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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 12:15:05 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 12:15:05 +0000 |
commit | 46651ce6fe013220ed397add242004d764fc0153 (patch) | |
tree | 6e5299f990f88e60174a1d3ae6e48eedd2688b2b /src/include/storage/off.h | |
parent | Initial commit. (diff) | |
download | postgresql-14-upstream.tar.xz postgresql-14-upstream.zip |
Adding upstream version 14.5.upstream/14.5upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/include/storage/off.h')
-rw-r--r-- | src/include/storage/off.h | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/src/include/storage/off.h b/src/include/storage/off.h new file mode 100644 index 0000000..a5df0ab --- /dev/null +++ b/src/include/storage/off.h @@ -0,0 +1,57 @@ +/*------------------------------------------------------------------------- + * + * off.h + * POSTGRES disk "offset" definitions. + * + * + * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * src/include/storage/off.h + * + *------------------------------------------------------------------------- + */ +#ifndef OFF_H +#define OFF_H + +#include "storage/itemid.h" +/* + * OffsetNumber: + * + * this is a 1-based index into the linp (ItemIdData) array in the + * header of each disk page. + */ +typedef uint16 OffsetNumber; + +#define InvalidOffsetNumber ((OffsetNumber) 0) +#define FirstOffsetNumber ((OffsetNumber) 1) +#define MaxOffsetNumber ((OffsetNumber) (BLCKSZ / sizeof(ItemIdData))) + +/* ---------------- + * support macros + * ---------------- + */ + +/* + * OffsetNumberIsValid + * True iff the offset number is valid. + */ +#define OffsetNumberIsValid(offsetNumber) \ + ((bool) ((offsetNumber != InvalidOffsetNumber) && \ + (offsetNumber <= MaxOffsetNumber))) + +/* + * OffsetNumberNext + * OffsetNumberPrev + * Increments/decrements the argument. These macros look pointless + * but they help us disambiguate the different manipulations on + * OffsetNumbers (e.g., sometimes we subtract one from an + * OffsetNumber to move back, and sometimes we do so to form a + * real C array index). + */ +#define OffsetNumberNext(offsetNumber) \ + ((OffsetNumber) (1 + (offsetNumber))) +#define OffsetNumberPrev(offsetNumber) \ + ((OffsetNumber) (-1 + (offsetNumber))) + +#endif /* OFF_H */ |