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#include <kstd/cstring>
#include <algorithm>
#include <bit>
#include <cstddef>
#include <iterator>
#include <span>
namespace kstd::libc
{
auto memcpy(void * dest, void const * src, std::size_t size) -> void *
{
auto dest_span = std::span{static_cast<std::byte *>(dest), size};
auto src_span = std::span{static_cast<std::byte const *>(src), size};
for (std::size_t i = 0; i < size; ++i)
{
dest_span[i] = src_span[i];
}
return dest;
}
auto memset(void * dest, int value, std::size_t size) -> void *
{
auto const byte_value = static_cast<std::byte>(static_cast<unsigned char>(value));
auto dest_span = std::span{static_cast<std::byte *>(dest), size};
for (std::size_t i = 0; i < size; ++i)
{
dest_span[i] = byte_value;
}
return dest;
}
auto memcmp(void const * lhs, void const * rhs, std::size_t size) -> std::size_t
{
auto left_span = std::span{static_cast<std::byte const *>(lhs), size};
auto right_span = std::span{static_cast<std::byte const *>(rhs), size};
auto mismatched = std::ranges::mismatch(left_span, right_span);
if (mismatched.in1 == left_span.end())
{
return 0;
}
return std::bit_cast<char>(*mismatched.in1) - std::bit_cast<char>(*mismatched.in2);
}
auto memmove(void * dest, void const * src, std::size_t size) -> void *
{
auto dest_span = std::span{static_cast<std::byte *>(dest), size};
auto src_span = std::span{static_cast<std::byte const *>(src), size};
if (dest < src)
{
for (std::size_t i = 0; i < size; ++i)
{
dest_span[i] = src_span[i];
}
}
else
{
for (std::size_t i = size; i > 0; --i)
{
dest_span[i - 1] = src_span[i - 1];
}
}
return dest;
}
auto strlen(char const * string) -> std::size_t
{
return std::distance(string, std::ranges::find(string, nullptr, '\0'));
}
} // namespace kstd::libc
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