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diff --git a/contrib/bloom/bloom.h b/contrib/bloom/bloom.h
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+/*-------------------------------------------------------------------------
+ *
+ * bloom.h
+ *	  Header for bloom index.
+ *
+ * Copyright (c) 2016-2021, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *	  contrib/bloom/bloom.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef _BLOOM_H_
+#define _BLOOM_H_
+
+#include "access/amapi.h"
+#include "access/generic_xlog.h"
+#include "access/itup.h"
+#include "access/xlog.h"
+#include "fmgr.h"
+#include "nodes/pathnodes.h"
+
+/* Support procedures numbers */
+#define BLOOM_HASH_PROC			1
+#define BLOOM_OPTIONS_PROC		2
+#define BLOOM_NPROC				2
+
+/* Scan strategies */
+#define BLOOM_EQUAL_STRATEGY	1
+#define BLOOM_NSTRATEGIES		1
+
+/* Opaque for bloom pages */
+typedef struct BloomPageOpaqueData
+{
+	OffsetNumber maxoff;		/* number of index tuples on page */
+	uint16		flags;			/* see bit definitions below */
+	uint16		unused;			/* placeholder to force maxaligning of size of
+								 * BloomPageOpaqueData and to place
+								 * bloom_page_id exactly at the end of page */
+	uint16		bloom_page_id;	/* for identification of BLOOM indexes */
+} BloomPageOpaqueData;
+
+typedef BloomPageOpaqueData *BloomPageOpaque;
+
+/* Bloom page flags */
+#define BLOOM_META		(1<<0)
+#define BLOOM_DELETED	(2<<0)
+
+/*
+ * The page ID is for the convenience of pg_filedump and similar utilities,
+ * which otherwise would have a hard time telling pages of different index
+ * types apart.  It should be the last 2 bytes on the page.  This is more or
+ * less "free" due to alignment considerations.
+ *
+ * See comments above GinPageOpaqueData.
+ */
+#define BLOOM_PAGE_ID		0xFF83
+
+/* Macros for accessing bloom page structures */
+#define BloomPageGetOpaque(page) ((BloomPageOpaque) PageGetSpecialPointer(page))
+#define BloomPageGetMaxOffset(page) (BloomPageGetOpaque(page)->maxoff)
+#define BloomPageIsMeta(page) \
+	((BloomPageGetOpaque(page)->flags & BLOOM_META) != 0)
+#define BloomPageIsDeleted(page) \
+	((BloomPageGetOpaque(page)->flags & BLOOM_DELETED) != 0)
+#define BloomPageSetDeleted(page) \
+	(BloomPageGetOpaque(page)->flags |= BLOOM_DELETED)
+#define BloomPageSetNonDeleted(page) \
+	(BloomPageGetOpaque(page)->flags &= ~BLOOM_DELETED)
+#define BloomPageGetData(page)		((BloomTuple *)PageGetContents(page))
+#define BloomPageGetTuple(state, page, offset) \
+	((BloomTuple *)(PageGetContents(page) \
+		+ (state)->sizeOfBloomTuple * ((offset) - 1)))
+#define BloomPageGetNextTuple(state, tuple) \
+	((BloomTuple *)((Pointer)(tuple) + (state)->sizeOfBloomTuple))
+
+/* Preserved page numbers */
+#define BLOOM_METAPAGE_BLKNO	(0)
+#define BLOOM_HEAD_BLKNO		(1) /* first data page */
+
+/*
+ * We store Bloom signatures as arrays of uint16 words.
+ */
+typedef uint16 BloomSignatureWord;
+
+#define SIGNWORDBITS ((int) (BITS_PER_BYTE * sizeof(BloomSignatureWord)))
+
+/*
+ * Default and maximum Bloom signature length in bits.
+ */
+#define DEFAULT_BLOOM_LENGTH	(5 * SIGNWORDBITS)
+#define MAX_BLOOM_LENGTH		(256 * SIGNWORDBITS)
+
+/*
+ * Default and maximum signature bits generated per index key.
+ */
+#define DEFAULT_BLOOM_BITS		2
+#define MAX_BLOOM_BITS			(MAX_BLOOM_LENGTH - 1)
+
+/* Bloom index options */
+typedef struct BloomOptions
+{
+	int32		vl_len_;		/* varlena header (do not touch directly!) */
+	int			bloomLength;	/* length of signature in words (not bits!) */
+	int			bitSize[INDEX_MAX_KEYS];	/* # of bits generated for each
+											 * index key */
+} BloomOptions;
+
+/*
+ * FreeBlockNumberArray - array of block numbers sized so that metadata fill
+ * all space in metapage.
+ */
+typedef BlockNumber FreeBlockNumberArray[
+										 MAXALIGN_DOWN(
+													   BLCKSZ - SizeOfPageHeaderData - MAXALIGN(sizeof(BloomPageOpaqueData))
+													   - MAXALIGN(sizeof(uint16) * 2 + sizeof(uint32) + sizeof(BloomOptions))
+													   ) / sizeof(BlockNumber)
+];
+
+/* Metadata of bloom index */
+typedef struct BloomMetaPageData
+{
+	uint32		magickNumber;
+	uint16		nStart;
+	uint16		nEnd;
+	BloomOptions opts;
+	FreeBlockNumberArray notFullPage;
+} BloomMetaPageData;
+
+/* Magic number to distinguish bloom pages among anothers */
+#define BLOOM_MAGICK_NUMBER (0xDBAC0DED)
+
+/* Number of blocks numbers fit in BloomMetaPageData */
+#define BloomMetaBlockN		(sizeof(FreeBlockNumberArray) / sizeof(BlockNumber))
+
+#define BloomPageGetMeta(page)	((BloomMetaPageData *) PageGetContents(page))
+
+typedef struct BloomState
+{
+	FmgrInfo	hashFn[INDEX_MAX_KEYS];
+	Oid			collations[INDEX_MAX_KEYS];
+	BloomOptions opts;			/* copy of options on index's metapage */
+	int32		nColumns;
+
+	/*
+	 * sizeOfBloomTuple is index-specific, and it depends on reloptions, so
+	 * precompute it
+	 */
+	Size		sizeOfBloomTuple;
+} BloomState;
+
+#define BloomPageGetFreeSpace(state, page) \
+	(BLCKSZ - MAXALIGN(SizeOfPageHeaderData) \
+		- BloomPageGetMaxOffset(page) * (state)->sizeOfBloomTuple \
+		- MAXALIGN(sizeof(BloomPageOpaqueData)))
+
+/*
+ * Tuples are very different from all other relations
+ */
+typedef struct BloomTuple
+{
+	ItemPointerData heapPtr;
+	BloomSignatureWord sign[FLEXIBLE_ARRAY_MEMBER];
+} BloomTuple;
+
+#define BLOOMTUPLEHDRSZ offsetof(BloomTuple, sign)
+
+/* Opaque data structure for bloom index scan */
+typedef struct BloomScanOpaqueData
+{
+	BloomSignatureWord *sign;	/* Scan signature */
+	BloomState	state;
+} BloomScanOpaqueData;
+
+typedef BloomScanOpaqueData *BloomScanOpaque;
+
+/* blutils.c */
+extern void _PG_init(void);
+extern void initBloomState(BloomState *state, Relation index);
+extern void BloomFillMetapage(Relation index, Page metaPage);
+extern void BloomInitMetapage(Relation index);
+extern void BloomInitPage(Page page, uint16 flags);
+extern Buffer BloomNewBuffer(Relation index);
+extern void signValue(BloomState *state, BloomSignatureWord *sign, Datum value, int attno);
+extern BloomTuple *BloomFormTuple(BloomState *state, ItemPointer iptr, Datum *values, bool *isnull);
+extern bool BloomPageAddItem(BloomState *state, Page page, BloomTuple *tuple);
+
+/* blvalidate.c */
+extern bool blvalidate(Oid opclassoid);
+
+/* index access method interface functions */
+extern bool blinsert(Relation index, Datum *values, bool *isnull,
+					 ItemPointer ht_ctid, Relation heapRel,
+					 IndexUniqueCheck checkUnique,
+					 bool indexUnchanged,
+					 struct IndexInfo *indexInfo);
+extern IndexScanDesc blbeginscan(Relation r, int nkeys, int norderbys);
+extern int64 blgetbitmap(IndexScanDesc scan, TIDBitmap *tbm);
+extern void blrescan(IndexScanDesc scan, ScanKey scankey, int nscankeys,
+					 ScanKey orderbys, int norderbys);
+extern void blendscan(IndexScanDesc scan);
+extern IndexBuildResult *blbuild(Relation heap, Relation index,
+								 struct IndexInfo *indexInfo);
+extern void blbuildempty(Relation index);
+extern IndexBulkDeleteResult *blbulkdelete(IndexVacuumInfo *info,
+										   IndexBulkDeleteResult *stats, IndexBulkDeleteCallback callback,
+										   void *callback_state);
+extern IndexBulkDeleteResult *blvacuumcleanup(IndexVacuumInfo *info,
+											  IndexBulkDeleteResult *stats);
+extern bytea *bloptions(Datum reloptions, bool validate);
+extern void blcostestimate(PlannerInfo *root, IndexPath *path,
+						   double loop_count, Cost *indexStartupCost,
+						   Cost *indexTotalCost, Selectivity *indexSelectivity,
+						   double *indexCorrelation, double *indexPages);
+
+#endif