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// { dg-do run }
using size_t = __SIZE_TYPE__;
inline void* operator new(size_t, void* p) noexcept
{ return p; }
inline void operator delete(void*, void*)
{ }
struct long_t
{
size_t is_short : 1;
size_t length : (__SIZEOF_SIZE_T__ * __CHAR_BIT__ - 1);
size_t capacity;
char* pointer;
};
union long_raw_t {
unsigned char data[sizeof(long_t)];
struct __attribute__((aligned(alignof(long_t)))) { } align;
};
struct short_header
{
unsigned char is_short : 1;
unsigned char length : (__CHAR_BIT__ - 1);
};
struct short_t
{
short_header h;
char data[23];
};
union repr_t
{
long_raw_t r;
short_t s;
const short_t& short_repr() const
{ return s; }
const long_t& long_repr() const
{ return *static_cast<const long_t*>(static_cast<const void*>(&r)); }
short_t& short_repr()
{ return s; }
long_t& long_repr()
{ return *static_cast<long_t*>(static_cast<void*>(&r)); }
};
class string
{
public:
string()
{
short_t& s = m_repr.short_repr();
s.h.is_short = 1;
s.h.length = 0;
s.data[0] = '\0';
}
string(const char* str)
{
size_t length = __builtin_strlen(str);
if (length + 1 > 23) {
long_t& l = m_repr.long_repr();
l.is_short = 0;
l.length = length;
l.capacity = length + 1;
l.pointer = new char[l.capacity];
__builtin_memcpy(l.pointer, str, length + 1);
} else {
short_t& s = m_repr.short_repr();
s.h.is_short = 1;
s.h.length = length;
__builtin_memcpy(s.data, str, length + 1);
}
}
string(string&& other)
: string{}
{
swap_data(other);
}
~string()
{
if (!is_short()) {
delete[] m_repr.long_repr().pointer;
}
}
size_t length() const
{ return is_short() ? short_length() : long_length(); }
private:
bool is_short() const
{ return m_repr.s.h.is_short != 0; }
size_t short_length() const
{ return m_repr.short_repr().h.length; }
size_t long_length() const
{ return m_repr.long_repr().length; }
void swap_data(string& other)
{
if (is_short()) {
if (other.is_short()) {
repr_t tmp(m_repr);
m_repr = other.m_repr;
other.m_repr = tmp;
} else {
short_t short_backup(m_repr.short_repr());
m_repr.short_repr().~short_t();
::new(&m_repr.long_repr()) long_t(other.m_repr.long_repr());
other.m_repr.long_repr().~long_t();
::new(&other.m_repr.short_repr()) short_t(short_backup);
}
} else {
if (other.is_short()) {
short_t short_backup(other.m_repr.short_repr());
other.m_repr.short_repr().~short_t();
::new(&other.m_repr.long_repr()) long_t(m_repr.long_repr());
m_repr.long_repr().~long_t();
::new(&m_repr.short_repr()) short_t(short_backup);
} else {
long_t tmp(m_repr.long_repr());
m_repr.long_repr() = other.m_repr.long_repr();
other.m_repr.long_repr() = tmp;
}
}
}
repr_t m_repr;
};
struct foo
{
__attribute__((noinline))
foo(string str)
: m_str{static_cast<string&&>(str)},
m_len{m_str.length()}
{ }
string m_str;
size_t m_len;
};
int main()
{
foo f{"the quick brown fox jumps over the lazy dog"};
if (f.m_len == 0) {
__builtin_abort();
}
return 0;
}
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