/*

 * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>

 *

 * Permission is hereby granted, free of charge, to any person obtaining 

 * a copy of this software and associated documentation files (the

 * "Software"), to deal in the Software without restriction, including

 * without limitation the rights to use, copy, modify, merge, publish,

 * distribute, sublicense, and/or sell copies of the Software, and to

 * permit persons to whom the Software is furnished to do so, subject to

 * the following conditions:

 *

 * The above copyright notice and this permission notice shall be 

 * included in all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 

 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 

 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS

 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN

 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN

 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

 * SOFTWARE.

 */

#include "inner.h"

/* see inner.h */

void

br_ecdsa_i31_bits2int(uint32_t *x,

  const void *src, size_t len, uint32_t ebitlen)

{

  uint32_t bitlen, hbitlen;

  int sc;

  bitlen = ebitlen - (ebitlen >> 5);

  hbitlen = (uint32_t)len << 3;

  if (hbitlen > bitlen) {

    len = (bitlen + 7) >> 3;

    sc = (int)((hbitlen - bitlen) & 7);

  } else {

    sc = 0;

  }

  br_i31_zero(x, ebitlen);

  br_i31_decode(x, src, len);

  br_i31_rshift(x, sc);

  x[0] = ebitlen;

}