Rich Felker
400c5e5c83
to deal with the fact that the public headers may be used with pre-c99 compilers, __restrict is used in place of restrict, and defined appropriately for any supported compiler. we also avoid the form [restrict] since older versions of gcc rejected it due to a bug in the original c99 standard, and instead use the form *restrict.
30 lines
635 B
C
30 lines
635 B
C
#include <string.h>
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#include <stdlib.h>
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#include <stdint.h>
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#define SS (sizeof(size_t))
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#define ALIGN (sizeof(size_t)-1)
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#define ONES ((size_t)-1/UCHAR_MAX)
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void *memcpy(void *restrict dest, const void *restrict src, size_t n)
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{
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unsigned char *d = dest;
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const unsigned char *s = src;
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if (((uintptr_t)d & ALIGN) != ((uintptr_t)s & ALIGN))
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goto misaligned;
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for (; ((uintptr_t)d & ALIGN) && n; n--) *d++ = *s++;
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if (n) {
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size_t *wd = (void *)d;
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const size_t *ws = (const void *)s;
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for (; n>=SS; n-=SS) *wd++ = *ws++;
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d = (void *)wd;
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s = (const void *)ws;
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misaligned:
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for (; n; n--) *d++ = *s++;
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}
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return dest;
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}
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