mirror of
https://github.com/rad9800/misc
synced 2026-06-08 16:56:08 +00:00
rad9800
47 lines
1.4 KiB
C++
47 lines
1.4 KiB
C++
#include <array>
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#include <cstdio>
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template<typename T, size_t N>
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constexpr auto stack(const T(&str)[N])
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{
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std::array<T, N> ret{};
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std::copy(std::begin(str), std::end(str), ret.begin());
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return ret;
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}
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/*++
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*
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* Setup stack strings in an easier fashion using constexpr macros
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* Some may get optimized into mmx registers some many not
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*
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* Credit to @JonasLyk for pushing me in the right direction and
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* his nt code
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*
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--*/
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int main()
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{
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printf("hello world : plaintext \n");
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const char stack_0[] = {'h', 'e', 'l', 'l', 'o', ' ', 'w', 'o', 'r', 'l', 'd' ,'\0'};
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printf("%s\n", stack_0);
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// works as a stack string
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constexpr auto stack_1 = stack(L"hello world : widechar");
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static_assert(std::is_same_v<decltype(stack_1), const std::array<wchar_t, 23>>);
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printf("%S\n", &stack_1[0]);
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// gets optimized to xmmword
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// this means the first 128 of the strings will be made available
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// movdqa xmm0, XMMWORD PTR __xmm@6863203a20646c726f77206f6c6c6568
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// lea rdx, QWORD PTR stack_2$[rbp-128]
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// lea rcx, OFFSET FLAT:`string'
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// mov WORD PTR stack_2$[rbp-112], 29281 ; 00007261H
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// https://godbolt.org/z/rEcGffdh1
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constexpr auto stack_2 = stack("hello world : char");
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static_assert(std::is_same_v<decltype(stack_2), const std::array<char, 19>>);
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printf("%s\n", &stack_2[0]);
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return 0;
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}
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