~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

 *

 *  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

 */

#ifndef DRIZZLED_JOIN_CACHE_H

#define DRIZZLED_JOIN_CACHE_H

namespace drizzled

{

class Field_blob;

typedef JoinTable JoinTable;

/**

  CacheField and JoinCache is used on full join to cache records in outer

  table

*/

class CacheField {

  /*

    Where source data is located (i.e. this points to somewhere in

    tableX->getInsertRecord())

  */

public:

  unsigned char *str;

  uint32_t length; /* Length of data at *str, in bytes */

  uint32_t blob_length; /* Valid IFF blob_field != 0 */

  Field_blob *blob_field;

  bool strip; /* true <=> Strip endspaces ?? */

  Table *get_rowid; /* _ != NULL <=> */

  CacheField():

    str(NULL),

    length(0),

    blob_length(0),

    blob_field(NULL),

    strip(false),

    get_rowid(NULL)

  {}

};

class JoinCache

{

public:

  unsigned char *buff;

  unsigned char *pos;    /* Start of free space in the buffer */

  unsigned char *end;

  uint32_t records;  /* # of row cominations currently stored in the cache */

  uint32_t record_nr;

  uint32_t ptr_record;

  /*

    Number of fields (i.e. cache_field objects). Those correspond to table

    columns, and there are also special fields for

     - table's column null bits

     - table's null-complementation byte

     - [new] table's rowid.

  */

  uint32_t fields;

  uint32_t length;

  uint32_t blobs;

  CacheField *field;

  CacheField **blob_ptr;

  optimizer::SqlSelect *select;

  JoinCache():

    buff(NULL),

    pos(NULL),

    end(NULL),

    records(0),

    record_nr(0),

    ptr_record(0),

    fields(0),

    length(0),

    blobs(0),

    field(NULL),

    blob_ptr(NULL),

    select(NULL)

  {}

  void reset_cache_read();

  void reset_cache_write();

  bool store_record_in_cache();

};

int join_init_cache(Session *session, JoinTable *tables, uint32_t table_count);

} /* namespace drizzled */

#endif /* DRIZZLED_JOIN_CACHE_H */