From 82df656cc7b1a9e30a5405a535b0c0e641fd1bbf Mon Sep 17 00:00:00 2001
From: Scott Lahteine <github@thinkyhead.com>
Date: Sun, 26 Nov 2017 18:19:32 -0600
Subject: [PATCH] Tweak readDir code
---
Marlin/SdBaseFile.cpp | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)
diff --git a/Marlin/SdBaseFile.cpp b/Marlin/SdBaseFile.cpp
index 15de6f7255..c1d8012e27 100644
--- a/Marlin/SdBaseFile.cpp
+++ b/Marlin/SdBaseFile.cpp
@@ -1061,7 +1061,7 @@ int8_t SdBaseFile::readDir(dir_t* dir, char* longFilename) {
while (1) {
n = read(dir, sizeof(dir_t));
- if (n != sizeof(dir_t)) return n == 0 ? 0 : -1;
+ if (n != sizeof(dir_t)) return n ? -1 : 0;
// last entry if DIR_NAME_FREE
if (dir->name[0] == DIR_NAME_FREE) return 0;
@@ -1074,13 +1074,16 @@ int8_t SdBaseFile::readDir(dir_t* dir, char* longFilename) {
if (longFilename != NULL && DIR_IS_LONG_NAME(dir)) {
vfat_t* VFAT = (vfat_t*)dir;
// Sanity-check the VFAT entry. The first cluster is always set to zero. And the sequence number should be higher than 0
- if (VFAT->firstClusterLow == 0 && (VFAT->sequenceNumber & 0x1F) > 0 && (VFAT->sequenceNumber & 0x1F) <= MAX_VFAT_ENTRIES) {
- // TODO: Store the filename checksum to verify if a long-filename-unaware system modified the file table.
- n = ((VFAT->sequenceNumber & 0x1F) - 1) * (FILENAME_LENGTH);
- for (uint8_t i = 0; i < FILENAME_LENGTH; i++)
- longFilename[n + i] = (i < 5) ? VFAT->name1[i] : (i < 11) ? VFAT->name2[i - 5] : VFAT->name3[i - 11];
- // If this VFAT entry is the last one, add a NUL terminator at the end of the string
- if (VFAT->sequenceNumber & 0x40) longFilename[n + FILENAME_LENGTH] = '\0';
+ if (VFAT->firstClusterLow == 0) {
+ const uint8_t seq = VFAT->sequenceNumber & 0x1F;
+ if (WITHIN(seq, 1, MAX_VFAT_ENTRIES)) {
+ // TODO: Store the filename checksum to verify if a long-filename-unaware system modified the file table.
+ n = (seq - 1) * (FILENAME_LENGTH);
+ for (uint8_t i = 0; i < FILENAME_LENGTH; i++)
+ longFilename[n + i] = (i < 5) ? VFAT->name1[i] : (i < 11) ? VFAT->name2[i - 5] : VFAT->name3[i - 11];
+ // If this VFAT entry is the last one, add a NUL terminator at the end of the string
+ if (VFAT->sequenceNumber & 0x40) longFilename[n + FILENAME_LENGTH] = '\0';
+ }
}
}
// Return if normal file or subdirectory