diff options
Diffstat (limited to 'src/backend/nodes/bitmapset.c')
| -rw-r--r-- | src/backend/nodes/bitmapset.c | 32 |
1 files changed, 31 insertions, 1 deletions
diff --git a/src/backend/nodes/bitmapset.c b/src/backend/nodes/bitmapset.c index 5798b726497..45c6ead0fc0 100644 --- a/src/backend/nodes/bitmapset.c +++ b/src/backend/nodes/bitmapset.c @@ -14,7 +14,7 @@ * Copyright (c) 2003, PostgreSQL Global Development Group * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/nodes/bitmapset.c,v 1.1 2003/02/08 20:20:53 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/nodes/bitmapset.c,v 1.2 2003/06/29 23:05:04 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -389,6 +389,36 @@ bms_overlap(const Bitmapset *a, const Bitmapset *b) } /* + * bms_nonempty_difference - do sets have a nonempty difference? + */ +bool +bms_nonempty_difference(const Bitmapset *a, const Bitmapset *b) +{ + int shortlen; + int i; + + /* Handle cases where either input is NULL */ + if (a == NULL) + return false; + if (b == NULL) + return !bms_is_empty(a); + /* Check words in common */ + shortlen = Min(a->nwords, b->nwords); + for (i = 0; i < shortlen; i++) + { + if ((a->words[i] & ~ b->words[i]) != 0) + return true; + } + /* Check extra words in a */ + for (; i < a->nwords; i++) + { + if (a->words[i] != 0) + return true; + } + return false; +} + +/* * bms_singleton_member - return the sole integer member of set * * Raises error if |a| is not 1. |