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| author | serg@serg.mylan <> | 2003-08-05 21:14:15 +0200 |
|---|---|---|
| committer | serg@serg.mylan <> | 2003-08-05 21:14:15 +0200 |
| commit | 79922d946ac7c7c9c77c10fd7f831f14f2a9892c (patch) | |
| tree | 7f824b71d5779659b28c60ef72d0b119daa9ccf9 /mysys | |
| parent | 6ac0c55c103685c9e4bcd76080a5d5cb428c6130 (diff) | |
| download | mariadb-git-79922d946ac7c7c9c77c10fd7f831f14f2a9892c.tar.gz | |
table checksum background:
my_checksum() mysys function
NISAM checksum code moved from mysys to isam/ - it's obsolete
MyISAM checksum code moved to mysys
table's checksum accessible from sql layer
SHOW TABLE STATUS shows checksum (WL#646)
code cleanup
Diffstat (limited to 'mysys')
| -rw-r--r-- | mysys/checksum.c | 21 |
1 files changed, 11 insertions, 10 deletions
diff --git a/mysys/checksum.c b/mysys/checksum.c index 1dd135c7ad9..2ae139b81c3 100644 --- a/mysys/checksum.c +++ b/mysys/checksum.c @@ -19,19 +19,20 @@ #include "my_sys.h" /* - Calculate a long checksum for a memoryblock. Used to verify pack_isam - + Calculate a long checksum for a memoryblock. + SYNOPSIS - checksum() - mem Pointer to memory block - count Count of bytes + my_checksum() + crc start value for crc + pos pointer to memory block + length length of the block */ -ulong checksum(const byte *mem, uint count) +ha_checksum my_checksum(ha_checksum crc, const byte *pos, uint length) { - ulong crc; - for (crc= 0; count-- ; mem++) - crc= ((crc << 1) + *((uchar*) mem)) + - test(crc & ((ulong) 1L << (8*sizeof(ulong)-1))); + const byte *end=pos+length; + for ( ; pos != end ; pos++) + crc=((crc << 8) + *((uchar*) pos)) + (crc >> (8*sizeof(ha_checksum)-8)); return crc; } + |