43 lines
850 B
C
43 lines
850 B
C
#include <string.h>
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#include <stdint.h>
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#ifdef __GNUC__
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typedef __attribute__((__may_alias__)) size_t WT;
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#define WS (sizeof(WT))
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#endif
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void *memmove(void *dest, const void *src, size_t n)
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{
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char *d = dest;
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const char *s = src;
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if (d==s) return d;
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if ((uintptr_t)s-(uintptr_t)d-n <= -2*n) return memcpy(d, s, n);
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if (d<s) {
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#ifdef __GNUC__
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if ((uintptr_t)s % WS == (uintptr_t)d % WS) {
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while ((uintptr_t)d % WS) {
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if (!n--) return dest;
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*d++ = *s++;
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}
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for (; n>=WS; n-=WS, d+=WS, s+=WS) *(WT *)d = *(WT *)s;
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}
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#endif
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for (; n; n--) *d++ = *s++;
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} else {
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#ifdef __GNUC__
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if ((uintptr_t)s % WS == (uintptr_t)d % WS) {
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while ((uintptr_t)(d+n) % WS) {
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if (!n--) return dest;
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d[n] = s[n];
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}
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while (n>=WS) n-=WS, *(WT *)(d+n) = *(WT *)(s+n);
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}
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#endif
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while (n) n--, d[n] = s[n];
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}
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return dest;
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}
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