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Diffstat (limited to 'src/include/nodes/bitmapset.h')
| -rw-r--r-- | src/include/nodes/bitmapset.h | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/src/include/nodes/bitmapset.h b/src/include/nodes/bitmapset.h new file mode 100644 index 0000000000..4e06d7a284 --- /dev/null +++ b/src/include/nodes/bitmapset.h @@ -0,0 +1,80 @@ +/*------------------------------------------------------------------------- + * + * bitmapset.h + * PostgreSQL generic bitmap set package + * + * A bitmap set can represent any set of nonnegative integers, although + * it is mainly intended for sets where the maximum value is not large, + * say at most a few hundred. By convention, a NULL pointer is always + * accepted by all operations to represent the empty set. (But beware + * that this is not the only representation of the empty set. Use + * bms_is_empty() in preference to testing for NULL.) + * + * + * Copyright (c) 2003, PostgreSQL Global Development Group + * + * $Id: bitmapset.h,v 1.1 2003/02/08 20:20:55 tgl Exp $ + * + *------------------------------------------------------------------------- + */ +#ifndef BITMAPSET_H +#define BITMAPSET_H + +/* + * Data representation + */ + +/* The unit size can be adjusted by changing these three declarations: */ +#define BITS_PER_BITMAPWORD 32 +typedef uint32 bitmapword; /* must be an unsigned type */ +typedef int32 signedbitmapword; /* must be the matching signed type */ + +typedef struct Bitmapset { + int nwords; /* number of words in array */ + bitmapword words[1]; /* really [nwords] */ +} Bitmapset; /* VARIABLE LENGTH STRUCT */ + + +/* result of bms_membership */ +typedef enum +{ + BMS_EMPTY_SET, /* 0 members */ + BMS_SINGLETON, /* 1 member */ + BMS_MULTIPLE /* >1 member */ +} BMS_Membership; + + +/* + * function prototypes in nodes/bitmapset.c + */ + +extern Bitmapset *bms_copy(const Bitmapset *a); +extern bool bms_equal(const Bitmapset *a, const Bitmapset *b); +extern Bitmapset *bms_make_singleton(int x); +extern void bms_free(Bitmapset *a); + +extern Bitmapset *bms_union(const Bitmapset *a, const Bitmapset *b); +extern Bitmapset *bms_intersect(const Bitmapset *a, const Bitmapset *b); +extern Bitmapset *bms_difference(const Bitmapset *a, const Bitmapset *b); +extern bool bms_is_subset(const Bitmapset *a, const Bitmapset *b); +extern bool bms_is_member(int x, const Bitmapset *a); +extern bool bms_overlap(const Bitmapset *a, const Bitmapset *b); +extern int bms_singleton_member(const Bitmapset *a); +extern int bms_num_members(const Bitmapset *a); +/* optimized tests when we don't need to know exact membership count: */ +extern BMS_Membership bms_membership(const Bitmapset *a); +extern bool bms_is_empty(const Bitmapset *a); + +/* these routines recycle (modify or free) their non-const inputs: */ + +extern Bitmapset *bms_add_member(Bitmapset *a, int x); +extern Bitmapset *bms_del_member(Bitmapset *a, int x); +extern Bitmapset *bms_add_members(Bitmapset *a, const Bitmapset *b); +extern Bitmapset *bms_int_members(Bitmapset *a, const Bitmapset *b); +extern Bitmapset *bms_del_members(Bitmapset *a, const Bitmapset *b); +extern Bitmapset *bms_join(Bitmapset *a, Bitmapset *b); + +/* support for iterating through the integer elements of a set: */ +extern int bms_first_member(Bitmapset *a); + +#endif /* BITMAPSET_H */ |