cpp11/inst/include/cpp11/r_string.hpp at master · tmastny/cpp11 · GitHub

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#pragma once

#include <string> // for string, basic_string, operator==

#include <type_traits> // for is_convertible, enable_if

#include "R_ext/Memory.h" // for vmaxget, vmaxset

#include "cpp11/R.hpp" // for SEXP, SEXPREC, Rf_mkCharCE, Rf_translat...

#include "cpp11/as.hpp" // for as_sexp

#include "cpp11/protect.hpp" // for unwind_protect, protect, protect::function

#include "cpp11/sexp.hpp" // for sexp

namespace cpp11 {

class r_string {

public:

r_string() = default;

r_string(SEXP data) : data_(data) {}

r_string(const char* data) : data_(safe[Rf_mkCharCE](data, CE_UTF8)) {}

r_string(const std::string& data) : data_(safe[Rf_mkCharCE](data.c_str(), CE_UTF8)) {}

operator SEXP() const { return data_; }

operator sexp() const { return data_; }

operator std::string() const {

std::string res;

res.reserve(size());

void* vmax = vmaxget();

unwind_protect([&] { res.assign(Rf_translateCharUTF8(data_)); });

vmaxset(vmax);

return res;

}

bool operator==(const r_string& rhs) const { return data_.data() == rhs.data_.data(); }

bool operator==(const SEXP rhs) const { return data_.data() == rhs; }

bool operator==(const char* rhs) const {

return static_cast<std::string>(*this) == rhs;

}

bool operator==(const std::string& rhs) const {

return static_cast<std::string>(*this) == rhs;

}

R_xlen_t size() const { return Rf_xlength(data_); }

private:

sexp data_ = R_NilValue;

}; // namespace cpp11

template <typename T>

using is_convertible_to_cpp11_string =

typename std::enable_if<std::is_convertible<T, cpp11::r_string>::value &&

!std::is_convertible<T, const char*>::value,

T>::type;

/* This will translate the r_string to UTF-8, but I think that is actually the

* right thing to do */

template <typename T, is_convertible_to_cpp11_string<T>* = nullptr>

inline SEXP as_sexp(T from) {

r_string str(from);

sexp res;

unwind_protect([&] {

res = Rf_allocVector(STRSXP, 1);

if (str == NA_STRING) {

SET_STRING_ELT(res, 0, str);

} else {

SET_STRING_ELT(res, 0, Rf_mkCharCE(Rf_translateCharUTF8(str), CE_UTF8));

}

});

return res;

}

template <>

inline SEXP as_sexp(std::initializer_list<r_string> il) {

R_xlen_t size = il.size();

sexp data;

unwind_protect([&] {

data = Rf_allocVector(STRSXP, size);

auto it = il.begin();

for (R_xlen_t i = 0; i < size; ++i, ++it) {

if (*it == NA_STRING) {

SET_STRING_ELT(data, i, *it);

} else {

SET_STRING_ELT(data, i, Rf_mkCharCE(Rf_translateCharUTF8(*it), CE_UTF8));

}

});

return data;

}

inline bool is_na(const r_string& x) { return x == NA_STRING; }

} // namespace cpp11

cpp11/inst/include/cpp11/r_string.hpp at master · tmastny/cpp11 · GitHub

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