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Add fieldptrvw manipulator for printing out member object pointer #1248

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Merged
trcrsired merged 6 commits into from
Dec 26, 2025
Merged

Add fieldptrvw manipulator for printing out member object pointer #1248

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31a95dc
ignore __wasi_sched_yield()'s warning
trcrsired Dec 23, 2025
1cc311e
Add experimental fieldptrvw
trcrsired Dec 26, 2025
606aed2
fieldptrvw neeeds special treat for msvc abi
trcrsired Dec 26, 2025
f12a4ad
use constexpr variable in fieldptrvw to avoid as less annoying
trcrsired Dec 26, 2025
127b4b7
the example should contain fieldptrvw
trcrsired Dec 26, 2025
67f8969
fieldptrvw on msvc abi is super annoying because it can alias to mult…
trcrsired Dec 26, 2025
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117 changes: 78 additions & 39 deletions examples/0003.manipulators/pointer.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,7 @@ struct A
virtual void f() noexcept
{}
};

struct B
{
virtual void g() noexcept
Expand All @@ -23,59 +24,97 @@ struct C : A, B
{
};

struct S
{
int x;
double y;
int z;
};

struct VA
{
int a;
};

struct VB : virtual VA
{
int b;
};

using namespace fast_io::io;

void foo(){}
void foo()
{}

int main()
{
using namespace fast_io::mnp;

int fd{3};
int *ptr{::std::addressof(fd)};

char const *ptr2 = "hello";

void (C::*downcptr)() noexcept = &B::g;

println("funcvw(foo):", funcvw(foo),
"\n"
"pointervw(ptr):",
pointervw(ptr),
"\n"
"handlevw(fd):",
handlevw(fd),
"\n"
"handlevw(ptr):",
handlevw(ptr),
"\n"
"pointervw(ptr2):",
pointervw(ptr2),
"\n"
"dec(pointervw(ptr2)):",
dec(pointervw(ptr2)),
"\n"
"os_c_str(ptr2):",
os_c_str(ptr2),
"\n"
"methodvw(&dummy_class::dummy_method):",
methodvw(&dummy_class::dummy_method),
"\n"
"dec(methodvw(&dummy_class::dummy_method)):",
dec(methodvw(&dummy_class::dummy_method)),
"\n"
"methodvw(downcptr):",
methodvw(downcptr));
println(
"funcvw(foo):", funcvw(foo),
"\n"
"pointervw(ptr):",
pointervw(ptr),
"\n"
"handlevw(fd):",
handlevw(fd),
"\n"
"handlevw(ptr):",
handlevw(ptr),
"\n"
"pointervw(ptr2):",
pointervw(ptr2),
"\n"
"dec(pointervw(ptr2)):",
dec(pointervw(ptr2)),
"\n"
"os_c_str(ptr2):",
os_c_str(ptr2),
"\n"
"methodvw(&dummy_class::dummy_method):",
methodvw(&dummy_class::dummy_method),
"\n"
"dec(methodvw(&dummy_class::dummy_method)):",
dec(methodvw(&dummy_class::dummy_method)),
"\n"
"methodvw(downcptr):",
methodvw(downcptr),
"\n"
"fieldptrvw(&S::x):",
fieldptrvw(&S::x),
"\n"
"fieldptrvw(&S::y):",
fieldptrvw(&S::y),
"\n"
"fieldptrvw(&S::z):",
fieldptrvw(&S::z),
"\n"
"fieldptrvw(&VB::b):",
fieldptrvw(&VB::b),
"\n"
"fieldptrvw(&VA::a):",
fieldptrvw(&VA::a));
}

/*
funcvw(foo):0x00007ff75abf27c0
pointervw(ptr):0x000000c232d0fa9c
funcvw(foo):0x0000000102368570
pointervw(ptr):0x000000016da96e1c
handlevw(fd):3
handlevw(ptr):0x000000c232d0fa9c
pointervw(ptr2):0x00007ff75abf4540
dec(pointervw(ptr2)):140700356134208
handlevw(ptr):0x000000016da96e1c
pointervw(ptr2):0x0000000102369f0c
dec(pointervw(ptr2)):4332101388
os_c_str(ptr2):hello
methodvw(&dummy_class::dummy_method):0x00007ff75abf34b0+0x0
dec(methodvw(&dummy_class::dummy_method)):140700356129968+0
methodvw(downcptr):0x0000000000000001+0x8
methodvw(&dummy_class::dummy_method):0x0000000102369400+0x0
dec(methodvw(&dummy_class::dummy_method)):4332098560+0
methodvw(downcptr):0x0000000000000000+0x11
fieldptrvw(&S::x):0x0000000000000000
fieldptrvw(&S::y):0x0000000000000008
fieldptrvw(&S::z):0x0000000000000010
fieldptrvw(&VB::b):0x0000000000000008
fieldptrvw(&VA::a):0x0000000000000000
*/
26 changes: 26 additions & 0 deletions include/fast_io_core_impl/integers/impl.h
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Original file line number Diff line number Diff line change
Expand Up @@ -625,6 +625,32 @@ inline constexpr auto funcvw(scalar_type *t) noexcept
::fast_io::details::base_mani_flags_cache<16, uppercase, true, true, false>>(::std::bit_cast<::std::size_t>(t));
}

template <bool uppercase = false, typename scalar_type>
requires(::std::is_member_object_pointer_v<scalar_type>)
inline constexpr auto fieldptrvw(scalar_type t) noexcept
{
if constexpr (sizeof(t) == sizeof(::fast_io::manipulators::member_function_pointer_holder_t))
{
return ::fast_io::details::scalar_flags_int_cache<
::fast_io::details::base_mani_flags_cache<16, uppercase, true, true, false>>(
::std::bit_cast<::fast_io::manipulators::member_function_pointer_holder_t>(t));
}
else
{
using equivalentsizetype = ::std::conditional_t<
sizeof(scalar_type) == sizeof(::std::size_t), ::std::size_t,
::std::conditional_t<sizeof(scalar_type) == sizeof(::std::uint_least64_t),
::std::uint_least64_t,
::std::conditional_t<sizeof(scalar_type) == sizeof(::std::uint_least32_t),
::std::uint_least32_t,
::std::conditional_t<sizeof(scalar_type) == sizeof(::std::uint_least16_t),
::std::uint_least16_t,
::std::uint_least8_t>>>>;
return ::fast_io::details::scalar_flags_int_cache<
::fast_io::details::base_mani_flags_cache<16, uppercase, true, true, false>>(::std::bit_cast<equivalentsizetype>(t));
}
}

template <bool uppercase = false, typename scalar_type>
requires(::std::is_member_function_pointer_v<scalar_type> && (sizeof(scalar_type) % sizeof(::std::size_t) == 0))
inline constexpr auto methodvw(scalar_type t) noexcept
Expand Down
2 changes: 1 addition & 1 deletion include/fast_io_hosted/threads/thread/wasi.h
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Original file line number Diff line number Diff line change
Expand Up @@ -270,7 +270,7 @@ inline
#endif
void yield() noexcept
{
__wasi_sched_yield();
(void)__wasi_sched_yield();
}

} // namespace this_thread
Expand Down
28 changes: 28 additions & 0 deletions tests/0011.manipulators/fieldptrvw.cc
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Original file line number Diff line number Diff line change
@@ -0,0 +1,28 @@
#include <fast_io.h>

struct S
{
int x;
double y;
int z;
};
struct A
{
int a;
};
struct B
{
int b;
};
struct C : A, B
{}; // multiple inheritance

int main()
{
using namespace ::fast_io::iomnp;
println("&B::b = ", fieldptrvw(&B::b), "\n"
"&C::b = ",
fieldptrvw(&C::b), "\n"
"&S::z = ",
fieldptrvw(&S::z));
}