86 lines
3.6 KiB
C
86 lines
3.6 KiB
C
/* Copyright (C) 1992, 1997, 1999 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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/*
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* Copyright (c) 1990 Regents of the University of California.
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* All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Chris Torek.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <stdlib.h>
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/* Return the `div_t' representation of NUMER over DENOM. */
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div_t
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div (numer, denom)
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int numer, denom;
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{
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div_t result;
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result.quot = numer / denom;
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result.rem = numer % denom;
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/* The ANSI standard says that |QUOT| <= |NUMER / DENOM|, where
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NUMER / DENOM is to be computed in infinite precision. In
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other words, we should always truncate the quotient towards
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zero, never -infinity. Machine division and remainer may
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work either way when one or both of NUMER or DENOM is
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negative. If only one is negative and QUOT has been
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truncated towards -infinity, REM will have the same sign as
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DENOM and the opposite sign of NUMER; if both are negative
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and QUOT has been truncated towards -infinity, REM will be
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positive (will have the opposite sign of NUMER). These are
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considered `wrong'. If both are NUM and DENOM are positive,
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RESULT will always be positive. This all boils down to: if
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NUMER >= 0, but REM < 0, we got the wrong answer. In that
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case, to get the right answer, add 1 to QUOT and subtract
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DENOM from REM. */
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if (numer >= 0 && result.rem < 0)
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{
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++result.quot;
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result.rem -= denom;
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}
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return result;
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}
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