mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-12-21 08:29:39 +08:00
70 lines
1.7 KiB
C
70 lines
1.7 KiB
C
#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);
|
|
}
|