memcpy_musl_093.c

   1 #include <string.h>
   2 #include <stdlib.h>
   3 #include <stdint.h>
   4
   5 #define SS (sizeof(size_t))
   6 #define ALIGN (sizeof(size_t)-1)
   7 #define ONES ((size_t)-1/UCHAR_MAX)
   8
   9 void *mymemcpy(void *dest, const void *src, size_t n)
  10 {
  11         unsigned char *d = dest;
  12         const unsigned char *s = src;
  13
  14         if (((uintptr_t)d & ALIGN) != ((uintptr_t)s & ALIGN))
  15                 goto misaligned;
  16
  17         for (; ((uintptr_t)d & ALIGN) && n; n--) *d++ = *s++;
  18         if (n) {
  19                 size_t *wd = (void *)d;
  20                 const size_t *ws = (const void *)s;
  21
  22                 for (; n>=SS; n-=SS) *wd++ = *ws++;
  23                 d = (void *)wd;
  24                 s = (const void *)ws;
  25 misaligned:
  26                 for (; n; n--) *d++ = *s++;
  27         }
  28         return dest;
  29 }