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