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09d8d110a6
Replace some bogus "x[1]" declarations with "x[FLEXIBLE_ARRAY_MEMBER]". Aside from being more self-documenting, this should help prevent bogus warnings from static code analyzers and perhaps compiler misoptimizations. This patch is just a down payment on eliminating the whole problem, but it gets rid of a lot of easy-to-fix cases. Note that the main problem with doing this is that one must no longer rely on computing sizeof(the containing struct), since the result would be compiler-dependent. Instead use offsetof(struct, lastfield). Autoconf also warns against spelling that offsetof(struct, lastfield[0]). Michael Paquier, review and additional fixes by me.
98 lines
3.5 KiB
C
98 lines
3.5 KiB
C
/*-------------------------------------------------------------------------
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*
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* bitmapset.h
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* PostgreSQL generic bitmap set package
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*
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* A bitmap set can represent any set of nonnegative integers, although
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* it is mainly intended for sets where the maximum value is not large,
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* say at most a few hundred. By convention, a NULL pointer is always
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* accepted by all operations to represent the empty set. (But beware
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* that this is not the only representation of the empty set. Use
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* bms_is_empty() in preference to testing for NULL.)
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*
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*
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* Copyright (c) 2003-2015, PostgreSQL Global Development Group
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*
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* src/include/nodes/bitmapset.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef BITMAPSET_H
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#define BITMAPSET_H
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/*
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* Data representation
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*/
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/* The unit size can be adjusted by changing these three declarations: */
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#define BITS_PER_BITMAPWORD 32
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typedef uint32 bitmapword; /* must be an unsigned type */
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typedef int32 signedbitmapword; /* must be the matching signed type */
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typedef struct Bitmapset
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{
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int nwords; /* number of words in array */
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bitmapword words[FLEXIBLE_ARRAY_MEMBER]; /* really [nwords] */
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} Bitmapset;
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/* result of bms_subset_compare */
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typedef enum
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{
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BMS_EQUAL, /* sets are equal */
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BMS_SUBSET1, /* first set is a subset of the second */
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BMS_SUBSET2, /* second set is a subset of the first */
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BMS_DIFFERENT /* neither set is a subset of the other */
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} BMS_Comparison;
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/* result of bms_membership */
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typedef enum
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{
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BMS_EMPTY_SET, /* 0 members */
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BMS_SINGLETON, /* 1 member */
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BMS_MULTIPLE /* >1 member */
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} BMS_Membership;
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/*
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* function prototypes in nodes/bitmapset.c
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*/
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extern Bitmapset *bms_copy(const Bitmapset *a);
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extern bool bms_equal(const Bitmapset *a, const Bitmapset *b);
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extern Bitmapset *bms_make_singleton(int x);
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extern void bms_free(Bitmapset *a);
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extern Bitmapset *bms_union(const Bitmapset *a, const Bitmapset *b);
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extern Bitmapset *bms_intersect(const Bitmapset *a, const Bitmapset *b);
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extern Bitmapset *bms_difference(const Bitmapset *a, const Bitmapset *b);
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extern bool bms_is_subset(const Bitmapset *a, const Bitmapset *b);
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extern BMS_Comparison bms_subset_compare(const Bitmapset *a, const Bitmapset *b);
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extern bool bms_is_member(int x, const Bitmapset *a);
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extern bool bms_overlap(const Bitmapset *a, const Bitmapset *b);
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extern bool bms_nonempty_difference(const Bitmapset *a, const Bitmapset *b);
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extern int bms_singleton_member(const Bitmapset *a);
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extern bool bms_get_singleton_member(const Bitmapset *a, int *member);
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extern int bms_num_members(const Bitmapset *a);
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/* optimized tests when we don't need to know exact membership count: */
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extern BMS_Membership bms_membership(const Bitmapset *a);
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extern bool bms_is_empty(const Bitmapset *a);
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/* these routines recycle (modify or free) their non-const inputs: */
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extern Bitmapset *bms_add_member(Bitmapset *a, int x);
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extern Bitmapset *bms_del_member(Bitmapset *a, int x);
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extern Bitmapset *bms_add_members(Bitmapset *a, const Bitmapset *b);
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extern Bitmapset *bms_int_members(Bitmapset *a, const Bitmapset *b);
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extern Bitmapset *bms_del_members(Bitmapset *a, const Bitmapset *b);
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extern Bitmapset *bms_join(Bitmapset *a, Bitmapset *b);
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/* support for iterating through the integer elements of a set: */
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extern int bms_first_member(Bitmapset *a);
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extern int bms_next_member(const Bitmapset *a, int prevbit);
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/* support for hashtables using Bitmapsets as keys: */
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extern uint32 bms_hash_value(const Bitmapset *a);
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#endif /* BITMAPSET_H */
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