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#include <errno.h> // for EINVAL, ERANGE
#include <stddef.h> // for NULL, errno_t
#include <stdint.h>
#include <string.h> // for rsize_t, memcpy, size_t, memcpy_s
#include <sys/cdefs.h>
__weak void *memcpy(void *restrict s1, const void *restrict s2, size_t n);
void *memcpy(void *restrict s1, const void *restrict s2, size_t n)
{
unsigned char *d = (unsigned char *)s1;
const unsigned char *s = (const unsigned char *)s2;
if (n == 0)
return s1;
if (n < 16) {
if (n >= 8) {
*(uint64_t *)d = *(const uint64_t *)s;
d += 8;
s += 8;
n -= 8;
}
if (n >= 4) {
*(uint32_t *)d = *(const uint32_t *)s;
d += 4;
s += 4;
n -= 4;
}
if (n >= 2) {
*(uint16_t *)d = *(const uint16_t *)s;
d += 2;
s += 2;
n -= 2;
}
if (n)
*d = *s;
return s1;
}
uintptr_t align_mask = 15;
size_t misalign = (uintptr_t)d & align_mask;
if (misalign) {
size_t to_align = 16 - misalign;
if (to_align > n)
to_align = n;
for (size_t i = 0; i < to_align; ++i)
*d++ = *s++;
n -= to_align;
}
while (n >= 128) {
#pragma unroll
for (int i = 0; i < 8; ++i) {
((i128 *)d)[i] = ((const i128 *)s)[i];
}
d += 128;
s += 128;
n -= 128;
}
while (n >= 64) {
#pragma unroll
for (int i = 0; i < 4; ++i) {
((i128 *)d)[i] = ((const i128 *)s)[i];
}
d += 64;
s += 64;
n -= 64;
}
while (n >= 32) {
#pragma unroll
for (int i = 0; i < 2; ++i) {
((i128 *)d)[i] = ((const i128 *)s)[i];
}
d += 32;
s += 32;
n -= 32;
}
while (n >= 16) {
*(i128 *)d = *(const i128 *)s;
d += 16;
s += 16;
n -= 16;
}
if (n >= 8) {
*(uint64_t *)d = *(const uint64_t *)s;
d += 8;
s += 8;
n -= 8;
}
if (n >= 4) {
*(uint32_t *)d = *(const uint32_t *)s;
d += 4;
s += 4;
n -= 4;
}
if (n >= 2) {
*(uint16_t *)d = *(const uint16_t *)s;
d += 2;
s += 2;
n -= 2;
}
if (n)
*d = *s;
return s1;
}
errno_t memcpy_s(void *restrict dest, rsize_t destsz, const void *restrict src, rsize_t count)
{
if (dest == NULL || src == NULL) {
if (dest != NULL && destsz > 0) {
unsigned char *d = dest;
for (rsize_t i = 0; i < destsz; i++) {
d[i] = 0;
}
}
return EINVAL;
}
const unsigned char *s = src;
unsigned char *d = dest;
if ((d > s && d < s + count) || (s > d && s < d + count)) {
for (rsize_t i = 0; i < destsz; i++) {
d[i] = 0;
}
return EINVAL;
}
if (count > destsz) {
for (rsize_t i = 0; i < destsz; i++) {
d[i] = 0;
}
return ERANGE;
}
for (rsize_t i = 0; i < count; i++) {
d[i] = s[i];
}
return 0;
}
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