tty: sysrq: use switch in sysrq_key_table_key2index()

Using switch with range cases makes the code more aligned and readable.
Expand also that 36 as explicit addition of 10 + 26 to make the source
of the constant more obvious.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20230712081811.29004-5-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index 0a55662..28127bc 100644 (file)
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -532,17 +532,16 @@ static const struct sysrq_key_op *sysrq_key_table[62] = {
 /* key2index calculation, -1 on invalid index */
 static int sysrq_key_table_key2index(u8 key)
 {
-       int retval;
-
-       if ((key >= '0') && (key <= '9'))
-               retval = key - '0';
-       else if ((key >= 'a') && (key <= 'z'))
-               retval = key + 10 - 'a';
-       else if ((key >= 'A') && (key <= 'Z'))
-               retval = key + 36 - 'A';
-       else
-               retval = -1;
-       return retval;
+       switch (key) {
+       case '0' ... '9':
+               return key - '0';
+       case 'a' ... 'z':
+               return key - 'a' + 10;
+       case 'A' ... 'Z':
+               return key - 'A' + 10 + 26;
+       default:
+               return -1;
+       }
 }
 
 /*