~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/concat.h>

#include <drizzled/error.h>

#include <drizzled/session.h>

#include <algorithm>

using namespace std;

namespace drizzled

{

String *Item_func_concat::val_str(String *str)

{

  assert(fixed == 1);

  String *res,*res2,*use_as_buff;

  uint32_t 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;

    }

    else

    {

      if (!(res2=args[i]->val_str(use_as_buff)))

        goto null;

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

        continue;

      if (res->length()+res2->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 (!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 == res2)

          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_t) (res2->ptr() - tmp_value.ptr()) +

                         res2->length());

        /* Place res2 at start of tmp_value, remove chars before res2 */

        if (tmp_value.replace(0,(uint32_t) (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.

        */

        size_t 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

          {

            uint32_t 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()

{

  uint64_t max_result_length= 0;

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

    return;

  for (uint32_t 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;

}

/**

  concat with separator. First arg is the separator

  concat_ws takes at least two arguments.

*/

String *Item_func_concat_ws::val_str(String *str)

{

  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;

  uint32_t i;

  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)))

      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() >

        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 (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 == res2)

      {						// This is quote 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_t) (res2->ptr() - tmp_value.ptr()) +

                       res2->length());

      /* Place res2 at start of tmp_value, remove chars before res2 */

      if (tmp_value.replace(0,(uint32_t) (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.

      */

      size_t 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

        {

          uint32_t 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()

{

  uint64_t 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= (uint64_t) args[0]->max_length * (arg_count - 2);

  for (uint32_t 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;

}

} /* namespace drizzled */