Fix some system.c insanity

`str_utf8_isspace` now returns true if the passed code point renders as
a space, instead of when not.

Add `str_utf8_trim_right`, use this function and
`str_utf8_skip_whitespaces` in the server.

Add tests for the three functions

src/base/system.c

@@ -2685,11 +2685,11 @@ float str_tofloat(const char *str) { return atof(str); }
 
 int str_utf8_isspace(int code)
 {
-	return code > 0x20 && code != 0xA0 && code != 0x034F && code != 0x2800 &&
+	return !(code > 0x20 && code != 0xA0 && code != 0x034F && code != 0x2800 &&
 		(code < 0x2000 || code > 0x200F) && (code < 0x2028 || code > 0x202F) &&
 		(code < 0x205F || code > 0x2064) && (code < 0x206A || code > 0x206F) &&
 		(code < 0xFE00 || code > 0xFE0F) && code != 0xFEFF &&
-		(code < 0xFFF9 || code > 0xFFFC);
+		(code < 0xFFF9 || code > 0xFFFC));
 }
 
 const char *str_utf8_skip_whitespaces(const char *str)
@@ -2703,7 +2703,7 @@ const char *str_utf8_skip_whitespaces(const char *str)
 		code = str_utf8_decode(&str);
 
 		// check if unicode is not empty
-		if(str_utf8_isspace(code))
+		if(!str_utf8_isspace(code))
 		{
 			return str_old;
 		}
@@ -2712,6 +2712,31 @@ const char *str_utf8_skip_whitespaces(const char *str)
 	return str;
 }
 
+void str_utf8_trim_right(char *param)
+{
+	const char *str = param;
+	char *end = 0;
+	while(*str)
+	{
+		char *str_old = (char *)str;
+		int code = str_utf8_decode(&str);
+
+		// check if unicode is not empty
+		if(!str_utf8_isspace(code))
+		{
+			end = 0;
+		}
+		else if(!end)
+		{
+			end = str_old;
+		}
+	}
+	if(end)
+	{
+		*end = 0;
+	}
+}
+
 int str_utf8_isstart(char c)
 {
 	if((c&0xC0) == 0x80) /* 10xxxxxx */

src/base/system.h

@@ -1581,12 +1581,50 @@ int str_utf8_to_skeleton(const char *str, int *buf, int buf_len);
 */
 int str_utf8_comp_confusable(const char *a, const char *b);
 
+/*
+	Function: str_utf8_isspace
+		Checks whether the given Unicode codepoint renders as space.
+
+	Parameters:
+		code - Unicode codepoint to check.
+
+	Returns:
+		0 if the codepoint does not render as space, != 0 if it does.
+*/
 int str_utf8_isspace(int code);
 
 int str_utf8_isstart(char c);
 
+/*
+	Function: str_utf8_skip_whitespaces
+		Skips leading characters that render as spaces.
+
+	Parameters:
+		str - Pointer to the string.
+
+	Returns:
+		Pointer to the first non-whitespace character found
+		within the string.
+
+	Remarks:
+		- The strings are treated as zero-terminated strings.
+*/
 const char *str_utf8_skip_whitespaces(const char *str);
 
+/*
+	Function: str_utf8_trim_right
+		Removes trailing characters that render as spaces by modifying
+		the string in-place.
+
+	Parameters:
+		str - Pointer to the string.
+
+	Remarks:
+		- The strings are treated as zero-terminated strings.
+		- The string is modified in-place.
+*/
+void str_utf8_trim_right(char *str);
+
 /*
 	Function: str_utf8_rewind
 		Moves a cursor backwards in an utf8 string

src/engine/server/server.cpp

@@ -44,43 +44,6 @@
 	#include <windows.h>
 #endif
 
-static const char *StrLtrim(const char *pStr)
-{
-	while(*pStr)
-	{
-		const char *pStrOld = pStr;
-		int Code = str_utf8_decode(&pStr);
-
-		// check if unicode is not empty
-		if(str_utf8_isspace(Code))
-		{
-			return pStrOld;
-		}
-	}
-	return pStr;
-}
-
-static void StrRtrim(char *pStr)
-{
-	const char *p = pStr;
-	const char *pEnd = 0;
-	while(*p)
-	{
-		const char *pStrOld = p;
-		int Code = str_utf8_decode(&p);
-
-		// check if unicode is not empty
-		if(str_utf8_isspace(Code))
-		{
-			pEnd = 0;
-		}
-		else if(pEnd == 0)
-			pEnd = pStrOld;
-	}
-	if(pEnd != 0)
-		*(const_cast<char *>(pEnd)) = 0;
-}
-
 
 CSnapIDPool::CSnapIDPool()
 {
@@ -343,14 +306,13 @@ CServer::CServer()
 	Init();
 }
 
-
 int CServer::TrySetClientName(int ClientID, const char *pName)
 {
 	char aTrimmedName[64];
 
 	// trim the name
-	str_copy(aTrimmedName, StrLtrim(pName), sizeof(aTrimmedName));
-	StrRtrim(aTrimmedName);
+	str_copy(aTrimmedName, str_utf8_skip_whitespaces(pName), sizeof(aTrimmedName));
+	str_utf8_trim_right(aTrimmedName);
 
 	// check for empty names
 	if(!aTrimmedName[0])

src/game/client/components/chat.cpp

@@ -462,7 +462,7 @@ void CChat::AddLine(int ClientID, int Team, const char *pLine)
 		int Code = str_utf8_decode(&pStr);
 
 		// check if unicode is not empty
-		if(str_utf8_isspace(Code))
+		if(!str_utf8_isspace(Code))
 		{
 			pEnd = 0;
 		}

src/game/server/gamecontext.cpp

@@ -1171,7 +1171,7 @@ void CGameContext::OnMessage(int MsgID, CUnpacker *pUnpacker, int ClientID)
 				int Code = str_utf8_decode(&p);
 
 				// check if unicode is not empty
-				if(str_utf8_isspace(Code))
+				if(!str_utf8_isspace(Code))
 				{
 					pEnd = 0;
 				}

src/test/str.cpp

@@ -17,3 +17,23 @@ TEST(Str, Dist)
 	EXPECT_EQ(str_utf8_dist("flaw", "lawn"), 2);
 	EXPECT_EQ(str_utf8_dist("saturday", "sunday"), 3);
 }
+
+TEST(Str, Utf8Isspace)
+{
+	EXPECT_TRUE(str_utf8_isspace(' '));
+	EXPECT_FALSE(str_utf8_isspace('a'));
+}
+
+TEST(Str, Utf8SkipWhitespaces)
+{
+	EXPECT_STREQ(str_utf8_skip_whitespaces("abc"), "abc");
+	EXPECT_STREQ(str_utf8_skip_whitespaces("abc   "), "abc   ");
+	EXPECT_STREQ(str_utf8_skip_whitespaces("    abc"), "abc");
+}
+
+TEST(Str, Utf8TrimRight)
+{
+	char A1[] = "abc"; str_utf8_trim_right(A1); EXPECT_STREQ(A1, "abc");
+	char A2[] = "   abc"; str_utf8_trim_right(A2); EXPECT_STREQ(A2, "   abc");
+	char A3[] = "abc   "; str_utf8_trim_right(A3); EXPECT_STREQ(A3, "abc");
+}