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| author | John Naylor <john.naylor@postgresql.org> | 2022-02-20 13:22:08 +0700 |
|---|---|---|
| committer | John Naylor <john.naylor@postgresql.org> | 2022-02-20 13:22:08 +0700 |
| commit | 4b35408f1ed59dd590f683ae0f015bbaf3b84d3d (patch) | |
| tree | f0fbcde2e180f22114c14331512b8bcfacfcf5e6 /src/include/port/pg_bitutils.h | |
| parent | d7a978601d4e469f1a8f19122c049bb25fd7f096 (diff) | |
| download | postgresql-4b35408f1ed59dd590f683ae0f015bbaf3b84d3d.tar.gz postgresql-4b35408f1ed59dd590f683ae0f015bbaf3b84d3d.zip | |
Use bitwise rotate functions in more places
There were a number of places in the code that used bespoke bit-twiddling
expressions to do bitwise rotation. While we've had pg_rotate_right32()
for a while now, we hadn't gotten around to standardizing on that. Do so
now. Since many potential call sites look more natural with the "left"
equivalent, add that function too.
Reviewed by Tom Lane and Yugo Nagata
Discussion:
https://www.postgresql.org/message-id/CAFBsxsH7c1LC0CGZ0ADCBXLHU5-%3DKNXx-r7tHYPAW51b2HK4Qw%40mail.gmail.com
Diffstat (limited to 'src/include/port/pg_bitutils.h')
| -rw-r--r-- | src/include/port/pg_bitutils.h | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/src/include/port/pg_bitutils.h b/src/include/port/pg_bitutils.h index 44c74fb9743..04e58cd1c44 100644 --- a/src/include/port/pg_bitutils.h +++ b/src/include/port/pg_bitutils.h @@ -285,12 +285,18 @@ extern int pg_popcount64(uint64 word); extern uint64 pg_popcount(const char *buf, int bytes); /* - * Rotate the bits of "word" to the right by n bits. + * Rotate the bits of "word" to the right/left by n bits. */ static inline uint32 pg_rotate_right32(uint32 word, int n) { - return (word >> n) | (word << (sizeof(word) * BITS_PER_BYTE - n)); + return (word >> n) | (word << (32 - n)); +} + +static inline uint32 +pg_rotate_left32(uint32 word, int n) +{ + return (word << n) | (word >> (32 - n)); } #endif /* PG_BITUTILS_H */ |