~drizzle-trunk/drizzle/development

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

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

 *

 *  Copyright (C) 2008 Sun Microsystems, Inc.

 *

 *  This program is free software; you can redistribute it and/or modify

 *  it under the terms of the GNU General Public License as published by

 *  the Free Software Foundation; version 2 of the License.

 *

 *  This program is distributed in the hope that it will be useful,

 *  but WITHOUT ANY WARRANTY; without even the implied warranty of

 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *  GNU General Public License for more details.

 *

 *  You should have received a copy of the GNU General Public License

 *  along with this program; if not, write to the Free Software

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

 */

#include <config.h>

#include <drizzled/function/str/replace.h>

#include <drizzled/error.h>

#include <drizzled/session.h>

#include <drizzled/system_variables.h>

namespace drizzled {

/**

  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

*/

String *Item_func_replace::val_str(String *str)

{

  assert(fixed == 1);

  String *res,*res2,*res3;

  int offset;

  uint32_t from_length,to_length;

  bool alloced=0;

  const char *ptr,*end,*strend,*search,*search_end;

  uint32_t l;

  bool binary_cmp;

  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);

  binary_cmp = ((res->charset()->state & MY_CS_BINSORT) || !use_mb(res->charset()));

  if (res2->length() == 0)

    return res;

  offset=0;

  if (binary_cmp && (offset=res->strstr(*res2)) < 0)

    return res;

  if (!(res3=args[2]->val_str(&tmp_value2)))

    goto null;

  from_length= res2->length();

  to_length=   res3->length();

  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)

        {

          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 >

              session.variables.max_allowed_packet)

          {

            push_warning_printf(&session, DRIZZLE_ERROR::WARN_LEVEL_WARN,

                                ER_WARN_ALLOWED_PACKET_OVERFLOWED,

                                ER(ER_WARN_ALLOWED_PACKET_OVERFLOWED),

                                func_name(),

                                session.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

    do

    {

      if (res->length()-from_length + to_length >

          session.variables.max_allowed_packet)

      {

        push_warning_printf(&session, DRIZZLE_ERROR::WARN_LEVEL_WARN,

                            ER_WARN_ALLOWED_PACKET_OVERFLOWED,

                            ER(ER_WARN_ALLOWED_PACKET_OVERFLOWED), func_name(),

                            session.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()

{

  uint64_t 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

    uint64_t 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;

}

} /* namespace drizzled */