Merge #4818

4818: Add str_startswith_nocase and str_endswith_nocase r=def- a=ChillerDragon

Gets rid of the more complex str_comp_nocase_num usage

## Checklist

- [x] Tested the change ingame
- [ ] Provided screenshots if it is a visual change
- [ ] Tested in combination with possibly related configuration options
- [x] Written a unit test if it works standalone, system.c especially
- [ ] Considered possible null pointers and out of bounds array indexing
- [x] Changed no physics that affect existing maps
- [ ] Tested the change with [ASan+UBSan or valgrind's memcheck](https://github.com/ddnet/ddnet/#using-addresssanitizer--undefinedbehavioursanitizer-or-valgrinds-memcheck) (optional)


Co-authored-by: ChillerDragon <ChillerDragon@gmail.com>

src/base/system.cpp

@@ -2912,6 +2912,19 @@ int str_comp_filenames(const char *a, const char *b)
 	return *a - *b;
 }
 
+const char *str_startswith_nocase(const char *str, const char *prefix)
+{
+	int prefixl = str_length(prefix);
+	if(str_comp_nocase_num(str, prefix, prefixl) == 0)
+	{
+		return str + prefixl;
+	}
+	else
+	{
+		return 0;
+	}
+}
+
 const char *str_startswith(const char *str, const char *prefix)
 {
 	int prefixl = str_length(prefix);
@@ -2925,6 +2938,26 @@ const char *str_startswith(const char *str, const char *prefix)
 	}
 }
 
+const char *str_endswith_nocase(const char *str, const char *suffix)
+{
+	int strl = str_length(str);
+	int suffixl = str_length(suffix);
+	const char *strsuffix;
+	if(strl < suffixl)
+	{
+		return 0;
+	}
+	strsuffix = str + strl - suffixl;
+	if(str_comp_nocase(strsuffix, suffix) == 0)
+	{
+		return strsuffix;
+	}
+	else
+	{
+		return 0;
+	}
+}
+
 const char *str_endswith(const char *str, const char *suffix)
 {
 	int strl = str_length(str);

src/base/system.h

@@ -1347,9 +1347,26 @@ int str_comp_num(const char *a, const char *b, int num);
 */
 int str_comp_filenames(const char *a, const char *b);
 
+/*
+       Function: str_startswith_nocase
+               Checks case insensitive whether the string begins with a certain prefix.
+
+       Parameter:
+               str - String to check.
+               prefix - Prefix to look for.
+
+       Returns:
+               A pointer to the string str after the string prefix, or 0 if
+               the string prefix isn't a prefix of the string str.
+
+       Remarks:
+               - The strings are treated as zero-terminated strings.
+*/
+const char *str_startswith_nocase(const char *str, const char *prefix);
+
 /*
 	Function: str_startswith
-		Checks whether the string begins with a certain prefix.
+		Checks case sensitive whether the string begins with a certain prefix.
 
 	Parameter:
 		str - String to check.
@@ -1364,9 +1381,26 @@ int str_comp_filenames(const char *a, const char *b);
 */
 const char *str_startswith(const char *str, const char *prefix);
 
+/*
+       Function: str_endswith_nocase
+               Checks case insensitive whether the string ends with a certain suffix.
+
+       Parameter:
+               str - String to check.
+               suffix - Suffix to look for.
+
+       Returns:
+               A pointer to the beginning of the suffix in the string str, or
+               0 if the string suffix isn't a suffix of the string str.
+
+       Remarks:
+               - The strings are treated as zero-terminated strings.
+*/
+const char *str_endswith_nocase(const char *str, const char *suffix);
+
 /*
 	Function: str_endswith
-		Checks whether the string ends with a certain suffix.
+		Checks case sensitive whether the string ends with a certain suffix.
 
 	Parameter:
 		str - String to check.

src/engine/client/serverbrowser.cpp

@@ -1763,7 +1763,7 @@ bool IsBlockInfectionZ(const CServerInfo *pInfo)
 
 bool IsBlockWorlds(const CServerInfo *pInfo)
 {
-	return (str_comp_nocase_num(pInfo->m_aGameType, "bw  ", 4) == 0) || (str_comp_nocase(pInfo->m_aGameType, "bw") == 0);
+	return (str_startswith(pInfo->m_aGameType, "bw  ")) || (str_comp_nocase(pInfo->m_aGameType, "bw") == 0);
 }
 
 bool IsCity(const CServerInfo *pInfo)

src/engine/server/server.cpp

@@ -2853,7 +2853,7 @@ static int GetAuthLevel(const char *pLevel)
 	int Level = -1;
 	if(!str_comp_nocase(pLevel, "admin"))
 		Level = AUTHED_ADMIN;
-	else if(!str_comp_nocase_num(pLevel, "mod", 3))
+	else if(str_startswith(pLevel, "mod"))
 		Level = AUTHED_MOD;
 	else if(!str_comp_nocase(pLevel, "helper"))
 		Level = AUTHED_HELPER;

src/game/client/components/chat.cpp

@@ -382,7 +382,7 @@ bool CChat::OnInput(IInput::CEvent Event)
 
 				auto &Command = m_Commands[Index];
 
-				if(str_comp_nocase_num(Command.pName, pCommandStart, str_length(pCommandStart)) == 0)
+				if(str_startswith(Command.pName, pCommandStart))
 				{
 					pCompletionCommand = &Command;
 					m_CompletionChosen = Index + SearchType * NumCommands;

src/game/server/gamecontext.cpp

@@ -1790,25 +1790,25 @@ void CGameContext::OnMessage(int MsgID, CUnpacker *pUnpacker, int ClientID)
 
 			if(pMsg->m_pMessage[0] == '/')
 			{
-				if(str_comp_nocase_num(pMsg->m_pMessage + 1, "w ", 2) == 0)
+				if(str_startswith(pMsg->m_pMessage + 1, "w "))
 				{
 					char aWhisperMsg[256];
 					str_copy(aWhisperMsg, pMsg->m_pMessage + 3, 256);
 					Whisper(pPlayer->GetCID(), aWhisperMsg);
 				}
-				else if(str_comp_nocase_num(pMsg->m_pMessage + 1, "whisper ", 8) == 0)
+				else if(str_startswith(pMsg->m_pMessage + 1, "whisper "))
 				{
 					char aWhisperMsg[256];
 					str_copy(aWhisperMsg, pMsg->m_pMessage + 9, 256);
 					Whisper(pPlayer->GetCID(), aWhisperMsg);
 				}
-				else if(str_comp_nocase_num(pMsg->m_pMessage + 1, "c ", 2) == 0)
+				else if(str_startswith(pMsg->m_pMessage + 1, "c "))
 				{
 					char aWhisperMsg[256];
 					str_copy(aWhisperMsg, pMsg->m_pMessage + 3, 256);
 					Converse(pPlayer->GetCID(), aWhisperMsg);
 				}
-				else if(str_comp_nocase_num(pMsg->m_pMessage + 1, "converse ", 9) == 0)
+				else if(str_startswith(pMsg->m_pMessage + 1, "converse "))
 				{
 					char aWhisperMsg[256];
 					str_copy(aWhisperMsg, pMsg->m_pMessage + 10, 256);

src/test/str.cpp

@@ -141,6 +141,25 @@ TEST(Str, Startswith)
 	EXPECT_EQ(str_startswith(ABCDEFG, ABC) - ABCDEFG, str_length(ABC));
 }
 
+TEST(Str, StartswithNocase)
+{
+	EXPECT_TRUE(str_startswith_nocase("Abcdef", "abc"));
+	EXPECT_FALSE(str_startswith_nocase("aBc", "abcdef"));
+
+	EXPECT_TRUE(str_startswith_nocase("xYz", ""));
+	EXPECT_FALSE(str_startswith_nocase("", "xYz"));
+
+	EXPECT_FALSE(str_startswith_nocase("house", "home"));
+	EXPECT_FALSE(str_startswith_nocase("Blackboard", "board"));
+
+	EXPECT_TRUE(str_startswith_nocase("поплавать", "по"));
+	EXPECT_FALSE(str_startswith_nocase("плавать", "по"));
+
+	static const char ABCDEFG[] = "aBcdefg";
+	static const char ABC[] = "abc";
+	EXPECT_EQ(str_startswith_nocase(ABCDEFG, ABC) - ABCDEFG, str_length(ABC));
+}
+
 TEST(Str, Endswith)
 {
 	EXPECT_TRUE(str_endswith("abcdef", "def"));
@@ -161,6 +180,26 @@ TEST(Str, Endswith)
 		str_length(ABCDEFG) - str_length(DEFG));
 }
 
+TEST(Str, EndswithNocase)
+{
+	EXPECT_TRUE(str_endswith_nocase("abcdef", "deF"));
+	EXPECT_FALSE(str_endswith_nocase("def", "abcdef"));
+
+	EXPECT_TRUE(str_endswith_nocase("xyz", ""));
+	EXPECT_FALSE(str_endswith_nocase("", "xyz"));
+
+	EXPECT_FALSE(str_endswith_nocase("rhyme", "minE"));
+	EXPECT_FALSE(str_endswith_nocase("blackboard", "black"));
+
+	EXPECT_TRUE(str_endswith_nocase("люди", "юди"));
+	EXPECT_FALSE(str_endswith_nocase("люди", "любовь"));
+
+	static const char ABCDEFG[] = "abcdefG";
+	static const char DEFG[] = "defg";
+	EXPECT_EQ(str_endswith_nocase(ABCDEFG, DEFG) - ABCDEFG,
+		str_length(ABCDEFG) - str_length(DEFG));
+}
+
 TEST(Str, HexDecode)
 {
 	char aOut[5] = {'a', 'b', 'c', 'd', 0};