lib/other/memccpy.c

   1 #include <lib.h>
   2 /* memccpy - copy bytes up to a certain char
   3  *
   4  * CHARBITS should be defined only if the compiler lacks "unsigned char".
   5  * It should be a mask, e.g. 0377 for an 8-bit machine.
   6  */
   7
   8 #include <ansi.h>
   9 #include <stddef.h>
  10
  11 _PROTOTYPE( void *memccpy, (void *dst, const void *src,
  12                             int ucharstop, size_t size));
  13 #ifndef CHARBITS
  14 #       define  UNSCHAR(c)      ((unsigned char)(c))
  15 #else
  16 #       define  UNSCHAR(c)      ((c)&CHARBITS)
  17 #endif
  18
  19 void *memccpy(dst, src, ucharstop, size)
  20 void * dst;
  21 _CONST void * src;
  22 int ucharstop;
  23 _SIZET size;
  24 {
  25   register char *d;
  26   register _CONST char *s;
  27   register _SIZET n;
  28   register int uc;
  29
  30   if (size <= 0) return( (void *) NULL);
  31
  32   s = (char *) src;
  33   d = (char *) dst;
  34   uc = UNSCHAR(ucharstop);
  35   for (n = size; n > 0; n--)
  36         if (UNSCHAR(*d++ = *s++) == (char) uc) return( (void *) d);
  37
  38   return( (void *) NULL);
  39 }