Although SdFat use short names for the files and directories (8.3 format), the long name is registered some where in the memory of the card.
I am sure there is a way to read this long name, using some low level routine.
Any body had do that, know how to do that or know where I can get the information to do it?
Note: I use an Arduino Due, but I think this is not revelant for that purpose.
I get this two pages explaining VFAT (virtual FAT) long file name:
Here is a sketch that prints short and long file names for files in the volume working directory.
#include <SdFat.h>
SdFat sd;
const uint8_t SD_CS_PIN = SS;
//------------------------------------------------------------------------------
// does not implement directory byte 12 for lowercase bits with 8.3 names.
// bit 0X10 means lowercase extension and bit 0X08 lowercase basename
//
void listLfn(SdBaseFile* dirFile) {
uint8_t offset[] = {1, 3, 5, 7, 9, 14, 16, 18, 20, 22, 24, 28, 30};
char name[13];
char lfn[131];
bool haveLong = false;
dir_t dir;
uint8_t i;
uint8_t lfnIn = 130;
uint8_t ndir;
uint8_t sum;
uint8_t test;
dirFile->rewind();
while (dirFile->read(&dir, 32) == 32) {
if (DIR_IS_LONG_NAME(&dir)) {
if (!haveLong) {
if ((dir.name[0] & 0XE0) != 0X40) continue;
ndir = dir.name[0] & 0X1F;
test = dir.creationTimeTenths;
haveLong = true;
lfnIn = 130;
lfn[lfnIn] = 0;
} else if (dir.name[0] != --ndir || test != dir.creationTimeTenths) {
haveLong = false;
continue;
}
char *p = (char*)&dir;
if (lfnIn > 0) {
lfnIn -= 13;
for (i = 0; i < 13; i++) {
lfn[lfnIn + i] = p[offset[i]];
}
}
} else if (DIR_IS_FILE_OR_SUBDIR(&dir)
&& dir.name[0] != DIR_NAME_DELETED
&& dir.name[0] != DIR_NAME_FREE) {
if (haveLong) {
for (sum = i = 0; i < 11; i++) {
sum = (((sum & 1) << 7) | ((sum & 0xfe) >> 1)) + dir.name[i];
}
if (sum != test || ndir != 1) haveLong = false;
}
SdFile::dirName(dir, name);
Serial.print(name);
if (haveLong) {
Serial.print(" ");
Serial.print(lfn + lfnIn);
} else if (dir.reservedNT) {
Serial.print(" 8.3 lowercase bits: ");
Serial.print(dir.reservedNT, HEX);
}
Serial.println();
haveLong = false;
} else {
if (dir.name[0] == DIR_NAME_FREE) return;
haveLong = false;
}
}
}
//------------------------------------------------------------------------------
void setup() {
Serial.begin(9600);
if (!sd.begin(SD_CS_PIN)) sd.initErrorHalt();
// list files in root directory (volume working directory)
listLfn(sd.vwd());
Serial.println("Done");
}
void loop() {}
Here is typical output:
LONGFI~1.TXT Longfilename.txt
SHORT.TXT
NAMEWI~1.TXT Name with blanks.txt
LOWER.TXT 8.3 lowercase bits: 18
Done
Note that there is no long file name for the entry "LOWER.TXT". This file has the lower case bits 0X18 set so its lfn is "lower.txt".
Thank you fat16lib
You are faster than an Arduino Due 
I shall study your code right now
fat16lib, thanks to your sketch, I write a couple of functions to manage long file and directory names (read only)
I use them in my project (basically a mp3 reader). But I suppose they can be useful for other projects. For example a web server based on pages stored in a SD card.
May be you can include this functions or something equivalent in your library?
Here is the sketch to demonstrate their use
#include <SPI.h>
#include <SdFat.h>
// Control Select pin of SD card
const uint8_t SD_CS_PIN = 9;
SdFat sd;
SdBaseFile* dirFile;
// Search for the first file in a directory
//
// parameters:
// char * lfn : where to store the 'long name' file
// (must have a dim of at least 131 char)
// char * sdn : the directory (short name) we want to scan
//
// return:
// a dir_t object pointing to the founded file
dir_t dirLfnFirst( char * lfn, char * sdn )
{
sd.chdir( sdn );
dirFile = sd.vwd();
dirFile->rewind();
return dirLfnNext( lfn );
}
// Search for the next file
//
// parameters:
// char * lfn : where to store the 'long name' file
// (must have a dim of at least 131 char)
//
// return:
// a dir_t object pointing to the founded file
dir_t dirLfnNext( char * lfn )
{
uint8_t offset[] = {1, 3, 5, 7, 9, 14, 16, 18, 20, 22, 24, 28, 30};
dir_t dir;
uint8_t lfnIn = 130;
uint8_t i;
uint8_t ndir;
uint8_t sum;
uint8_t test;
bool haveLong = false;
while( dirFile->read( &dir, 32 ) == 32 )
{
if( DIR_IS_LONG_NAME( &dir ) )
{
if( ! haveLong )
{
if(( dir.name[0] & 0XE0 ) != 0X40 )
continue;
ndir = dir.name[0] & 0X1F;
test = dir.creationTimeTenths;
haveLong = true;
lfnIn = 130;
lfn[ lfnIn ] = 0;
}
else if( dir.name[0] != --ndir || test != dir.creationTimeTenths )
{
haveLong = false;
continue;
}
char *p = (char*) & dir;
if( lfnIn > 0 )
{
lfnIn -= 13;
for( i = 0; i < 13; i++ )
lfn[lfnIn + i] = p[offset[i]];
}
}
else if( DIR_IS_FILE_OR_SUBDIR( &dir )
&& dir.name[0] != DIR_NAME_DELETED
&& dir.name[0] != DIR_NAME_FREE
&& dir.name[0] != '.' )
{
if( haveLong )
{
for( sum = i = 0; i < 11; i++ )
sum = (((sum & 1) << 7) | ((sum & 0xfe) >> 1)) + dir.name[i];
if( sum != test || ndir != 1 )
haveLong = false;
}
if( haveLong )
{
for( i = 0; lfnIn + i <= 130 ; i++ )
lfn[i] = lfn[lfnIn + i];
return dir;
}
// else if( dir.reservedNT )
// return "Reserved NT";
else
{
SdFile::dirName( dir, lfn );
return dir;
}
}
else
{
if( dir.name[0] == DIR_NAME_FREE )
break;
haveLong = false;
}
}
lfn[ 0 ] = 0;
return dir;
}
// Convert a 'long name' file to a 'short name' file
//
// parameters:
// char * sn : where to store the 'short name' file
// char * dn : the directory (short name) where is the file
// char * ln : the 'long name' file we want to convert
// size_t lln : the length of the long name file. If 0 (default),
// calculated with strlen( ln )
//
// return:
// true, if convertion is done
boolean l2sName( char * sn, char * dn, char * ln, size_t lln = 0 );
boolean l2sName( char * sn, char * dn, char * ln, size_t lln )
{
char ln0[131];
ln0[0] = 0;
dir_t dir = dirLfnFirst( ln0, dn );
if( lln == 0 )
lln = strlen( ln );
while(( strlen( ln0 ) > 0 ) && ( strncmp( ln0, ln, lln ) != 0 ))
dir = dirLfnNext( ln0 );
SdFile::dirName( dir, sn );
return strlen( sn ) != 0;
}
// Convert a 'long name' path to a 'short name' path
//
// parameters:
// char * snd : where to store the 'short name' path
// char * lnd : the 'long name' path we want to convert
// size_t maxsnl : the length of snd string
//
// return:
// true, if convertion is done
boolean l2sPath( char * snd, char * lnd, size_t maxsnl )
{
char * dir0 = lnd + 1;
char * dir1;
char * snd1;
strcpy( snd, "/" );
while( strlen( dir0 ) > 1 )
{
dir1 = strchr( dir0, '/' );
if( dir1 == 0 )
return true;
if( maxsnl <= strlen( snd ) + 8 )
return false;
snd1 = strrchr( snd, 0 );
// same as: snd1 = snd + strlen( snd );
if( ! l2sName( snd1 , snd, dir0, dir1 - dir0 ))
return false;
strcat( snd, "/" );
dir0 = dir1 + 1;
}
return true;
}
// Convert a long full name (path+name) to a short full name
//
// parameters:
// char * sfn : where to store the short full name
// char * lfn : the long full name we want to convert
// size_t maxsfn : the length of sfn string
//
// return:
// true, if convertion is done
boolean l2sFullName( char * sfn, char * lfn, size_t maxsfn )
{
if( ! l2sPath( sfn, lfn, maxsfn ))
return false;
char * sfn1 = strrchr( sfn, 0 );
char * ln = strrchr( lfn, '/' ) + 1;
if( ln == 0 )
return false;
return l2sName( sfn1, sfn, ln );
}
//
// DEMONSTRATE THE USE OF PREVIOUS FUNCTIONS
//
// You must modify content of strings theDir , theLongNameDir , theLongName
// and theLongFullName according to content of your SD card
//
void setup()
{
Serial.begin( 9600 );
// Control Select of SD card of MP3 shield set to high
pinMode( SD_CS_PIN, OUTPUT );
digitalWrite( SD_CS_PIN, HIGH );
if( ! sd.begin( SD_CS_PIN ))
sd.initErrorHalt();
// Demonsrate use of dirLfnFirst() and dirLfnNext()
char * theDir = "/THEBEA~1/PLEASE~1/";
Serial.println( "List all files by their long name in directory" );
Serial.println( theDir );
Serial.println( "given by his short name:" );
Serial.println( );
char fileName[131];
dirLfnFirst( fileName, theDir );
while( strlen( fileName ) > 0 )
{
Serial.println( fileName );
dirLfnNext( fileName );
}
// Demonsrate use of l2sPath(), dirLfnFirst() and dirLfnNext()
// Show use of returned dir object to recover short name
char * theLongNameDir = "/The Beatles/Please Please Me/";
Serial.println( ); Serial.println( );
Serial.println( "List all files by their short and long names in directory" );
Serial.println( theLongNameDir );
Serial.println( "given by his long name:" );
Serial.println( );
char shortPath[100];
char shortName[13];
dir_t dir;
if( l2sPath( shortPath, theLongNameDir, 100 ))
{
dir = dirLfnFirst( fileName, shortPath );
while( strlen( fileName ) > 0 )
{
SdFile::dirName( dir, shortName );
Serial.print( shortName );
Serial.print( " ; " );
Serial.println( fileName );
dir = dirLfnNext( fileName );
}
}
else
Serial.println( " not found!" );
// Demonsrate use of l2sName()
char shortFileName[13];
char * theLongName = "07-Please Please Me.mp3";
Serial.println( ); Serial.println( );
Serial.println( "The short name of " );
Serial.println( theLongName );
Serial.println( "in directory" );
Serial.println( theDir );
Serial.println( "is:" );
Serial.println( );
if( l2sName( shortFileName, theDir, theLongName ))
Serial.println( shortFileName );
else
Serial.println( "not found :(" );
// Demonsrate use of l2sFullName()
char * theLongFullName = "/The Beatles/Please Please Me/11-Do You Want To Know A Secret.mp3";
Serial.println( ); Serial.println( );
Serial.println( "The short full name of " );
Serial.println( theLongFullName );
Serial.println( "is:" );
Serial.println( );
if( l2sFullName( shortPath, theLongFullName, 100 ))
Serial.println( shortPath );
else
Serial.println( "not found :(" );
}
void loop()
{
}
When I try your code, I get this error-message:
\Arduino\sketch_feb14a\sketch_feb14a.ino: In function 'void listLfn(SdBaseFile*)':
sketch_feb14a:51:32: error: no matching function for call to 'SdFile::dirName(dir_t&, char [13])'
I just copyed your code and try to load it...