From 0be3eff8e815667b4dd9152ef6835121e6a19f22 Mon Sep 17 00:00:00 2001
From: Jianyong Wu <jianyong.wu@arm.com>
Date: Wed, 5 Jul 2023 10:02:18 +0000
Subject: [PATCH] fat: Improve handling of longer filenames

This patch increases the size of the byte array to 12 bytes (so that the
'.' can be included for files that are named the full 8 + 3 bytes. If
the string presented is exactly 11 bytes then adjust it to correctly
included the '.' separator.

Fixes: #261
Signed-off-by: Jianyong Wu <jianyong.wu@arm.com>
---
 src/fat.rs | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/src/fat.rs b/src/fat.rs
index 93d003d7..f4c155f8 100644
--- a/src/fat.rs
+++ b/src/fat.rs
@@ -232,6 +232,17 @@ fn name_to_str(input: &str, output: &mut [u8]) {
             break;
         }
     }
+
+    // If name is exactly 11 characters long then ensure separator is correctly added
+    if (output[10] >= b'a' && output[10] <= b'z' || output[10] >= b'A' && output[10] <= b'Z')
+        && output[7] != b' '
+        && output[7] != b'.'
+    {
+        output[11] = output[10];
+        output[10] = output[9];
+        output[9] = output[8];
+        output[8] = b'.';
+    }
 }
 
 impl<'a> Read for Node<'a> {
@@ -403,9 +414,9 @@ impl<'a> Directory<'a> {
         }
     }
 
-    pub fn next_node(&mut self) -> Result<(Node, [u8; 11]), Error> {
+    pub fn next_node(&mut self) -> Result<(Node, [u8; 12]), Error> {
         let de = self.next_entry()?;
-        let mut name = [0_u8; 11];
+        let mut name = [0_u8; 12];
         name_to_str(core::str::from_utf8(&de.name).unwrap(), &mut name);
 
         match de.file_type {
@@ -1172,17 +1183,17 @@ mod tests {
 
     #[test]
     fn test_name_to_str() {
-        let mut s = [0_u8; 11];
+        let mut s = [0_u8; 12];
         super::name_to_str("X       ABC", &mut s);
         assert_eq!(crate::common::ascii_strip(&s), "X.ABC");
-        let mut s = [0_u8; 11];
+        let mut s = [0_u8; 12];
         super::name_to_str(".", &mut s);
         assert_eq!(crate::common::ascii_strip(&s), ".");
-        let mut s = [0_u8; 11];
+        let mut s = [0_u8; 12];
         super::name_to_str("..", &mut s);
         assert_eq!(crate::common::ascii_strip(&s), "..");
-        let mut s = [0_u8; 11];
+        let mut s = [0_u8; 12];
         super::name_to_str("ABCDEFGHIJK", &mut s);
-        assert_eq!(crate::common::ascii_strip(&s), "ABCDEFGHIJK");
+        assert_eq!(crate::common::ascii_strip(&s), "ABCDEFGH.IJK");
     }
 }