Eneboo - Documentación para desarrolladores: Fichero Fuente src/libpq/include/nodes/bitmapset.h

Eneboo - Documentación para desarrolladores
00001 /*-------------------------------------------------------------------------
00002  *
00003  * bitmapset.h
00004  *        PostgreSQL generic bitmap set package
00005  *
00006  * A bitmap set can represent any set of nonnegative integers, although
00007  * it is mainly intended for sets where the maximum value is not large,
00008  * say at most a few hundred.  By convention, a NULL pointer is always
00009  * accepted by all operations to represent the empty set.  (But beware
00010  * that this is not the only representation of the empty set.  Use
00011  * bms_is_empty() in preference to testing for NULL.)
00012  *
00013  *
00014  * Copyright (c) 2003-2005, PostgreSQL Global Development Group
00015  *
00016  * $PostgreSQL: pgsql/src/include/nodes/bitmapset.h,v 1.7 2005/06/08 23:02:05 tgl Exp $
00017  *
00018  *-------------------------------------------------------------------------
00019  */
00020 #ifndef BITMAPSET_H
00021 #define BITMAPSET_H
00022 
00023 /*
00024  * Data representation
00025  */
00026 
00027 /* The unit size can be adjusted by changing these three declarations: */
00028 #define BITS_PER_BITMAPWORD 32
00029 typedef uint32 bitmapword;              /* must be an unsigned type */
00030 typedef int32 signedbitmapword; /* must be the matching signed type */
00031 
00032 typedef struct Bitmapset
00033 {
00034         int                     nwords;                 /* number of words in array */
00035         bitmapword      words[1];               /* really [nwords] */
00036 } Bitmapset;                                    /* VARIABLE LENGTH STRUCT */
00037 
00038 
00039 /* result of bms_membership */
00040 typedef enum
00041 {
00042         BMS_EMPTY_SET,                          /* 0 members */
00043         BMS_SINGLETON,                          /* 1 member */
00044         BMS_MULTIPLE                            /* >1 member */
00045 } BMS_Membership;
00046 
00047 
00048 /*
00049  * function prototypes in nodes/bitmapset.c
00050  */
00051 
00052 extern Bitmapset *bms_copy(const Bitmapset *a);
00053 extern bool bms_equal(const Bitmapset *a, const Bitmapset *b);
00054 extern Bitmapset *bms_make_singleton(int x);
00055 extern void bms_free(Bitmapset *a);
00056 
00057 extern Bitmapset *bms_union(const Bitmapset *a, const Bitmapset *b);
00058 extern Bitmapset *bms_intersect(const Bitmapset *a, const Bitmapset *b);
00059 extern Bitmapset *bms_difference(const Bitmapset *a, const Bitmapset *b);
00060 extern bool bms_is_subset(const Bitmapset *a, const Bitmapset *b);
00061 extern bool bms_is_member(int x, const Bitmapset *a);
00062 extern bool bms_overlap(const Bitmapset *a, const Bitmapset *b);
00063 extern bool bms_nonempty_difference(const Bitmapset *a, const Bitmapset *b);
00064 extern int      bms_singleton_member(const Bitmapset *a);
00065 extern int      bms_num_members(const Bitmapset *a);
00066 
00067 /* optimized tests when we don't need to know exact membership count: */
00068 extern BMS_Membership bms_membership(const Bitmapset *a);
00069 extern bool bms_is_empty(const Bitmapset *a);
00070 
00071 /* these routines recycle (modify or free) their non-const inputs: */
00072 
00073 extern Bitmapset *bms_add_member(Bitmapset *a, int x);
00074 extern Bitmapset *bms_del_member(Bitmapset *a, int x);
00075 extern Bitmapset *bms_add_members(Bitmapset *a, const Bitmapset *b);
00076 extern Bitmapset *bms_int_members(Bitmapset *a, const Bitmapset *b);
00077 extern Bitmapset *bms_del_members(Bitmapset *a, const Bitmapset *b);
00078 extern Bitmapset *bms_join(Bitmapset *a, Bitmapset *b);
00079 
00080 /* support for iterating through the integer elements of a set: */
00081 extern int      bms_first_member(Bitmapset *a);
00082 
00083 /* support for hashtables using Bitmapsets as keys: */
00084 extern uint32 bms_hash_value(const Bitmapset *a);
00085 
00086 #endif   /* BITMAPSET_H */