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27b77ecf9f
Backpatch-through: 10
1195 lines
26 KiB
C
1195 lines
26 KiB
C
/*-------------------------------------------------------------------------
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*
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* bitmapset.c
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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) 2003-2022, PostgreSQL Global Development Group
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*
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* IDENTIFICATION
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* src/backend/nodes/bitmapset.c
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "common/hashfn.h"
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#include "nodes/bitmapset.h"
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#include "nodes/pg_list.h"
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#include "port/pg_bitutils.h"
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#define WORDNUM(x) ((x) / BITS_PER_BITMAPWORD)
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#define BITNUM(x) ((x) % BITS_PER_BITMAPWORD)
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#define BITMAPSET_SIZE(nwords) \
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(offsetof(Bitmapset, words) + (nwords) * sizeof(bitmapword))
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/*----------
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* This is a well-known cute trick for isolating the rightmost one-bit
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* in a word. It assumes two's complement arithmetic. Consider any
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* nonzero value, and focus attention on the rightmost one. The value is
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* then something like
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* xxxxxx10000
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* where x's are unspecified bits. The two's complement negative is formed
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* by inverting all the bits and adding one. Inversion gives
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* yyyyyy01111
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* where each y is the inverse of the corresponding x. Incrementing gives
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* yyyyyy10000
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* and then ANDing with the original value gives
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* 00000010000
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* This works for all cases except original value = zero, where of course
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* we get zero.
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*----------
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*/
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#define RIGHTMOST_ONE(x) ((signedbitmapword) (x) & -((signedbitmapword) (x)))
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#define HAS_MULTIPLE_ONES(x) ((bitmapword) RIGHTMOST_ONE(x) != (x))
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/* Select appropriate bit-twiddling functions for bitmap word size */
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#if BITS_PER_BITMAPWORD == 32
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#define bmw_leftmost_one_pos(w) pg_leftmost_one_pos32(w)
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#define bmw_rightmost_one_pos(w) pg_rightmost_one_pos32(w)
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#define bmw_popcount(w) pg_popcount32(w)
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#elif BITS_PER_BITMAPWORD == 64
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#define bmw_leftmost_one_pos(w) pg_leftmost_one_pos64(w)
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#define bmw_rightmost_one_pos(w) pg_rightmost_one_pos64(w)
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#define bmw_popcount(w) pg_popcount64(w)
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#else
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#error "invalid BITS_PER_BITMAPWORD"
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#endif
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/*
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* bms_copy - make a palloc'd copy of a bitmapset
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*/
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Bitmapset *
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bms_copy(const Bitmapset *a)
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{
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Bitmapset *result;
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size_t size;
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if (a == NULL)
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return NULL;
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size = BITMAPSET_SIZE(a->nwords);
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result = (Bitmapset *) palloc(size);
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memcpy(result, a, size);
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return result;
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}
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/*
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* bms_equal - are two bitmapsets equal?
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*
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* This is logical not physical equality; in particular, a NULL pointer will
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* be reported as equal to a palloc'd value containing no members.
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*/
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bool
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bms_equal(const Bitmapset *a, const Bitmapset *b)
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{
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const Bitmapset *shorter;
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const Bitmapset *longer;
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int shortlen;
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int longlen;
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int i;
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/* Handle cases where either input is NULL */
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if (a == NULL)
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{
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if (b == NULL)
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return true;
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return bms_is_empty(b);
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}
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else if (b == NULL)
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return bms_is_empty(a);
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/* Identify shorter and longer input */
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if (a->nwords <= b->nwords)
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{
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shorter = a;
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longer = b;
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}
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else
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{
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shorter = b;
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longer = a;
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}
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/* And process */
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shortlen = shorter->nwords;
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for (i = 0; i < shortlen; i++)
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{
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if (shorter->words[i] != longer->words[i])
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return false;
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}
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longlen = longer->nwords;
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for (; i < longlen; i++)
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{
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if (longer->words[i] != 0)
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return false;
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}
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return true;
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}
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/*
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* bms_compare - qsort-style comparator for bitmapsets
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*
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* This guarantees to report values as equal iff bms_equal would say they are
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* equal. Otherwise, the highest-numbered bit that is set in one value but
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* not the other determines the result. (This rule means that, for example,
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* {6} is greater than {5}, which seems plausible.)
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*/
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int
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bms_compare(const Bitmapset *a, const Bitmapset *b)
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{
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int shortlen;
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int i;
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/* Handle cases where either input is NULL */
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if (a == NULL)
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return bms_is_empty(b) ? 0 : -1;
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else if (b == NULL)
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return bms_is_empty(a) ? 0 : +1;
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/* Handle cases where one input is longer than the other */
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shortlen = Min(a->nwords, b->nwords);
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for (i = shortlen; i < a->nwords; i++)
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{
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if (a->words[i] != 0)
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return +1;
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}
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for (i = shortlen; i < b->nwords; i++)
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{
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if (b->words[i] != 0)
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return -1;
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}
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/* Process words in common */
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i = shortlen;
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while (--i >= 0)
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{
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bitmapword aw = a->words[i];
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bitmapword bw = b->words[i];
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if (aw != bw)
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return (aw > bw) ? +1 : -1;
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}
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return 0;
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}
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/*
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* bms_make_singleton - build a bitmapset containing a single member
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*/
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Bitmapset *
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bms_make_singleton(int x)
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{
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Bitmapset *result;
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int wordnum,
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bitnum;
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if (x < 0)
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elog(ERROR, "negative bitmapset member not allowed");
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wordnum = WORDNUM(x);
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bitnum = BITNUM(x);
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result = (Bitmapset *) palloc0(BITMAPSET_SIZE(wordnum + 1));
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result->nwords = wordnum + 1;
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result->words[wordnum] = ((bitmapword) 1 << bitnum);
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return result;
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}
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/*
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* bms_free - free a bitmapset
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*
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* Same as pfree except for allowing NULL input
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*/
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void
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bms_free(Bitmapset *a)
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{
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if (a)
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pfree(a);
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}
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/*
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* These operations all make a freshly palloc'd result,
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* leaving their inputs untouched
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*/
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/*
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* bms_union - set union
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*/
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Bitmapset *
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bms_union(const Bitmapset *a, const Bitmapset *b)
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{
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Bitmapset *result;
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const Bitmapset *other;
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int otherlen;
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int i;
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/* Handle cases where either input is NULL */
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if (a == NULL)
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return bms_copy(b);
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if (b == NULL)
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return bms_copy(a);
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/* Identify shorter and longer input; copy the longer one */
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if (a->nwords <= b->nwords)
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{
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result = bms_copy(b);
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other = a;
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}
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else
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{
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result = bms_copy(a);
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other = b;
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}
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/* And union the shorter input into the result */
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otherlen = other->nwords;
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for (i = 0; i < otherlen; i++)
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result->words[i] |= other->words[i];
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return result;
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}
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/*
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* bms_intersect - set intersection
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*/
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Bitmapset *
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bms_intersect(const Bitmapset *a, const Bitmapset *b)
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{
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Bitmapset *result;
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const Bitmapset *other;
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int resultlen;
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int i;
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/* Handle cases where either input is NULL */
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if (a == NULL || b == NULL)
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return NULL;
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/* Identify shorter and longer input; copy the shorter one */
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if (a->nwords <= b->nwords)
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{
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result = bms_copy(a);
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other = b;
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}
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else
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{
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result = bms_copy(b);
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other = a;
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}
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/* And intersect the longer input with the result */
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resultlen = result->nwords;
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for (i = 0; i < resultlen; i++)
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result->words[i] &= other->words[i];
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return result;
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}
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/*
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* bms_difference - set difference (ie, A without members of B)
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*/
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Bitmapset *
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bms_difference(const Bitmapset *a, const Bitmapset *b)
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{
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Bitmapset *result;
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int shortlen;
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int i;
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/* Handle cases where either input is NULL */
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if (a == NULL)
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return NULL;
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if (b == NULL)
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return bms_copy(a);
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/* Copy the left input */
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result = bms_copy(a);
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/* And remove b's bits from result */
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shortlen = Min(a->nwords, b->nwords);
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for (i = 0; i < shortlen; i++)
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result->words[i] &= ~b->words[i];
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return result;
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}
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/*
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* bms_is_subset - is A a subset of B?
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*/
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bool
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bms_is_subset(const Bitmapset *a, const Bitmapset *b)
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{
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int shortlen;
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int longlen;
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int i;
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/* Handle cases where either input is NULL */
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if (a == NULL)
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return true; /* empty set is a subset of anything */
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if (b == NULL)
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return bms_is_empty(a);
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/* Check common words */
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shortlen = Min(a->nwords, b->nwords);
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for (i = 0; i < shortlen; i++)
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{
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if ((a->words[i] & ~b->words[i]) != 0)
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return false;
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}
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/* Check extra words */
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if (a->nwords > b->nwords)
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{
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longlen = a->nwords;
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for (; i < longlen; i++)
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{
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if (a->words[i] != 0)
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return false;
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}
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}
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return true;
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}
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/*
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* bms_subset_compare - compare A and B for equality/subset relationships
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*
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* This is more efficient than testing bms_is_subset in both directions.
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*/
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BMS_Comparison
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bms_subset_compare(const Bitmapset *a, const Bitmapset *b)
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{
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BMS_Comparison result;
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int shortlen;
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int longlen;
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int i;
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/* Handle cases where either input is NULL */
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if (a == NULL)
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{
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if (b == NULL)
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return BMS_EQUAL;
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return bms_is_empty(b) ? BMS_EQUAL : BMS_SUBSET1;
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}
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if (b == NULL)
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return bms_is_empty(a) ? BMS_EQUAL : BMS_SUBSET2;
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/* Check common words */
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result = BMS_EQUAL; /* status so far */
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shortlen = Min(a->nwords, b->nwords);
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for (i = 0; i < shortlen; i++)
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{
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bitmapword aword = a->words[i];
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bitmapword bword = b->words[i];
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if ((aword & ~bword) != 0)
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{
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/* a is not a subset of b */
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if (result == BMS_SUBSET1)
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return BMS_DIFFERENT;
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result = BMS_SUBSET2;
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}
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if ((bword & ~aword) != 0)
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{
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/* b is not a subset of a */
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if (result == BMS_SUBSET2)
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return BMS_DIFFERENT;
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result = BMS_SUBSET1;
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}
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}
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/* Check extra words */
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if (a->nwords > b->nwords)
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{
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longlen = a->nwords;
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for (; i < longlen; i++)
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{
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if (a->words[i] != 0)
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{
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/* a is not a subset of b */
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if (result == BMS_SUBSET1)
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return BMS_DIFFERENT;
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result = BMS_SUBSET2;
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}
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}
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}
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else if (a->nwords < b->nwords)
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{
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longlen = b->nwords;
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for (; i < longlen; i++)
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{
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if (b->words[i] != 0)
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{
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/* b is not a subset of a */
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if (result == BMS_SUBSET2)
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return BMS_DIFFERENT;
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result = BMS_SUBSET1;
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}
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}
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}
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return result;
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}
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/*
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* bms_is_member - is X a member of A?
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*/
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bool
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bms_is_member(int x, const Bitmapset *a)
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{
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int wordnum,
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bitnum;
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/* XXX better to just return false for x<0 ? */
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if (x < 0)
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elog(ERROR, "negative bitmapset member not allowed");
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if (a == NULL)
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return false;
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wordnum = WORDNUM(x);
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bitnum = BITNUM(x);
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if (wordnum >= a->nwords)
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return false;
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if ((a->words[wordnum] & ((bitmapword) 1 << bitnum)) != 0)
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return true;
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return false;
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}
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/*
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* bms_member_index
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* determine 0-based index of member x in the bitmap
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*
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* Returns (-1) when x is not a member.
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*/
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int
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bms_member_index(Bitmapset *a, int x)
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{
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int i;
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int bitnum;
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int wordnum;
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int result = 0;
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bitmapword mask;
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/* return -1 if not a member of the bitmap */
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if (!bms_is_member(x, a))
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return -1;
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wordnum = WORDNUM(x);
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bitnum = BITNUM(x);
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/* count bits in preceding words */
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for (i = 0; i < wordnum; i++)
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{
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bitmapword w = a->words[i];
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/* No need to count the bits in a zero word */
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if (w != 0)
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result += bmw_popcount(w);
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}
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/*
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* Now add bits of the last word, but only those before the item. We can
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* do that by applying a mask and then using popcount again. To get
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* 0-based index, we want to count only preceding bits, not the item
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* itself, so we subtract 1.
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*/
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mask = ((bitmapword) 1 << bitnum) - 1;
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result += bmw_popcount(a->words[wordnum] & mask);
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return result;
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}
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/*
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* bms_overlap - do sets overlap (ie, have a nonempty intersection)?
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*/
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bool
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bms_overlap(const Bitmapset *a, const Bitmapset *b)
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{
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int shortlen;
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int i;
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/* Handle cases where either input is NULL */
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if (a == NULL || b == NULL)
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return false;
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/* Check words in common */
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shortlen = Min(a->nwords, b->nwords);
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for (i = 0; i < shortlen; i++)
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{
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if ((a->words[i] & b->words[i]) != 0)
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return true;
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}
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return false;
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}
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/*
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* bms_overlap_list - does a set overlap an integer list?
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*/
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bool
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bms_overlap_list(const Bitmapset *a, const List *b)
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{
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ListCell *lc;
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int wordnum,
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bitnum;
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if (a == NULL || b == NIL)
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return false;
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foreach(lc, b)
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{
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int x = lfirst_int(lc);
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if (x < 0)
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elog(ERROR, "negative bitmapset member not allowed");
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wordnum = WORDNUM(x);
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bitnum = BITNUM(x);
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if (wordnum < a->nwords)
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if ((a->words[wordnum] & ((bitmapword) 1 << bitnum)) != 0)
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return true;
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}
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return false;
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}
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|
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/*
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* bms_nonempty_difference - do sets have a nonempty difference?
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*
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* i.e., are any members set in 'a' that are not also set in 'b'.
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*/
|
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bool
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bms_nonempty_difference(const Bitmapset *a, const Bitmapset *b)
|
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{
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int shortlen;
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int i;
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|
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/* Handle cases where either input is NULL */
|
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if (a == NULL)
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return false;
|
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if (b == NULL)
|
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return !bms_is_empty(a);
|
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/* Check words in common */
|
|
shortlen = Min(a->nwords, b->nwords);
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for (i = 0; i < shortlen; i++)
|
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{
|
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if ((a->words[i] & ~b->words[i]) != 0)
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return true;
|
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}
|
|
/* Check extra words in a */
|
|
for (; i < a->nwords; i++)
|
|
{
|
|
if (a->words[i] != 0)
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* bms_singleton_member - return the sole integer member of set
|
|
*
|
|
* Raises error if |a| is not 1.
|
|
*/
|
|
int
|
|
bms_singleton_member(const Bitmapset *a)
|
|
{
|
|
int result = -1;
|
|
int nwords;
|
|
int wordnum;
|
|
|
|
if (a == NULL)
|
|
elog(ERROR, "bitmapset is empty");
|
|
nwords = a->nwords;
|
|
for (wordnum = 0; wordnum < nwords; wordnum++)
|
|
{
|
|
bitmapword w = a->words[wordnum];
|
|
|
|
if (w != 0)
|
|
{
|
|
if (result >= 0 || HAS_MULTIPLE_ONES(w))
|
|
elog(ERROR, "bitmapset has multiple members");
|
|
result = wordnum * BITS_PER_BITMAPWORD;
|
|
result += bmw_rightmost_one_pos(w);
|
|
}
|
|
}
|
|
if (result < 0)
|
|
elog(ERROR, "bitmapset is empty");
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* bms_get_singleton_member
|
|
*
|
|
* Test whether the given set is a singleton.
|
|
* If so, set *member to the value of its sole member, and return true.
|
|
* If not, return false, without changing *member.
|
|
*
|
|
* This is more convenient and faster than calling bms_membership() and then
|
|
* bms_singleton_member(), if we don't care about distinguishing empty sets
|
|
* from multiple-member sets.
|
|
*/
|
|
bool
|
|
bms_get_singleton_member(const Bitmapset *a, int *member)
|
|
{
|
|
int result = -1;
|
|
int nwords;
|
|
int wordnum;
|
|
|
|
if (a == NULL)
|
|
return false;
|
|
nwords = a->nwords;
|
|
for (wordnum = 0; wordnum < nwords; wordnum++)
|
|
{
|
|
bitmapword w = a->words[wordnum];
|
|
|
|
if (w != 0)
|
|
{
|
|
if (result >= 0 || HAS_MULTIPLE_ONES(w))
|
|
return false;
|
|
result = wordnum * BITS_PER_BITMAPWORD;
|
|
result += bmw_rightmost_one_pos(w);
|
|
}
|
|
}
|
|
if (result < 0)
|
|
return false;
|
|
*member = result;
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* bms_num_members - count members of set
|
|
*/
|
|
int
|
|
bms_num_members(const Bitmapset *a)
|
|
{
|
|
int result = 0;
|
|
int nwords;
|
|
int wordnum;
|
|
|
|
if (a == NULL)
|
|
return 0;
|
|
nwords = a->nwords;
|
|
for (wordnum = 0; wordnum < nwords; wordnum++)
|
|
{
|
|
bitmapword w = a->words[wordnum];
|
|
|
|
/* No need to count the bits in a zero word */
|
|
if (w != 0)
|
|
result += bmw_popcount(w);
|
|
}
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* bms_membership - does a set have zero, one, or multiple members?
|
|
*
|
|
* This is faster than making an exact count with bms_num_members().
|
|
*/
|
|
BMS_Membership
|
|
bms_membership(const Bitmapset *a)
|
|
{
|
|
BMS_Membership result = BMS_EMPTY_SET;
|
|
int nwords;
|
|
int wordnum;
|
|
|
|
if (a == NULL)
|
|
return BMS_EMPTY_SET;
|
|
nwords = a->nwords;
|
|
for (wordnum = 0; wordnum < nwords; wordnum++)
|
|
{
|
|
bitmapword w = a->words[wordnum];
|
|
|
|
if (w != 0)
|
|
{
|
|
if (result != BMS_EMPTY_SET || HAS_MULTIPLE_ONES(w))
|
|
return BMS_MULTIPLE;
|
|
result = BMS_SINGLETON;
|
|
}
|
|
}
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* bms_is_empty - is a set empty?
|
|
*
|
|
* This is even faster than bms_membership().
|
|
*/
|
|
bool
|
|
bms_is_empty(const Bitmapset *a)
|
|
{
|
|
int nwords;
|
|
int wordnum;
|
|
|
|
if (a == NULL)
|
|
return true;
|
|
nwords = a->nwords;
|
|
for (wordnum = 0; wordnum < nwords; wordnum++)
|
|
{
|
|
bitmapword w = a->words[wordnum];
|
|
|
|
if (w != 0)
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
|
|
/*
|
|
* These operations all "recycle" their non-const inputs, ie, either
|
|
* return the modified input or pfree it if it can't hold the result.
|
|
*
|
|
* These should generally be used in the style
|
|
*
|
|
* foo = bms_add_member(foo, x);
|
|
*/
|
|
|
|
|
|
/*
|
|
* bms_add_member - add a specified member to set
|
|
*
|
|
* Input set is modified or recycled!
|
|
*/
|
|
Bitmapset *
|
|
bms_add_member(Bitmapset *a, int x)
|
|
{
|
|
int wordnum,
|
|
bitnum;
|
|
|
|
if (x < 0)
|
|
elog(ERROR, "negative bitmapset member not allowed");
|
|
if (a == NULL)
|
|
return bms_make_singleton(x);
|
|
wordnum = WORDNUM(x);
|
|
bitnum = BITNUM(x);
|
|
|
|
/* enlarge the set if necessary */
|
|
if (wordnum >= a->nwords)
|
|
{
|
|
int oldnwords = a->nwords;
|
|
int i;
|
|
|
|
a = (Bitmapset *) repalloc(a, BITMAPSET_SIZE(wordnum + 1));
|
|
a->nwords = wordnum + 1;
|
|
/* zero out the enlarged portion */
|
|
for (i = oldnwords; i < a->nwords; i++)
|
|
a->words[i] = 0;
|
|
}
|
|
|
|
a->words[wordnum] |= ((bitmapword) 1 << bitnum);
|
|
return a;
|
|
}
|
|
|
|
/*
|
|
* bms_del_member - remove a specified member from set
|
|
*
|
|
* No error if x is not currently a member of set
|
|
*
|
|
* Input set is modified in-place!
|
|
*/
|
|
Bitmapset *
|
|
bms_del_member(Bitmapset *a, int x)
|
|
{
|
|
int wordnum,
|
|
bitnum;
|
|
|
|
if (x < 0)
|
|
elog(ERROR, "negative bitmapset member not allowed");
|
|
if (a == NULL)
|
|
return NULL;
|
|
wordnum = WORDNUM(x);
|
|
bitnum = BITNUM(x);
|
|
if (wordnum < a->nwords)
|
|
a->words[wordnum] &= ~((bitmapword) 1 << bitnum);
|
|
return a;
|
|
}
|
|
|
|
/*
|
|
* bms_add_members - like bms_union, but left input is recycled
|
|
*/
|
|
Bitmapset *
|
|
bms_add_members(Bitmapset *a, const Bitmapset *b)
|
|
{
|
|
Bitmapset *result;
|
|
const Bitmapset *other;
|
|
int otherlen;
|
|
int i;
|
|
|
|
/* Handle cases where either input is NULL */
|
|
if (a == NULL)
|
|
return bms_copy(b);
|
|
if (b == NULL)
|
|
return a;
|
|
/* Identify shorter and longer input; copy the longer one if needed */
|
|
if (a->nwords < b->nwords)
|
|
{
|
|
result = bms_copy(b);
|
|
other = a;
|
|
}
|
|
else
|
|
{
|
|
result = a;
|
|
other = b;
|
|
}
|
|
/* And union the shorter input into the result */
|
|
otherlen = other->nwords;
|
|
for (i = 0; i < otherlen; i++)
|
|
result->words[i] |= other->words[i];
|
|
if (result != a)
|
|
pfree(a);
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* bms_add_range
|
|
* Add members in the range of 'lower' to 'upper' to the set.
|
|
*
|
|
* Note this could also be done by calling bms_add_member in a loop, however,
|
|
* using this function will be faster when the range is large as we work at
|
|
* the bitmapword level rather than at bit level.
|
|
*/
|
|
Bitmapset *
|
|
bms_add_range(Bitmapset *a, int lower, int upper)
|
|
{
|
|
int lwordnum,
|
|
lbitnum,
|
|
uwordnum,
|
|
ushiftbits,
|
|
wordnum;
|
|
|
|
/* do nothing if nothing is called for, without further checking */
|
|
if (upper < lower)
|
|
return a;
|
|
|
|
if (lower < 0)
|
|
elog(ERROR, "negative bitmapset member not allowed");
|
|
uwordnum = WORDNUM(upper);
|
|
|
|
if (a == NULL)
|
|
{
|
|
a = (Bitmapset *) palloc0(BITMAPSET_SIZE(uwordnum + 1));
|
|
a->nwords = uwordnum + 1;
|
|
}
|
|
else if (uwordnum >= a->nwords)
|
|
{
|
|
int oldnwords = a->nwords;
|
|
int i;
|
|
|
|
/* ensure we have enough words to store the upper bit */
|
|
a = (Bitmapset *) repalloc(a, BITMAPSET_SIZE(uwordnum + 1));
|
|
a->nwords = uwordnum + 1;
|
|
/* zero out the enlarged portion */
|
|
for (i = oldnwords; i < a->nwords; i++)
|
|
a->words[i] = 0;
|
|
}
|
|
|
|
wordnum = lwordnum = WORDNUM(lower);
|
|
|
|
lbitnum = BITNUM(lower);
|
|
ushiftbits = BITS_PER_BITMAPWORD - (BITNUM(upper) + 1);
|
|
|
|
/*
|
|
* Special case when lwordnum is the same as uwordnum we must perform the
|
|
* upper and lower masking on the word.
|
|
*/
|
|
if (lwordnum == uwordnum)
|
|
{
|
|
a->words[lwordnum] |= ~(bitmapword) (((bitmapword) 1 << lbitnum) - 1)
|
|
& (~(bitmapword) 0) >> ushiftbits;
|
|
}
|
|
else
|
|
{
|
|
/* turn on lbitnum and all bits left of it */
|
|
a->words[wordnum++] |= ~(bitmapword) (((bitmapword) 1 << lbitnum) - 1);
|
|
|
|
/* turn on all bits for any intermediate words */
|
|
while (wordnum < uwordnum)
|
|
a->words[wordnum++] = ~(bitmapword) 0;
|
|
|
|
/* turn on upper's bit and all bits right of it. */
|
|
a->words[uwordnum] |= (~(bitmapword) 0) >> ushiftbits;
|
|
}
|
|
|
|
return a;
|
|
}
|
|
|
|
/*
|
|
* bms_int_members - like bms_intersect, but left input is recycled
|
|
*/
|
|
Bitmapset *
|
|
bms_int_members(Bitmapset *a, const Bitmapset *b)
|
|
{
|
|
int shortlen;
|
|
int i;
|
|
|
|
/* Handle cases where either input is NULL */
|
|
if (a == NULL)
|
|
return NULL;
|
|
if (b == NULL)
|
|
{
|
|
pfree(a);
|
|
return NULL;
|
|
}
|
|
/* Intersect b into a; we need never copy */
|
|
shortlen = Min(a->nwords, b->nwords);
|
|
for (i = 0; i < shortlen; i++)
|
|
a->words[i] &= b->words[i];
|
|
for (; i < a->nwords; i++)
|
|
a->words[i] = 0;
|
|
return a;
|
|
}
|
|
|
|
/*
|
|
* bms_del_members - like bms_difference, but left input is recycled
|
|
*/
|
|
Bitmapset *
|
|
bms_del_members(Bitmapset *a, const Bitmapset *b)
|
|
{
|
|
int shortlen;
|
|
int i;
|
|
|
|
/* Handle cases where either input is NULL */
|
|
if (a == NULL)
|
|
return NULL;
|
|
if (b == NULL)
|
|
return a;
|
|
/* Remove b's bits from a; we need never copy */
|
|
shortlen = Min(a->nwords, b->nwords);
|
|
for (i = 0; i < shortlen; i++)
|
|
a->words[i] &= ~b->words[i];
|
|
return a;
|
|
}
|
|
|
|
/*
|
|
* bms_join - like bms_union, but *both* inputs are recycled
|
|
*/
|
|
Bitmapset *
|
|
bms_join(Bitmapset *a, Bitmapset *b)
|
|
{
|
|
Bitmapset *result;
|
|
Bitmapset *other;
|
|
int otherlen;
|
|
int i;
|
|
|
|
/* Handle cases where either input is NULL */
|
|
if (a == NULL)
|
|
return b;
|
|
if (b == NULL)
|
|
return a;
|
|
/* Identify shorter and longer input; use longer one as result */
|
|
if (a->nwords < b->nwords)
|
|
{
|
|
result = b;
|
|
other = a;
|
|
}
|
|
else
|
|
{
|
|
result = a;
|
|
other = b;
|
|
}
|
|
/* And union the shorter input into the result */
|
|
otherlen = other->nwords;
|
|
for (i = 0; i < otherlen; i++)
|
|
result->words[i] |= other->words[i];
|
|
if (other != result) /* pure paranoia */
|
|
pfree(other);
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* bms_first_member - find and remove first member of a set
|
|
*
|
|
* Returns -1 if set is empty. NB: set is destructively modified!
|
|
*
|
|
* This is intended as support for iterating through the members of a set.
|
|
* The typical pattern is
|
|
*
|
|
* while ((x = bms_first_member(inputset)) >= 0)
|
|
* process member x;
|
|
*
|
|
* CAUTION: this destroys the content of "inputset". If the set must
|
|
* not be modified, use bms_next_member instead.
|
|
*/
|
|
int
|
|
bms_first_member(Bitmapset *a)
|
|
{
|
|
int nwords;
|
|
int wordnum;
|
|
|
|
if (a == NULL)
|
|
return -1;
|
|
nwords = a->nwords;
|
|
for (wordnum = 0; wordnum < nwords; wordnum++)
|
|
{
|
|
bitmapword w = a->words[wordnum];
|
|
|
|
if (w != 0)
|
|
{
|
|
int result;
|
|
|
|
w = RIGHTMOST_ONE(w);
|
|
a->words[wordnum] &= ~w;
|
|
|
|
result = wordnum * BITS_PER_BITMAPWORD;
|
|
result += bmw_rightmost_one_pos(w);
|
|
return result;
|
|
}
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
/*
|
|
* bms_next_member - find next member of a set
|
|
*
|
|
* Returns smallest member greater than "prevbit", or -2 if there is none.
|
|
* "prevbit" must NOT be less than -1, or the behavior is unpredictable.
|
|
*
|
|
* This is intended as support for iterating through the members of a set.
|
|
* The typical pattern is
|
|
*
|
|
* x = -1;
|
|
* while ((x = bms_next_member(inputset, x)) >= 0)
|
|
* process member x;
|
|
*
|
|
* Notice that when there are no more members, we return -2, not -1 as you
|
|
* might expect. The rationale for that is to allow distinguishing the
|
|
* loop-not-started state (x == -1) from the loop-completed state (x == -2).
|
|
* It makes no difference in simple loop usage, but complex iteration logic
|
|
* might need such an ability.
|
|
*/
|
|
int
|
|
bms_next_member(const Bitmapset *a, int prevbit)
|
|
{
|
|
int nwords;
|
|
int wordnum;
|
|
bitmapword mask;
|
|
|
|
if (a == NULL)
|
|
return -2;
|
|
nwords = a->nwords;
|
|
prevbit++;
|
|
mask = (~(bitmapword) 0) << BITNUM(prevbit);
|
|
for (wordnum = WORDNUM(prevbit); wordnum < nwords; wordnum++)
|
|
{
|
|
bitmapword w = a->words[wordnum];
|
|
|
|
/* ignore bits before prevbit */
|
|
w &= mask;
|
|
|
|
if (w != 0)
|
|
{
|
|
int result;
|
|
|
|
result = wordnum * BITS_PER_BITMAPWORD;
|
|
result += bmw_rightmost_one_pos(w);
|
|
return result;
|
|
}
|
|
|
|
/* in subsequent words, consider all bits */
|
|
mask = (~(bitmapword) 0);
|
|
}
|
|
return -2;
|
|
}
|
|
|
|
/*
|
|
* bms_prev_member - find prev member of a set
|
|
*
|
|
* Returns largest member less than "prevbit", or -2 if there is none.
|
|
* "prevbit" must NOT be more than one above the highest possible bit that can
|
|
* be set at the Bitmapset at its current size.
|
|
*
|
|
* To ease finding the highest set bit for the initial loop, the special
|
|
* prevbit value of -1 can be passed to have the function find the highest
|
|
* valued member in the set.
|
|
*
|
|
* This is intended as support for iterating through the members of a set in
|
|
* reverse. The typical pattern is
|
|
*
|
|
* x = -1;
|
|
* while ((x = bms_prev_member(inputset, x)) >= 0)
|
|
* process member x;
|
|
*
|
|
* Notice that when there are no more members, we return -2, not -1 as you
|
|
* might expect. The rationale for that is to allow distinguishing the
|
|
* loop-not-started state (x == -1) from the loop-completed state (x == -2).
|
|
* It makes no difference in simple loop usage, but complex iteration logic
|
|
* might need such an ability.
|
|
*/
|
|
|
|
int
|
|
bms_prev_member(const Bitmapset *a, int prevbit)
|
|
{
|
|
int wordnum;
|
|
int ushiftbits;
|
|
bitmapword mask;
|
|
|
|
/*
|
|
* If set is NULL or if there are no more bits to the right then we've
|
|
* nothing to do.
|
|
*/
|
|
if (a == NULL || prevbit == 0)
|
|
return -2;
|
|
|
|
/* transform -1 to the highest possible bit we could have set */
|
|
if (prevbit == -1)
|
|
prevbit = a->nwords * BITS_PER_BITMAPWORD - 1;
|
|
else
|
|
prevbit--;
|
|
|
|
ushiftbits = BITS_PER_BITMAPWORD - (BITNUM(prevbit) + 1);
|
|
mask = (~(bitmapword) 0) >> ushiftbits;
|
|
for (wordnum = WORDNUM(prevbit); wordnum >= 0; wordnum--)
|
|
{
|
|
bitmapword w = a->words[wordnum];
|
|
|
|
/* mask out bits left of prevbit */
|
|
w &= mask;
|
|
|
|
if (w != 0)
|
|
{
|
|
int result;
|
|
|
|
result = wordnum * BITS_PER_BITMAPWORD;
|
|
result += bmw_leftmost_one_pos(w);
|
|
return result;
|
|
}
|
|
|
|
/* in subsequent words, consider all bits */
|
|
mask = (~(bitmapword) 0);
|
|
}
|
|
return -2;
|
|
}
|
|
|
|
/*
|
|
* bms_hash_value - compute a hash key for a Bitmapset
|
|
*
|
|
* Note: we must ensure that any two bitmapsets that are bms_equal() will
|
|
* hash to the same value; in practice this means that trailing all-zero
|
|
* words must not affect the result. Hence we strip those before applying
|
|
* hash_any().
|
|
*/
|
|
uint32
|
|
bms_hash_value(const Bitmapset *a)
|
|
{
|
|
int lastword;
|
|
|
|
if (a == NULL)
|
|
return 0; /* All empty sets hash to 0 */
|
|
for (lastword = a->nwords; --lastword >= 0;)
|
|
{
|
|
if (a->words[lastword] != 0)
|
|
break;
|
|
}
|
|
if (lastword < 0)
|
|
return 0; /* All empty sets hash to 0 */
|
|
return DatumGetUInt32(hash_any((const unsigned char *) a->words,
|
|
(lastword + 1) * sizeof(bitmapword)));
|
|
}
|
|
|
|
/*
|
|
* bitmap_hash - hash function for keys that are (pointers to) Bitmapsets
|
|
*
|
|
* Note: don't forget to specify bitmap_match as the match function!
|
|
*/
|
|
uint32
|
|
bitmap_hash(const void *key, Size keysize)
|
|
{
|
|
Assert(keysize == sizeof(Bitmapset *));
|
|
return bms_hash_value(*((const Bitmapset *const *) key));
|
|
}
|
|
|
|
/*
|
|
* bitmap_match - match function to use with bitmap_hash
|
|
*/
|
|
int
|
|
bitmap_match(const void *key1, const void *key2, Size keysize)
|
|
{
|
|
Assert(keysize == sizeof(Bitmapset *));
|
|
return !bms_equal(*((const Bitmapset *const *) key1),
|
|
*((const Bitmapset *const *) key2));
|
|
}
|