1/* mpz_rootrem(root, rem, u, nth) --  Set ROOT to trunc(U^(1/nth)) and
2   set REM to the remainder.
3
4Copyright 1999-2003, 2005, 2012 Free Software Foundation, Inc.
5
6This file is part of the GNU MP Library.
7
8The GNU MP Library is free software; you can redistribute it and/or modify
9it under the terms of either:
10
11  * the GNU Lesser General Public License as published by the Free
12    Software Foundation; either version 3 of the License, or (at your
13    option) any later version.
14
15or
16
17  * the GNU General Public License as published by the Free Software
18    Foundation; either version 2 of the License, or (at your option) any
19    later version.
20
21or both in parallel, as here.
22
23The GNU MP Library is distributed in the hope that it will be useful, but
24WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
25or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
26for more details.
27
28You should have received copies of the GNU General Public License and the
29GNU Lesser General Public License along with the GNU MP Library.  If not,
30see https://www.gnu.org/licenses/.  */
31
32#include <stdio.h>		/* for NULL */
33#include "gmp-impl.h"
34
35void
36mpz_rootrem (mpz_ptr root, mpz_ptr rem, mpz_srcptr u, unsigned long int nth)
37{
38  mp_ptr rootp, up, remp;
39  mp_size_t us, un, rootn, remn;
40  TMP_DECL;
41
42  us = SIZ(u);
43
44  /* even roots of negatives provoke an exception */
45  if (UNLIKELY (us < 0 && (nth & 1) == 0))
46    SQRT_OF_NEGATIVE;
47
48  /* root extraction interpreted as c^(1/nth) means a zeroth root should
49     provoke a divide by zero, do this even if c==0 */
50  if (UNLIKELY (nth == 0))
51    DIVIDE_BY_ZERO;
52
53  if (us == 0)
54    {
55      if (root != NULL)
56	SIZ(root) = 0;
57      SIZ(rem) = 0;
58      return;
59    }
60
61  un = ABS (us);
62  rootn = (un - 1) / nth + 1;
63
64  TMP_MARK;
65
66  /* FIXME: Perhaps disallow root == NULL */
67  if (root != NULL && u != root)
68    rootp = MPZ_NEWALLOC (root, rootn);
69  else
70    rootp = TMP_ALLOC_LIMBS (rootn);
71
72  if (u != rem)
73    remp = MPZ_NEWALLOC (rem, un);
74  else
75    remp = TMP_ALLOC_LIMBS (un);
76
77  up = PTR(u);
78
79  if (nth == 1)
80    {
81      MPN_COPY (rootp, up, un);
82      remn = 0;
83    }
84  else
85    {
86      remn = mpn_rootrem (rootp, remp, up, un, (mp_limb_t) nth);
87    }
88
89  if (root != NULL)
90    {
91      SIZ(root) = us >= 0 ? rootn : -rootn;
92      if (u == root)
93	MPN_COPY (up, rootp, rootn);
94    }
95
96  if (u == rem)
97    MPN_COPY (up, remp, remn);
98  SIZ(rem) = us >= 0 ? remn : -remn;
99  TMP_FREE;
100}
101