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mirror of https://github.com/mariadb-corporation/mariadb-columnstore-engine.git synced 2025-04-23 07:05:36 +03:00
Sergey Zefirov b53c231ca6 MCOL-271 empty strings should not be NULLs (#2794)
This patch improves handling of NULLs in textual fields in ColumnStore.
Previously empty strings were considered NULLs and it could be a problem
if data scheme allows for empty strings. It was also one of major
reasons of behavior difference between ColumnStore and other engines in
MariaDB family.

Also, this patch fixes some other bugs and incorrect behavior, for
example, incorrect comparison for "column <= ''" which evaluates to
constant True for all purposes before this patch.
2023-03-30 21:18:29 +03:00

117 lines
2.6 KiB
C++

/* Copyright (C) 2014 InfiniDB, 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 Street, Fifth Floor, Boston,
MA 02110-1301, USA. */
/****************************************************************************
* $Id: func_unhex.cpp 3923 2013-06-19 21:43:06Z bwilkinson $
*
*
****************************************************************************/
#include <cstdlib>
#include <string>
#include <sstream>
using namespace std;
#include "functor_str.h"
#include "funchelpers.h"
#include "functioncolumn.h"
#include "rowgroup.h"
using namespace execplan;
#include "dataconvert.h"
namespace
{
inline int hex_to_int(char c, bool& isNull)
{
if (c <= '9' && c >= '0')
return c - '0';
c |= 32;
if (c <= 'f' && c >= 'a')
return c - 'a' + 10;
isNull = true;
return -1;
}
inline string cleanup(char* to)
{
delete[] to;
return "";
}
} // namespace
namespace funcexp
{
CalpontSystemCatalog::ColType Func_unhex::operationType(FunctionParm& fp,
CalpontSystemCatalog::ColType& resultType)
{
return resultType;
}
string Func_unhex::getStrVal(rowgroup::Row& row, FunctionParm& parm, bool& isNull,
CalpontSystemCatalog::ColType& op_ct)
{
const auto& nfrom = parm[0]->data()->getStrVal(row, isNull);
if (nfrom.isNull())
return "";
const auto& from = nfrom.unsafeStringRef();
char* to = new char[2 + from.size() / 2];
uint64_t from_pos = 0, to_pos = 0;
int hex_char = 0;
if (from.size() % 2)
{
hex_char = hex_to_int(from[from_pos++], isNull);
if (hex_char == -1)
return cleanup(to);
to[to_pos++] = hex_char;
}
for (; from_pos < from.size(); from_pos += 2)
{
hex_char = hex_to_int(from[from_pos], isNull) << 4;
if (hex_char == -1)
return cleanup(to);
to[to_pos] = hex_char;
hex_char = hex_to_int(from[from_pos + 1], isNull);
if (hex_char == -1)
return cleanup(to);
to[to_pos++] |= hex_char;
}
to[to_pos] = 0;
string tmp = string(to);
delete[] to;
return tmp;
}
} // namespace funcexp