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sql_sort.h
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/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
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* vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
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*
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* Copyright (C) 2008 Sun Microsystems, Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#pragma once
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#include <unistd.h>
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#include <drizzled/base.h>
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#include <drizzled/common_fwd.h>
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#include <drizzled/qsort_cmp.h>
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namespace
drizzled {
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/*
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The structure sort_addon_field describes a fixed layout
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for field values appended to sorted values in records to be sorted
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in the sort buffer.
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Only fixed layout is supported now.
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Null bit maps for the appended values is placed before the values
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themselves. Offsets are from the last sorted field, that is from the
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record referefence, which is still last component of sorted records.
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It is preserved for backward compatiblility.
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The structure is used tp store values of the additional fields
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in the sort buffer. It is used also when these values are read
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from a temporary file/buffer. As the reading procedures are beyond the
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scope of the 'filesort' code the values have to be retrieved via
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the callback function 'unpack_addon_fields'.
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*/
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class
sort_addon_field
{
/* Sort addon packed field */
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public
:
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Field
*field;
/* Original field */
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uint32_t offset;
/* Offset from the last sorted field */
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uint32_t null_offset;
/* Offset to to null bit from the last sorted field */
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uint32_t length;
/* Length in the sort buffer */
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uint8_t null_bit;
/* Null bit mask for the field */
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sort_addon_field
() :
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field(NULL),
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offset(0),
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null_offset(0),
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length(0),
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null_bit(0)
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{ }
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};
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class
buffpek
{
/* Struktur om sorteringsbuffrarna */
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public
:
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off_t file_pos;
/* Where we are in the sort file */
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unsigned
char
*base;
/* key pointers */
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unsigned
char
*key;
/* key pointers */
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ha_rows count;
/* Number of rows in table */
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size_t
mem_count;
/* numbers of keys in memory */
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size_t
max_keys;
/* Max keys in buffert */
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buffpek
() :
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file_pos(0),
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base(0),
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key(0),
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count(0),
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mem_count(0),
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max_keys(0)
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{ }
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};
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}
/* namespace drizzled */
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drizzled
sql_sort.h
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