Implement << operator for std basic_ostream and etl string_view

ETLCPP · Mar 1, 2025 · 0c2b5ae · 0c2b5ae
1 parent e1b263a
commit 0c2b5ae
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diff --git a/include/etl/string_view.h b/include/etl/string_view.h
@@ -47,6 +47,10 @@ SOFTWARE.
   #include <string_view>
 #endif
 
+#if ETL_USING_STL
+  #include <ostream>
+#endif
+
 #include <stdint.h>
 
 namespace etl
@@ -972,6 +976,19 @@ void swap(etl::basic_string_view<T, etl::char_traits<T> >& lhs, etl::basic_strin
   lhs.swap(rhs);
 }
 
+//*************************************************************************
+/// Function overload to write to std ostream
+//*************************************************************************
+#ifdef ETL_USING_STL
+template <typename T>
+std::basic_ostream<T, std::char_traits<T> > &operator<<(std::basic_ostream<T, std::char_traits<T> > &os, 
+                                                        etl::basic_string_view<T, etl::char_traits<T> > text)
+{
+  os.write(text.data(), text.size());
+  return os;
+}
+#endif
+
 #include "private/minmax_pop.h"
 
 #endif

diff --git a/test/test_string_view.cpp b/test/test_string_view.cpp
@@ -1120,5 +1120,40 @@ namespace
       CHECK_TRUE((u16view == U16View{ u"Hello World", etl::strlen(u"Hello World") }));
       CHECK_TRUE((u32view == U32View{ U"Hello World", etl::strlen(U"Hello World") }));
     }
+
+    //*************************************************************************
+#if ETL_USING_STL
+    TEST(write_to_std_stream)
+    {
+      View view{ "Hello World" };
+      WView wview{ L"Hello World" };
+      U16View u16view{ u"Hello World" };
+      U32View u32view{ U"Hello World" };
+
+      std::stringstream sstream;
+      std::wstringstream wsstream;
+      std::basic_stringstream<char16_t> u16sstream;
+      std::basic_stringstream<char32_t> u32sstream;
+
+      sstream << view;
+      std::string sstream_string = sstream.str();
+      wsstream << wview;
+      std::wstring wsstream_string = wsstream.str();
+      u16sstream << u16view;
+      std::u16string u16sstream_string = u16sstream.str();
+      u32sstream << u32view;
+      std::u32string u32sstream_string = u32sstream.str();
+
+      View sstream_view(sstream_string.data(), sstream_string.size());
+      WView wsstream_view(wsstream_string.data(), wsstream_string.size());
+      U16View u16sstream_view(u16sstream_string.data(), u16sstream_string.size());
+      U32View u32sstream_view(u32sstream_string.data(), u32sstream_string.size());
+
+      CHECK_TRUE(view == sstream_view);
+      CHECK_TRUE(wview == wsstream_view);
+      CHECK_TRUE(u16view == u16sstream_view);
+      CHECK_TRUE(u32view == u32sstream_view);
+    }
+#endif
   };
 }