Files
ESP8266lib/ext/sd/fat32/DirIterator.h
2021-02-21 09:33:08 +01:00

154 lines
3.1 KiB
C++

class DirIterator {
static constexpr const char* NAME = "FAT32_DirI";
FS& fs;
ClusterNr curCluster;
uint8_t curEntryInSector; // current DirEntry within the current sector
uint8_t curSectorInCluster; // current Sector within the current cluster
uint8_t buf[512];
public:
DirIterator(FS& fs, ClusterNr clusterNr) : fs(fs), curCluster(clusterNr), curEntryInSector(0), curSectorInCluster(0) {
Log::addInfo(NAME, "init @ Cluster %d", curCluster);
// read the first sector in the first cluster
read(curCluster, 0);
}
/** get the next usable entry within the current directory */
DirEntryAt nextUsable() {
while(true) {
DirEntryAt dea = next(false);
// check it
if (!dea.isValid()) {return DirEntryAt::invalid();}
if (dea.isLongFileName()) {continue;}
if (dea.isUnused()) {continue;}
if (dea.isEndOfDirectory()) {return DirEntryAt::invalid();}
// usable!
return dea;
}
}
/** get (or create) a free entry within the current directory */
DirEntryAt nextFree() {
while(true) {
DirEntryAt dea = next(true);
// check it
if (!dea.isValid()) {return DirEntryAt::invalid();}
if (dea.isUnused()) {
// switch from "unused" to something usable
//dea.setName("NEW.ONE");
//dea.entry.attr.raw = 0;
//return dea;
}
if (dea.isEndOfDirectory()) {
// add a new EndOfDirectory entry afterwards
DirEntryAt dea2 = next(true);
dea2.setEndOfDirectory();
fs.write(dea2);
// switch from "end of directory" to something usable
dea.setName("NEW.ONE");
dea.entry.attr.raw = 0;
return dea;
}
}
}
private:
DirEntryAt cur() {
AbsPos pos = fs.clusterToAbsPos(curCluster) + (curSectorInCluster * fs.desc.bytesPerSector) + (curEntryInSector * sizeof(DirEntry));
DirEntry* dirEntry = reinterpret_cast<DirEntry*>(buf + (curEntryInSector * sizeof(DirEntry)));
return DirEntryAt(pos, dirEntry);
}
DirEntryAt next(bool allocIfNeeded) {
while(true) {
// end of sector reached?
if (curEntryInSector >= fs.tmp.dirEntriesPerSector) {
// next sector
++curSectorInCluster;
curEntryInSector = 0;
// end of cluster reached?
if (curSectorInCluster >= fs.desc.sectorsPerCluster) {
// find next cluster (if any)
const ClusterNr nextCluster = fs.getNextCluster(curCluster);
// reached end of clusters?
if (nextCluster.isEndOfClusters()) {
// do not alloc new entries? -> done here
if (!allocIfNeeded) {
return DirEntryAt::invalid();
} else {
curCluster = fs.allocFreeCluster(curCluster);
}
} else {
curCluster = nextCluster;
}
curSectorInCluster = 0;
}
// fetch from disk
read(curCluster, curSectorInCluster);
}
// the current entry
DirEntryAt dea = cur();
++curEntryInSector;
return dea;
}
}
private:
/** fetch one sector within a cluster */
void read(ClusterNr clusterNr, uint8_t sectorInCluster) {
Log::addInfo(NAME, "fetching sector %d in clusterNr %d", sectorInCluster, clusterNr) ;
const AbsPos pos = fs.clusterToAbsPos(clusterNr) + (curSectorInCluster * fs.desc.bytesPerSector);
fs.dev.read(pos, fs.desc.bytesPerSector, buf);
}
};