add some utf8 converting methods

add new methods:
- bool int_to_stream(int c, pt::Stream & stream);
- template<typename OutputFunction>
  bool utf8_to_output_function(const Stream & stream, OutputFunction output_function, int mode = 1);
- template<typename StreamIteratorType, typename OutputFunction>
  bool utf8_to_output_function(StreamIteratorType & iterator_in, const StreamIteratorType & iterator_end, OutputFunction output_function, int mode = 1);
- template<typename StreamType, typename OutputFunction>
  bool wide_to_output_function(StreamType & buffer, OutputFunction output_function, int mode = 1);

make some methods public:
- size_t wide_to_int(const wchar_t * wide_string, size_t string_len, int & z, bool & correct)
- size_t wide_to_int(const wchar_t * wide_string, int & z, bool & correct)

rename and make some methods public:
- template<typename OutputFunction>
  utf8_to_wide_generic(const char * utf8, size_t utf8_len, OutputFunction convert_function, int mode) -> utf8_to_output_function(...)

while here:
- fix: correctly convert characters in Log::put_multiline_generic()

src/log/log.h

@@ -5,7 +5,7 @@
  */
 
 /*
- * Copyright (c) 2018-2022, Tomasz Sowa
+ * Copyright (c) 2018-2024, Tomasz Sowa
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -36,7 +36,6 @@
 #define headerfile_pikotools_src_log_log
 
 #include <string>
-#include <fstream>
 #include "textstream/textstream.h"
 #include "filelog.h"
 
@@ -246,6 +245,7 @@ void Log::put_multiline_generic(const CharType * prefix, const CharType * msg)
 		{
 			was_new_line = true;
 			put_prefix = true;
+			msg += 1;
 		}
 		else
 		{
@@ -265,11 +265,32 @@ void Log::put_multiline_generic(const CharType * prefix, const CharType * msg)
 				put_prefix = false;
 			}
 
-			operator<<(*msg);
+			if constexpr ( sizeof(CharType) == sizeof(char) )
+			{
+				int c;
+				bool correct;
+				msg += utf8_to_int(msg, c, correct);
+
+				if( correct )
+					int_to_stream(c, *this);
+				else
+					int_to_stream(0xFFFD, *this); // replacement character
+			}
+			else
+			if constexpr ( sizeof(CharType) == sizeof(wchar_t) )
+			{
+				operator<<(*msg);
+				msg += 1;
+			}
+			else
+			{
+				// what is the CharType?
+				// at the moment do not print anything
+				msg += 1;
+			}
+
 			was_something_printed = true;
 		}
-
-		msg += 1;
 	}
 
 	if( was_something_printed )