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/*****************************************************************************
Copyright (c) 1995, 2016, Oracle and/or its affiliates. All Rights Reserved.
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, Suite 500, Boston, MA 02110-1335 USA
*****************************************************************************/
/**************************************************//**
@file buf/buf0checksum.cc
Buffer pool checksum functions, also linked from /extra/innochecksum.cc
Created Aug 11, 2011 Vasil Dimov
*******************************************************/
#include "univ.i"
#include "fil0fil.h"
#include "ut0crc32.h"
#include "ut0rnd.h"
#include "buf0checksum.h"
#ifndef UNIV_INNOCHECKSUM
#include "srv0srv.h"
#endif /* !UNIV_INNOCHECKSUM */
#include "buf0types.h"
/** the macro MYSQL_SYSVAR_ENUM() requires "long unsigned int" and if we
use srv_checksum_algorithm_t here then we get a compiler error:
ha_innodb.cc:12251: error: cannot convert 'srv_checksum_algorithm_t*' to
'long unsigned int*' in initialization */
ulong srv_checksum_algorithm = SRV_CHECKSUM_ALGORITHM_INNODB;
/** set if we have found pages matching legacy big endian checksum */
bool legacy_big_endian_checksum = false;
/** Calculates the CRC32 checksum of a page. The value is stored to the page
when it is written to a file and also checked for a match when reading from
the file. When reading we allow both normal CRC32 and CRC-legacy-big-endian
variants. Note that we must be careful to calculate the same value on 32-bit
and 64-bit architectures.
@param[in] page buffer page (UNIV_PAGE_SIZE bytes)
@param[in] use_legacy_big_endian if true then use big endian
byteorder when converting byte strings to integers
@return checksum */
uint32_t
buf_calc_page_crc32(
const byte* page,
bool use_legacy_big_endian /* = false */)
{
/* Since the field FIL_PAGE_FILE_FLUSH_LSN, and in versions <= 4.1.x
FIL_PAGE_ARCH_LOG_NO_OR_SPACE_ID, are written outside the buffer pool
to the first pages of data files, we have to skip them in the page
checksum calculation.
We must also skip the field FIL_PAGE_SPACE_OR_CHKSUM where the
checksum is stored, and also the last 8 bytes of page because
there we store the old formula checksum. */
ut_crc32_func_t crc32_func = use_legacy_big_endian
? ut_crc32_legacy_big_endian
: ut_crc32;
const uint32_t c1 = crc32_func(
page + FIL_PAGE_OFFSET,
FIL_PAGE_FILE_FLUSH_LSN_OR_KEY_VERSION - FIL_PAGE_OFFSET);
const uint32_t c2 = crc32_func(
page + FIL_PAGE_DATA,
UNIV_PAGE_SIZE - FIL_PAGE_DATA - FIL_PAGE_END_LSN_OLD_CHKSUM);
return(c1 ^ c2);
}
/********************************************************************//**
Calculates a page checksum which is stored to the page when it is written
to a file. Note that we must be careful to calculate the same value on
32-bit and 64-bit architectures.
@return checksum */
ulint
buf_calc_page_new_checksum(
/*=======================*/
const byte* page) /*!< in: buffer page */
{
ulint checksum;
/* Since the field FIL_PAGE_FILE_FLUSH_LSN, and in versions <= 4.1.x
FIL_PAGE_ARCH_LOG_NO_OR_SPACE_ID, are written outside the buffer pool
to the first pages of data files, we have to skip them in the page
checksum calculation.
We must also skip the field FIL_PAGE_SPACE_OR_CHKSUM where the
checksum is stored, and also the last 8 bytes of page because
there we store the old formula checksum. */
checksum = ut_fold_binary(page + FIL_PAGE_OFFSET,
FIL_PAGE_FILE_FLUSH_LSN_OR_KEY_VERSION
- FIL_PAGE_OFFSET)
+ ut_fold_binary(page + FIL_PAGE_DATA,
UNIV_PAGE_SIZE - FIL_PAGE_DATA
- FIL_PAGE_END_LSN_OLD_CHKSUM);
checksum = checksum & 0xFFFFFFFFUL;
return(checksum);
}
/********************************************************************//**
In versions < 4.0.14 and < 4.1.1 there was a bug that the checksum only
looked at the first few bytes of the page. This calculates that old
checksum.
NOTE: we must first store the new formula checksum to
FIL_PAGE_SPACE_OR_CHKSUM before calculating and storing this old checksum
because this takes that field as an input!
@return checksum */
ulint
buf_calc_page_old_checksum(
/*=======================*/
const byte* page) /*!< in: buffer page */
{
ulint checksum;
checksum = ut_fold_binary(page, FIL_PAGE_FILE_FLUSH_LSN_OR_KEY_VERSION);
checksum = checksum & 0xFFFFFFFFUL;
return(checksum);
}
/********************************************************************//**
Return a printable string describing the checksum algorithm.
@return algorithm name */
const char*
buf_checksum_algorithm_name(
/*========================*/
srv_checksum_algorithm_t algo) /*!< in: algorithm */
{
switch (algo) {
case SRV_CHECKSUM_ALGORITHM_CRC32:
return("crc32");
case SRV_CHECKSUM_ALGORITHM_STRICT_CRC32:
return("strict_crc32");
case SRV_CHECKSUM_ALGORITHM_INNODB:
return("innodb");
case SRV_CHECKSUM_ALGORITHM_STRICT_INNODB:
return("strict_innodb");
case SRV_CHECKSUM_ALGORITHM_NONE:
return("none");
case SRV_CHECKSUM_ALGORITHM_STRICT_NONE:
return("strict_none");
}
ut_error;
return(NULL);
}
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