PolarDB-for-PostgreSQL

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/*
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 * contrib/btree_gist/btree_uuid.c
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 */
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#include "postgres.h"
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#include "btree_gist.h"
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#include "btree_utils_num.h"
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#include "port/pg_bswap.h"
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#include "utils/uuid.h"
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typedef struct
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{
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	pg_uuid_t	lower,
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				upper;
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} uuidKEY;
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/*
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 * UUID ops
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 */
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PG_FUNCTION_INFO_V1(gbt_uuid_compress);
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PG_FUNCTION_INFO_V1(gbt_uuid_fetch);
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PG_FUNCTION_INFO_V1(gbt_uuid_union);
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PG_FUNCTION_INFO_V1(gbt_uuid_picksplit);
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PG_FUNCTION_INFO_V1(gbt_uuid_consistent);
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PG_FUNCTION_INFO_V1(gbt_uuid_penalty);
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PG_FUNCTION_INFO_V1(gbt_uuid_same);
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static int
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uuid_internal_cmp(const pg_uuid_t *arg1, const pg_uuid_t *arg2)
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{
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	return memcmp(arg1->data, arg2->data, UUID_LEN);
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}
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static bool
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gbt_uuidgt(const void *a, const void *b, FmgrInfo *flinfo)
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{
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	return uuid_internal_cmp((const pg_uuid_t *) a, (const pg_uuid_t *) b) > 0;
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}
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static bool
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gbt_uuidge(const void *a, const void *b, FmgrInfo *flinfo)
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{
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	return uuid_internal_cmp((const pg_uuid_t *) a, (const pg_uuid_t *) b) >= 0;
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}
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static bool
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gbt_uuideq(const void *a, const void *b, FmgrInfo *flinfo)
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{
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	return uuid_internal_cmp((const pg_uuid_t *) a, (const pg_uuid_t *) b) == 0;
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}
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static bool
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gbt_uuidle(const void *a, const void *b, FmgrInfo *flinfo)
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{
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	return uuid_internal_cmp((const pg_uuid_t *) a, (const pg_uuid_t *) b) <= 0;
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}
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static bool
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gbt_uuidlt(const void *a, const void *b, FmgrInfo *flinfo)
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{
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	return uuid_internal_cmp((const pg_uuid_t *) a, (const pg_uuid_t *) b) < 0;
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}
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static int
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gbt_uuidkey_cmp(const void *a, const void *b, FmgrInfo *flinfo)
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{
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	uuidKEY    *ia = (uuidKEY *) (((const Nsrt *) a)->t);
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	uuidKEY    *ib = (uuidKEY *) (((const Nsrt *) b)->t);
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	int			res;
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	res = uuid_internal_cmp(&ia->lower, &ib->lower);
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	if (res == 0)
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		res = uuid_internal_cmp(&ia->upper, &ib->upper);
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	return res;
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}
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static const gbtree_ninfo tinfo =
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{
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	gbt_t_uuid,
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	UUID_LEN,
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	32,							/* sizeof(gbtreekey32) */
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	gbt_uuidgt,
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	gbt_uuidge,
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	gbt_uuideq,
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	gbt_uuidle,
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	gbt_uuidlt,
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	gbt_uuidkey_cmp,
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	NULL
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};
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/**************************************************
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 * uuid ops
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 **************************************************/
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Datum
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gbt_uuid_compress(PG_FUNCTION_ARGS)
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{
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	GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
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	GISTENTRY  *retval;
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	if (entry->leafkey)
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	{
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		char	   *r = (char *) palloc(2 * UUID_LEN);
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		pg_uuid_t  *key = DatumGetUUIDP(entry->key);
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		retval = palloc(sizeof(GISTENTRY));
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		memcpy((void *) r, (void *) key, UUID_LEN);
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		memcpy((void *) (r + UUID_LEN), (void *) key, UUID_LEN);
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		gistentryinit(*retval, PointerGetDatum(r),
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					  entry->rel, entry->page,
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					  entry->offset, false);
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	}
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	else
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		retval = entry;
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	PG_RETURN_POINTER(retval);
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}
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Datum
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gbt_uuid_fetch(PG_FUNCTION_ARGS)
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{
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	GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
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	PG_RETURN_POINTER(gbt_num_fetch(entry, &tinfo));
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}
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Datum
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gbt_uuid_consistent(PG_FUNCTION_ARGS)
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{
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	GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
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	pg_uuid_t  *query = PG_GETARG_UUID_P(1);
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	StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2);
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	/* Oid		subtype = PG_GETARG_OID(3); */
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	bool	   *recheck = (bool *) PG_GETARG_POINTER(4);
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	uuidKEY    *kkk = (uuidKEY *) DatumGetPointer(entry->key);
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	GBT_NUMKEY_R key;
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	/* All cases served by this function are exact */
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	*recheck = false;
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	key.lower = (GBT_NUMKEY *) &kkk->lower;
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	key.upper = (GBT_NUMKEY *) &kkk->upper;
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	PG_RETURN_BOOL(
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				   gbt_num_consistent(&key, (void *) query, &strategy,
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									  GIST_LEAF(entry), &tinfo, fcinfo->flinfo)
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		);
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}
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Datum
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gbt_uuid_union(PG_FUNCTION_ARGS)
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{
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	GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
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	void	   *out = palloc(sizeof(uuidKEY));
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	*(int *) PG_GETARG_POINTER(1) = sizeof(uuidKEY);
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	PG_RETURN_POINTER(gbt_num_union((void *) out, entryvec, &tinfo, fcinfo->flinfo));
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}
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/*
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 * Convert a uuid to a "double" value for estimating sizes of ranges.
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 */
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static double
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uuid_2_double(const pg_uuid_t *u)
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{
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	uint64		uu[2];
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	const double two64 = 18446744073709551616.0;	/* 2^64 */
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	/* Source data may not be suitably aligned, so copy */
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	memcpy(uu, u->data, UUID_LEN);
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	/*
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	 * uuid values should be considered as big-endian numbers, since that
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	 * corresponds to how memcmp will compare them.  On a little-endian
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	 * machine, byte-swap each half so we can use native uint64 arithmetic.
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	 */
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#ifndef WORDS_BIGENDIAN
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	uu[0] = pg_bswap64(uu[0]);
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	uu[1] = pg_bswap64(uu[1]);
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#endif
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	/*
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	 * 2^128 is about 3.4e38, which in theory could exceed the range of
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	 * "double" (POSIX only requires 1e37).  To avoid any risk of overflow,
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	 * put the decimal point between the two halves rather than treating the
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	 * uuid value as a 128-bit integer.
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	 */
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	return (double) uu[0] + (double) uu[1] / two64;
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}
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Datum
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gbt_uuid_penalty(PG_FUNCTION_ARGS)
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{
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	uuidKEY    *origentry = (uuidKEY *) DatumGetPointer(((GISTENTRY *) PG_GETARG_POINTER(0))->key);
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	uuidKEY    *newentry = (uuidKEY *) DatumGetPointer(((GISTENTRY *) PG_GETARG_POINTER(1))->key);
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	float	   *result = (float *) PG_GETARG_POINTER(2);
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	double		olower,
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				oupper,
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				nlower,
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				nupper;
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	olower = uuid_2_double(&origentry->lower);
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	oupper = uuid_2_double(&origentry->upper);
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	nlower = uuid_2_double(&newentry->lower);
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	nupper = uuid_2_double(&newentry->upper);
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	penalty_num(result, olower, oupper, nlower, nupper);
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	PG_RETURN_POINTER(result);
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}
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Datum
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gbt_uuid_picksplit(PG_FUNCTION_ARGS)
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{
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	PG_RETURN_POINTER(gbt_num_picksplit(
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										(GistEntryVector *) PG_GETARG_POINTER(0),
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										(GIST_SPLITVEC *) PG_GETARG_POINTER(1),
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										&tinfo, fcinfo->flinfo
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										));
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}
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Datum
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gbt_uuid_same(PG_FUNCTION_ARGS)
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{
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	uuidKEY    *b1 = (uuidKEY *) PG_GETARG_POINTER(0);
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	uuidKEY    *b2 = (uuidKEY *) PG_GETARG_POINTER(1);
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	bool	   *result = (bool *) PG_GETARG_POINTER(2);
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	*result = gbt_num_same((void *) b1, (void *) b2, &tinfo, fcinfo->flinfo);
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	PG_RETURN_POINTER(result);
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}
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