50 lines
1.3 KiB
C
50 lines
1.3 KiB
C
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/*-------------------------------------------------------------------------
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*
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* pg_crc32c.h
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* Routines for computing CRC-32C checksums.
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*
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*
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* Portions Copyright (c) 1996-2015, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/port/pg_crc32c.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef PG_CRC32C_H
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#define PG_CRC32C_H
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typedef uint32 pg_crc32c;
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#define INIT_CRC32C(crc) ((crc) = 0xFFFFFFFF)
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#define EQ_CRC32C(c1, c2) ((c1) == (c2))
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/*
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* Use slicing-by-8 algorithm.
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*
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* On big-endian systems, the intermediate value is kept in reverse byte
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* order, to avoid byte-swapping during the calculation. FIN_CRC32C reverses
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* the bytes to the final order.
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*/
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#define COMP_CRC32C(crc, data, len) \
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((crc) = pg_comp_crc32c_sb8((crc), (data), (len)))
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#ifdef WORDS_BIGENDIAN
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#ifdef HAVE__BUILTIN_BSWAP32
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#define BSWAP32(x) __builtin_bswap32(x)
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#else
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#define BSWAP32(x) (((x << 24) & 0xff000000) | \
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((x << 8) & 0x00ff0000) | \
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((x >> 8) & 0x0000ff00) | \
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((x >> 24) & 0x000000ff))
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#endif
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#define FIN_CRC32C(crc) ((crc) = BSWAP32(crc) ^ 0xFFFFFFFF)
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#else
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#define FIN_CRC32C(crc) ((crc) ^= 0xFFFFFFFF)
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#endif
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extern pg_crc32c pg_comp_crc32c_sb8(pg_crc32c crc, const void *data, size_t len);
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#endif /* PG_CRC32C_H */
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