From 293913568e6a7a86fd1479e1cff8e2ecb58d6568 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 13 Apr 2024 15:44:03 +0200 Subject: Adding upstream version 16.2. Signed-off-by: Daniel Baumann --- src/include/access/sdir.h | 67 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 67 insertions(+) create mode 100644 src/include/access/sdir.h (limited to 'src/include/access/sdir.h') diff --git a/src/include/access/sdir.h b/src/include/access/sdir.h new file mode 100644 index 0000000..322aeb3 --- /dev/null +++ b/src/include/access/sdir.h @@ -0,0 +1,67 @@ +/*------------------------------------------------------------------------- + * + * sdir.h + * POSTGRES scan direction definitions. + * + * + * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * src/include/access/sdir.h + * + *------------------------------------------------------------------------- + */ +#ifndef SDIR_H +#define SDIR_H + + +/* + * Defines the direction for scanning a table or an index. Scans are never + * invoked using NoMovementScanDirectionScans. For convenience, we use the + * values -1 and 1 for backward and forward scans. This allows us to perform + * a few mathematical tricks such as what is done in ScanDirectionCombine. + */ +typedef enum ScanDirection +{ + BackwardScanDirection = -1, + NoMovementScanDirection = 0, + ForwardScanDirection = 1 +} ScanDirection; + +/* + * Determine the net effect of two direction specifications. + * This relies on having ForwardScanDirection = +1, BackwardScanDirection = -1, + * and will probably not do what you want if applied to any other values. + */ +#define ScanDirectionCombine(a, b) ((a) * (b)) + +/* + * ScanDirectionIsValid + * True iff scan direction is valid. + */ +#define ScanDirectionIsValid(direction) \ + ((bool) (BackwardScanDirection <= (direction) && \ + (direction) <= ForwardScanDirection)) + +/* + * ScanDirectionIsBackward + * True iff scan direction is backward. + */ +#define ScanDirectionIsBackward(direction) \ + ((bool) ((direction) == BackwardScanDirection)) + +/* + * ScanDirectionIsNoMovement + * True iff scan direction indicates no movement. + */ +#define ScanDirectionIsNoMovement(direction) \ + ((bool) ((direction) == NoMovementScanDirection)) + +/* + * ScanDirectionIsForward + * True iff scan direction is forward. + */ +#define ScanDirectionIsForward(direction) \ + ((bool) ((direction) == ForwardScanDirection)) + +#endif /* SDIR_H */ -- cgit v1.2.3