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  1. /*
  2. FUNCTION
  3. <<ldiv>>---divide two long integers
  4.  
  5. INDEX
  6.         ldiv
  7.  
  8. ANSI_SYNOPSIS
  9.         #include <stdlib.h>
  10.         ldiv_t ldiv(long <[n]>, long <[d]>);
  11.  
  12. TRAD_SYNOPSIS
  13.         #include <stdlib.h>
  14.         ldiv_t ldiv(<[n]>, <[d]>)
  15.         long <[n]>, <[d]>;
  16.  
  17. DESCRIPTION
  18. Divide
  19. @tex
  20. $n/d$,
  21. @end tex
  22. @ifnottex
  23. <[n]>/<[d]>,
  24. @end ifnottex
  25. returning quotient and remainder as two long integers in a structure <<ldiv_t>>.
  26.  
  27. RETURNS
  28. The result is represented with the structure
  29.  
  30. . typedef struct
  31. . {
  32. .  long quot;
  33. .  long rem;
  34. . } ldiv_t;
  35.  
  36. where the <<quot>> field represents the quotient, and <<rem>> the
  37. remainder.  For nonzero <[d]>, if `<<<[r]> = ldiv(<[n]>,<[d]>);>>' then
  38. <[n]> equals `<<<[r]>.rem + <[d]>*<[r]>.quot>>'.
  39.  
  40. To divide <<int>> rather than <<long>> values, use the similar
  41. function <<div>>.
  42.  
  43. PORTABILITY
  44. <<ldiv>> is ANSI.
  45.  
  46. No supporting OS subroutines are required.
  47. */
  48.  
  49.  
  50. /*
  51.  * Copyright (c) 1990 Regents of the University of California.
  52.  * All rights reserved.
  53.  *
  54.  * This code is derived from software contributed to Berkeley by
  55.  * Chris Torek.
  56.  *
  57.  * Redistribution and use in source and binary forms, with or without
  58.  * modification, are permitted provided that the following conditions
  59.  * are met:
  60.  * 1. Redistributions of source code must retain the above copyright
  61.  *    notice, this list of conditions and the following disclaimer.
  62.  * 2. Redistributions in binary form must reproduce the above copyright
  63.  *    notice, this list of conditions and the following disclaimer in the
  64.  *    documentation and/or other materials provided with the distribution.
  65.  * 3. All advertising materials mentioning features or use of this software
  66.  *    must display the following acknowledgement:
  67.  *      This product includes software developed by the University of
  68.  *      California, Berkeley and its contributors.
  69.  * 4. Neither the name of the University nor the names of its contributors
  70.  *    may be used to endorse or promote products derived from this software
  71.  *    without specific prior written permission.
  72.  *
  73.  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  74.  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  75.  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  76.  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  77.  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  78.  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  79.  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  80.  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  81.  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  82.  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  83.  * SUCH DAMAGE.
  84.  */
  85.  
  86. #include <_ansi.h>
  87. #include <stdlib.h>             /* ldiv_t */
  88.  
  89. ldiv_t
  90. _DEFUN (ldiv, (num, denom),
  91.         long num _AND
  92.         long denom)
  93. {
  94.         ldiv_t r;
  95.  
  96.         /* see div.c for comments */
  97.  
  98.         r.quot = num / denom;
  99.         r.rem = num % denom;
  100.         if (num >= 0 && r.rem < 0) {
  101.                 ++r.quot;
  102.                 r.rem -= denom;
  103.         }
  104.         else if (num < 0 && r.rem > 0) {
  105.                 --r.quot;
  106.                 r.rem += denom;
  107.         }
  108.         return (r);
  109. }
  110.