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/* Copyright (C) 2002 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 */


#ifdef STANDARD
/* STANDARD is defined, don't use any mysql functions */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#ifdef __WIN__
typedef unsigned __int64 ulonglong;	/* Microsofts 64 bit types */
typedef __int64 longlong;
#else
typedef unsigned long long ulonglong;
typedef long long longlong;
#endif /*__WIN__*/
#else
#include <my_global.h>
#include <my_sys.h>
#if defined(MYSQL_SERVER)
#include <m_string.h>		/* To get strmov() */
#else
/* when compiled as standalone */
#include <string.h>
#define strmov(a,b) stpcpy(a,b)
#define bzero(a,b) memset(a,0,b)
#define memcpy_fixed(a,b,c) memcpy(a,b,c)
#endif
#endif
#include <mysql.h>
#include <ctype.h>

#ifdef HAVE_DLOPEN

#define CHAR_LIM 256

static const char* default_dups = "abcdfglmnoprstvz";

typedef struct 
{
  char dup_map[CHAR_LIM]; 
  my_bool inited;
} Dup_map; 

/* These must be right or mysqld will not find the symbol! */

my_bool remove_dups_init(UDF_INIT *initid, UDF_ARGS *args, char *message);
void remove_dups_deinit(UDF_INIT *initid);
char *remove_dups(UDF_INIT *initid, UDF_ARGS *args, char *result,
	       unsigned long *length, char *is_null, char *error);

void init_dup_map(Dup_map* m, const char* dups, uint dup_len);

void init_dup_map(Dup_map* m, const char* dups, uint dup_len)
{
  const char* dup_end = dups + dup_len;
  bzero(m->dup_map, sizeof(m->dup_map));

  for (;dups < dup_end; dups++)
  {
    m->dup_map[(unsigned char)toupper(*dups)] = 1;
    m->dup_map[(unsigned char)tolower(*dups)] = 1;
  }

  m->inited = 1;
}

my_bool remove_dups_init(UDF_INIT *initid __attribute__((unused)), 
                        UDF_ARGS *args, char *message)
{
  if (args->arg_count < 1 || 
    args->arg_count > 2 || args->arg_type[0] != STRING_RESULT ||
    (args->arg_count == 2 && args->arg_type[1] != STRING_RESULT))
  {
    strcpy(message,"Usage: remove_dups(s[,dup_list])");
    return 1;
  }

  if (!(initid->ptr=(char*) malloc(sizeof(Dup_map))))
  {
    strmov(message,"Couldn't allocate memory");
    return 1;
  }
  ((Dup_map*)initid->ptr)->inited = 0;
  return 0;
}


void remove_dups_deinit(UDF_INIT *initid __attribute__((unused)))
{
  if (initid->ptr)
  {  
    free(initid->ptr);
    initid->ptr = 0;
  }  
}



char *remove_dups(UDF_INIT *initid __attribute__((unused)),
               UDF_ARGS *args, char *result, unsigned long *length,
               char *is_null, char *error __attribute__((unused)))
{
  const char *s=args->args[0], *p;
  char* res_p;
  const char* s_end;
  unsigned long res_len = 0;
  int last_removed = CHAR_LIM;
  Dup_map* m = (Dup_map*)initid->ptr;

  if (!s)
  {
     *is_null = 1;
     return 0;
  }

  if (!m->inited)
  {
    const char* dups;
    uint dup_len;

    if (args->arg_count == 1)
    {
      dups = default_dups;
      dup_len = strlen(default_dups);
    }
    else
    {
      dups = args->args[1];
      dup_len = args->lengths[1];
    }
    init_dup_map(m, dups, dup_len);
  }

  s_end = s + args->lengths[0];
  res_p = result;

  for (p = s;p < s_end; p++)
  {
    int lower_p = tolower(*p);
    if (p > s && tolower(p[-1]) == lower_p && 
      m->dup_map[(unsigned char)*p] && last_removed != lower_p)
    {
      last_removed = lower_p;
      continue;
    }  
    *res_p++ = *p; 
    last_removed = CHAR_LIM;
  }

  *length= (unsigned long)(res_p - result);
  return result;
}



#endif /* HAVE_DLOPEN */