feat: support freestanding

include/emio/buffer.hpp

@@ -9,7 +9,11 @@
 #include <iterator>
 #include <limits>
 #include <span>
-#include <string>
+
+#if __STDC_HOSTED__
+#  include <string>
+#endif
+
 #include <string_view>
 #include <type_traits>
 
@@ -155,13 +159,15 @@ class memory_buffer final : public buffer {
     return {vec_.data(), used_ + this->get_used_count()};
   }
 
+#if __STDC_HOSTED__
   /**
    * Obtains a copy of the underlying string object.
    * @return The string.
    */
   [[nodiscard]] std::string str() const {
     return std::string{view()};
   }
+#endif
 
   /**
    * Resets the buffer's read and write position to the beginning of the internal storage.
@@ -227,13 +233,15 @@ class span_buffer : public buffer {
     return {span_.data(), this->get_used_count()};
   }
 
+#if __STDC_HOSTED__
   /**
    * Obtains a copy of the underlying string object.
    * @return The string.
    */
   [[nodiscard]] std::string str() const {
     return std::string{view()};
   }
+#endif
 
   /**
    * Resets the buffer's read and write position to the beginning of the span.
@@ -303,10 +311,12 @@ struct get_value_type<std::back_insert_iterator<Container>> {
   using type = typename Container::value_type;
 };
 
+#if __STDC_HOSTED__
 template <typename Char, typename Traits>
 struct get_value_type<std::ostreambuf_iterator<Char, Traits>> {
   using type = Char;
 };
+#endif
 
 template <typename T>
 using get_value_type_t = typename get_value_type<T>::type;

include/emio/detail/ct_vector.hpp

@@ -9,7 +9,6 @@
 #include <algorithm>
 #include <array>
 #include <cstddef>
-#include <string>
 
 #include "conversion.hpp"
 #include "predef.hpp"

include/emio/detail/validated_string.hpp

@@ -27,10 +27,12 @@ class runtime_string {
   constexpr runtime_string() = default;
 
   // Don't allow temporary strings or any nullptr.
-  // NOLINTNEXTLINE(cppcoreguidelines-rvalue-reference-param-not-moved): as intended
-  constexpr runtime_string(std::string&&) = delete;
   constexpr runtime_string(std::nullptr_t) = delete;
   constexpr runtime_string(int) = delete;
+#if __STDC_HOSTED__
+  // NOLINTNEXTLINE(cppcoreguidelines-rvalue-reference-param-not-moved): as intended
+  constexpr runtime_string(std::string&&) = delete;
+#endif
 
   /**
    * Constructs the runtime format/scan string from any suitable char sequence.

include/emio/format.hpp

@@ -181,6 +181,7 @@ constexpr result<OutputIt> format_to(OutputIt out, emio::format_string<Args...>
   return buf.out();
 }
 
+#if __STDC_HOSTED__
 /**
  * Formats arguments according to the format string, and returns the result as string.
  * @param args The format args with the format string.
@@ -219,6 +220,7 @@ template <typename T, typename... Args>
 result<std::string> format(T format_str, const Args&... args) noexcept {
   return emio::vformat(emio::make_format_args(format_str, args...));
 }
+#endif
 
 /**
  * Return type of (v)format_to_n functions.

include/emio/formatter.hpp

@@ -299,9 +299,11 @@ constexpr const void* ptr(const std::unique_ptr<T, Deleter>& p) {
   return p.get();
 }
 
+#if __STDC_HOSTED__
 template <typename T>
 const void* ptr(const std::shared_ptr<T>& p) {
   return p.get();
 }
+#endif
 
 }  // namespace emio

include/emio/reader.hpp

@@ -50,9 +50,11 @@ class reader {
   constexpr reader() = default;
 
   // Don't allow temporary strings or any nullptr.
-  constexpr reader(std::string&&) = delete;  // NOLINT(cppcoreguidelines-rvalue-reference-param-not-moved): as intended
   constexpr reader(std::nullptr_t) = delete;
   constexpr reader(int) = delete;
+#if __STDC_HOSTED__
+  constexpr reader(std::string&&) = delete;  // NOLINT(cppcoreguidelines-rvalue-reference-param-not-moved): as intended
+#endif
 
   /**
    * Constructs the reader from any suitable char sequence.

include/emio/result.hpp

@@ -9,7 +9,9 @@
 #include <concepts>
 #include <cstdint>
 #include <optional>
-#include <stdexcept>
+#if __STDC_HOSTED__
+#  include <stdexcept>
+#endif
 #include <type_traits>
 
 #include "detail/predef.hpp"
@@ -82,14 +84,32 @@ inline constexpr struct {
  * - "no value" -> a value should be accessed but result<T> held an error
  * - "no error" -> a error should be accessed but result<T> held an value
  */
+#if __STDC_HOSTED__
 class bad_result_access : public std::logic_error {
  public:
   /**
    * Constructs the bad result access from a message.
    * @param msg The exception message.
    */
-  explicit bad_result_access(const std::string_view& msg) : logic_error{msg.data()} {}
+  explicit bad_result_access(const std::string_view& msg) : logic_error{std::string{msg}} {}
 };
+#else
+class bad_result_access : public std::exception {
+ public:
+  /**
+   * Constructs the bad result access from a message.
+   * @param msg The exception message.
+   */
+  explicit bad_result_access(const std::string_view& msg) : msg_{msg} {}
+
+  [[nodiscard]] const char* what() const noexcept override {
+    return msg_.data();
+  }
+
+ private:
+  std::string_view msg_;
+};
+#endif
 
 namespace detail {
 

include/emio/scanner.hpp

@@ -147,6 +147,7 @@ class scanner<std::string_view> {
   reader format_rdr_;
 };
 
+#if __STDC_HOSTED__
 /**
  * Scanner for std::string.
  */
@@ -160,5 +161,6 @@ class scanner<std::string> : public scanner<std::string_view> {
     return success;
   }
 };
+#endif
 
 }  // namespace emio

include/emio/std.hpp

@@ -7,7 +7,9 @@
 #pragma once
 
 #include <exception>
-#include <filesystem>
+#if __STDC_HOSTED__
+#  include <filesystem>
+#endif
 #include <optional>
 #include <variant>
 
@@ -58,6 +60,7 @@ class formatter<T> : public formatter<std::string_view> {
   }
 };
 
+#if __STDC_HOSTED__
 /**
  * Formatter for std::filesystem::path.
  */
@@ -68,6 +71,7 @@ class formatter<std::filesystem::path> : public formatter<std::string_view> {
     return formatter<std::string_view>::format(out, arg.native());
   }
 };
+#endif
 
 /**
  * Formatter for std::monostate.

test/compile_test/CMakeLists.txt

@@ -10,12 +10,21 @@ if (PROJECT_IS_TOP_LEVEL)
     enable_testing()
 endif ()
 
-add_executable(emio_compile ../compile_test/compile.cpp)
+add_executable(emio_compile compile.cpp)
 
 target_link_libraries(emio_compile
         emio::emio
 )
 
 target_compile_features(emio_compile PRIVATE cxx_std_20)
 
+add_executable(emio_compile_freestanding compile.cpp)
+
+target_link_libraries(emio_compile_freestanding
+        emio::emio
+)
+
+target_compile_features(emio_compile_freestanding PRIVATE cxx_std_20)
+target_compile_options(emio_compile_freestanding PRIVATE -ffreestanding)
+
 add_folders(CompileTest)

test/compile_test/compile.cpp

@@ -1,7 +1,4 @@
-//
-// Created by neubertt on 09.03.2024.
-//
-#include "emio/emio.hpp"
+#include <emio/emio.hpp>
 
 consteval auto created_with_span_buffer() {
   std::array<char, 5> storage{};
@@ -35,9 +32,11 @@ consteval auto created_with_iterator_buffer() {
   return storage;
 }
 
-int main() {
-  created_with_span_buffer();
-  created_with_static_buffer();
-  created_with_memory_buffer();
-  created_with_iterator_buffer();
+extern "C" int main() {
+  const auto a = created_with_span_buffer();
+  const auto b = created_with_static_buffer();
+  const auto c = created_with_memory_buffer();
+  const auto d = created_with_iterator_buffer();
+
+  return a.size() + b.size() + c.size() + d.size();
 }