1 files changed, 98 insertions, 0 deletions
diff --git a/src/arrow/r/inst/include/cpp11/r_string.hpp b/src/arrow/r/inst/include/cpp11/r_string.hpp
new file mode 100644
index 000000000..d62f7270f
--- /dev/null
+++ b/src/arrow/r/inst/include/cpp11/r_string.hpp
@@ -0,0 +1,98 @@
+// cpp11 version: 0.3.1.1
+// vendored on: 2021-08-11
+#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_mkCharLenCE](data.c_str(), data.size(), 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;
+};
+
+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;
+}
+
+template <typename T, typename R = void>
+using enable_if_r_string = enable_if_t<std::is_same<T, cpp11::r_string>::value, R>;
+
+template <typename T>
+enable_if_r_string<T, 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 r_string na() {
+  return NA_STRING;
+}
+
+}  // namespace cpp11