Function make_int64_key

src/jrd/btr.cpp:6388–6431

static INT64_KEY make_int64_key(SINT64 q, SSHORT scale)
{
/**************************************
 *
 *	m a k e _ i n t 6 4 _ k e y
 *
 **************************************
 *
 * Functional description
 *	Make an Index key for a 64-bit Integer value.
 *
 **************************************/

	// Following structure declared above in the modules global section
	//
	// static const struct {
	//     FB_UINT64 limit;		--- if abs(q) is >= this, ...
	//     SINT64 factor;		--- then multiply by this, ...
	//     SSHORT scale_change;	--- and add this to the scale.
	// } int64_scale_control[];
	//

	// Before converting the scaled int64 to a double, multiply it by the
	// largest power of 10 which will NOT cause an overflow, and adjust
	// the scale accordingly.  This ensures that two different
	// representations of the same value, entered at times when the
	// declared scale of the column was different, actually wind up
	// being mapped to the same key.

	int n = 0;
	const FB_UINT64 uq = (FB_UINT64) ((q >= 0) ? q : -q);	// absolute value

	while (uq < int64_scale_control[n].limit)
		n++;

	q *= int64_scale_control[n].factor;
	scale -= int64_scale_control[n].scale_change;

	INT64_KEY key;
	key.d_part = ((double) (q / 10000)) / powerof10(scale);
	key.s_part = (SSHORT) (q % 10000);

	return key;
}


#ifdef DEBUG_INDEXKEY