53 lines
976 B
C
53 lines
976 B
C
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#include <stddef.h>
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#include <stdint.h>
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#include <string.h>
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void * memmove(void * dest, const void * src, size_t n) {
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char * d = dest;
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const char * s = src;
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if (d==s) {
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return d;
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}
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if (s+n <= d || d+n <= s) {
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return memcpy(d, s, n);
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}
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if (d<s) {
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if ((uintptr_t)s % sizeof(size_t) == (uintptr_t)d % sizeof(size_t)) {
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while ((uintptr_t)d % sizeof(size_t)) {
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if (!n--) {
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return dest;
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}
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*d++ = *s++;
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}
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for (; n >= sizeof(size_t); n -= sizeof(size_t), d += sizeof(size_t), s += sizeof(size_t)) {
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*(size_t *)d = *(size_t *)s;
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}
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}
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for (; n; n--) {
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*d++ = *s++;
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}
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} else {
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if ((uintptr_t)s % sizeof(size_t) == (uintptr_t)d % sizeof(size_t)) {
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while ((uintptr_t)(d+n) % sizeof(size_t)) {
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if (!n--) {
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return dest;
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}
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d[n] = s[n];
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}
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while (n >= sizeof(size_t)) {
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n -= sizeof(size_t);
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*(size_t *)(d+n) = *(size_t *)(s+n);
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}
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}
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while (n) {
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n--;
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d[n] = s[n];
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}
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}
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return dest;
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}
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