winsup/cygwin/lsearch.cc

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