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db_include/nodes/bitmapset.h

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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 */