🐛 Fix M23 long filename support (MarlinFirmware#25540)

Marlin/src/sd/SdBaseFile.cpp

@@ -703,14 +703,18 @@ bool SdBaseFile::open(SdBaseFile *dirFile, const uint8_t dname[11]
  // Get VFat dir entry
  pvFat = (vfat_t *) p;
  // Get checksum from the last entry of the sequence
- if (pvFat->sequenceNumber & 0x40) lfnChecksum = pvFat->checksum;
+ if (pvFat->sequenceNumber & 0x40) {
+ lfnChecksum = pvFat->checksum;
+ ZERO(lfnName);
+ }
  // Get LFN sequence number
  lfnSequenceNumber = pvFat->sequenceNumber & 0x1F;
  if WITHIN(lfnSequenceNumber, 1, reqEntriesNum) {
  // Check checksum for all other entries with the starting checksum fetched before
  if (lfnChecksum == pvFat->checksum) {
  // Set chunk of LFN from VFAT entry into lfnName
  getLFNName(pvFat, (char *)lfnName, lfnSequenceNumber);
+ TERN_(UTF_FILENAME_SUPPORT, convertUtf16ToUtf8((char *)lfnName));
  // LFN found?
  if (!strncasecmp((char*)dlname, (char*)lfnName, lfnNameLength)) lfnFileFound = true;
  }
@@ -1132,13 +1136,13 @@ bool SdBaseFile::openNext(SdBaseFile *dirFile, uint8_t oflag) {
  * Get the LFN filename block from a dir. Get the block in lname at startOffset
  */
  void SdBaseFile::getLFNName(vfat_t *pFatDir, char *lname, uint8_t sequenceNumber) {
- uint8_t startOffset = (sequenceNumber - 1) * FILENAME_LENGTH;
+ const uint8_t startOffset = (sequenceNumber - 1) * FILENAME_LENGTH;
  LOOP_L_N(i, FILENAME_LENGTH) {
  const uint16_t utf16_ch = (i >= 11) ? pFatDir->name3[i - 11] : (i >= 5) ? pFatDir->name2[i - 5] : pFatDir->name1[i];
  #if ENABLED(UTF_FILENAME_SUPPORT)
  // We can't reconvert to UTF-8 here as UTF-8 is variable-size encoding, but joining LFN blocks
  // needs static bytes addressing. So here just store full UTF-16LE words to re-convert later.
- uint16_t idx = (startOffset + i) * 2; // This is fixed as FAT LFN always contain UTF-16LE encoding
+ const uint16_t idx = (startOffset + i) * 2; // This is fixed as FAT LFN always contain UTF-16LE encoding
  lname[idx] = utf16_ch & 0xFF;
  lname[idx + 1] = (utf16_ch >> 8) & 0xFF;
  #else
@@ -1152,8 +1156,8 @@ bool SdBaseFile::openNext(SdBaseFile *dirFile, uint8_t oflag) {
  * Set the LFN filename block lname to a dir. Put the block based on sequence number
  */
  void SdBaseFile::setLFNName(vfat_t *pFatDir, char *lname, uint8_t sequenceNumber) {
- uint8_t startOffset = (sequenceNumber - 1) * FILENAME_LENGTH;
- uint8_t nameLength = strlen(lname);
+ const uint8_t startOffset = (sequenceNumber - 1) * FILENAME_LENGTH,
+   nameLength = strlen(lname);
  LOOP_L_N(i, FILENAME_LENGTH) {
  uint16_t ch = 0;
  if ((startOffset + i) < nameLength)
@@ -1424,7 +1428,7 @@ int16_t SdBaseFile::read(void *buf, uint16_t nbyte) {
  * readDir() called before a directory has been opened, this is not
  * a directory file or an I/O error occurred.
  */
-int8_t SdBaseFile::readDir(dir_t *dir, char *longFilename) {
+int8_t SdBaseFile::readDir(dir_t *dir, char * const longFilename) {
  int16_t n;
  // if not a directory file or miss-positioned return an error
  if (!isDir() || (0x1F & curPosition_)) return -1;
@@ -1506,44 +1510,55 @@ int8_t SdBaseFile::readDir(dir_t *dir, char *longFilename) {
  // Post-process normal file or subdirectory longname, if any
  if (DIR_IS_FILE_OR_SUBDIR(dir)) {
  #if ENABLED(UTF_FILENAME_SUPPORT)
- #if LONG_FILENAME_CHARSIZE > 2
- // Add warning for developers for unsupported 3-byte cases.
- // (Converting 2-byte codepoints to 3-byte in-place would break the rest of filename.)
- #error "Currently filename re-encoding is done in-place. It may break the remaining chars to use 3-byte codepoints."
- #endif
-
  // Is there a long filename to decode?
  if (longFilename) {
- // Reset n to the start of the long name
- n = 0;
- for (uint16_t idx = 0; idx < (LONG_FILENAME_LENGTH); idx += 2) { // idx is fixed since FAT LFN always contains UTF-16LE encoding
- const uint16_t utf16_ch = longFilename[idx] | (longFilename[idx + 1] << 8);
- if (0xD800 == (utf16_ch & 0xF800)) // Surrogate pair - encode as '_'
- longFilename[n++] = '_';
- else if (0 == (utf16_ch & 0xFF80)) // Encode as 1-byte UTF-8 char
- longFilename[n++] = utf16_ch & 0x007F;
- else if (0 == (utf16_ch & 0xF800)) { // Encode as 2-byte UTF-8 char
- longFilename[n++] = 0xC0 | ((utf16_ch >> 6) & 0x1F);
- longFilename[n++] = 0x80 | ( utf16_ch & 0x3F);
- }
- else {
- #if LONG_FILENAME_CHARSIZE > 2 // Encode as 3-byte UTF-8 char
- longFilename[n++] = 0xE0 | ((utf16_ch >> 12) & 0x0F);
- longFilename[n++] = 0xC0 | ((utf16_ch >> 6) & 0x3F);
- longFilename[n++] = 0xC0 | ( utf16_ch & 0x3F);
- #else // Encode as '_'
- longFilename[n++] = '_';
- #endif
- }
- if (0 == utf16_ch) break; // End of filename
- } // idx
- } // longFilename
+ n = convertUtf16ToUtf8(longFilename);
+ }
  #endif
  return n;
  } // DIR_IS_FILE_OR_SUBDIR
  }
 }
 
+#if ENABLED(UTF_FILENAME_SUPPORT)
+
+ uint8_t SdBaseFile::convertUtf16ToUtf8(char * const longFilename) {
+ #if LONG_FILENAME_CHARSIZE > 2
+ // Add warning for developers for unsupported 3-byte cases.
+ // (Converting 2-byte codepoints to 3-byte in-place would break the rest of filename.)
+ #error "Currently filename re-encoding is done in-place. It may break the remaining chars to use 3-byte codepoints."
+ #endif
+
+ int16_t n;
+ // Reset n to the start of the long name
+ n = 0;
+ for (uint16_t idx = 0; idx < (LONG_FILENAME_LENGTH); idx += 2) { // idx is fixed since FAT LFN always contains UTF-16LE encoding
+ const uint16_t utf16_ch = longFilename[idx] | (longFilename[idx + 1] << 8);
+ if (0xD800 == (utf16_ch & 0xF800)) // Surrogate pair - encode as '_'
+ longFilename[n++] = '_';
+ else if (0 == (utf16_ch & 0xFF80)) // Encode as 1-byte UTF-8 char
+ longFilename[n++] = utf16_ch & 0x007F;
+ else if (0 == (utf16_ch & 0xF800)) { // Encode as 2-byte UTF-8 char
+ longFilename[n++] = 0xC0 | ((utf16_ch >> 6) & 0x1F);
+ longFilename[n++] = 0x80 | ( utf16_ch & 0x3F);
+ }
+ else {
+ #if LONG_FILENAME_CHARSIZE > 2 // Encode as 3-byte UTF-8 char
+ longFilename[n++] = 0xE0 | ((utf16_ch >> 12) & 0x0F);
+ longFilename[n++] = 0xC0 | ((utf16_ch >> 6) & 0x3F);
+ longFilename[n++] = 0xC0 | ( utf16_ch & 0x3F);
+ #else // Encode as '_'
+ longFilename[n++] = '_';
+ #endif
+ }
+ if (0 == utf16_ch) break; // End of filename
+ } // idx
+
+ return n;
+ }
+
+#endif // UTF_FILENAME_SUPPORT
+
 // Read next directory entry into the cache
 // Assumes file is correctly positioned
 dir_t* SdBaseFile::readDirCache() {

Marlin/src/sd/SdBaseFile.h

@@ -298,7 +298,7 @@ class SdBaseFile {
  bool printName();
  int16_t read();
  int16_t read(void *buf, uint16_t nbyte);
- int8_t readDir(dir_t *dir, char *longFilename);
+ int8_t readDir(dir_t *dir, char * const longFilename);
  static bool remove(SdBaseFile *dirFile, const char *path);
  bool remove();
 
@@ -392,14 +392,16 @@ class SdBaseFile {
  bool openCachedEntry(uint8_t cacheIndex, uint8_t oflags);
  dir_t* readDirCache();
 
+ #if ENABLED(UTF_FILENAME_SUPPORT)
+ uint8_t convertUtf16ToUtf8(char * const longFilename);
+ #endif
+
  // Long Filename create/write support
  #if ENABLED(LONG_FILENAME_WRITE_SUPPORT)
  static bool isDirLFN(const dir_t* dir);
  static bool isDirNameLFN(const char *dirname);
  static bool parsePath(const char *str, uint8_t *name, uint8_t *lname, const char **ptr);
- /**
- * Return the number of entries needed in the FAT for this LFN
- */
+ // Return the number of entries needed in the FAT for this LFN
  static inline uint8_t getLFNEntriesNum(const char *lname) { return (strlen(lname) + 12) / 13; }
  static void getLFNName(vfat_t *vFatDir, char *lname, uint8_t startOffset);
  static void setLFNName(vfat_t *vFatDir, char *lname, uint8_t lfnSequenceNumber);