1 /*-------------------------------------------------------------------------
4 * PostgreSQL generic bitmap set package
6 * A bitmap set can represent any set of nonnegative integers, although
7 * it is mainly intended for sets where the maximum value is not large,
8 * say at most a few hundred. By convention, a NULL pointer is always
9 * accepted by all operations to represent the empty set. (But beware
10 * that this is not the only representation of the empty set. Use
11 * bms_is_empty() in preference to testing for NULL.)
14 * Copyright (c) 2003-2014, PostgreSQL Global Development Group
16 * src/include/nodes/bitmapset.h
18 *-------------------------------------------------------------------------
27 /* The unit size can be adjusted by changing these three declarations: */
28 #define BITS_PER_BITMAPWORD 32
29 typedef uint32 bitmapword; /* must be an unsigned type */
30 typedef int32 signedbitmapword; /* must be the matching signed type */
32 typedef struct Bitmapset
34 int nwords; /* number of words in array */
35 bitmapword words[1]; /* really [nwords] */
36 } Bitmapset; /* VARIABLE LENGTH STRUCT */
39 /* result of bms_subset_compare */
42 BMS_EQUAL, /* sets are equal */
43 BMS_SUBSET1, /* first set is a subset of the second */
44 BMS_SUBSET2, /* second set is a subset of the first */
45 BMS_DIFFERENT /* neither set is a subset of the other */
48 /* result of bms_membership */
51 BMS_EMPTY_SET, /* 0 members */
52 BMS_SINGLETON, /* 1 member */
53 BMS_MULTIPLE /* >1 member */
58 * function prototypes in nodes/bitmapset.c
61 extern Bitmapset *bms_copy(const Bitmapset *a);
62 extern bool bms_equal(const Bitmapset *a, const Bitmapset *b);
63 extern Bitmapset *bms_make_singleton(int x);
64 extern void bms_free(Bitmapset *a);
66 extern Bitmapset *bms_union(const Bitmapset *a, const Bitmapset *b);
67 extern Bitmapset *bms_intersect(const Bitmapset *a, const Bitmapset *b);
68 extern Bitmapset *bms_difference(const Bitmapset *a, const Bitmapset *b);
69 extern bool bms_is_subset(const Bitmapset *a, const Bitmapset *b);
70 extern BMS_Comparison bms_subset_compare(const Bitmapset *a, const Bitmapset *b);
71 extern bool bms_is_member(int x, const Bitmapset *a);
72 extern bool bms_overlap(const Bitmapset *a, const Bitmapset *b);
73 extern bool bms_nonempty_difference(const Bitmapset *a, const Bitmapset *b);
74 extern int bms_singleton_member(const Bitmapset *a);
75 extern int bms_num_members(const Bitmapset *a);
77 /* optimized tests when we don't need to know exact membership count: */
78 extern BMS_Membership bms_membership(const Bitmapset *a);
79 extern bool bms_is_empty(const Bitmapset *a);
81 /* these routines recycle (modify or free) their non-const inputs: */
83 extern Bitmapset *bms_add_member(Bitmapset *a, int x);
84 extern Bitmapset *bms_del_member(Bitmapset *a, int x);
85 extern Bitmapset *bms_add_members(Bitmapset *a, const Bitmapset *b);
86 extern Bitmapset *bms_int_members(Bitmapset *a, const Bitmapset *b);
87 extern Bitmapset *bms_del_members(Bitmapset *a, const Bitmapset *b);
88 extern Bitmapset *bms_join(Bitmapset *a, Bitmapset *b);
90 /* support for iterating through the integer elements of a set: */
91 extern int bms_first_member(Bitmapset *a);
92 extern int bms_next_member(const Bitmapset *a, int prevbit);
94 /* support for hashtables using Bitmapsets as keys: */
95 extern uint32 bms_hash_value(const Bitmapset *a);
97 #endif /* BITMAPSET_H */