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wdenk4a5b6a32001-04-28 17:59:11 +00001/* Copyright (C) 1992, 1997 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Library General Public License as
6 published by the Free Software Foundation; either version 2 of the
7 License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Library General Public License for more details.
13
14 You should have received a copy of the GNU Library General Public
15 License along with the GNU C Library; see the file COPYING.LIB. If not,
16 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 Boston, MA 02111-1307, USA. */
18
19typedef struct {
wdenk8bde7f72003-06-27 21:31:46 +000020 long quot;
21 long rem;
wdenk4a5b6a32001-04-28 17:59:11 +000022} ldiv_t;
23/* Return the `ldiv_t' representation of NUMER over DENOM. */
24ldiv_t
25ldiv (long int numer, long int denom)
26{
27 ldiv_t result;
28
29 result.quot = numer / denom;
30 result.rem = numer % denom;
31
32 /* The ANSI standard says that |QUOT| <= |NUMER / DENOM|, where
33 NUMER / DENOM is to be computed in infinite precision. In
34 other words, we should always truncate the quotient towards
35 zero, never -infinity. Machine division and remainer may
36 work either way when one or both of NUMER or DENOM is
37 negative. If only one is negative and QUOT has been
38 truncated towards -infinity, REM will have the same sign as
39 DENOM and the opposite sign of NUMER; if both are negative
40 and QUOT has been truncated towards -infinity, REM will be
41 positive (will have the opposite sign of NUMER). These are
42 considered `wrong'. If both are NUM and DENOM are positive,
43 RESULT will always be positive. This all boils down to: if
44 NUMER >= 0, but REM < 0, we got the wrong answer. In that
45 case, to get the right answer, add 1 to QUOT and subtract
46 DENOM from REM. */
47
48 if (numer >= 0 && result.rem < 0)
49 {
50 ++result.quot;
51 result.rem -= denom;
52 }
53
54 return result;
55}