add char* strdup_NFC(string_view s). FIXME: The more efficient implementation needs some more internal re-work, that's why this correct but stupid quick'n'dirty implementation is there for now.

src/nfc.cc

@@ -11,6 +11,8 @@
 
 #include "nfc_sets.hh"
 
+#include <pEp/pEp_string.h>
+
 namespace
 {
 	// unicode to hex string
@@ -628,6 +630,39 @@ std::basic_string<CharT> toNFC(basic_string_view<CharT> s)
 }
 
 
+// convenience function to avoid ::strdup(pEp::toNFC<char>(text).c_str());
+// and unecessary temporary std::string etc.
+char* strdup_NFC(string_view s)
+{
+	if(isNFC_quick_check(s)==IsNFC::Yes)
+		return ::new_string(s.data(), s.size());
+	
+	// implement the hard way more efficient
+/********** FIXME: need more re-work, so I'll do the dumb way first
+	
+	const std::u32string& u32 = createNFC( fromUtf_decompose(s) );
+	const size_t out_len = utf8len(u32);
+	char* ret = ::new_string(nullptr, out_len );
+	char* iter{ret};
+	for(const char32_t c : u32)
+	{
+		toUtf<char, char*>(c, iter);
+	}
+	
+	if(iter > ret+out_len) // should never happen. ;)
+	{
+		throw std::logic_error("internal error: strdup_NFC() exceeded output string size");
+	}
+	
+	return ret;
+********************/
+
+	// Correct but inefficient:
+	const std::string ret = toNFC<char>(s);
+	return ::new_string(ret.data(), 0);
+}
+
+
 // used only to initialize the NFC Compose mapping:
 std::map< std::pair<unsigned, unsigned>, unsigned> generate_nfc_compose()
 {

src/nfc.hh

@@ -68,6 +68,10 @@ std::basic_string<CharT> toNFC(basic_string_view<CharT> s);
 // creates a UTF-8-encoded NFC string from s
 std::string toNFC_8(u16string_view s);
 
+// convenience function to avoid ::strdup(pEp::toNFC<char>(text).c_str());
+// and unecessary temporary std::string etc.
+char* strdup_NFC(string_view s);
+
 
 } // end of namespace pEp