From b75bee106481f955898072010d30912facfbb36a Mon Sep 17 00:00:00 2001
From: Kacper K <149746050+kk1201@users.noreply.github.com>
Date: Wed, 8 Jul 2026 21:51:08 +0100
Subject: [PATCH] Improve CD key prevalidation (#880)

* Improve CD key prevalidation
* Use tolower instead of ascii math
---
 code/client/cl_main.c | 31 ++++++++++++++-----------------
 code/q3_ui/ui_cdkey.c |  2 +-
 2 files changed, 15 insertions(+), 18 deletions(-)

diff --git a/code/client/cl_main.c b/code/client/cl_main.c
index 1fe312ef..086cc7e5 100644
--- a/code/client/cl_main.c
+++ b/code/client/cl_main.c
@@ -4719,26 +4719,23 @@ qboolean CL_CDKeyValidate( const char *key, const char *checksum ) {
 	// for loop gets rid of conditional assignment warning
 	for (i = 0; i < len; i++) {
 		ch = *key++;
-		if (ch>='a' && ch<='z') {
-			ch -= 32;
-		}
-		switch( ch ) {
+		switch(tolower(ch)) {
 		case '2':
 		case '3':
 		case '7':
-		case 'A':
-		case 'B':
-		case 'C':
-		case 'D':
-		case 'G':
-		case 'H':
-		case 'J':
-		case 'L':
-		case 'P':
-		case 'R':
-		case 'S':
-		case 'T':
-		case 'W':
+		case 'a':
+		case 'b':
+		case 'c':
+		case 'd':
+		case 'g':
+		case 'h':
+		case 'j':
+		case 'l':
+		case 'p':
+		case 'r':
+		case 's':
+		case 't':
+		case 'w':
 			sum += ch;
 			continue;
 		default:
diff --git a/code/q3_ui/ui_cdkey.c b/code/q3_ui/ui_cdkey.c
index ec3029bd..c4c96f95 100644
--- a/code/q3_ui/ui_cdkey.c
+++ b/code/q3_ui/ui_cdkey.c
@@ -96,7 +96,7 @@ static int UI_CDKeyMenu_PreValidateKey( const char *key ) {
 	}
 
 	while( ( ch = *key++ ) ) {
-		switch( ch ) {
+		switch(tolower(ch)) {
 		case '2':
 		case '3':
 		case '7':