Function initBloomState

contrib/bloom/blutils.c:160–208

* Fill BloomState structure for particular index. */

 * Fill BloomState structure for particular index.
 */
void
initBloomState(BloomState *state, Relation index)
{
	int			i;

	state->nColumns = index->rd_att->natts;

	/* Initialize hash function for each attribute */
	for (i = 0; i < index->rd_att->natts; i++)
	{
		fmgr_info_copy(&(state->hashFn[i]),
					   index_getprocinfo(index, i + 1, BLOOM_HASH_PROC),
					   CurrentMemoryContext);
		state->collations[i] = index->rd_indcollation[i];
	}

	/* Initialize amcache if needed with options from metapage */
	if (!index->rd_amcache)
	{
		Buffer		buffer;
		Page		page;
		BloomMetaPageData *meta;
		BloomOptions *opts;

		opts = MemoryContextAlloc(index->rd_indexcxt, sizeof(BloomOptions));

		buffer = ReadBuffer(index, BLOOM_METAPAGE_BLKNO);
		LockBuffer(buffer, BUFFER_LOCK_SHARE);

		page = BufferGetPage(buffer);

		if (!BloomPageIsMeta(page))
			elog(ERROR, "Relation is not a bloom index");
		meta = BloomPageGetMeta(BufferGetPage(buffer));

		if (meta->magickNumber != BLOOM_MAGICK_NUMBER)
			elog(ERROR, "Relation is not a bloom index");

		*opts = meta->opts;

		UnlockReleaseBuffer(buffer);

		index->rd_amcache = (void *) opts;
	}

	memcpy(&state->opts, index->rd_amcache, sizeof(state->opts));
	state->sizeOfBloomTuple = BLOOMTUPLEHDRSZ +
		sizeof(BloomSignatureWord) * state->opts.bloomLength;
}

/*
 * Random generator copied from FreeBSD.  Using own random generator here for