mirror of
https://git.postgresql.org/git/postgresql.git
synced 2026-02-11 06:57:29 +08:00
2ff501590b
Also performed an initial run through of upgrading our Copyright date to extend to 2005 ... first run here was very simple ... change everything where: grep 1996-2004 && the word 'Copyright' ... scanned through the generated list with 'less' first, and after, to make sure that I only picked up the right entries ...
115 lines
3.5 KiB
C
115 lines
3.5 KiB
C
/*
|
|
* pg_crc.h
|
|
*
|
|
* PostgreSQL 64-bit CRC support
|
|
*
|
|
* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
|
|
* Portions Copyright (c) 1994, Regents of the University of California
|
|
*
|
|
* $PostgreSQL: pgsql/src/include/utils/pg_crc.h,v 1.12 2004/12/31 22:03:46 pgsql Exp $
|
|
*/
|
|
#ifndef PG_CRC_H
|
|
#define PG_CRC_H
|
|
|
|
/*
|
|
* If we have a 64-bit integer type, then a 64-bit CRC looks just like the
|
|
* usual sort of implementation. (See Ross Williams' excellent introduction
|
|
* A PAINLESS GUIDE TO CRC ERROR DETECTION ALGORITHMS, available from
|
|
* ftp://ftp.rocksoft.com/papers/crc_v3.txt or several other net sites.)
|
|
* If we have no working 64-bit type, then fake it with two 32-bit registers.
|
|
*
|
|
* The present implementation is a normal (not "reflected", in Williams'
|
|
* terms) 64-bit CRC, using initial all-ones register contents and a final
|
|
* bit inversion. The chosen polynomial is borrowed from the DLT1 spec
|
|
* (ECMA-182, available from http://www.ecma.ch/ecma1/STAND/ECMA-182.HTM):
|
|
*
|
|
* x^64 + x^62 + x^57 + x^55 + x^54 + x^53 + x^52 + x^47 + x^46 + x^45 +
|
|
* x^40 + x^39 + x^38 + x^37 + x^35 + x^33 + x^32 + x^31 + x^29 + x^27 +
|
|
* x^24 + x^23 + x^22 + x^21 + x^19 + x^17 + x^13 + x^12 + x^10 + x^9 +
|
|
* x^7 + x^4 + x + 1
|
|
*/
|
|
|
|
#ifdef INT64_IS_BUSTED
|
|
|
|
/*
|
|
* crc0 represents the LSBs of the 64-bit value, crc1 the MSBs. Note that
|
|
* with crc0 placed first, the output of 32-bit and 64-bit implementations
|
|
* will be bit-compatible only on little-endian architectures. If it were
|
|
* important to make the two possible implementations bit-compatible on
|
|
* all machines, we could do a configure test to decide how to order the
|
|
* two fields, but it seems not worth the trouble.
|
|
*/
|
|
typedef struct crc64
|
|
{
|
|
uint32 crc0;
|
|
uint32 crc1;
|
|
} crc64;
|
|
|
|
/* Initialize a CRC accumulator */
|
|
#define INIT_CRC64(crc) ((crc).crc0 = 0xffffffff, (crc).crc1 = 0xffffffff)
|
|
|
|
/* Finish a CRC calculation */
|
|
#define FIN_CRC64(crc) ((crc).crc0 ^= 0xffffffff, (crc).crc1 ^= 0xffffffff)
|
|
|
|
/* Accumulate some (more) bytes into a CRC */
|
|
#define COMP_CRC64(crc, data, len) \
|
|
do { \
|
|
uint32 __crc0 = (crc).crc0; \
|
|
uint32 __crc1 = (crc).crc1; \
|
|
unsigned char *__data = (unsigned char *) (data); \
|
|
uint32 __len = (len); \
|
|
\
|
|
while (__len-- > 0) \
|
|
{ \
|
|
int __tab_index = ((int) (__crc1 >> 24) ^ *__data++) & 0xFF; \
|
|
__crc1 = crc_table1[__tab_index] ^ ((__crc1 << 8) | (__crc0 >> 24)); \
|
|
__crc0 = crc_table0[__tab_index] ^ (__crc0 << 8); \
|
|
} \
|
|
(crc).crc0 = __crc0; \
|
|
(crc).crc1 = __crc1; \
|
|
} while (0)
|
|
|
|
/* Check for equality of two CRCs */
|
|
#define EQ_CRC64(c1,c2) ((c1).crc0 == (c2).crc0 && (c1).crc1 == (c2).crc1)
|
|
|
|
/* Constant table for CRC calculation */
|
|
extern const uint32 crc_table0[];
|
|
extern const uint32 crc_table1[];
|
|
|
|
#else /* int64 works */
|
|
|
|
typedef struct crc64
|
|
{
|
|
uint64 crc0;
|
|
} crc64;
|
|
|
|
/* Initialize a CRC accumulator */
|
|
#define INIT_CRC64(crc) ((crc).crc0 = UINT64CONST(0xffffffffffffffff))
|
|
|
|
/* Finish a CRC calculation */
|
|
#define FIN_CRC64(crc) ((crc).crc0 ^= UINT64CONST(0xffffffffffffffff))
|
|
|
|
/* Accumulate some (more) bytes into a CRC */
|
|
#define COMP_CRC64(crc, data, len) \
|
|
do { \
|
|
uint64 __crc0 = (crc).crc0; \
|
|
unsigned char *__data = (unsigned char *) (data); \
|
|
uint32 __len = (len); \
|
|
\
|
|
while (__len-- > 0) \
|
|
{ \
|
|
int __tab_index = ((int) (__crc0 >> 56) ^ *__data++) & 0xFF; \
|
|
__crc0 = crc_table[__tab_index] ^ (__crc0 << 8); \
|
|
} \
|
|
(crc).crc0 = __crc0; \
|
|
} while (0)
|
|
|
|
/* Check for equality of two CRCs */
|
|
#define EQ_CRC64(c1,c2) ((c1).crc0 == (c2).crc0)
|
|
|
|
/* Constant table for CRC calculation */
|
|
extern const uint64 crc_table[];
|
|
#endif /* INT64_IS_BUSTED */
|
|
|
|
#endif /* PG_CRC_H */
|