+package be.nikiroo.utils;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Arrays;
+
+/**
+ * A simple {@link InputStream} that is buffered with a bytes array.
+ * <p>
+ * It is mostly intended to be used as a base class to create new
+ * {@link InputStream}s with special operation modes, and to give some default
+ * methods.
+ *
+ * @author niki
+ */
+public class BufferedInputStream extends InputStream {
+ protected int pos;
+ protected int len;
+ protected byte[] buffer;
+ protected boolean eof;
+
+ private boolean closed;
+ private InputStream in;
+ private int openCounter;
+
+ // special use, prefetched next buffer
+ private byte[] buffer2;
+ private int pos2;
+ private int len2;
+ private byte[] originalBuffer;
+
+ private long bytesRead;
+
+ /**
+ * Create a new {@link BufferedInputStream} that wraps the given
+ * {@link InputStream}.
+ *
+ * @param in
+ * the {@link InputStream} to wrap
+ */
+ public BufferedInputStream(InputStream in) {
+ this.in = in;
+
+ this.buffer = new byte[4096];
+ this.originalBuffer = this.buffer;
+ this.pos = 0;
+ this.len = 0;
+ }
+
+ /**
+ * Create a new {@link BufferedInputStream} that wraps the given bytes array
+ * as a data source.
+ *
+ * @param in
+ * the array to wrap, cannot be NULL
+ */
+ public BufferedInputStream(byte[] in) {
+ this(in, 0, in.length);
+ }
+
+ /**
+ * Create a new {@link BufferedInputStream} that wraps the given bytes array
+ * as a data source.
+ *
+ * @param in
+ * the array to wrap, cannot be NULL
+ * @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 BufferedInputStream(byte[] in, 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.buffer = in;
+ this.originalBuffer = this.buffer;
+ this.pos = offset;
+ this.len = length;
+ }
+
+ /**
+ * Return this very same {@link BufferedInputStream}, but keep a counter of
+ * how many streams were open this way. When calling
+ * {@link BufferedInputStream#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;
+ }
+
+ // 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).
+ * <p>
+ * Note: an empty stream that is still not started will return FALSE, as we
+ * don't know yet if it is empty.
+ *
+ * @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;
+ }
+
+ return buffer[pos++];
+ }
+
+ @Override
+ public int read(byte[] b) throws IOException {
+ return read(b, 0, b.length);
+ }
+
+ @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) {
+ throw new IndexOutOfBoundsException();
+ } else if (blen == 0) {
+ return 0;
+ }
+
+ int done = 0;
+ while (hasMoreData() && done < blen) {
+ preRead();
+ if (hasMoreData()) {
+ int now = Math.min(blen, len) - pos;
+ if (now > 0) {
+ System.arraycopy(buffer, pos, b, boff, now);
+ pos += now;
+ done += now;
+ }
+ }
+ }
+
+ return done > 0 ? done : -1;
+ }
+
+ @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 BufferedInputStream#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 BufferedInputStream#close()} once more
+ * than {@link BufferedInputStream#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 BufferedInputStream#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 BufferedInputStream#close()} once more
+ * than {@link BufferedInputStream#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
+ */
+ protected boolean preRead() throws IOException {
+ boolean hasRead = false;
+ if (!eof && in != null && pos >= len) {
+ pos = 0;
+ if (buffer2 != null) {
+ buffer = buffer2;
+ pos = pos2;
+ len = len2;
+
+ buffer2 = null;
+ pos2 = 0;
+ len2 = 0;
+ } else {
+ buffer = originalBuffer;
+
+ len = read(in, buffer);
+ if (len > 0) {
+ bytesRead += len;
+ }
+ }
+
+ hasRead = true;
+ }
+
+ if (pos >= len) {
+ eof = true;
+ }
+
+ return hasRead;
+ }
+
+ /**
+ * Read the under-laying stream into the local buffer.
+ *
+ * @param in
+ * the under-laying {@link InputStream}
+ * @param buffer
+ * the buffer we use in this {@link BufferedInputStream}
+ *
+ * @return the number of bytes read
+ *
+ * @throws IOException
+ * in case of I/O error
+ */
+ protected int read(InputStream in, byte[] buffer) throws IOException {
+ return in.read(buffer);
+ }
+
+ /**
+ * We have more data available in the buffer or we can fetch more.
+ *
+ * @return TRUE if it is the case, FALSE if not
+ */
+ protected boolean hasMoreData() {
+ return !closed && !(eof && pos >= len);
+ }
+
+ /**
+ * Check that the stream was not closed, and throw an {@link IOException} if
+ * it was.
+ *
+ * @throws IOException
+ * if it was closed
+ */
+ protected 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 / commitdiff