/*
  This file is part of TALER
  (C) 2018 Taler Systems SA

  TALER is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as
  published by the Free Software Foundation; either version 3,
  or (at your option) any later version.

  TALER is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public
  License along with TALER; see the file COPYING.  If not, see
  <http://www.gnu.org/licenses/>
*/

/**
 * @file wire/wire_helper.c
 * @brief Helper functions for dealing with wire formats

 * @author Christian Grothoff <christian@grothoff.org>
 */
#include "platform.h"
#include "taler_util.h"
#include "taler_wire_lib.h"

/**
 * Prefix of PAYTO URLs.
 */
#define PAYTO "payto://"


/**
 * Obtain the payment method from a @a payto_url
 *
 * @param payto_url the URL to parse
 * @return NULL on error (malformed @a payto_url)
 */
char *
TALER_WIRE_payto_get_method (const char *payto_url)
{
  const char *start;
  const char *end;

  if (0 != strncmp (payto_url,
                    PAYTO,
                    strlen (PAYTO)))
    return NULL;
  start = &payto_url[strlen (PAYTO)];
  end = strchr (start,
                (unsigned char) '/');
  if (NULL == end)
    return NULL;
  return GNUNET_strndup (start,
                         end - start);
}


/**
 * Round the amount to something that can be
 * transferred on the wire.
 *
 * @param[in,out] amount amount to round down
 * @return #GNUNET_OK on success, #GNUNET_NO if rounding was unnecessary,
 *         #GNUNET_SYSERR if the amount or currency was invalid
 */
int
TALER_WIRE_amount_round (struct TALER_Amount *amount)
{
  uint32_t delta;

  delta = amount->fraction % (TALER_AMOUNT_FRAC_BASE / 100);
  if (0 == delta)
    return GNUNET_NO;
  amount->fraction -= delta;
  return GNUNET_OK;
}


/* end of wire_helper.c */