import java.io.IOException;
import java.io.InputStream;
+import java.util.Arrays;
+/**
+ * This {@link InputStream} can be separated into sub-streams (you can process
+ * it as a normal {@link InputStream} but, when it is spent, you can call
+ * {@link NextableInputStream#next()} on it to unlock new data).
+ * <p>
+ * The separation in sub-streams is done via {@link NextableInputStreamStep}.
+ *
+ * @author niki
+ */
public class NextableInputStream extends InputStream {
+ private NextableInputStreamStep step;
+ private boolean started;
+ private boolean stopped;
+ private boolean closed;
+
private InputStream in;
+ private int openCounter;
private boolean eof;
- private int pos = 0;
- private int len = 0;
- private byte[] buffer = new byte[4096];
+ private int pos;
+ private int len;
+ private byte[] buffer;
+
+ // special use, prefetched next buffer
+ private byte[] buffer2;
+ private int pos2;
+ private int len2;
+ private byte[] originalBuffer;
- public NextableInputStream(InputStream in) {
+ private long bytesRead;
+
+ /**
+ * Create a new {@link NextableInputStream} that wraps the given
+ * {@link InputStream}.
+ *
+ * @param in
+ * the {@link InputStream} to wrap
+ * @param step
+ * how to separate it into sub-streams (can be NULL, but in that
+ * case it will behave as a normal {@link InputStream})
+ */
+ public NextableInputStream(InputStream in, NextableInputStreamStep step) {
this.in = in;
+ this.step = step;
+
+ this.buffer = new byte[4096];
+ this.originalBuffer = this.buffer;
+ this.pos = 0;
+ this.len = 0;
+ }
+
+ /**
+ * Create a new {@link NextableInputStream} that wraps the given bytes array
+ * as a data source.
+ *
+ * @param in
+ * the array to wrap, cannot be NULL
+ * @param step
+ * how to separate it into sub-streams (can be NULL, but in that
+ * case it will behave as a normal {@link InputStream})
+ */
+ public NextableInputStream(byte[] in, NextableInputStreamStep step) {
+ this(in, step, 0, in.length);
+ }
+
+ /**
+ * Create a new {@link NextableInputStream} that wraps the given bytes array
+ * as a data source.
+ *
+ * @param in
+ * the array to wrap, cannot be NULL
+ * @param step
+ * how to separate it into sub-streams (can be NULL, but in that
+ * case it will behave as a normal {@link InputStream})
+ * @param offset
+ * the offset to start the reading at
+ * @param length
+ * the number of bytes to take into account in the array,
+ * starting from the offset
+ *
+ * @throws NullPointerException
+ * if the array is NULL
+ * @throws IndexOutOfBoundsException
+ * if the offset and length do not correspond to the given array
+ */
+ public NextableInputStream(byte[] in, NextableInputStreamStep step,
+ int offset, int length) {
+ if (in == null) {
+ throw new NullPointerException();
+ } else if (offset < 0 || length < 0 || length > in.length - offset) {
+ throw new IndexOutOfBoundsException();
+ }
+
+ this.in = null;
+ this.step = step;
+
+ this.buffer = in;
+ this.originalBuffer = this.buffer;
+ this.pos = offset;
+ this.len = length;
+
+ checkBuffer(true);
+ }
+
+ /**
+ * Return this very same {@link NextableInputStream}, but keep a counter of
+ * how many streams were open this way. When calling
+ * {@link NextableInputStream#close()}, decrease this counter if it is not
+ * already zero instead of actually closing the stream.
+ * <p>
+ * You are now responsible for it — you <b>must</b> close it.
+ * <p>
+ * This method allows you to use a wrapping stream around this one and still
+ * close the wrapping stream.
+ *
+ * @return the same stream, but you are now responsible for closing it
+ *
+ * @throws IOException
+ * in case of I/O error or if the stream is closed
+ */
+ public synchronized InputStream open() throws IOException {
+ checkClose();
+ openCounter++;
+ return this;
+ }
+
+ /**
+ * Unblock the processing of the next sub-stream.
+ * <p>
+ * It can only be called when the "current" stream is spent (i.e., you must
+ * first process the stream until it is spent).
+ * <p>
+ * We consider that when the under-laying {@link InputStream} is also spent,
+ * we cannot have a next sub-stream (it will thus return FALSE).
+ * <p>
+ * {@link IOException}s can happen when we have no data available in the
+ * buffer; in that case, we fetch more data to know if we can have a next
+ * sub-stream or not.
+ *
+ * @return TRUE if we unblocked the next sub-stream, FALSE if not
+ *
+ * @throws IOException
+ * in case of I/O error or if the stream is closed
+ */
+ public boolean next() throws IOException {
+ return next(false);
+ }
+
+ /**
+ * Unblock the next sub-stream as would have done
+ * {@link NextableInputStream#next()}, but disable the sub-stream systems.
+ * <p>
+ * That is, the next stream, if any, will be the last one and will not be
+ * subject to the {@link NextableInputStreamStep}.
+ *
+ * @return TRUE if we unblocked the next sub-stream, FALSE if not
+ *
+ * @throws IOException
+ * in case of I/O error or if the stream is closed
+ */
+ public boolean nextAll() throws IOException {
+ return next(true);
+ }
+
+ // max is buffer.size !
+ public boolean startsWiths(String search) throws IOException {
+ return startsWith(search.getBytes("UTF-8"));
+ }
+
+ // max is buffer.size !
+ public boolean startsWith(byte[] search) throws IOException {
+ if (search.length > originalBuffer.length) {
+ throw new IOException(
+ "This stream does not support searching for more than "
+ + buffer.length + " bytes");
+ }
+
+ checkClose();
+
+ if (available() < search.length) {
+ preRead();
+ }
+
+ if (available() >= search.length) {
+ // Easy path
+ return startsWith(search, buffer, pos);
+ } else if (!eof) {
+ // Harder path
+ if (buffer2 == null && buffer.length == originalBuffer.length) {
+ buffer2 = Arrays.copyOf(buffer, buffer.length * 2);
+
+ pos2 = buffer.length;
+ len2 = in.read(buffer2, pos2, buffer.length);
+ if (len2 > 0) {
+ bytesRead += len2;
+ }
+
+ // Note: here, len/len2 = INDEX of last good byte
+ len2 += pos2;
+ }
+
+ if (available() + (len2 - pos2) >= search.length) {
+ return startsWith(search, buffer2, pos2);
+ }
+ }
+
+ return false;
+ }
+
+ /**
+ * The number of bytes read from the under-laying {@link InputStream}.
+ *
+ * @return the number of bytes
+ */
+ public long getBytesRead() {
+ return bytesRead;
+ }
+
+ /**
+ * Check if this stream is totally spent (no more data to read or to
+ * process).
+ *
+ * @return TRUE if it is
+ */
+ public boolean eof() {
+ return closed || (len < 0 && !hasMoreData());
}
@Override
public int read() throws IOException {
+ checkClose();
+
preRead();
if (eof) {
return -1;
@Override
public int read(byte[] b, int boff, int blen) throws IOException {
+ checkClose();
+
if (b == null) {
throw new NullPointerException();
} else if (boff < 0 || blen < 0 || blen > b.length - boff) {
}
int done = 0;
- while (!eof && done < blen) {
+ while (hasMoreData() && done < blen) {
preRead();
- for (int i = pos; i < blen && i < len; i++) {
- b[boff + done] = buffer[i];
- pos++;
- done++;
+ if (hasMoreData()) {
+ for (int i = pos; i < blen && i < len; i++) {
+ b[boff + done] = buffer[i];
+ pos++;
+ done++;
+ }
}
}
return done > 0 ? done : -1;
}
- private void preRead() throws IOException {
- if (in != null && !eof && pos >= len) {
+ @Override
+ public long skip(long n) throws IOException {
+ if (n <= 0) {
+ return 0;
+ }
+
+ long skipped = 0;
+ while (hasMoreData() && n > 0) {
+ preRead();
+
+ long inBuffer = Math.min(n, available());
+ pos += inBuffer;
+ n -= inBuffer;
+ skipped += inBuffer;
+ }
+
+ return skipped;
+ }
+
+ @Override
+ public int available() {
+ if (closed) {
+ return 0;
+ }
+
+ return Math.max(0, len - pos);
+ }
+
+ /**
+ * Closes this stream and releases any system resources associated with the
+ * stream.
+ * <p>
+ * Including the under-laying {@link InputStream}.
+ * <p>
+ * <b>Note:</b> if you called the {@link NextableInputStream#open()} method
+ * prior to this one, it will just decrease the internal count of how many
+ * open streams it held and do nothing else. The stream will actually be
+ * closed when you have called {@link NextableInputStream#close()} once more
+ * than {@link NextableInputStream#open()}.
+ *
+ * @exception IOException
+ * in case of I/O error
+ */
+ @Override
+ public synchronized void close() throws IOException {
+ close(true);
+ }
+
+ /**
+ * Closes this stream and releases any system resources associated with the
+ * stream.
+ * <p>
+ * Including the under-laying {@link InputStream} if
+ * <tt>incudingSubStream</tt> is true.
+ * <p>
+ * You can call this method multiple times, it will not cause an
+ * {@link IOException} for subsequent calls.
+ * <p>
+ * <b>Note:</b> if you called the {@link NextableInputStream#open()} method
+ * prior to this one, it will just decrease the internal count of how many
+ * open streams it held and do nothing else. The stream will actually be
+ * closed when you have called {@link NextableInputStream#close()} once more
+ * than {@link NextableInputStream#open()}.
+ *
+ * @exception IOException
+ * in case of I/O error
+ */
+ public synchronized void close(boolean includingSubStream)
+ throws IOException {
+ if (!closed) {
+ if (openCounter > 0) {
+ openCounter--;
+ } else {
+ closed = true;
+ if (includingSubStream && in != null) {
+ in.close();
+ }
+ }
+ }
+ }
+
+ /**
+ * Check if we still have some data in the buffer and, if not, fetch some.
+ *
+ * @return TRUE if we fetched some data, FALSE if there are still some in
+ * the buffer
+ *
+ * @throws IOException
+ * in case of I/O error
+ */
+ private boolean preRead() throws IOException {
+ boolean hasRead = false;
+ if (!eof && in != null && pos >= len && !stopped) {
pos = 0;
- len = in.read(buffer);
- // checkNexts();
+ if (buffer2 != null) {
+ buffer = buffer2;
+ pos = pos2;
+ len = len2;
+
+ buffer2 = null;
+ pos2 = 0;
+ len2 = 0;
+ } else {
+ buffer = originalBuffer;
+ len = in.read(buffer);
+ if (len > 0) {
+ bytesRead += len;
+ }
+ }
+
+ checkBuffer(true);
+ hasRead = true;
}
if (pos >= len) {
eof = true;
}
+
+ return hasRead;
+ }
+
+ /**
+ * We have more data available in the buffer or we can fetch more.
+ *
+ * @return TRUE if it is the case, FALSE if not
+ */
+ private boolean hasMoreData() {
+ return !closed && started && !(eof && pos >= len);
+ }
+
+ /**
+ * Check that the buffer didn't overshot to the next item, and fix
+ * {@link NextableInputStream#len} if needed.
+ * <p>
+ * If {@link NextableInputStream#len} is fixed,
+ * {@link NextableInputStream#eof} and {@link NextableInputStream#stopped}
+ * are set to TRUE.
+ *
+ * @param newBuffer
+ * we changed the buffer, we need to clear some information in
+ * the {@link NextableInputStreamStep}
+ */
+ private void checkBuffer(boolean newBuffer) {
+ if (step != null && len > 0) {
+ if (newBuffer) {
+ step.clearBuffer();
+ }
+
+ int stopAt = step.stop(buffer, pos, len);
+ if (stopAt >= 0) {
+ len = stopAt;
+ eof = true;
+ stopped = true;
+ }
+ }
+ }
+
+ /**
+ * The implementation of {@link NextableInputStream#next()} and
+ * {@link NextableInputStream#nextAll()}.
+ *
+ * @param all
+ * TRUE for {@link NextableInputStream#nextAll()}, FALSE for
+ * {@link NextableInputStream#next()}
+ *
+ * @return TRUE if we unblocked the next sub-stream, FALSE if not
+ *
+ * @throws IOException
+ * in case of I/O error or if the stream is closed
+ */
+ private boolean next(boolean all) throws IOException {
+ checkClose();
+
+ if (!started) {
+ // First call before being allowed to read
+ started = true;
+
+ if (all) {
+ step = null;
+ }
+
+ return true;
+ }
+
+ if (step != null && !hasMoreData() && stopped) {
+ len = step.getResumeLen();
+ pos += step.getResumeSkip();
+ eof = false;
+
+ if (all) {
+ step = null;
+ }
+
+ if (!preRead()) {
+ checkBuffer(false);
+ }
+
+ // consider that if EOF, there is no next
+ return hasMoreData();
+ }
+
+ return false;
+ }
+
+ /**
+ * Check that the stream was not closed, and throw an {@link IOException} if
+ * it was.
+ *
+ * @throws IOException
+ * if it was closed
+ */
+ private void checkClose() throws IOException {
+ if (closed) {
+ throw new IOException(
+ "This NextableInputStream was closed, you cannot use it anymore.");
+ }
+ }
+
+ // buffer must be > search
+ static private boolean startsWith(byte[] search, byte[] buffer,
+ int offset) {
+ boolean same = true;
+ for (int i = 0; i < search.length; i++) {
+ if (search[i] != buffer[offset + i]) {
+ same = false;
+ break;
+ }
+ }
+
+ return same;
}
}
git://git.nikiroo.be / nikiroo-utils.git / blobdiff