::gcc_demangle

#include <cstdlib>
#include <cxxabi.h>
#include <memory>
#include <stdexcept>
#include <string>

std::string gcc_demangle(const char* mangled) {
    std::size_t length;
    int status;

    std::unique_ptr<char[], void(*)(char*)> demangled{
        abi::__cxa_demangle(mangled, nullptr, &length, &status),
        [](char* p) { std::free(p); }
    };

    switch(status) {
    case -1:
        throw std::bad_alloc{};
    case -2:
    case -3:
        throw std::invalid_argument{"::gcc_demangle"};
    case 0:
        return std::string{demangled.get(), length};
    default:
        std::abort();
    }
}