// Convert a chunk# into a chunk - does lazy-chunk creation. As chunks are
// asked-for the first time, we make the Key and an empty backing DVec.
// Touching the DVec will force the file load.
@Override
public Value chunkIdx(int cidx) {
final long nchk = nChunks();
assert 0 <= cidx && cidx < nchk;
Key dkey = chunkKey(cidx);
Value val1 = DKV.get(dkey); // Check for an existing one... will fetch data as needed
if (val1 != null) return val1; // Found an existing one?
// Lazily create a DVec for this chunk
int len = (int) (cidx < nchk - 1 ? ValueArray.CHUNK_SZ : (_len - chunk2StartElem(cidx)));
// DVec is just the raw file data with a null-compression scheme
Value val2 = new Value(dkey, len, null, TypeMap.C1CHUNK, Value.NFS);
val2.setdsk(); // It is already on disk.
// Atomically insert: fails on a race, but then return the old version
Value val3 = DKV.DputIfMatch(dkey, val2, null, null);
return val3 == null ? val2 : val3;
}
// Convert a chunk# into a chunk - does lazy-chunk creation. As chunks are
// asked-for the first time, we make the Key and an empty backing DVec.
// Touching the DVec will force the file load.
@Override
public Value chunkIdx(int cidx) {
final long nchk = nChunks();
assert 0 <= cidx && cidx < nchk;
Key dkey = chunkKey(cidx);
Value val1 = DKV.get(dkey); // Check for an existing one... will fetch data as needed
if (val1 != null) return val1; // Found an existing one?
// Lazily create a DVec for this chunk
int len = (int) (cidx < nchk - 1 ? CHUNK_SZ : (_len - chunk2StartElem(cidx)));
// DVec is just the raw file data with a null-compression scheme
Value val2 = new Value(dkey, len, null, TypeMap.C1NCHUNK, _be);
val2.setdsk(); // It is already on disk.
// If not-home, then block till the Key is everywhere. Most calls here are
// from the parser loading a text file, and the parser splits the work such
// that most puts here are on home - so this is a simple speed optimization:
// do not make a Futures nor block on it on home.
Futures fs = dkey.home() ? null : new Futures();
// Atomically insert: fails on a race, but then return the old version
Value val3 = DKV.DputIfMatch(dkey, val2, null, fs);
if (!dkey.home() && fs != null) fs.blockForPending();
return val3 == null ? val2 : val3;
}