->state & MY_CS_BINSORT) || !use_mb(res->charset()));
#endif

  if (res2->length() == 0)
    return res;
#ifndef USE_MB
  if ((offset=res->strstr(*res2)) < 0)
    return res;
#else
  offset=0;
  if (binary_cmp && (offset=res->strstr(*res2)) < 0)
    return res;
#endif
  if (!(res3=args[2]->val_str(&tmp_value2)))
    goto null;
  from_length= res2->length();
  to_length=   res3->length();

#ifdef USE_MB
  if (!binary_cmp)
  {
    search=res2->ptr();
    search_end=search+from_length;
redo:
    ptr=res->ptr()+offset;
    strend=res->ptr()+res->length();
    end=strend-from_length+1;
    while (ptr < end)
    {
        if (*ptr == *search)
        {
          register char *i,*j;
          i=(char*) ptr+1; j=(char*) search+1;
          while (j != search_end)
            if (*i++ != *j++) goto skip;
          offset= (int) (ptr-res->ptr());
          if (res->length()-from_length + to_length >
	      current_thd->variables.max_allowed_packet)
	  {
	    push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
				ER_WARN_ALLOWED_PACKET_OVERFLOWED,
				ER(ER_WARN_ALLOWED_PACKET_OVERFLOWED),
				func_name(),
				current_thd->variables.max_allowed_packet);

            goto null;
	  }
          if (!alloced)
          {
            alloced=1;
            res=copy_if_not_alloced(str,res,res->length()+to_length);
          }
          res->replace((uint) offset,from_length,*res3);
	  offset+=(int) to_length;
          goto redo;
        }
skip:
        if ((l=my_ismbchar(res->charset(), ptr,strend))) ptr+=l;
        else ++ptr;
    }
  }
  else
#endif /* USE_MB */
    do
    {
      if (res->length()-from_length + to_length >
	  current_thd->variables.max_allowed_packet)
      {
	push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
			    ER_WARN_ALLOWED_PACKET_OVERFLOWED,
			    ER(ER_WARN_ALLOWED_PACKET_OVERFLOWED), func_name(),
			    current_thd->variables.max_allowed_packet);
        goto null;
      }
      if (!alloced)
      {
        alloced=1;
        res=copy_if_not_alloced(str,res,res->length()+to_length);
      }
      res->replace((uint) offset,from_length,*res3);
      offset+=(int) to_length;
    }
    while ((offset=res->strstr(*res2,(uint) offset)) >= 0);
  return res;

null:
  null_value=1;
  return 0;
}


void Item_func_replace::fix_length_and_dec()
{
  ulonglong max_result_length= args[0]->max_length;
  int diff=(int) (args[2]->max_length - args[1]->max_length);
  if (diff > 0 && args[1]->max_length)
  {						// Calculate of maxreplaces
    ulonglong max_substrs= max_result_length/args[1]->max_length;
    max_result_length+= max_substrs * (uint) diff;
  }
  if (max_result_length >= MAX_BLOB_WIDTH)
  {
    max_result_length= MAX_BLOB_WIDTH;
    maybe_null= 1;
  }
  max_length= (ulong) max_result_length;
  
  if (agg_arg_charsets(collation, args, 3, MY_COLL_CMP_CONV, 1))
    return;
}


String *Item_func_insert::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  String *res,*res2;
  longlong start, length;  /* must be longlong to avoid truncation */

  null_value=0;
  res=args[0]->val_str(str);
  res2=args[3]->val_str(&tmp_value);
  start= args[1]->val_int() - 1;
  length= args[2]->val_int();

  if (args[0]->null_value || args[1]->null_value || args[2]->null_value ||
      args[3]->null_value)
    goto null; /* purecov: inspected */

  if ((start < 0) || (start > res->length()))
    return res;                                 // Wrong param; skip insert
  if ((length < 0) || (length > res->length()))
    length= res->length();

  /* start and length are now sufficiently valid to pass to charpos function */
   start= res->charpos((int) start);
   length= res->charpos((int) length, (uint32) start);

  /* Re-testing with corrected params */
  if (start > res->length())
    return res; /* purecov: inspected */        // Wrong param; skip insert
  if (length > res->length() - start)
    length= res->length() - start;

  if ((ulonglong) (res->length() - length + res2->length()) >
      (ulonglong) current_thd->variables.max_allowed_packet)
  {
    push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
			ER_WARN_ALLOWED_PACKET_OVERFLOWED,
			ER(ER_WARN_ALLOWED_PACKET_OVERFLOWED),
			func_name(), current_thd->variables.max_allowed_packet);
    goto null;
  }
  res=copy_if_not_alloced(str,res,res->length());
  res->replace((uint32) start,(uint32) length,*res2);
  return res;
null:
  null_value=1;
  return 0;
}


void Item_func_insert::fix_length_and_dec()
{
  ulonglong max_result_length;

  // Handle character set for args[0] and args[3].
  if (agg_arg_charsets(collation, &args[0], 2, MY_COLL_ALLOW_CONV, 3))
    return;
  max_result_length= ((ulonglong) args[0]->max_length+
                      (ulonglong) args[3]->max_length);
  if (max_result_length >= MAX_BLOB_WIDTH)
  {
    max_result_length= MAX_BLOB_WIDTH;
    maybe_null= 1;
  }
  max_length= (ulong) max_result_length;
}


String *Item_str_conv::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  String *res;
  if (!(res=args[0]->val_str(str)))
  {
    null_value=1; /* purecov: inspected */
    return 0; /* purecov: inspected */
  }
  null_value=0;
  if (multiply == 1)
  {
    uint len;
    res= copy_if_not_alloced(str,res,res->length());
    len= converter(collation.collation, (char*) res->ptr(), res->length(),
                                        (char*) res->ptr(), res->length());
    DBUG_ASSERT(len <= res->length());
    res->length(len);
  }
  else
  {
    uint len= res->length() * multiply;
    tmp_value.alloc(len);
    tmp_value.set_charset(collation.collation);
    len= converter(collation.collation, (char*) res->ptr(), res->length(),
                                        (char*) tmp_value.ptr(), len);
    tmp_value.length(len);
    res= &tmp_value;
  }
  return res;
}


void Item_func_lcase::fix_length_and_dec()
{
  collation.set(args[0]->collation);
  multiply= collation.collation->casedn_multiply;
  converter= collation.collation->cset->casedn;
  max_length= args[0]->max_length * multiply;
}

void Item_func_ucase::fix_length_and_dec()
{
  collation.set(args[0]->collation);
  multiply= collation.collation->caseup_multiply;
  converter= collation.collation->cset->caseup;
  max_length= args[0]->max_length * multiply;
}


String *Item_func_left::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  String *res= args[0]->val_str(str);

  /* must be longlong to avoid truncation */
  longlong length= args[1]->val_int();
  uint char_pos;

  if ((null_value=(args[0]->null_value || args[1]->null_value)))
    return 0;

  /* if "unsigned_flag" is set, we have a *huge* positive number. */
  if ((length <= 0) && (!args[1]->unsigned_flag))
    return &my_empty_string;

  if ((res->length() <= (ulonglong) length) ||
      (res->length() <= (char_pos= res->charpos((int) length))))
    return res;

  tmp_value.set(*res, 0, char_pos);
  return &tmp_value;
}


void Item_str_func::left_right_max_length()
{
  max_length=args[0]->max_length;
  if (args[1]->const_item())
  {
    int length=(int) args[1]->val_int()*collation.collation->mbmaxlen;
    if (length <= 0)
      max_length=0;
    else
      set_if_smaller(max_length,(uint) length);
  }
}


void Item_func_left::fix_length_and_dec()
{
  collation.set(args[0]->collation);
  left_right_max_length();
}


String *Item_func_right::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  String *res= args[0]->val_str(str);
  /* must be longlong to avoid truncation */
  longlong length= args[1]->val_int();

  if ((null_value=(args[0]->null_value || args[1]->null_value)))
    return 0; /* purecov: inspected */

  /* if "unsigned_flag" is set, we have a *huge* positive number. */
  if ((length <= 0) && (!args[1]->unsigned_flag))
    return &my_empty_string; /* purecov: inspected */

  if (res->length() <= (ulonglong) length)
    return res; /* purecov: inspected */

  uint start=res->numchars();
  if (start <= (uint) length)
    return res;
  start=res->charpos(start - (uint) length);
  tmp_value.set(*res,start,res->length()-start);
  return &tmp_value;
}


void Item_func_right::fix_length_and_dec()
{
  collation.set(args[0]->collation);
  left_right_max_length();
}


String *Item_func_substr::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  String *res  = args[0]->val_str(str);
  /* must be longlong to avoid truncation */
  longlong start= args[1]->val_int();
  /* Assumes that the maximum length of a String is < INT_MAX32. */
  /* Limit so that code sees out-of-bound value properly. */
  longlong length= arg_count == 3 ? args[2]->val_int() : INT_MAX32;
  longlong tmp_length;

  if ((null_value=(args[0]->null_value || args[1]->null_value ||
		   (arg_count == 3 && args[2]->null_value))))
    return 0; /* purecov: inspected */

  /* Negative or zero length, will return empty string. */
  if ((arg_count == 3) && (length <= 0) && 
      (length == 0 || !args[2]->unsigned_flag))
    return &my_empty_string;

  /* Assumes that the maximum length of a String is < INT_MAX32. */
  /* Set here so that rest of code sees out-of-bound value as such. */
  if ((length <= 0) || (length > INT_MAX32))
    length= INT_MAX32;

  /* if "unsigned_flag" is set, we have a *huge* positive number. */
  /* Assumes that the maximum length of a String is < INT_MAX32. */
  if ((!args[1]->unsigned_flag && (start < INT_MIN32 || start > INT_MAX32)) ||
      (args[1]->unsigned_flag && ((ulonglong) start > INT_MAX32)))
    return &my_empty_string;

  start= ((start < 0) ? res->numchars() + start : start - 1);
  start= res->charpos((int) start);
  if ((start < 0) || ((uint) start + 1 > res->length()))
    return &my_empty_string;

  length= res->charpos((int) length, (uint32) start);
  tmp_length= res->length() - start;
  length= min(length, tmp_length);

  if (!start && (longlong) res->length() == length)
    return res;
  tmp_value.set(*res, (uint32) start, (uint32) length);
  return &tmp_value;
}


void Item_func_substr::fix_length_and_dec()
{
  max_length=args[0]->max_length;

  collation.set(args[0]->collation);
  if (args[1]->const_item())
  {
    int32 start= (int32) args[1]->val_int();
    if (start < 0)
      max_length= ((uint)(-start) > max_length) ? 0 : (uint)(-start);
    else
      max_length-= min((uint)(start - 1), max_length);
  }
  if (arg_count == 3 && args[2]->const_item())
  {
    int32 length= (int32) args[2]->val_int();
    if (length <= 0)
      max_length=0; /* purecov: inspected */
    else
      set_if_smaller(max_length,(uint) length);
  }
  max_length*= collation.collation->mbmaxlen;
}


void Item_func_substr_index::fix_length_and_dec()
{ 
  max_length= args[0]->max_length;

  if (agg_arg_charsets(collation, args, 2, MY_COLL_CMP_CONV, 1))
    return;
}


String *Item_func_substr_index::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  String *res= args[0]->val_str(str);
  String *delimiter= args[1]->val_str(&tmp_value);
  int32 count= (int32) args[2]->val_int();
  uint offset;

  if (args[0]->null_value || args[1]->null_value || args[2]->null_value)
  {					// string and/or delim are null
    null_value=1;
    return 0;
  }
  null_value=0;
  uint delimiter_length= delimiter->length();
  if (!res->length() || !delimiter_length || !count)
    return &my_empty_string;		// Wrong parameters

  res->set_charset(collation.collation);

#ifdef USE_MB
  if (use_mb(res->charset()))
  {
    const char *ptr= res->ptr();
    const char *strend= ptr+res->length();
    const char *end= strend-delimiter_length+1;
    const char *search= delimiter->ptr();
    const char *search_end= search+delimiter_length;
    int32 n=0,c=count,pass;
    register uint32 l;
    for (pass=(count>0);pass<2;++pass)
    {
      while (ptr < end)
      {
        if (*ptr == *search)
        {
	  register char *i,*j;
	  i=(char*) ptr+1; j=(char*) search+1;
	  while (j != search_end)
	    if (*i++ != *j++) goto skip;
	  if (pass==0) ++n;
	  else if (!--c) break;
	  ptr+= delimiter_length;
	  continue;
	}
    skip:
        if ((l=my_ismbchar(res->charset(), ptr,strend))) ptr+=l;
        else ++ptr;
      } /* either not found or got total number when count<0 */
      if (pass == 0) /* count<0 */
      {
        c+=n+1;
        if (c<=0) return res; /* not found, return original string */
        ptr=res->ptr();
      }
      else
      {
        if (c) return res; /* Not found, return original string */
        if (count>0) /* return left part */
        {
	  tmp_value.set(*res,0,(ulong) (ptr-res->ptr()));
        }
        else /* return right part */
        {
	  ptr+= delimiter_length;
	  tmp_value.set(*res,(ulong) (ptr-res->ptr()), (ulong) (strend-ptr));
        }
      }
    }
  }
  else
#endif /* USE_MB */
  {
    if (count > 0)
    {					// start counting from the beginning
      for (offset=0; ; offset+= delimiter_length)
      {
	if ((int) (offset= res->strstr(*delimiter, offset)) < 0)
	  return res;			// Didn't find, return org string
	if (!--count)
	{
	  tmp_value.set(*res,0,offset);
	  break;
	}
      }
    }
    else
    {
      /*
        Negative index, start counting at the end
      */
      for (offset=res->length(); offset ;)
      {
        /* 
          this call will result in finding the position pointing to one 
          address space less than where the found substring is located
          in res
        */
	if ((int) (offset= res->strrstr(*delimiter, offset)) < 0)
	  return res;			// Didn't find, return org string
        /*
          At this point, we've searched for the substring
          the number of times as supplied by the index value
        */
	if (!++count)
	{
	  offset+= delimiter_length;
	  tmp_value.set(*res,offset,res->length()- offset);
	  break;
	}
      }
    }
  }
  /*
    We always mark tmp_value as const so that if val_str() is called again
    on this object, we don't disrupt the contents of tmp_value when it was
    derived from another String.
  */
  tmp_value.mark_as_const();
  return (&tmp_value);
}

/*
** The trim functions are extension to ANSI SQL because they trim substrings
** They ltrim() and rtrim() functions are optimized for 1 byte strings
** They also return the original string if possible, else they return
** a substring that points at the original string.
*/


String *Item_func_ltrim::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  char buff[MAX_FIELD_WIDTH], *ptr, *end;
  String tmp(buff,sizeof(buff),system_charset_info);
  String *res, *remove_str;
  uint remove_length;
  LINT_INIT(remove_length);

  res= args[0]->val_str(str);
  if ((null_value=args[0]->null_value))
    return 0;
  remove_str= &remove;                          /* Default value. */
  if (arg_count == 2)
  {
    remove_str= args[1]->val_str(&tmp);
    if ((null_value= args[1]->null_value))
      return 0;
  }

  if ((remove_length= remove_str->length()) == 0 ||
      remove_length > res->length())
    return res;

  ptr= (char*) res->ptr();
  end= ptr+res->length();
  if (remove_length == 1)
  {
    char chr=(*remove_str)[0];
    while (ptr != end && *ptr == chr)
      ptr++;
  }
  else
  {
    const char *r_ptr=remove_str->ptr();
    end-=remove_length;
    while (ptr <= end && !memcmp(ptr, r_ptr, remove_length))
      ptr+=remove_length;
    end+=remove_length;
  }
  if (ptr == res->ptr())
    return res;
  tmp_value.set(*res,(uint) (ptr - res->ptr()),(uint) (end-ptr));
  return &tmp_value;
}


String *Item_func_rtrim::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  char buff[MAX_FIELD_WIDTH], *ptr, *end;
  String tmp(buff, sizeof(buff), system_charset_info);
  String *res, *remove_str;
  uint remove_length;
  LINT_INIT(remove_length);

  res= args[0]->val_str(str);
  if ((null_value=args[0]->null_value))
    return 0;
  remove_str= &remove;                          /* Default value. */
  if (arg_count == 2)
  {
    remove_str= args[1]->val_str(&tmp);
    if ((null_value= args[1]->null_value))
      return 0;
  }

  if ((remove_length= remove_str->length()) == 0 ||
      remove_length > res->length())
    return res;

  ptr= (char*) res->ptr();
  end= ptr+res->length();
#ifdef USE_MB
  char *p=ptr;
  register uint32 l;
#endif
  if (remove_length == 1)
  {
    char chr=(*remove_str)[0];
#ifdef USE_MB
    if (use_mb(res->charset()))
    {
      while (ptr < end)
      {
	if ((l=my_ismbchar(res->charset(), ptr,end))) ptr+=l,p=ptr;
	else ++ptr;
      }
      ptr=p;
    }
#endif
    while (ptr != end  && end[-1] == chr)
      end--;
  }
  else
  {
    const char *r_ptr=remove_str->ptr();
#ifdef USE_MB
    if (use_mb(res->charset()))
    {
  loop:
      while (ptr + remove_length < end)
      {
	if ((l=my_ismbchar(res->charset(), ptr,end))) ptr+=l;
	else ++ptr;
      }
      if (ptr + remove_length == end && !memcmp(ptr,r_ptr,remove_length))
      {
	end-=remove_length;
	ptr=p;
	goto loop;
      }
    }
    else
#endif /* USE_MB */
    {
      while (ptr + remove_length <= end &&
	     !memcmp(end-remove_length, r_ptr, remove_length))
	end-=remove_length;
    }
  }
  if (end == res->ptr()+res->length())
    return res;
  tmp_value.set(*res,0,(uint) (end-res->ptr()));
  return &tmp_value;
}


String *Item_func_trim::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  char buff[MAX_FIELD_WIDTH], *ptr, *end;
  const char *r_ptr;
  String tmp(buff, sizeof(buff), system_charset_info);
  String *res, *remove_str;
  uint remove_length;
  LINT_INIT(remove_length);

  res= args[0]->val_str(str);
  if ((null_value=args[0]->null_value))
    return 0;
  remove_str= &remove;                          /* Default value. */
  if (arg_count == 2)
  {
    remove_str= args[1]->val_str(&tmp);
    if ((null_value= args[1]->null_value))
      return 0;
  }

  if ((remove_length= remove_str->length()) == 0 ||
      remove_length > res->length())
    return res;

  ptr= (char*) res->ptr();
  end= ptr+res->length();
  r_ptr= remove_str->ptr();
  while (ptr+remove_length <= end && !memcmp(ptr,r_ptr,remove_length))
    ptr+=remove_length;
#ifdef USE_MB
  if (use_mb(res->charset()))
  {
    char *p=ptr;
    register uint32 l;
 loop:
    while (ptr + remove_length < end)
    {
      if ((l=my_ismbchar(res->charset(), ptr,end))) ptr+=l;
      else ++ptr;
    }
    if (ptr + remove_length == end && !memcmp(ptr,r_ptr,remove_length))
    {
      end-=remove_length;
      ptr=p;
      goto loop;
    }
    ptr=p;
  }
  else
#endif /* USE_MB */
  {
    while (ptr + remove_length <= end &&
	   !memcmp(end-remove_length,r_ptr,remove_length))
      end-=remove_length;
  }
  if (ptr == res->ptr() && end == ptr+res->length())
    return res;
  tmp_value.set(*res,(uint) (ptr - res->ptr()),(uint) (end-ptr));
  return &tmp_value;
}

void Item_func_trim::fix_length_and_dec()
{
  max_length= args[0]->max_length;
  if (arg_count == 1)
  {
    collation.set(args[0]->collation);
    remove.set_charset(collation.collation);
    remove.set_ascii(" ",1);
  }
  else
  {
    // Handle character set for args[1] and args[0].
    // Note that we pass args[1] as the first item, and args[0] as the second.
    if (agg_arg_charsets(collation, &args[1], 2, MY_COLL_CMP_CONV, -1))
      return;
  }
}

void Item_func_trim::print(String *str, enum_query_type query_type)
{
  if (arg_count == 1)
  {
    Item_func::print(str, query_type);
    return;
  }
  str->append(Item_func_trim::func_name());
  str->append('(');
  str->append(mode_name());
  str->append(' ');
  args[1]->print(str, query_type);
  str->append(STRING_WITH_LEN(" from "));
  args[0]->print(str, query_type);
  str->append(')');
}


/* Item_func_password */

String *Item_func_password::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  String *res= args[0]->val_str(str); 
  if ((null_value=args[0]->null_value))
    return 0;
  if (res->length() == 0)
    return &my_empty_string;
  my_make_scrambled_password(tmp_value, res->ptr(), res->length());
  str->set(tmp_value, SCRAMBLED_PASSWORD_CHAR_LENGTH, res->charset());
  return str;
}

char *Item_func_password::alloc(THD *thd, const char *password,
                                size_t pass_len)
{
  char *buff= (char *) thd->alloc(SCRAMBLED_PASSWORD_CHAR_LENGTH+1);
  if (buff)
    my_make_scrambled_password(buff, password, pass_len);
  return buff;
}

/* Item_func_old_password */

String *Item_func_old_password::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  String *res= args[0]->val_str(str);
  if ((null_value=args[0]->null_value))
    return 0;
  if (res->length() == 0)
    return &my_empty_string;
  my_make_scrambled_password_323(tmp_value, res->ptr(), res->length());
  str->set(tmp_value, SCRAMBLED_PASSWORD_CHAR_LENGTH_323, res->charset());
  return str;
}

char *Item_func_old_password::alloc(THD *thd, const char *password,
                                    size_t pass_len)
{
  char *buff= (char *) thd->alloc(SCRAMBLED_PASSWORD_CHAR_LENGTH_323+1);
  if (buff)
    my_make_scrambled_password_323(buff, password, pass_len);
  return buff;
}


#define bin_to_ascii(c) ((c)>=38?((c)-38+'a'):(c)>=12?((c)-12+'A'):(c)+'.')

String *Item_func_encrypt::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  String *res  =args[0]->val_str(str);

#ifdef HAVE_CRYPT
  char salt[3],*salt_ptr;
  if ((null_value=args[0]->null_value))
    return 0;
  if (res->length() == 0)
    return &my_empty_string;

  if (arg_count == 1)
  {					// generate random salt
    time_t timestamp=current_thd->query_start();
    salt[0] = bin_to_ascii( (ulong) timestamp & 0x3f);
    salt[1] = bin_to_ascii(( (ulong) timestamp >> 5) & 0x3f);
    salt[2] = 0;
    salt_ptr=salt;
  }
  else
  {					// obtain salt from the first two bytes
    String *salt_str=args[1]->val_str(&tmp_value);
    if ((null_value= (args[1]->null_value || salt_str->length() < 2)))
      return 0;
    salt_ptr= salt_str->c_ptr_safe();
  }
  pthread_mutex_lock(&LOCK_crypt);
  char *tmp= crypt(res->c_ptr_safe(),salt_ptr);
  if (!tmp)
  {
    pthread_mutex_unlock(&LOCK_crypt);
    null_value= 1;
    return 0;
  }
  str->set(tmp, (uint) strlen(tmp), &my_charset_bin);
  str->copy();
  pthread_mutex_unlock(&LOCK_crypt);
  return str;
#else
  null_value=1;
  return 0;
#endif	/* HAVE_CRYPT */
}

bool Item_func_encode::seed()
{
  char buf[80];
  ulong rand_nr[2];
  String *key, tmp(buf, sizeof(buf), system_charset_info);

  if (!(key= args[1]->val_str(&tmp)))
    return TRUE;

  hash_password(rand_nr, key->ptr(), key->length());
  sql_crypt.init(rand_nr);

  return FALSE;
}

void Item_func_encode::fix_length_and_dec()
{
  max_length=args[0]->max_length;
  maybe_null=args[0]->maybe_null || args[1]->maybe_null;
  collation.set(&my_charset_bin);
  /* Precompute the seed state if the item is constant. */
  seeded= args[1]->const_item() &&
          (args[1]->result_type() == STRING_RESULT) && !seed();
}

String *Item_func_encode::val_str(String *str)
{
  String *res;
  DBUG_ASSERT(fixed == 1);

  if (!(res=args[0]->val_str(str)))
  {
    null_value= 1;
    return NULL;
  }

  if (!seeded && seed())
  {
    null_value= 1;
    return NULL;
  }

  null_value= 0;
  res= copy_if_not_alloced(str, res, res->length());
  crypto_transform(res);
  sql_crypt.reinit();

  return res;
}

void Item_func_encode::crypto_transform(String *res)
{
  sql_crypt.encode((char*) res->ptr(),res->length());
  res->set_charset(&my_charset_bin);
}

void Item_func_decode::crypto_transform(String *res)
{
  sql_crypt.decode((char*) res->ptr(),res->length());
}


Item *Item_func_sysconst::safe_charset_converter(CHARSET_INFO *tocs)
{
  Item_string *conv;
  uint conv_errors;
  String tmp, cstr, *ostr= val_str(&tmp);
  if (null_value)
  {
    Item *null_item= new Item_null((char *) fully_qualified_func_name());
    null_item->collation.set (tocs);
    return null_item;
  }
  cstr.copy(ostr->ptr(), ostr->length(), ostr->charset(), tocs, &conv_errors);
  if (conv_errors ||
      !(conv= new Item_static_string_func(fully_qualified_func_name(),
                                          cstr.ptr(), cstr.length(),
                                          cstr.charset(),
                                          collation.derivation)))
  {
    return NULL;
  }
  conv->str_value.copy();
  conv->str_value.mark_as_const();
  return conv;
}


String *Item_func_database::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  THD *thd= current_thd;
  if (thd->db == NULL)
  {
    null_value= 1;
    return 0;
  }
  else
    str->copy(thd->db, thd->db_length, system_charset_info);
  return str;
}


/**
  @note USER() is replicated correctly if binlog_format=ROW or (as of
  BUG#28086) binlog_format=MIXED, but is incorrectly replicated to ''
  if binlog_format=STATEMENT.
*/
bool Item_func_user::init(const char *user, const char *host)
{
  DBUG_ASSERT(fixed == 1);

  // For system threads (e.g. replication SQL thread) user may be empty
  if (user)
  {
    CHARSET_INFO *cs= str_value.charset();
    size_t res_length= (strlen(user)+strlen(host)+2) * cs->mbmaxlen;

    if (str_value.alloc((uint) res_length))
    {
      null_value=1;
      return TRUE;
    }

    res_length=cs->cset->snprintf(cs, (char*)str_value.ptr(), (uint) res_length,
                                  "%s@%s", user, host);
    str_value.length((uint) res_length);
    str_value.mark_as_const();
  }
  return FALSE;
}


bool Item_func_user::fix_fields(THD *thd, Item **ref)
{
  return (Item_func_sysconst::fix_fields(thd, ref) ||
          init(thd->main_security_ctx.user,
               thd->main_security_ctx.host_or_ip));
}


bool Item_func_current_user::fix_fields(THD *thd, Item **ref)
{
  if (Item_func_sysconst::fix_fields(thd, ref))
    return TRUE;

  Security_context *ctx=
#ifndef NO_EMBEDDED_ACCESS_CHECKS
                         (context->security_ctx
                          ? context->security_ctx : thd->security_ctx);
#else
                         thd->security_ctx;
#endif /*NO_EMBEDDED_ACCESS_CHECKS*/
  return init(ctx->priv_user, ctx->priv_host);
}


void Item_func_soundex::fix_length_and_dec()
{
  collation.set(args[0]->collation);
  max_length=args[0]->max_length;
  set_if_bigger(max_length, 4 * collation.collation->mbminlen);
  tmp_value.set_charset(collation.collation);
}


/**
  If alpha, map input letter to soundex code.
  If not alpha and remove_garbage is set then skip to next char
  else return 0
*/

static int soundex_toupper(int ch)
{
  return (ch >= 'a' && ch <= 'z') ? ch - 'a' + 'A' : ch;
}


static char get_scode(int wc)
{
  int ch= soundex_toupper(wc);
  if (ch < 'A' || ch > 'Z')
  {
					// Thread extended alfa (country spec)
    return '0';				// as vokal
  }
  return(soundex_map[ch-'A']);
}


static bool my_uni_isalpha(int wc)
{
  /*
    Return true for all Basic Latin letters: a..z A..Z.
    Return true for all Unicode characters with code higher than U+00C0:
    - characters between 'z' and U+00C0 are controls and punctuations.
    - "U+00C0 LATIN CAPITAL LETTER A WITH GRAVE" is the first letter after 'z'.
  */
  return (wc >= 'a' && wc <= 'z') ||
         (wc >= 'A' && wc <= 'Z') ||
         (wc >= 0xC0);
}


String *Item_func_soundex::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  String *res  =args[0]->val_str(str);
  char last_ch,ch;
  CHARSET_INFO *cs= collation.collation;
  my_wc_t wc;
  uint nchars;
  int rc;

  if ((null_value= args[0]->null_value))
    return 0; /* purecov: inspected */

  if (tmp_value.alloc(max(res->length(), 4 * cs->mbminlen)))
    return str; /* purecov: inspected */
  char *to= (char *) tmp_value.ptr();
  char *to_end= to + tmp_value.alloced_length();
  char *from= (char *) res->ptr(), *end= from + res->length();
  
  for ( ; ; ) /* Skip pre-space */
  {
    if ((rc= cs->cset->mb_wc(cs, &wc, (uchar*) from, (uchar*) end)) <= 0)
      return &my_empty_string; /* EOL or invalid byte sequence */
    
    if (rc == 1 && cs->ctype)
    {
      /* Single byte letter found */
      if (my_isalpha(cs, *from))
      {
        last_ch= get_scode(*from);       // Code of the first letter
        *to++= soundex_toupper(*from++); // Copy first letter
        break;
      }
      from++;
    }
    else
    {
      from+= rc;
      if (my_uni_isalpha(wc))
      {
        /* Multibyte letter found */
        wc= soundex_toupper(wc);
        last_ch= get_scode(wc);     // Code of the first letter
        if ((rc= cs->cset->wc_mb(cs, wc, (uchar*) to, (uchar*) to_end)) <= 0)
        {
          /* Extra safety - should not really happen */
          DBUG_ASSERT(false);
          return &my_empty_string;
        }
        to+= rc;
        break;
      }
    }
  }
  
  /*
     last_ch is now set to the first 'double-letter' check.
     loop on input letters until end of input
  */
  for (nchars= 1 ; ; )
  {
    if ((rc= cs->cset->mb_wc(cs, &wc, (uchar*) from, (uchar*) end)) <= 0)
      break; /* EOL or invalid byte sequence */

    if (rc == 1 && cs->ctype)
    {
      if (!my_isalpha(cs, *from++))
        continue;
    }
    else
    {
      from+= rc;
      if (!my_uni_isalpha(wc))
        continue;
    }
    
    ch= get_scode(wc);
    if ((ch != '0') && (ch != last_ch)) // if not skipped or double
    {
      // letter, copy to output
      if ((rc= cs->cset->wc_mb(cs, (my_wc_t) ch,
                               (uchar*) to, (uchar*) to_end)) <= 0)
      {
        // Extra safety - should not really happen
        DBUG_ASSERT(false);
        break;
      }
      to+= rc;
      nchars++;
      last_ch= ch;  // save code of last input letter
    }               // for next double-letter check
  }
  
  /* Pad up to 4 characters with DIGIT ZERO, if the string is shorter */
  if (nchars < 4) 
  {
    uint nbytes= (4 - nchars) * cs->mbminlen;
    cs->cset->fill(cs, to, nbytes, '0');
    to+= nbytes;
  }

  tmp_value.length((uint) (to-tmp_value.ptr()));
  return &tmp_value;
}


/**
  Change a number to format '3,333,333,333.000'.

  This should be 'internationalized' sometimes.
*/

const int FORMAT_MAX_DECIMALS= 30;

Item_func_format::Item_func_format(Item *org, Item *dec)
: Item_str_func(org, dec)
{
}

void Item_func_format::fix_length_and_dec()
{
  uint char_length= args[0]->max_length/args[0]->collation.collation->mbmaxlen;
  uint max_sep_count= char_length/3 + (decimals ? 1 : 0) + /*sign*/1;
  collation.set(default_charset());
  max_length= (char_length + max_sep_count + decimals) *
    collation.collation->mbmaxlen;
}


/**
  @todo
  This needs to be fixed for multi-byte character set where numbers
  are stored in more than one byte
*/

String *Item_func_format::val_str(String *str)
{
  uint32 length;
  uint32 str_length;
  /* Number of decimal digits */
  int dec;
  /* Number of characters used to represent the decimals, including '.' */
  uint32 dec_length;
  int diff;
  DBUG_ASSERT(fixed == 1);

  dec= (int) args[1]->val_int();
  if (args[1]->null_value)
  {
    null_value=1;
    return NULL;
  }

  dec= set_zone(dec, 0, FORMAT_MAX_DECIMALS);
  dec_length= dec ? dec+1 : 0;
  null_value=0;

  if (args[0]->result_type() == DECIMAL_RESULT ||
      args[0]->result_type() == INT_RESULT)
  {
    my_decimal dec_val, rnd_dec, *res;
    res= args[0]->val_decimal(&dec_val);
    if ((null_value=args[0]->null_value))
      return 0; /* purecov: inspected */
    my_decimal_round(E_DEC_FATAL_ERROR, res, dec, false, &rnd_dec);
    my_decimal2string(E_DEC_FATAL_ERROR, &rnd_dec, 0, 0, 0, str);
    str_length= str->length();
    if (rnd_dec.sign())
      str_length--;
  }
  else
  {
    double nr= args[0]->val_real();
    if ((null_value=args[0]->null_value))
      return 0; /* purecov: inspected */
    nr= my_double_round(nr, (longlong) dec, FALSE, FALSE);
    /* Here default_charset() is right as this is not an automatic conversion */
    str->set_real(nr, dec, default_charset());
    if (isnan(nr))
      return str;
    str_length=str->length();
    if (nr < 0)
      str_length--;				// Don't count sign
  }
  /* We need this test to handle 'nan' values */
  if (str_length >= dec_length+4)
  {
    char *tmp,*pos;
    length= str->length()+(diff=((int)(str_length- dec_length-1))/3);
    str= copy_if_not_alloced(&tmp_str,str,length);
    str->length(length);
    tmp= (char*) str->ptr()+length - dec_length-1;
    for (pos= (char*) str->ptr()+length-1; pos != tmp; pos--)
      pos[0]= pos[-diff];
    while (diff)
    {
      *pos= *(pos - diff);
      pos--;
      *pos= *(pos - diff);
      pos--;
      *pos= *(pos - diff);
      pos--;
      pos[0]=',';
      pos--;
      diff--;
    }
  }
  return str;
}


void Item_func_format::print(String *str, enum_query_type query_type)
{
  str->append(STRING_WITH_LEN("format("));
  args[0]->print(str, query_type);
  str->append(',');
  args[1]->print(str, query_type);
  str->append(')');
}

void Item_func_elt::fix_length_and_dec()
{
  max_length=0;
  decimals=0;

  if (agg_arg_charsets(collation, args+1, arg_count-1, MY_COLL_ALLOW_CONV, 1))
    return;

  for (uint i= 1 ; i < arg_count ; i++)
  {
    set_if_bigger(max_length,args[i]->max_length);
    set_if_bigger(decimals,args[i]->decimals);
  }
  maybe_null=1;					// NULL if wrong first arg
}


double Item_func_elt::val_real()
{
  DBUG_ASSERT(fixed == 1);
  uint tmp;
  null_value=1;
  if ((tmp=(uint) args[0]->val_int()) == 0 || tmp >= arg_count)
    return 0.0;
  double result= args[tmp]->val_real();
  null_value= args[tmp]->null_value;
  return result;
}


longlong Item_func_elt::val_int()
{
  DBUG_ASSERT(fixed == 1);
  uint tmp;
  null_value=1;
  if ((tmp=(uint) args[0]->val_int()) == 0 || tmp >= arg_count)
    return 0;

  longlong result= args[tmp]->val_int();
  null_value= args[tmp]->null_value;
  return result;
}


String *Item_func_elt::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  uint tmp;
  null_value=1;
  if ((tmp=(uint) args[0]->val_int()) == 0 || tmp >= arg_count)
    return NULL;

  String *result= args[tmp]->val_str(str);
  if (result)
    result->set_charset(collation.collation);
  null_value= args[tmp]->null_value;
  return result;
}


void Item_func_make_set::split_sum_func(THD *thd, Item **ref_pointer_array,
					List<Item> &fields)
{
  item->split_sum_func2(thd, ref_pointer_array, fields, &item, TRUE);
  Item_str_func::split_sum_func(thd, ref_pointer_array, fields);
}


void Item_func_make_set::fix_length_and_dec()
{
  max_length=arg_count-1;

  if (agg_arg_charsets(collation, args, arg_count, MY_COLL_ALLOW_CONV, 1))
    return;
  
  for (uint i=0 ; i < arg_count ; i++)
    max_length+=args[i]->max_length;

  used_tables_cache|=	  item->used_tables();
  not_null_tables_cache&= item->not_null_tables();
  const_item_cache&=	  item->const_item();
  with_sum_func= with_sum_func || item->with_sum_func;
}


void Item_func_make_set::update_used_tables()
{
  Item_func::update_used_tables();
  item->update_used_tables();
  used_tables_cache|=item->used_tables();
  const_item_cache&=item->const_item();
}


String *Item_func_make_set::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  ulonglong bits;
  bool first_found=0;
  Item **ptr=args;
  String *result=&my_empty_string;

  bits=item->val_int();
  if ((null_value=item->null_value))
    return NULL;

  if (arg_count < 64)
    bits &= ((ulonglong) 1 << arg_count)-1;

  for (; bits; bits >>= 1, ptr++)
  {
    if (bits & 1)
    {
      String *res= (*ptr)->val_str(str);
      if (res)					// Skip nulls
      {
	if (!first_found)
	{					// First argument
	  first_found=1;
	  if (res != str)
	    result=res;				// Use original string
	  else
	  {
	    if (tmp_str.copy(*res))		// Don't use 'str'
	      return &my_empty_string;
	    result= &tmp_str;
	  }
	}
	else
	{
	  if (result != &tmp_str)
	  {					// Copy data to tmp_str
	    if (tmp_str.alloc(result->length()+res->length()+1) ||
		tmp_str.copy(*result))
	      return &my_empty_string;
	    result= &tmp_str;
	  }
	  if (tmp_str.append(STRING_WITH_LEN(","), &my_charset_bin) || tmp_str.append(*res))
	    return &my_empty_string;
	}
      }
    }
  }
  return result;
}


Item *Item_func_make_set::transform(Item_transformer transformer, uchar *arg)
{
  DBUG_ASSERT(!current_thd->is_stmt_prepare());

  Item *new_item= item->transform(transformer, arg);
  if (!new_item)
    return 0;

  /*
    THD::change_item_tree() should be called only if the tree was
    really transformed, i.e. when a new item has been created.
    Otherwise we'll be allocating a lot of unnecessary memory for
    change records at each execution.
  */
  if (item != new_item)
    current_thd->change_item_tree(&item, new_item);
  return Item_str_func::transform(transformer, arg);
}


void Item_func_make_set::print(String *str, enum_query_type query_type)
{
  str->append(STRING_WITH_LEN("make_set("));
  item->print(str, query_type);
  if (arg_count)
  {
    str->append(',');
    print_args(str, 0, query_type);
  }
  str->append(')');
}


String *Item_func_char::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  str->length(0);
  str->set_charset(collation.collation);
  for (uint i=0 ; i < arg_count ; i++)
  {
    int32 num=(int32) args[i]->val_int();
    if (!args[i]->null_value)
    {
      char char_num= (char) num;
      if (num&0xFF000000L) {
        str->append((char)(num>>24));
        goto b2;
      } else if (num&0xFF0000L) {
    b2:        str->append((char)(num>>16));
        goto b1;
      } else if (num&0xFF00L) {
    b1:        str->append((char)(num>>8));
      }
      str->append(&char_num, 1);
    }
  }
  str->realloc(str->length());			// Add end 0 (for Purify)
  return check_well_formed_result(str);
}


inline String* alloc_buffer(String *res,String *str,String *tmp_value,
			    ulong length)
{
  if (res->alloced_length() < length)
  {
    if (str->alloced_length() >= length)
    {
      (void) str->copy(*res);
      str->length(length);
      return str;
    }
    if (tmp_value->alloc(length))
      return 0;
    (void) tmp_value->copy(*res);
    tmp_value->length(length);
    return tmp_value;
  }
  res->length(length);
  return res;
}


void Item_func_repeat::fix_length_and_dec()
{
  collation.set(args[0]->collation);
  if (args[1]->const_item())
  {
    /* must be longlong to avoid truncation */
    longlong count= args[1]->val_int();

    /* Assumes that the maximum length of a String is < INT_MAX32. */
    /* Set here so that rest of code sees out-of-bound value as such. */
    if (count > INT_MAX32)
      count= INT_MAX32;

    ulonglong max_result_length= (ulonglong) args[0]->max_length * count;
    if (max_result_length >= MAX_BLOB_WIDTH)
    {
      max_result_length= MAX_BLOB_WIDTH;
      maybe_null= 1;
    }
    max_length= (ulong) max_result_length;
  }
  else
  {
    max_length= MAX_BLOB_WIDTH;
    maybe_null= 1;
  }
}

/**
  Item_func_repeat::str is carefully written to avoid reallocs
  as much as possible at the cost of a local buffer
*/

String *Item_func_repeat::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  uint length,tot_length;
  char *to;
  /* must be longlong to avoid truncation */
  longlong count= args[1]->val_int();
  String *res= args[0]->val_str(str);

  if (args[0]->null_value || args[1]->null_value)
    goto err;				// string and/or delim are null
  null_value= 0;

  if (count <= 0 && (count == 0 || !args[1]->unsigned_flag))
    return &my_empty_string;

  /* Assumes that the maximum length of a String is < INT_MAX32. */
  /* Bounds check on count:  If this is triggered, we will error. */
  if ((ulonglong) count > INT_MAX32)
    count= INT_MAX32;
  if (count == 1)			// To avoid reallocs
    return res;
  length=res->length();
  // Safe length check
  if (length > current_thd->variables.max_allowed_packet / (uint) count)
  {
    push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
			ER_WARN_ALLOWED_PACKET_OVERFLOWED,
			ER(ER_WARN_ALLOWED_PACKET_OVERFLOWED),
			func_name(), current_thd->variables.max_allowed_packet);
    goto err;
  }
  tot_length= length*(uint) count;
  if (!(res= alloc_buffer(res,str,&tmp_value,tot_length)))
    goto err;

  to=(char*) res->ptr()+length;
  while (--count)
  {
    memcpy(to,res->ptr(),length);
    to+=length;
  }
  return (res);

err:
  null_value=1;
  return 0;
}


void Item_func_rpad::fix_length_and_dec()
{
  // Handle character set for args[0] and args[2].
  if (agg_arg_charsets(collation, &args[0], 2, MY_COLL_ALLOW_CONV, 2))
    return;
  if (args[1]->const_item())
  {
    ulonglong length= 0;

    if (collation.collation->mbmaxlen > 0)
    {
      ulonglong temp= (ulonglong) args[1]->val_int();

      /* Assumes that the maximum length of a String is < INT_MAX32. */
      /* Set here so that rest of code sees out-of-bound value as such. */
      if (temp > INT_MAX32)
	temp = INT_MAX32;

      length= temp * collation.collation->mbmaxlen;
    }

    if (length >= MAX_BLOB_WIDTH)
    {
      length= MAX_BLOB_WIDTH;
      maybe_null= 1;
    }
    max_length= (ulong) length;
  }
  else
  {
    max_length= MAX_BLOB_WIDTH;
    maybe_null= 1;
  }
}


String *Item_func_rpad::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  uint32 res_byte_length,res_char_length,pad_char_length,pad_byte_length;
  char *to;
  const char *ptr_pad;
  /* must be longlong to avoid truncation */
  longlong count= args[1]->val_int();
  longlong byte_count;
  String *res= args[0]->val_str(str);
  String *rpad= args[2]->val_str(&rpad_str);

  if (!res || args[1]->null_value || !rpad || 
      ((count < 0) && !args[1]->unsigned_flag))
    goto err;
  null_value=0;
  /* Assumes that the maximum length of a String is < INT_MAX32. */
  /* Set here so that rest of code sees out-of-bound value as such. */
  if ((ulonglong) count > INT_MAX32)
    count= INT_MAX32;
  if (count <= (res_char_length= res->numchars()))
  {						// String to pad is big enough
    res->length(res->charpos((int) count));	// Shorten result if longer
    return (res);
  }
  pad_char_length= rpad->numchars();

  byte_count= count * collation.collation->mbmaxlen;
  if ((ulonglong) byte_count > current_thd->variables.max_allowed_packet)
  {
    push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
			ER_WARN_ALLOWED_PACKET_OVERFLOWED,
			ER(ER_WARN_ALLOWED_PACKET_OVERFLOWED),
			func_name(), current_thd->variables.max_allowed_packet);
    goto err;
  }
  if (args[2]->null_value || !pad_char_length)
    goto err;
  res_byte_length= res->length();	/* Must be done before alloc_buffer */
  if (!(res= alloc_buffer(res,str,&tmp_value, (ulong) byte_count)))
    goto err;

  to= (char*) res->ptr()+res_byte_length;
  ptr_pad=rpad->ptr();
  pad_byte_length= rpad->length();
  count-= res_char_length;
  for ( ; (uint32) count > pad_char_length; count-= pad_char_length)
  {
    memcpy(to,ptr_pad,pad_byte_length);
    to+= pad_byte_length;
  }
  if (count)
  {
    pad_byte_length= rpad->charpos((int) count);
    memcpy(to,ptr_pad,(size_t) pad_byte_length);
    to+= pad_byte_length;
  }
  res->length((uint) (to- (char*) res->ptr()));
  return (res);

 err:
  null_value=1;
  return 0;
}


void Item_func_lpad::fix_length_and_dec()
{
  // Handle character set for args[0] and args[2].
  if (agg_arg_charsets(collation, &args[0], 2, MY_COLL_ALLOW_CONV, 2))
    return;
  
  if (args[1]->const_item())
  {
    ulonglong length= 0;

    if (collation.collation->mbmaxlen > 0)
    {
      ulonglong temp= (ulonglong) args[1]->val_int();

      /* Assumes that the maximum length of a String is < INT_MAX32. */
      /* Set here so that rest of code sees out-of-bound value as such. */
      if (temp > INT_MAX32)
        temp= INT_MAX32;

      length= temp * collation.collation->mbmaxlen;
    }

    if (length >= MAX_BLOB_WIDTH)
    {
      length= MAX_BLOB_WIDTH;
      maybe_null= 1;
    }
    max_length= (ulong) length;
  }
  else
  {
    max_length= MAX_BLOB_WIDTH;
    maybe_null= 1;
  }
}


String *Item_func_lpad::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  uint32 res_char_length,pad_char_length;
  /* must be longlong to avoid truncation */
  longlong count= args[1]->val_int();
  longlong byte_count;
  String *res= args[0]->val_str(&tmp_value);
  String *pad= args[2]->val_str(&lpad_str);

  if (!res || args[1]->null_value || !pad ||  
      ((count < 0) && !args[1]->unsigned_flag))
    goto err;  
  null_value=0;
  /* Assumes that the maximum length of a String is < INT_MAX32. */
  /* Set here so that rest of code sees out-of-bound value as such. */
  if ((ulonglong) count > INT_MAX32)
    count= INT_MAX32;

  res_char_length= res->numchars();

  if (count <= res_char_length)
  {
    res->length(res->charpos((int) count));
    return res;
  }
  
  pad_char_length= pad->numchars();
  byte_count= count * collation.collation->mbmaxlen;
  
  if ((ulonglong) byte_count > current_thd->variables.max_allowed_packet)
  {
    push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
			ER_WARN_ALLOWED_PACKET_OVERFLOWED,
			ER(ER_WARN_ALLOWED_PACKET_OVERFLOWED),
			func_name(), current_thd->variables.max_allowed_packet);
    goto err;
  }

  if (args[2]->null_value || !pad_char_length ||
      str->alloc((uint32) byte_count))
    goto err;
  
  str->length(0);
  str->set_charset(collation.collation);
  count-= res_char_length;
  while (count >= pad_char_length)
  {
    str->append(*pad);
    count-= pad_char_length;
  }
  if (count > 0)
    str->append(pad->ptr(), pad->charpos((int) count), collation.collation);

  str->append(*res);
  null_value= 0;
  return str;

err:
  null_value= 1;
  return 0;
}


String *Item_func_conv::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  String *res= args[0]->val_str(str);
  char *endptr,ans[65],*ptr;
  longlong dec;
  int from_base= (int) args[1]->val_int();
  int to_base= (int) args[2]->val_int();
  int err;

  if (args[0]->null_value || args[1]->null_value || args[2]->null_value ||
      abs(to_base) > 36 || abs(to_base) < 2 ||
      abs(from_base) > 36 || abs(from_base) < 2 || !(res->length()))
  {
    null_value= 1;
    return NULL;
  }
  null_value= 0;
  unsigned_flag= !(from_base < 0);

  if (args[0]->field_type() == MYSQL_TYPE_BIT) 
  {
    /* 
     Special case: The string representation of BIT doesn't resemble the
     decimal representation, so we shouldn't change it to string and then to
     decimal. 
    */
    dec= args[0]->val_int();
  }
  else
  {
    if (from_base < 0)
      dec= my_strntoll(res->charset(), res->ptr(), res->length(),
                       -from_base, &endptr, &err);
    else
      dec= (longlong) my_strntoull(res->charset(), res->ptr(), res->length(),
                                   from_base, &endptr, &err);
  }

  ptr= longlong2str(dec, ans, to_base);
  if (str->copy(ans, (uint32) (ptr-ans), default_charset()))
    return &my_empty_string;
  return str;
}


String *Item_func_conv_charset::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  if (use_cached_value)
    return null_value ? 0 : &str_value;
  /* 
    Here we don't pass 'str' as a parameter to args[0]->val_str()
    as 'str' may point to 'str_value' (e.g. see Item::save_in_field()),
    which we use below to convert string. 
    Use argument's 'str_value' instead.
  */
  String *arg= args[0]->val_str(&args[0]->str_value);
  uint dummy_errors;
  if (!arg)
  {
    null_value=1;
    return 0;
  }
  null_value= str_value.copy(arg->ptr(),arg->length(),arg->charset(),
                             conv_charset, &dummy_errors);
  return null_value ? 0 : check_well_formed_result(&str_value);
}

void Item_func_conv_charset::fix_length_and_dec()
{
  collation.set(conv_charset, DERIVATION_IMPLICIT);
  max_length = args[0]->max_length*conv_charset->mbmaxlen;
}

void Item_func_conv_charset::print(String *str, enum_query_type query_type)
{
  str->append(STRING_WITH_LEN("convert("));
  args[0]->print(str, query_type);
  str->append(STRING_WITH_LEN(" using "));
  str->append(conv_charset->csname);
  str->append(')');
}

String *Item_func_set_collation::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  str=args[0]->val_str(str);
  if ((null_value=args[0]->null_value))
    return 0;
  str->set_charset(collation.collation);
  return str;
}

void Item_func_set_collation::fix_length_and_dec()
{
  CHARSET_INFO *set_collation;
  const char *colname;
  String tmp, *str= args[1]->val_str(&tmp);
  colname= str->c_ptr();
  if (colname == binary_keyword)
    set_collation= get_charset_by_csname(args[0]->collation.collation->csname,
					 MY_CS_BINSORT,MYF(0));
  else
  {
    if (!(set_collation= get_charset_by_name(colname,MYF(0))))
    {
      my_error(ER_UNKNOWN_COLLATION, MYF(0), colname);
      return;
    }
  }

  if (!set_collation || 
      !my_charset_same(args[0]->collation.collation,set_collation))
  {
    my_error(ER_COLLATION_CHARSET_MISMATCH, MYF(0),
             colname, args[0]->collation.collation->csname);
    return;
  }
  collation.set(set_collation, DERIVATION_EXPLICIT,
                args[0]->collation.repertoire);
  max_length= args[0]->max_length;
}


bool Item_func_set_collation::eq(const Item *item, bool binary_cmp) const
{
  /* Assume we don't have rtti */
  if (this == item)
    return 1;
  if (item->type() != FUNC_ITEM)
    return 0;
  Item_func *item_func=(Item_func*) item;
  if (arg_count != item_func->arg_count ||
      functype() != item_func->functype())
    return 0;
  Item_func_set_collation *item_func_sc=(Item_func_set_collation*) item;
  if (collation.collation != item_func_sc->collation.collation)
    return 0;
  for (uint i=0; i < arg_count ; i++)
    if (!args[i]->eq(item_func_sc->args[i], binary_cmp))
      return 0;
  return 1;
}


void Item_func_set_collation::print(String *str, enum_query_type query_type)
{
  str->append('(');
  args[0]->print(str, query_type);
  str->append(STRING_WITH_LEN(" collate "));
  DBUG_ASSERT(args[1]->basic_const_item() &&
              args[1]->type() == Item::STRING_ITEM);
  args[1]->str_value.print(str);
  str->append(')');
}

String *Item_func_charset::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  uint dummy_errors;

  CHARSET_INFO *cs= args[0]->collation.collation; 
  null_value= 0;
  str->copy(cs->csname, (uint) strlen(cs->csname),
	    &my_charset_latin1, collation.collation, &dummy_errors);
  return str;
}

String *Item_func_collation::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  uint dummy_errors;
  CHARSET_INFO *cs= args[0]->collation.collation; 

  null_value= 0;
  str->copy(cs->name, (uint) strlen(cs->name),
	    &my_charset_latin1, collation.collation, &dummy_errors);
  return str;
}


String *Item_func_hex::val_str(String *str)
{
  String *res;
  DBUG_ASSERT(fixed == 1);
  if (args[0]->result_type() != STRING_RESULT)
  {
    ulonglong dec;
    char ans[65],*ptr;
    /* Return hex of unsigned longlong value */
    if (args[0]->result_type() == REAL_RESULT ||
        args[0]->result_type() == DECIMAL_RESULT)
    {
      double val= args[0]->val_real();
      if ((val <= (double) LONGLONG_MIN) || 
          (val >= (double) (ulonglong) ULONGLONG_MAX))
        dec=  ~(longlong) 0;
      else
        dec= (ulonglong) (val + (val > 0 ? 0.5 : -0.5));
    }
    else
      dec= (ulonglong) args[0]->val_int();

    if ((null_value= args[0]->null_value))
      return 0;
    ptr= longlong2str(dec,ans,16);
    if (str->copy(ans,(uint32) (ptr-ans),default_charset()))
      return &my_empty_string;			// End of memory
    return str;
  }

  /* Convert given string to a hex string, character by character */
  res= args[0]->val_str(str);
  if (!res || tmp_value.alloc(res->length()*2+1))
  {
    null_value=1;
    return 0;
  }
  null_value=0;
  tmp_value.length(res->length()*2);

  octet2hex((char*) tmp_value.ptr(), res->ptr(), res->length());
  return &tmp_value;
}

  /** Convert given hex string to a binary string. */

String *Item_func_unhex::val_str(String *str)
{
  const char *from, *end;
  char *to;
  String *res;
  uint length;
  DBUG_ASSERT(fixed == 1);

  res= args[0]->val_str(str);
  if (!res || tmp_value.alloc(length= (1+res->length())/2))
  {
    null_value=1;
    return 0;
  }

  from= res->ptr();
  null_value= 0;
  tmp_value.length(length);
  to= (char*) tmp_value.ptr();
  if (res->length() % 2)
  {
    int hex_char;
    *to++= hex_char= hexchar_to_int(*from++);
    if ((null_value= (hex_char == -1)))
      return 0;
  }
  for (end=res->ptr()+res->length(); from < end ; from+=2, to++)
  {
    int hex_char;
    *to= (hex_char= hexchar_to_int(from[0])) << 4;
    if ((null_value= (hex_char == -1)))
      return 0;
    *to|= hex_char= hexchar_to_int(from[1]);
    if ((null_value= (hex_char == -1)))
      return 0;
  }
  return &tmp_value;
}


void Item_func_binary::print(String *str, enum_query_type query_type)
{
  str->append(STRING_WITH_LEN("cast("));
  args[0]->print(str, query_type);
  str->append(STRING_WITH_LEN(" as binary)"));
}


#include <my_dir.h>				// For my_stat

String *Item_load_file::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  String *file_name;
  File file;
  MY_STAT stat_info;
  char path[FN_REFLEN];
  DBUG_ENTER("load_file");

  if (!(file_name= args[0]->val_str(str))
#ifndef NO_EMBEDDED_ACCESS_CHECKS
      || !(current_thd->security_ctx->master_access & FILE_ACL)
#endif
      )
    goto err;

  (void) fn_format(path, file_name->c_ptr_safe(), mysql_real_data_home, "",
		   MY_RELATIVE_PATH | MY_UNPACK_FILENAME);

  /* Read only allowed from within dir specified by secure_file_priv */
  if (opt_secure_file_priv &&
      strncmp(opt_secure_file_priv, path, strlen(opt_secure_file_priv)))
    goto err;

  if (!my_stat(path, &stat_info, MYF(0)))
    goto err;

  if (!(stat_info.st_mode & S_IROTH))
  {
    /* my_error(ER_TEXTFILE_NOT_READABLE, MYF(0), file_name->c_ptr()); */
    goto err;
  }
  if (stat_info.st_size > (long) current_thd->variables.max_allowed_packet)
  {
    push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
			ER_WARN_ALLOWED_PACKET_OVERFLOWED,
			ER(ER_WARN_ALLOWED_PACKET_OVERFLOWED),
			func_name(), current_thd->variables.max_allowed_packet);
    goto err;
  }
  if (tmp_value.alloc(stat_info.st_size))
    goto err;
  if ((file = my_open(file_name->ptr(), O_RDONLY, MYF(0))) < 0)
    goto err;
  if (my_read(file, (uchar*) tmp_value.ptr(), stat_info.st_size, MYF(MY_NABP)))
  {
    my_close(file, MYF(0));
    goto err;
  }
  tmp_value.length(stat_info.st_size);
  my_close(file, MYF(0));
  null_value = 0;
  DBUG_RETURN(&tmp_value);

err:
  null_value = 1;
  DBUG_RETURN(0);
}


String* Item_func_export_set::val_str(String* str)
{
  DBUG_ASSERT(fixed == 1);
  ulonglong the_set = (ulonglong) args[0]->val_int();
  String yes_buf, *yes;
  yes = args[1]->val_str(&yes_buf);
  String no_buf, *no;
  no = args[2]->val_str(&no_buf);
  String *sep = NULL, sep_buf ;

  uint num_set_values = 64;
  ulonglong mask = 0x1;
  str->length(0);
  str->set_charset(collation.collation);

  /* Check if some argument is a NULL value */
  if (args[0]->null_value || args[1]->null_value || args[2]->null_value)
  {
    null_value=1;
    return 0;
  }
  /*
    Arg count can only be 3, 4 or 5 here. This is guaranteed from the
    grammar for EXPORT_SET()
  */
  switch(arg_count) {
  case 5:
    num_set_values = (uint) args[4]->val_int();
    if (num_set_values > 64)
      num_set_values=64;
    if (args[4]->null_value)
    {
      null_value=1;
      return 0;
    }
    /* Fall through */
  case 4:
    if (!(sep = args[3]->val_str(&sep_buf)))	// Only true if NULL
    {
      null_value=1;
      return 0;
    }
    break;
  case 3:
    {
      /* errors is not checked - assume "," can always be converted */
      uint errors;
      sep_buf.copy(STRING_WITH_LEN(","), &my_charset_bin, collation.collation, &errors);
      sep = &sep_buf;
    }
    break;
  default:
    DBUG_ASSERT(0); // cannot happen
  }
  null_value=0;

  for (uint i = 0; i < num_set_values; i++, mask = (mask << 1))
  {
    if (the_set & mask)
      str->append(*yes);
    else
      str->append(*no);
    if (i != num_set_values - 1)
      str->append(*sep);
  }
  return str;
}

void Item_func_export_set::fix_length_and_dec()
{
  uint length=max(args[1]->max_length,args[2]->max_length);
  uint sep_length=(arg_count > 3 ? args[3]->max_length : 1);
  max_length=length*64+sep_length*63;

  if (agg_arg_charsets(collation, args+1, min(4,arg_count)-1,
                       MY_COLL_ALLOW_CONV, 1))
    return;
}

String* Item_func_inet_ntoa::val_str(String* str)
{
  DBUG_ASSERT(fixed == 1);
  uchar buf[8], *p;
  ulonglong n = (ulonglong) args[0]->val_int();
  char num[4];

  /*
    We do not know if args[0] is NULL until we have called
    some val function on it if args[0] is not a constant!

    Also return null if n > 255.255.255.255
  */
  if ((null_value= (args[0]->null_value || n > (ulonglong) LL(4294967295))))
    return 0;					// Null value

  str->length(0);
  int4store(buf,n);

  /* Now we can assume little endian. */

  num[3]='.';
  for (p=buf+4 ; p-- > buf ; )
  {
    uint c = *p;
    uint n1,n2;					// Try to avoid divisions
    n1= c / 100;				// 100 digits
    c-= n1*100;
    n2= c / 10;					// 10 digits
    c-=n2*10;					// last digit
    num[0]=(char) n1+'0';
    num[1]=(char) n2+'0';
    num[2]=(char) c+'0';
    uint length=(n1 ? 4 : n2 ? 3 : 2);		// Remove pre-zero

    (void) str->append(num+4-length,length);
  }
  str->length(str->length()-1);			// Remove last '.';
  return str;
}


#define get_esc_bit(mask, num) (1 & (*((mask) + ((num) >> 3))) >> ((num) & 7))

/**
  QUOTE() function returns argument string in single quotes suitable for
  using in a SQL statement.

  Adds a \\ before all characters that needs to be escaped in a SQL string.
  We also escape '^Z' (END-OF-FILE in windows) to avoid probelms when
  running commands from a file in windows.

  This function is very useful when you want to generate SQL statements.

  @note
    QUOTE(NULL) returns the string 'NULL' (4 letters, without quotes).

  @retval
    str	   Quoted string
  @retval
    NULL	   Out of memory.
*/

String *Item_func_quote::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  /*
    Bit mask that has 1 for set for the position of the following characters:
    0, \, ' and ^Z
  */

  static uchar escmask[32]=
  {
    0x01, 0x00, 0x00, 0x04, 0x80, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x10, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
  };

  char *from, *to, *end, *start;
  String *arg= args[0]->val_str(str);
  uint arg_length, new_length;
  if (!arg)					// Null argument
  {
    /* Return the string 'NULL' */
    str->copy(STRING_WITH_LEN("NULL"), collation.collation);
    null_value= 0;
    return str;
  }

  arg_length= arg->length();
  new_length= arg_length+2; /* for beginning and ending ' signs */

  for (from= (char*) arg->ptr(), end= from + arg_length; from < end; from++)
    new_length+= get_esc_bit(escmask, (uchar) *from);

  if (tmp_value.alloc(new_length))
    goto null;

  /*
    We replace characters from the end to the beginning
  */
  to= (char*) tmp_value.ptr() + new_length - 1;
  *to--= '\'';
  for (start= (char*) arg->ptr(),end= start + arg_length; end-- != start; to--)
  {
    /*
      We can't use the bitmask here as we want to replace \O and ^Z with 0
      and Z
    */
    switch (*end)  {
    case 0:
      *to--= '0';
      *to=   '\\';
      break;
    case '\032':
      *to--= 'Z';
      *to=   '\\';
      break;
    case '\'':
    case '\\':
      *to--= *end;
      *to=   '\\';
      break;
    default:
      *to= *end;
      break;
    }
  }
  *to= '\'';
  tmp_value.length(new_length);
  tmp_value.set_charset(collation.collation);
  null_value= 0;
  return &tmp_value;

null:
  null_value= 1;
  return 0;
}

longlong Item_func_uncompressed_length::val_int()
{
  DBUG_ASSERT(fixed == 1);
  String *res= args[0]->val_str(&value);
  if (!res)
  {
    null_value=1;
    return 0; /* purecov: inspected */
  }
  null_value=0;
  if (res->is_empty()) return 0;

  /*
    If length is <= 4 bytes, data is corrupt. This is the best we can do
    to detect garbage input without decompressing it.
  */
  if (res->length() <= 4)
  {
    push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_ERROR,
                        ER_ZLIB_Z_DATA_ERROR,
                        ER(ER_ZLIB_Z_DATA_ERROR));
    null_value= 1;
    return 0;
  }

 /*
    res->ptr() using is safe because we have tested that string is at least
    5 bytes long.
    res->c_ptr() is not used because:
      - we do not need \0 terminated string to get first 4 bytes
      - c_ptr() tests simbol after string end (uninitialiozed memory) which
        confuse valgrind
  */
  return uint4korr(res->ptr()) & 0x3FFFFFFF;
}

longlong Item_func_crc32::val_int()
{
  DBUG_ASSERT(fixed == 1);
  String *res=args[0]->val_str(&value);
  if (!res)
  {
    null_value=1;
    return 0; /* purecov: inspected */
  }
  null_value=0;
  return (longlong) crc32(0L, (uchar*)res->ptr(), res->length());
}

#ifdef HAVE_COMPRESS
#include "zlib.h"

String *Item_func_compress::val_str(String *str)
{
  int err= Z_OK, code;
  ulong new_size;
  String *res;
  Byte *body;
  char *tmp, *last_char;
  DBUG_ASSERT(fixed == 1);

  if (!(res= args[0]->val_str(str)))
  {
    null_value= 1;
    return 0;
  }
  null_value= 0;
  if (res->is_empty()) return res;

  /*
    Citation from zlib.h (comment for compress function):

    Compresses the source buffer into the destination buffer.  sourceLen is
    the byte length of the source buffer. Upon entry, destLen is the total
    size of the destination buffer, which must be at least 0.1% larger than
    sourceLen plus 12 bytes.
    We assume here that the buffer can't grow more than .25 %.
  */
  new_size= res->length() + res->length() / 5 + 12;

  // Check new_size overflow: new_size <= res->length()
  if (((uint32) (new_size+5) <= res->length()) || 
      buffer.realloc((uint32) new_size + 4 + 1))
  {
    null_value= 1;
    return 0;
  }

  body= ((Byte*)buffer.ptr()) + 4;

  // As far as we have checked res->is_empty() we can use ptr()
  if ((err= compress(body, &new_size,
		     (const Bytef*)res->ptr(), res->length())) != Z_OK)
  {
    code= err==Z_MEM_ERROR ? ER_ZLIB_Z_MEM_ERROR : ER_ZLIB_Z_BUF_ERROR;
    push_warning(current_thd,MYSQL_ERROR::WARN_LEVEL_ERROR,code,ER(code));
    null_value= 1;
    return 0;
  }

  tmp= (char*)buffer.ptr(); // int4store is a macro; avoid side effects
  int4store(tmp, res->length() & 0x3FFFFFFF);

  /* This is to ensure that things works for CHAR fields, which trim ' ': */
  last_char= ((char*)body)+new_size-1;
  if (*last_char == ' ')
  {
    *++last_char= '.';
    new_size++;
  }

  buffer.length((uint32)new_size + 4);
  return &buffer;
}


String *Item_func_uncompress::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  String *res= args[0]->val_str(str);
  ulong new_size;
  int err;
  uint code;

  if (!res)
    goto err;
  null_value= 0;
  if (res->is_empty())
    return res;

  /* If length is less than 4 bytes, data is corrupt */
  if (res->length() <= 4)
  {
    push_warning_printf(current_thd,MYSQL_ERROR::WARN_LEVEL_ERROR,
			ER_ZLIB_Z_DATA_ERROR,
			ER(ER_ZLIB_Z_DATA_ERROR));
    goto err;
  }

  /* Size of uncompressed data is stored as first 4 bytes of field */
  new_size= uint4korr(res->ptr()) & 0x3FFFFFFF;
  if (new_size > current_thd->variables.max_allowed_packet)
  {
    push_warning_printf(current_thd,MYSQL_ERROR::WARN_LEVEL_ERROR,
			ER_TOO_BIG_FOR_UNCOMPRESS,
			ER(ER_TOO_BIG_FOR_UNCOMPRESS),
                        current_thd->variables.max_allowed_packet);
    goto err;
  }
  if (buffer.realloc((uint32)new_size))
    goto err;

  if ((err= uncompress((Byte*)buffer.ptr(), &new_size,
		       ((const Bytef*)res->ptr())+4,res->length())) == Z_OK)
  {
    buffer.length((uint32) new_size);
    return &buffer;
  }

  code= ((err == Z_BUF_ERROR) ? ER_ZLIB_Z_BUF_ERROR :
	 ((err == Z_MEM_ERROR) ? ER_ZLIB_Z_MEM_ERROR : ER_ZLIB_Z_DATA_ERROR));
  push_warning(current_thd,MYSQL_ERROR::WARN_LEVEL_ERROR,code,ER(code));

err:
  null_value= 1;
  return 0;
}
#endif

/*
  UUID, as in
    DCE 1.1: Remote Procedure Call,
    Open Group Technical Standard Document Number C706, October 1997,
    (supersedes C309 DCE: Remote Procedure Call 8/1994,
    which was basis for ISO/IEC 11578:1996 specification)
*/

static struct rand_struct uuid_rand;
static uint nanoseq;
static ulonglong uuid_time=0;
static char clock_seq_and_node_str[]="-0000-000000000000";

/**
  number of 100-nanosecond intervals between
  1582-10-15 00:00:00.00 and 1970-01-01 00:00:00.00.
*/
#define UUID_TIME_OFFSET ((ulonglong) 141427 * 24 * 60 * 60 * \
                          1000 * 1000 * 10)

#define UUID_VERSION      0x1000
#define UUID_VARIANT      0x8000

static void tohex(char *to, uint from, uint len)
{
  to+= len;
  while (len--)
  {
    *--to= _dig_vec_lower[from & 15];
    from >>= 4;
  }
}

static void set_clock_seq_str()
{
  uint16 clock_seq= ((uint)(my_rnd(&uuid_rand)*16383)) | UUID_VARIANT;
  tohex(clock_seq_and_node_str+1, clock_seq, 4);
  nanoseq= 0;
}

String *Item_func_uuid::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  char *s;
  THD *thd= current_thd;

  pthread_mutex_lock(&LOCK_uuid_generator);
  if (! uuid_time) /* first UUID() call. initializing data */
  {
    ulong tmp=sql_rnd_with_mutex();
    uchar mac[6];
    int i;
    if (my_gethwaddr(mac))
    {
      /* purecov: begin inspected */
      /*
        generating random "hardware addr"
        and because specs explicitly specify that it should NOT correlate
        with a clock_seq value (initialized random below), we use a separate
        randominit() here
      */
      randominit(&uuid_rand, tmp + (ulong) thd, tmp + (ulong)global_query_id);
      for (i=0; i < (int)sizeof(mac); i++)
        mac[i]=(uchar)(my_rnd(&uuid_rand)*255);
      /* purecov: end */    
    }
    s=clock_seq_and_node_str+sizeof(clock_seq_and_node_str)-1;
    for (i=sizeof(mac)-1 ; i>=0 ; i--)
    {
      *--s=_dig_vec_lower[mac[i] & 15];
      *--s=_dig_vec_lower[mac[i] >> 4];
    }
    randominit(&uuid_rand, tmp + (ulong) server_start_time,
	       tmp + (ulong) thd->status_var.bytes_sent);
    set_clock_seq_str();
  }

  ulonglong tv= my_getsystime() + UUID_TIME_OFFSET + nanoseq;

  if (likely(tv > uuid_time))
  {
    /*
      Current time is ahead of last timestamp, as it should be.
      If we "borrowed time", give it back, just as long as we
      stay ahead of the previous timestamp.
    */
    if (nanoseq)
    {
      DBUG_ASSERT((tv > uuid_time) && (nanoseq > 0));
      /*
        -1 so we won't make tv= uuid_time for nanoseq >= (tv - uuid_time)
      */
      ulong delta= min(nanoseq, (ulong) (tv - uuid_time -1));
      tv-= delta;
      nanoseq-= delta;
    }
  }
  else
  {
    if (unlikely(tv == uuid_time))
    {
      /*
        For low-res system clocks. If several requests for UUIDs
        end up on the same tick, we add a nano-second to make them
        different.
        ( current_timestamp + nanoseq * calls_in_this_period )
        may end up > next_timestamp; this is OK. Nonetheless, we'll
        try to unwind nanoseq when we get a chance to.
        If nanoseq overflows, we'll start over with a new numberspace
        (so the if() below is needed so we can avoid the ++tv and thus
        match the follow-up if() if nanoseq overflows!).
      */
      if (likely(++nanoseq))
        ++tv;
    }

    if (unlikely(tv <= uuid_time))
    {
      /*
        If the admin changes the system clock (or due to Daylight
        Saving Time), the system clock may be turned *back* so we
        go through a period once more for which we already gave out
        UUIDs.  To avoid duplicate UUIDs despite potentially identical
        times, we make a new random component.
        We also come here if the nanoseq "borrowing" overflows.
        In either case, we throw away any nanoseq borrowing since it's
        irrelevant in the new numberspace.
      */
      set_clock_seq_str();
      tv= my_getsystime() + UUID_TIME_OFFSET;
      nanoseq= 0;
      DBUG_PRINT("uuid",("making new numberspace"));
    }
  }

  uuid_time=tv;
  pthread_mutex_unlock(&LOCK_uuid_generator);

  uint32 time_low=            (uint32) (tv & 0xFFFFFFFF);
  uint16 time_mid=            (uint16) ((tv >> 32) & 0xFFFF);
  uint16 time_hi_and_version= (uint16) ((tv >> 48) | UUID_VERSION);

  str->realloc(UUID_LENGTH+1);
  str->length(UUID_LENGTH);
  str->set_charset(system_charset_info);
  s=(char *) str->ptr();
  s[8]=s[13]='-';
  tohex(s, time_low, 8);
  tohex(s+9, time_mid, 4);
  tohex(s+14, time_hi_and_version, 4);
  strmov(s+18, clock_seq_and_node_str);
  return str;
}