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5b3ad94c7b
We used to define a native unary function CRC32() that computes the CRC-32
of a string using the ISO 3309 polynomial that is being used by zlib
and many others.
Often, a CRC is computed in pieces. To faciliate this, we introduce a
2-ary variant of the function that inputs a previous CRC as the first
argument: CRC32('MariaDB')=CRC32(CRC32('Maria'),'DB').
InnoDB and MyRocks use a different polynomial, which was implemented
in SSE4.2 instructions that were introduced in the
Intel Nehalem microarchitecture. This is commonly called CRC-32C
(Castagnoli).
We introduce a native function that uses the Castagnoli polynomial:
CRC32C('MariaDB')=CRC32C(CRC32C('Maria'),'DB'). This allows
SELECT...INTO DUMPFILE to be used for the creation of files with
valid checksums, such as a logically empty InnoDB redo log file
ib_logfile0 corresponding to a particular log sequence number.
61 lines
1.9 KiB
C++
61 lines
1.9 KiB
C++
/* Copyright (c) 2020, 2022, MariaDB
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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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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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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 02110-1335 USA */
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#include <my_global.h>
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#include <my_sys.h>
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#include <zlib.h>
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/* TODO: remove this once zlib adds inherent support for hardware accelerated
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crc32 for all architectures. */
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static unsigned int my_crc32_zlib(unsigned int crc, const void *data,
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size_t len)
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{
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return (unsigned int) crc32(crc, (const Bytef *)data, (unsigned int) len);
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}
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#ifdef HAVE_PCLMUL
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extern "C" int crc32_pclmul_enabled();
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extern "C" unsigned int crc32_pclmul(unsigned int, const void *, size_t);
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#elif defined(__GNUC__) && defined(HAVE_ARMV8_CRC)
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extern "C" int crc32_aarch64_available();
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extern "C" unsigned int crc32_aarch64(unsigned int, const void *, size_t);
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#endif
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typedef unsigned int (*my_crc32_t)(unsigned int, const void *, size_t);
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static my_crc32_t init_crc32()
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{
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#ifdef HAVE_PCLMUL
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if (crc32_pclmul_enabled())
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return crc32_pclmul;
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#elif defined(__GNUC__) && defined(HAVE_ARMV8_CRC)
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if (crc32_aarch64_available())
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return crc32_aarch64;
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#endif
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return my_crc32_zlib;
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}
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static const my_crc32_t my_checksum_func= init_crc32();
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#ifdef __powerpc64__
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# error "my_checksum() is defined in mysys/crc32/crc32_ppc64.c"
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#endif
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extern "C"
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uint32 my_checksum(uint32 crc, const void *data, size_t len)
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{
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return my_checksum_func(crc, data, len);
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}
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