From 1bdaa38c7ab3247cbb4ecf78514a2c0c297f7b40 Mon Sep 17 00:00:00 2001
From: James R <justsomejames2@gmail.com>
Date: Fri, 2 Feb 2024 04:25:30 -0800
Subject: [PATCH] Replace CopyCaretColors with D_ParseCarets

- New function also sanitizes input
---
 src/d_clisrv.c   | 67 +-----------------------------------------------
 src/sanitize.cpp | 61 +++++++++++++++++++++++++++++++++++++++++++
 src/sanitize.h   | 10 ++++++++
 3 files changed, 72 insertions(+), 66 deletions(-)

diff --git a/src/d_clisrv.c b/src/d_clisrv.c
index 9345dcdb0..8f149d998 100644
--- a/src/d_clisrv.c
+++ b/src/d_clisrv.c
@@ -1002,70 +1002,6 @@ static boolean CL_SendKey(void)
 	return HSendPacket(servernode, false, 0, sizeof (clientkey_pak) );
 }
 
-static void
-CopyCaretColors (char *p, const char *s, int n)
-{
-	char *t;
-	int   m;
-	int   c;
-	if (!n)
-		return;
-	while (( t = strchr(s, '^') ))
-	{
-		m = ( t - s );
-
-		if (m >= n)
-		{
-			memcpy(p, s, n);
-			return;
-		}
-		else
-			memcpy(p, s, m);
-
-		p += m;
-		n -= m;
-		s += m;
-
-		if (!n)
-			return;
-
-		if (s[1])
-		{
-			c = toupper(s[1]);
-			if (isdigit(c))
-				c = 0x80 + ( c - '0' );
-			else if (c >= 'A' && c <= 'F')
-				c = 0x80 + ( c - 'A' );
-			else
-				c = 0;
-
-			if (c)
-			{
-				*p++ = c;
-				n--;
-
-				if (!n)
-					return;
-			}
-			else
-			{
-				if (n < 2)
-					break;
-
-				memcpy(p, s, 2);
-
-				p += 2;
-				n -= 2;
-			}
-
-			s += 2;
-		}
-		else
-			break;
-	}
-	strncpy(p, s, n);
-}
-
 static void SV_SendServerInfo(INT32 node, tic_t servertime)
 {
 	UINT8 *p;
@@ -1112,8 +1048,7 @@ static void SV_SendServerInfo(INT32 node, tic_t servertime)
 		(dedicated ? SV_DEDICATED : 0)
 	);
 
-	CopyCaretColors(netbuffer->u.serverinfo.servername, cv_servername.string,
-		MAXSERVERNAME);
+	D_ParseCarets(netbuffer->u.serverinfo.servername, cv_servername.string, MAXSERVERNAME);
 
 	M_Memcpy(netbuffer->u.serverinfo.mapmd5, mapmd5, 16);
 
diff --git a/src/sanitize.cpp b/src/sanitize.cpp
index 0fbe146f9..9aa58fff6 100644
--- a/src/sanitize.cpp
+++ b/src/sanitize.cpp
@@ -43,6 +43,18 @@ std::string& filter_out(std::string& out, const std::string_view& range, F filte
 	return out;
 };
 
+int hexconv(int c)
+{
+	if (std::isdigit(c))
+		return c - '0';
+
+	c = std::toupper(c);
+	if (c >= 'A' && c <= 'F')
+		return 10 + (c - 'A');
+
+	return -1;
+}
+
 }; // namespace
 
 namespace srb2::sanitize
@@ -64,9 +76,58 @@ std::string sanitize(std::string_view in, SanitizeMode mode)
 		}());
 }
 
+std::string parse_carets(std::string_view in, ParseMode mode)
+{
+	std::string out;
+
+	using std::size_t;
+	for (;;)
+	{
+		size_t p = in.find('^');
+
+		// copy chars up until the caret
+		// but filter out codes outside of the ASCII range
+		filter_out(out, in.substr(0, p), print_filter);
+
+		if (p == in.npos)
+		{
+			break; // end of input
+		}
+
+		in.remove_prefix(p);
+
+		// need two characters for caret code
+		// convert to color byte
+		if (int c; in.length() > 1 && (c = hexconv(in[1])) != -1)
+		{
+			out.push_back(0x80 | c);
+		}
+
+		if (mode != ParseMode::kConsume)
+		{
+			// preserve caret code in output
+			filter_out(out, in.substr(0, 2), print_filter);
+		}
+
+		if (in.length() < 2)
+		{
+			break;
+		}
+
+		in.remove_prefix(2);
+	}
+
+	return out;
+}
+
 }; // namespace srb2
 
 void D_SanitizeKeepColors(char *out, const char *in, size_t out_size)
 {
 	strlcpy(out, sanitize(in, SanitizeMode::kKeepColors).c_str(), out_size);
 }
+
+void D_ParseCarets(char *out, const char *in, size_t out_size)
+{
+	strlcpy(out, parse_carets(in, ParseMode::kConsume).c_str(), out_size);
+}
diff --git a/src/sanitize.h b/src/sanitize.h
index 24e757a15..f413923b5 100644
--- a/src/sanitize.h
+++ b/src/sanitize.h
@@ -25,15 +25,25 @@ enum class SanitizeMode
 	kKeepColors,
 };
 
+enum class ParseMode
+{
+	kConsume,
+	kPreserve,
+};
+
 // sanitizes string of all 0x80 codes
 std::string sanitize(std::string_view in, SanitizeMode mode);
 
+// sanitizes string of all 0x80 codes then parses caret codes
+std::string parse_carets(std::string_view in, ParseMode mode);
+
 }; // namespace srb2
 
 extern "C" {
 #endif
 
 void D_SanitizeKeepColors(char *out, const char *in, size_t out_size); // SanitizeMode::kKeepColors
+void D_ParseCarets(char *out, const char *in, size_t out_size); // ParseMode::kConsume
 
 #ifdef __cplusplus
 } // extern "C"