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/*-------------------------------------------------------------------------
*
* 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) 2003-2021, PostgreSQL Global Development Group
*
* src/include/nodes/bitmapset.h
*
*-------------------------------------------------------------------------
*/
#ifndef BITMAPSET_H
#define BITMAPSET_H
/*
* Forward decl to save including pg_list.h
*/
struct List;
/*
* Data representation
*
* Larger bitmap word sizes generally give better performance, so long as
* they're not wider than the processor can handle efficiently. We use
* 64-bit words if pointers are that large, else 32-bit words.
*/
#if SIZEOF_VOID_P >= 8
#define BITS_PER_BITMAPWORD 64
typedef uint64 bitmapword; /* must be an unsigned type */
typedef int64 signedbitmapword; /* must be the matching signed type */
#else
#define BITS_PER_BITMAPWORD 32
typedef uint32 bitmapword; /* must be an unsigned type */
typedef int32 signedbitmapword; /* must be the matching signed type */
#endif
typedef struct Bitmapset
{
int nwords; /* number of words in array */
bitmapword words[FLEXIBLE_ARRAY_MEMBER]; /* really [nwords] */
} Bitmapset;
/* result of bms_subset_compare */
typedef enum
{
BMS_EQUAL, /* sets are equal */
BMS_SUBSET1, /* first set is a subset of the second */
BMS_SUBSET2, /* second set is a subset of the first */
BMS_DIFFERENT /* neither set is a subset of the other */
} BMS_Comparison;
/* 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 int bms_compare(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 BMS_Comparison bms_subset_compare(const Bitmapset *a, const Bitmapset *b);
extern bool bms_is_member(int x, const Bitmapset *a);
extern int bms_member_index(Bitmapset *a, int x);
extern bool bms_overlap(const Bitmapset *a, const Bitmapset *b);
extern bool bms_overlap_list(const Bitmapset *a, const struct List *b);
extern bool bms_nonempty_difference(const Bitmapset *a, const Bitmapset *b);
extern int bms_singleton_member(const Bitmapset *a);
extern bool bms_get_singleton_member(const Bitmapset *a, int *member);
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_add_range(Bitmapset *a, int lower, int upper);
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);
extern int bms_next_member(const Bitmapset *a, int prevbit);
extern int bms_prev_member(const Bitmapset *a, int prevbit);
/* support for hashtables using Bitmapsets as keys: */
extern uint32 bms_hash_value(const Bitmapset *a);
extern uint32 bitmap_hash(const void *key, Size keysize);
extern int bitmap_match(const void *key1, const void *key2, Size keysize);
#endif /* BITMAPSET_H */
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