lib/libc/stdlib/lsearch.c

   1 /*
   2  * Initial implementation:
   3  * Copyright (c) 2002 Robert Drehmel
   4  * All rights reserved.
   5  *
   6  * As long as the above copyright statement and this notice remain
   7  * unchanged, you can do what ever you want with this file.
   8  *
   9  * $FreeBSD: src/lib/libc/stdlib/lsearch.c,v 1.1 2002/10/16 14:29:22 robert Exp $
  10  * $DragonFly: src/lib/libc/stdlib/lsearch.c,v 1.1 2008/05/19 10:06:34 corecode Exp $
  11  */
  12 #include <sys/types.h>
  13
  14 #define _SEARCH_PRIVATE
  15 #include <search.h>
  16 #include <stdint.h>     /* for uint8_t */
  17 #include <stdlib.h>     /* for NULL */
  18 #include <string.h>     /* for memcpy() prototype */
  19
  20 static void *lwork(const void *, const void *, size_t *, size_t,
  21     int (*)(const void *, const void *), int);
  22
  23 void *lsearch(const void *key, void *base, size_t *nelp, size_t width,
  24     int (*compar)(const void *, const void *))
  25 {
  26
  27         return (lwork(key, base, nelp, width, compar, 1));
  28 }
  29
  30 void *lfind(const void *key, const void *base, size_t *nelp, size_t width,
  31     int (*compar)(const void *, const void *))
  32 {
  33
  34         return (lwork(key, base, nelp, width, compar, 0));
  35 }
  36
  37 static void *
  38 lwork(const void *key, const void *base, size_t *nelp, size_t width,
  39     int (*compar)(const void *, const void *), int addelem)
  40 {
  41         uint8_t *ep, *endp;
  42
  43         /*
  44          * Cast to an integer value first to avoid the warning for removing
  45          * 'const' via a cast.
  46          */
  47         ep = (uint8_t *)(uintptr_t)base;
  48         for (endp = (uint8_t *)(ep + width * *nelp); ep < endp; ep += width) {
  49                 if (compar(key, ep) == 0)
  50                         return (ep);
  51         }
  52
  53         /* lfind() shall return when the key was not found. */
  54         if (!addelem)
  55                 return (NULL);
  56
  57         /*
  58          * lsearch() adds the key to the end of the table and increments
  59          * the number of elements.
  60          */
  61         memcpy(endp, key, width);
  62         ++*nelp;
  63
  64         return (endp);
  65 }