fix: fall back to unordered_map if mph cannot be used

src/os_utils.cpp

@@ -4,14 +4,24 @@
 #include <string_view>
 #include <utility>
 
-#include <mph>
+#if defined(__SIZEOF_INT128__) && __SIZEOF_INT128__ && __cplusplus >= 202002L
+#    include <mph>
+#    define USE_MPH
+#    define CONTAINER           std::array
+#    define CONTAINER_CONSTEXPR constexpr
+#else
+#    include <unordered_map>
+#    define CONTAINER           std::unordered_map
+#    define CONTAINER_CONSTEXPR const
+#endif
+
 #include <opentelemetry/sdk/resource/semantic_conventions.h>
 
 using std::literals::operator""sv;
 
 namespace {
 
-constexpr auto machine_to_arch = std::array{
+CONTAINER_CONSTEXPR auto machine_to_arch = CONTAINER{
     std::pair{"x86_64"sv, opentelemetry::sdk::resource::SemanticConventions::HostArchValues::kAmd64},
     std::pair{"amd64"sv, opentelemetry::sdk::resource::SemanticConventions::HostArchValues::kAmd64},
     std::pair{"aarch64"sv, opentelemetry::sdk::resource::SemanticConventions::HostArchValues::kArm64},
@@ -32,7 +42,7 @@ constexpr auto machine_to_arch = std::array{
     std::pair{"ia64"sv, opentelemetry::sdk::resource::SemanticConventions::HostArchValues::kIa64}
 };
 
-constexpr auto os_to_type = std::array{
+CONTAINER_CONSTEXPR auto os_to_type = CONTAINER{
     std::pair{"Linux"sv, opentelemetry::sdk::resource::SemanticConventions::OsTypeValues::kLinux},
     std::pair{"Windows_NT"sv, opentelemetry::sdk::resource::SemanticConventions::OsTypeValues::kWindows},
     std::pair{"DragonFly"sv, opentelemetry::sdk::resource::SemanticConventions::OsTypeValues::kDragonflybsd},
@@ -50,18 +60,30 @@ constexpr auto os_to_type = std::array{
 
 std::string get_host_arch(std::string_view machine)
 {
+#ifdef USE_MPH
     if (const auto arch = mph::find<machine_to_arch>(machine); arch) {
         return arch.value;
     }
+#else
+    if (const auto it = machine_to_arch.find(machine); it != machine_to_arch.end()) {
+        return it->second;
+    }
+#endif
 
     return {machine.data(), machine.length()};
 }
 
 std::string get_os_type(std::string_view os)
 {
+#ifdef USE_MPH
     if (const auto type = mph::find<os_to_type>(os); type) {
         return type.value;
     }
+#else
+    if (const auto it = os_to_type.find(os); it != os_to_type.end()) {
+        return it->second;
+    }
+#endif
 
     if (os.starts_with("CYGWIN") || os.starts_with("MINGW") || os.starts_with("MSYS")) {
         return opentelemetry::sdk::resource::SemanticConventions::OsTypeValues::kWindows;