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#include "btree_gist.h"
PG_FUNCTION_INFO_V1(btree_decompress);
Datum btree_decompress(PG_FUNCTION_ARGS);
/*
** GiST DeCompress methods
** do not do anything.
*/
Datum
btree_decompress(PG_FUNCTION_ARGS)
{
PG_RETURN_POINTER(PG_GETARG_POINTER(0));
}
/**************************************************
* Common btree-function (for all ops)
**************************************************/
/*
** The GiST PickSplit method
*/
extern GIST_SPLITVEC *
btree_picksplit(bytea *entryvec, GIST_SPLITVEC *v, BINARY_UNION bu, CMPFUNC cmp)
{
OffsetNumber i;
RIX *array;
OffsetNumber maxoff;
int nbytes;
maxoff = ((VARSIZE(entryvec) - VARHDRSZ) / sizeof(GISTENTRY)) - 1;
nbytes = (maxoff + 2) * sizeof(OffsetNumber);
v->spl_left = (OffsetNumber *) palloc(nbytes);
v->spl_right = (OffsetNumber *) palloc(nbytes);
v->spl_nleft = 0;
v->spl_nright = 0;
v->spl_ldatum = PointerGetDatum(0);
v->spl_rdatum = PointerGetDatum(0);
array = (RIX *) palloc(sizeof(RIX) * (maxoff + 1));
/* copy the data into RIXes, and sort the RIXes */
for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
{
array[i].index = i;
array[i].r = (char *) DatumGetPointer((((GISTENTRY *) (VARDATA(entryvec)))[i].key));
}
qsort((void *) &array[FirstOffsetNumber], maxoff - FirstOffsetNumber + 1,
sizeof(RIX), cmp);
for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
{
if (i <= (maxoff - FirstOffsetNumber + 1) / 2)
{
v->spl_left[v->spl_nleft] = array[i].index;
v->spl_nleft++;
(*bu) (&v->spl_ldatum, array[i].r);
}
else
{
v->spl_right[v->spl_nright] = array[i].index;
v->spl_nright++;
(*bu) (&v->spl_rdatum, array[i].r);
}
}
pfree(array);
return (v);
}
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