From 7378b5a081a0d839c3bd63f6ddd359bca50be695 Mon Sep 17 00:00:00 2001 From: Florian Dold Date: Fri, 17 Jan 2020 18:59:15 +0100 Subject: amount rounding a la Christian --- src/util/amount.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) (limited to 'src/util/amount.c') diff --git a/src/util/amount.c b/src/util/amount.c index 48f5d9891..1f00b1d6e 100644 --- a/src/util/amount.c +++ b/src/util/amount.c @@ -674,23 +674,27 @@ TALER_amount_divide (struct TALER_Amount *result, /** * Round the amount to something that can be transferred on the wire. + * The rounding mode is specified via the smallest transferable unit, + * which must only have a fractional part. * * @param[in,out] amount amount to round down - * @param max_fractional_digits number of fractional digits to round down to + * @param[in] round_unit unit that should be rounded down to, + * the value part of this amount must be zero * @return #GNUNET_OK on success, #GNUNET_NO if rounding was unnecessary, * #GNUNET_SYSERR if the amount or currency was invalid */ int TALER_amount_round_down (struct TALER_Amount *amount, - uint8_t max_fractional_digits) + const struct TALER_Amount *round_unit) { uint32_t delta; - uint32_t divisor = 1; - for (unsigned int i = 0; i < max_fractional_digits; i++) - divisor *= 10; + GNUNET_break (0 == round_unit->value); - delta = amount->fraction % (TALER_AMOUNT_FRAC_BASE / divisor); + if (0 == round_unit->fraction) + return GNUNET_OK; + + delta = amount->fraction % round_unit->fraction; if (0 == delta) return GNUNET_NO; amount->fraction -= delta; -- cgit v1.2.3