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Directory.h
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Directory.h
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#pragma once
/*
A namespace of helper functions for the manipulation of strings that indicate a directory, and I guess also other shit, innit?
*/
namespace Directory
{
// Go up one directory from this directory
std::string DotDot(std::string);
// Get the last word token within this dir, returning emptystring if there is none and dir if there's no slash
std::string lastword(std::string);
bool is_base_of(std::string, std::string);
}
namespace string
{
std::string replace_all(std::string, char, char);
}
namespace math
{
Value round(const std::vector<Value>&);
Value round_safe([[maybe_unused]] Interpreter& interp, const std::vector<Value>&);
//A math-"library" wrapper around whatever builtin/fallback is actually happening in this context.
constexpr size_t popcount(size_t x)
{
#ifdef __cpp_lib_bitops // Prefer a standard-library thing over weird builtins
return std::popcount(x);
#elif defined(__GNUG__)
if constexpr (sizeof(size_t) == 4) // x32
{
return __builtin_popcount(x);
}
else
{
return __builtin_popcountll(x);
}
#else // Final fallback >:/
size_t sum = 0;
for (int b = 0; b < sizeof(size_t) * 8; ++b)
{
if (x & (1ull << b))
++sum;
}
return sum;
#endif
}
//Returns the power of two that is larger than or equal to this number. Assumes x is not a power of two.
constexpr size_t get_greater_power_of_two(size_t x)
{
#ifdef __cpp_lib_bitops // If we can just use C++20, then do so
return std::bit_ceil(x);
#endif
//otherwise... *sigh*
if (popcount(x) == 1) // If it's already a power of two
return x; //bam
x <<= 1; // shunt the bit over so it's slightly easier to find
for (int b = (sizeof(size_t) * 8 - 1); b > 0; --b) // Find the first bit
{
if (x & (1ull << b)) // If this is the first bit
{
return 1ull << b; // Then that's your answer.
}
}
return size_t(1) << (sizeof(size_t)*8 - 1);
}
constexpr size_t get_high_bit(size_t x)
{
constexpr size_t size_t_max_shift = sizeof(size_t) * 8 - 1;
#ifndef __cpp_lib_bitops
for (int b = size_t_max_shift; b >= 0; --b)
{
if (x & (1 << b))
return 1 << b;
}
return 0;
#else
//Assumes x != 0
return 1 << (size_t_max_shift - std::countl_zero(x));
#endif
}
template<typename... Args>
//FIXME: Allow this to take a StringBuilder argument :3
std::string concat(Args&&... args)
{
#ifndef __cpp_fold_expressions
#error "The C++17 Fold Expressions feature is required for compilation."
#endif
std::string result;
result.reserve(512);
return (result + ... + args);
}
}