@Override
public void close() throws IOException {
if (!mClosed && mCurrentBlockInStream != null) {
mCurrentBlockInStream.close();
}
mClosed = true;
}
private void checkAndAdvanceBlockInStream() throws IOException {
if (mCurrentBlockLeft == 0) {
if (mCurrentBlockInStream != null) {
mCurrentBlockInStream.close();
}
mCurrentBlockIndex = getCurrentBlockIndex();
mCurrentBlockInStream = BlockInStream.get(FILE, READ_TYPE, mCurrentBlockIndex);
mCurrentBlockLeft = BLOCK_CAPACITY;
}
}
@Override
public void seek(long pos) throws IOException {
if (mCurrentPosition == pos) {
return;
}
if (pos < 0) {
throw new IOException("pos is negative: " + pos);
}
if ((int) (pos / BLOCK_CAPACITY) != mCurrentBlockIndex) {
mCurrentBlockIndex = (int) (pos / BLOCK_CAPACITY);
if (mCurrentBlockInStream != null) {
mCurrentBlockInStream.close();
}
mCurrentBlockInStream = BlockInStream.get(FILE, READ_TYPE, mCurrentBlockIndex);
}
mCurrentBlockInStream.seek(pos % BLOCK_CAPACITY);
mCurrentPosition = pos;
mCurrentBlockLeft = BLOCK_CAPACITY - (pos % BLOCK_CAPACITY);
}
@Override
public long skip(long n) throws IOException {
if (n <= 0) {
return 0;
}
long ret = n;
if (mCurrentPosition + n >= FILE.length()) {
ret = FILE.length() - mCurrentPosition;
mCurrentPosition += ret;
} else {
mCurrentPosition += n;
}
int tBlockIndex = (int) (mCurrentPosition / BLOCK_CAPACITY);
if (tBlockIndex != mCurrentBlockIndex) {
if (mCurrentBlockInStream != null) {
mCurrentBlockInStream.close();
}
mCurrentBlockIndex = tBlockIndex;
mCurrentBlockInStream = BlockInStream.get(FILE, READ_TYPE, mCurrentBlockIndex);
long shouldSkip = mCurrentPosition % BLOCK_CAPACITY;
long skip = mCurrentBlockInStream.skip(shouldSkip);
mCurrentBlockLeft = BLOCK_CAPACITY - skip;
if (skip != shouldSkip) {
throw new IOException(
"The underlayer BlockInStream only skip " + skip + " instead of " + shouldSkip);
}
} else {
long skip = mCurrentBlockInStream.skip(ret);
if (skip != ret) {
throw new IOException(
"The underlayer BlockInStream only skip " + skip + " instead of " + ret);
}
}
return ret;
}