[winpr,stream] Added functions to read/write utf-8

* Stream_Write_UTF16_String_From_UTF8 writes a UTF-8 string to a
      stream in UTF-16 encoding
    * Stream_Read_UTF16_String_To_UTF8 reads a UTF-16 encoded string
      from the stream and returns it in UTF-8 encoding

winpr/include/winpr/stream.h

@@ -467,8 +467,48 @@ extern "C"
 		return TRUE;
 	}
 
-	WINPR_API BOOL Stream_Read_UTF16_String(wStream* s, WCHAR* dst, size_t length);
-	WINPR_API BOOL Stream_Write_UTF16_String(wStream* s, const WCHAR* src, size_t length);
+	WINPR_API BOOL Stream_Read_UTF16_String(wStream* s, WCHAR* dst, size_t charLength);
+	WINPR_API BOOL Stream_Write_UTF16_String(wStream* s, const WCHAR* src, size_t charLength);
+
+	/** \brief Reads a WCHAR string from a stream and converts it to UTF-8 and returns a newly
+	 * allocated string
+	 *
+	 *  \param s The stream to read data from
+	 *  \param wcharLength The number of WCHAR characters to read (NOT the size in bytes!)
+	 *  \param pUtfCharLength Ignored if \b NULL, otherwise will be set to the number of
+	 *         characters in the resulting UTF-8 string
+	 *  \return A '\0' terminated UTF-8 encoded string or NULL for any failure.
+	 */
+	WINPR_API char* Stream_Read_UTF16_String_As_UTF8(wStream* s, size_t wcharLength,
+	                                                 size_t* pUtfCharLength);
+
+	/** \brief Reads a WCHAR string from a stream and converts it to UTF-8 and
+	 *  writes it to the supplied buffer
+	 *
+	 *  \param s The stream to read data from
+	 *  \param wcharLength The number of WCHAR characters to read (NOT the size in bytes!)
+	 *  \param utfBuffer A pointer to a buffer holding the result string
+	 *  \param utfBufferCharLength The size of the result buffer
+	 *  \return The char length (strlen) of the result string or -1 for failure
+	 */
+	WINPR_API SSIZE_T Stream_Read_UTF16_String_As_UTF8_Buffer(wStream* s, size_t wcharLength,
+	                                                          char* utfBuffer,
+	                                                          size_t utfBufferCharLength);
+
+	/** \brief Writes a UTF-8 string UTF16 encoded to the stream. If the UTF-8
+	 *  string is short, the remainig characters are filled up with '\0'
+	 *
+	 *  \param s The stream to write to
+	 *  \param wcharLength the length (in WCHAR characters) to write
+	 *  \param src The source data buffer with the UTF-8 data
+	 *  \param length The length in bytes of the UTF-8 buffer
+	 *  \param fill If \b TRUE fill the unused parts of the wcharLength with 0
+	 *
+	 *  \b return number of used characters for success, /b -1 for failure
+	 */
+	WINPR_API SSIZE_T Stream_Write_UTF16_String_From_UTF8(wStream* s, size_t wcharLength,
+	                                                      const char* src, size_t length,
+	                                                      BOOL fill);
 
 	/* StreamPool */
 

winpr/libwinpr/utils/stream.c

@@ -379,3 +379,63 @@ BOOL Stream_CheckAndLogRequiredLengthWLogExVa(wLog* log, DWORD level, wStream* s
 	}
 	return TRUE;
 }
+
+SSIZE_T Stream_Write_UTF16_String_From_UTF8(wStream* s, size_t dlen, const char* src, size_t length,
+                                            BOOL fill)
+{
+	const size_t wlen = Stream_GetRemainingCapacity(s) / sizeof(WCHAR);
+	union
+	{
+		WCHAR* wc;
+		BYTE* b;
+	} cnv;
+	cnv.b = Stream_Pointer(s);
+
+	if (length == 0)
+		return 0;
+
+	if (wlen < dlen)
+		return -1;
+
+	SSIZE_T rc = ConvertUtf8NToWChar(src, length, cnv.wc, dlen);
+	if (rc < 0)
+		return -1;
+
+	Stream_Seek(s, (size_t)rc * sizeof(WCHAR));
+
+	if (fill)
+		Stream_Zero(s, (dlen - (size_t)rc) * sizeof(WCHAR));
+	return rc;
+}
+
+char* Stream_Read_UTF16_String_As_UTF8(wStream* s, size_t dlen, size_t* psize)
+{
+	union
+	{
+		const WCHAR* wc;
+		const BYTE* b;
+	} cnv;
+	cnv.b = Stream_Pointer(s);
+	if (dlen > SIZE_MAX / sizeof(WCHAR))
+		return NULL;
+
+	if (!Stream_CheckAndLogRequiredLength(STREAM_TAG, s, dlen * sizeof(WCHAR)))
+		return NULL;
+
+	Stream_Seek(s, dlen * sizeof(WCHAR));
+	return ConvertWCharNToUtf8Alloc(cnv.wc, dlen, psize);
+}
+
+SSIZE_T Stream_Read_UTF16_String_As_UTF8_Buffer(wStream* s, size_t wcharLength, char* utfBuffer,
+                                                size_t utfBufferCharLength)
+{
+	const WCHAR* ptr = (const WCHAR*)Stream_Pointer(s);
+	if (wcharLength > SIZE_MAX / sizeof(WCHAR))
+		return -1;
+
+	if (!Stream_CheckAndLogRequiredLength(STREAM_TAG, s, wcharLength * sizeof(WCHAR)))
+		return -1;
+
+	Stream_Seek(s, wcharLength * sizeof(WCHAR));
+	return ConvertWCharNToUtf8(ptr, wcharLength, utfBuffer, utfBufferCharLength);
+}