public void seekRelative(long relativeOffset) throws IOException {
ensureReadyOnFirstUse();
long pos = streamDataInput.getAbsolutePosition();
pos += relativeOffset;
if (pos < filePositionOfStreamData) pos = filePositionOfStreamData;
// It's alright to seek beyond the end, it's just that read operations will fail
streamDataInput.seekAbsolute(pos);
}
private void endCurrentUse() throws IOException {
// System.out.println("SICW.endCurrentUse() About to ... " + this);
if (usedYet) {
streamDataInput.seekAbsolute(filePositionBeforeUse);
usedYet = false;
}
endThreadAccess();
// System.out.println("SICW.endCurrentUse() ... Done " + this);
}
private void ensureReadyOnFirstUse() throws IOException {
beginThreadAccess();
if (usedYet) return;
usedYet = true;
// System.out.println("SICW.ensureReadyOnFirstUse() About to ... " + this);
filePositionBeforeUse = streamDataInput.getAbsolutePosition();
streamDataInput.seekAbsolute(filePositionOfStreamData);
// System.out.println("SICW.ensureReadyOnFirstUse() ... Done " + this);
}
public void seekAbsolute(long absolutePosition) throws IOException {
ensureReadyOnFirstUse();
// The wrapper exists in a different coordinate system,
// where its beginning is location 0
if (absolutePosition < 0L)
throw new IOException("Attempt to absolutely seek to negative location: " + absolutePosition);
// It's alright to seek beyond the end, it's just that read operations will fail
absolutePosition += filePositionOfStreamData;
streamDataInput.seekAbsolute(absolutePosition);
}
public void seekEnd() throws IOException {
ensureReadyOnFirstUse();
streamDataInput.seekAbsolute(filePositionOfStreamData + lengthOfStreamData);
}