/*!
* copy datum <c>dat</c> into the offset of position <c>index</c> of
* the mfv sketch stored in <c>transblob</c>.
*
* <i>Caller beware: this helper return assumes that
* <c>dat</c> is small enough to fit in the storage
* currently used by the datum at position <c>index</c>.</i>
*
* \param transblob a bytea holding and mfv transval
* \param index the index of the destination for copying
* \param dat the datum to be copied into the transval
*/
void mfv_copy_datum(bytea *transblob, int index, Datum dat)
{
mfvtransval *transval = (mfvtransval *)VARDATA(transblob);
size_t datumLen = ExtractDatumLen(dat, transval->typLen, transval->typByVal, -1);
void * curval = (char*)transval + transval->mfvs[index].offset;
memmove(curval, (void *)DatumExtractPointer(dat, transval->typByVal), datumLen);
}
/*!
* copy datum <c>dat</c> into the offset of position <c>index</c> of
* the mfv sketch stored in <c>transblob</c>.
*
* <i>Caller beware: this helper return assumes that
* <c>dat</c> is small enough to fit in the storage
* currently used by the datum at position <c>index</c>.</i>
*
* \param transblob a bytea holding and mfv transval
* \param index the index of the destination for copying
* \param dat the datum to be copied into the transval
*/
void mfv_copy_datum(bytea *transblob, int index, Datum dat)
{
mfvtransval *transval = (mfvtransval *)VARDATA(transblob);
size_t datumLen = ExtractDatumLen(dat, transval->typLen, transval->typByVal, -1);
void * curval = mfv_transval_getval(transblob,index);
memmove(curval, (void *)DatumExtractPointer(dat, transval->typByVal), datumLen);
}
/*!
* look to see if the mfvsketch currently has <c>val</c>
* stored as one of its most-frequent values.
* Returns the offset in the <c>mfvs</c> array, or -1
* if not found.
* NOTE: a 0 return value means the item <i>was found</i>
* at offset 0!
* \param blob a bytea holding an mfv transval
* \param val the datum to search for
*/
int mfv_find(bytea *blob, Datum val)
{
mfvtransval *transval = (mfvtransval *)VARDATA(blob);
unsigned i;
uint32 len;
void * datp;
Datum iDat;
void *valp = DatumExtractPointer(val, transval->typByVal);
/* look for existing entry for this value */
for (i = 0; i < transval->next_mfv; i++) {
/* if they're the same */
datp = mfv_transval_getval(blob,i);
iDat = PointerExtractDatum(datp, transval->typByVal);
if ((len = ExtractDatumLen(iDat, transval->typLen, transval->typByVal, -1))
== ExtractDatumLen(val, transval->typLen, transval->typByVal, -1)) {
if (!memcmp(datp, valp, len))
/* arg is an mfv */
return(i);
}
}
return(-1);
}
