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/utf8/utf8.cpp

@@ -5,7 +5,7 @@
  */
 
 /* 
- * Copyright (c) 2010-2023, Tomasz Sowa
+ * Copyright (c) 2010-2024, Tomasz Sowa
  * All rights reserved.
  * 
  * Redistribution and use in source and binary forms, with or without
@@ -42,9 +42,6 @@ namespace pt
 {
 
 
-
-
-
 /*!
 	returns true if 'c' is a correct unicode character
 */
@@ -128,6 +125,83 @@ bool surrogate_pair_to_int(int c1, int c2, int & z)
 
 
 
+/*
+	an auxiliary function for converting from wide characters to UTF-8
+	converting a wide character into one int
+
+	returns how many wide characters were used
+	if string_len is greater than 0 then the return value is always greater than zero too
+*/
+size_t wide_to_int(const wchar_t * wide_string, size_t string_len, int & z, bool & correct)
+{
+	if( string_len == 0 )
+	{
+		z = 0;
+		correct = false;
+		return 0;
+	}
+
+	z = static_cast<int>(*wide_string);
+	correct = true;
+
+	if( sizeof(wchar_t) == 2 && is_first_surrogate_char(z) )
+	{
+		if( string_len > 1 )
+		{
+			int z2 = *(wide_string+1);
+
+			if( is_second_surrogate_char(z2) )
+			{
+				z = 0x10000 + (((z & 0x3FF) << 10) | (z2 & 0x3FF));
+				return 2;
+			}
+			else
+			{
+				correct = false;
+				return 1;
+			}
+		}
+		else
+		{
+			correct = false;
+			return 1;
+		}
+	}
+	else
+	{
+		correct = utf8_check_range(z);
+		return 1;
+	}
+}
+
+
+
+/*
+	an auxiliary function for converting from wide characters to UTF-8
+	converting a wide character into one int
+
+	returns how many wide characters were used
+	if wide_string has at least one character then the return value is always greater than zero too
+*/
+size_t wide_to_int(const wchar_t * wide_string, int & z, bool & correct)
+{
+size_t min_str_len = 1;
+
+	if( *wide_string == 0 )
+	{
+		z = 0;
+		correct = false;
+		return 0;
+	}
+
+	if( *(wide_string+1) != 0 )
+		min_str_len = 2;
+
+return wide_to_int(wide_string, min_str_len, z, correct);
+}
+
+
+
 /*
  * converts an int to a wide string
  *
@@ -185,6 +259,26 @@ bool int_to_wide(int c, std::wstring & res)
 }
 
 
+/*
+ * return true if c was a correct unicode character
+ * and has been put the the stream
+ */
+bool int_to_stream(int c, pt::Stream & stream)
+{
+	if( stream.is_char_stream() )
+	{
+		return int_to_utf8(c, stream) > 0;
+	}
+	else
+	if( stream.is_wchar_stream() )
+	{
+		return int_to_wide(c, stream);
+	}
+
+	return false;
+}
+
+
 
 
 /*!
@@ -410,9 +504,9 @@ bool utf8_to_wide(const char * utf8, size_t utf8_len, std::wstring & res, bool c
 	if( clear )
 		res.clear();
 
-	bool status = private_namespace::utf8_to_wide_generic(utf8, utf8_len, mode, [&res](int c) {
+	bool status = utf8_to_output_function(utf8, utf8_len, [&res](int c) {
 		int_to_wide(c, res);
-	});
+	}, mode);
 
 	return status;
 }