NewPipe-app-android/app/src/main/java/us/shandian/giga/io/ChunkFileInputStream.java

149 lines
3.0 KiB
Java

package us.shandian.giga.io;
import org.schabi.newpipe.streams.io.SharpStream;
import java.io.IOException;
public class ChunkFileInputStream extends SharpStream {
private SharpStream source;
private final long offset;
private final long length;
private long position;
public ChunkFileInputStream(SharpStream target, long start) throws IOException {
this(target, start, target.length());
}
public ChunkFileInputStream(SharpStream target, long start, long end) throws IOException {
source = target;
offset = start;
length = end - start;
position = 0;
if (length < 1) {
source.close();
throw new IOException("The chunk is empty or invalid");
}
if (source.length() < end) {
try {
throw new IOException(String.format("invalid file length. expected = %s found = %s", end, source.length()));
} finally {
source.close();
}
}
source.seek(offset);
}
/**
* Get absolute position on file
*
* @return the position
*/
public long getFilePointer() {
return offset + position;
}
@Override
public int read() throws IOException {
if ((position + 1) > length) {
return 0;
}
int res = source.read();
if (res >= 0) {
position++;
}
return res;
}
@Override
public int read(byte b[]) throws IOException {
return read(b, 0, b.length);
}
@Override
public int read(byte b[], int off, int len) throws IOException {
if ((position + len) > length) {
len = (int) (length - position);
}
if (len == 0) {
return 0;
}
int res = source.read(b, off, len);
position += res;
return res;
}
@Override
public long skip(long pos) throws IOException {
pos = Math.min(pos + position, length);
if (pos == 0) {
return 0;
}
source.seek(offset + pos);
long oldPos = position;
position = pos;
return pos - oldPos;
}
@Override
public long available() {
return (int) (length - position);
}
@SuppressWarnings("EmptyCatchBlock")
@Override
public void close() {
source.close();
source = null;
}
@Override
public boolean isClosed() {
return source == null;
}
@Override
public void rewind() throws IOException {
position = 0;
source.seek(offset);
}
@Override
public boolean canRewind() {
return true;
}
@Override
public boolean canRead() {
return true;
}
@Override
public boolean canWrite() {
return false;
}
@Override
public void write(byte value) {
}
@Override
public void write(byte[] buffer) {
}
@Override
public void write(byte[] buffer, int offset, int count) {
}
}