import java.io.IOException;
import java.io.InputStream;
-import java.util.Arrays;
+import java.util.AbstractMap;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map.Entry;
import be.nikiroo.utils.StringUtils;
public class BufferedInputStream extends InputStream {
/**
* The size of the internal buffer (can be different if you pass your own
- * buffer, of course).
+ * buffer, of course, and can also expand to search for longer "startsWith"
+ * data).
* <p>
- * A second buffer of twice the size can sometimes be created as needed for
- * the {@link BufferedInputStream#startsWith(byte[])} search operation.
+ * Note that special "push-back" buffers can also be created during the life
+ * of this stream.
*/
static private final int BUFFER_SIZE = 4096;
private boolean closed;
private InputStream in;
private int openCounter;
+ private byte[] singleByteReader = new byte[1];
- // special use, prefetched next buffer
- private byte[] buffer2;
- private int pos2;
- private int len2;
- private byte[] originalBuffer;
+ /** array + offset of pushed-back buffers */
+ private List<Entry<byte[], Integer>> backBuffers;
private long bytesRead;
this.in = in;
this.buffer = new byte[BUFFER_SIZE];
- this.originalBuffer = this.buffer;
this.start = 0;
this.stop = 0;
+ this.backBuffers = new ArrayList<Entry<byte[], Integer>>();
}
/**
this.in = null;
this.buffer = in;
- this.originalBuffer = this.buffer;
this.start = offset;
this.stop = length;
- }
-
- /**
- * The internal buffer size (can be useful to know for search methods).
- *
- * @return the size of the internal buffer, in bytes.
- */
- public int getInternalBufferSize() {
- return originalBuffer.length;
+ this.backBuffers = new ArrayList<Entry<byte[], Integer>>();
}
/**
*/
public boolean is(byte[] search) throws IOException {
if (startsWith(search)) {
- return (stop - start) == search.length;
+ return available() == search.length;
}
return false;
* greater than the internal buffer
*/
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) {
+ while (consolidatePushBack(search.length) < search.length) {
preRead();
- }
-
- if (available() >= search.length) {
- // Easy path
- return StreamUtils.startsWith(search, buffer, start, stop);
- } else if (in != null && !eof) {
- // Harder path
- if (buffer2 == null && buffer.length == originalBuffer.length) {
- buffer2 = Arrays.copyOf(buffer, buffer.length * 2);
-
- pos2 = buffer.length;
- len2 = read(in, buffer2, pos2, buffer.length);
- if (len2 > 0) {
- bytesRead += len2;
- }
-
- // Note: here, len/len2 = INDEX of last good byte
- len2 += pos2;
+ if (start >= stop) {
+ // Not enough data left to start with that
+ return false;
}
- return StreamUtils.startsWith(search, buffer2, pos2, len2);
+ byte[] newBuffer = new byte[stop - start];
+ System.arraycopy(buffer, start, newBuffer, 0, stop - start);
+ pushback(newBuffer, 0);
+ start = stop;
}
- return false;
+ Entry<byte[], Integer> bb = backBuffers.get(backBuffers.size() - 1);
+ byte[] bbBuffer = bb.getKey();
+ int bbOffset = bb.getValue();
+
+ return StreamUtils.startsWith(search, bbBuffer, bbOffset,
+ bbBuffer.length);
}
/**
}
/**
- * Check if this stream is spent (no more data to read or to
- * process).
+ * Check if this stream is spent (no more data to read or to process).
*
* @return TRUE if it is
*
@Override
public int read() throws IOException {
- checkClose();
-
- preRead();
- if (eof) {
+ if (read(singleByteReader) < 0) {
return -1;
}
- return buffer[start++];
+ return singleByteReader[0];
}
@Override
return 0;
}
+ // Read from the pushed-back buffers if any
+ if (backBuffers.isEmpty()) {
+ preRead(); // an implementation could pushback in preRead()
+ }
+
+ if (!backBuffers.isEmpty()) {
+ int read = 0;
+
+ Entry<byte[], Integer> bb = backBuffers
+ .remove(backBuffers.size() - 1);
+ byte[] bbBuffer = bb.getKey();
+ int bbOffset = bb.getValue();
+ int bbSize = bbBuffer.length - bbOffset;
+
+ if (bbSize > blen) {
+ read = blen;
+ System.arraycopy(bbBuffer, bbOffset, b, boff, read);
+ pushback(bbBuffer, bbOffset + read);
+ } else {
+ read = bbSize;
+ System.arraycopy(bbBuffer, bbOffset, b, boff, read);
+ }
+
+ return read;
+ }
+
int done = 0;
while (hasMoreData() && done < blen) {
preRead();
}
long skipped = 0;
+ while (!backBuffers.isEmpty() && n > 0) {
+ Entry<byte[], Integer> bb = backBuffers
+ .remove(backBuffers.size() - 1);
+ byte[] bbBuffer = bb.getKey();
+ int bbOffset = bb.getValue();
+ int bbSize = bbBuffer.length - bbOffset;
+
+ int localSkip = 0;
+ localSkip = (int) Math.min(n, bbSize);
+
+ n -= localSkip;
+ bbSize -= localSkip;
+
+ if (bbSize > 0) {
+ pushback(bbBuffer, bbOffset + localSkip);
+ }
+ }
while (hasMoreData() && n > 0) {
preRead();
return 0;
}
- return Math.max(0, stop - start);
+ int avail = 0;
+ for (Entry<byte[], Integer> entry : backBuffers) {
+ avail += entry.getKey().length - entry.getValue();
+ }
+
+ return avail + Math.max(0, stop - start);
}
/**
}
}
+ /**
+ * Consolidate the push-back buffers so the last one is at least the given
+ * size, if possible.
+ * <p>
+ * If there is not enough data in the push-back buffers, they will all be
+ * consolidated.
+ *
+ * @param size
+ * the minimum size of the consolidated buffer, or -1 to force
+ * the consolidation of all push-back buffers
+ *
+ * @return the size of the last, consolidated buffer; can be less than the
+ * requested size if not enough data
+ */
+ protected int consolidatePushBack(int size) {
+ int bbIndex = -1;
+ int bbUpToSize = 0;
+ for (Entry<byte[], Integer> entry : backBuffers) {
+ bbIndex++;
+ bbUpToSize += entry.getKey().length - entry.getValue();
+
+ if (size >= 0 && bbUpToSize >= size) {
+ break;
+ }
+ }
+
+ // Index 0 means "the last buffer is already big enough"
+ if (bbIndex > 0) {
+ byte[] consolidatedBuffer = new byte[bbUpToSize];
+ int consolidatedPos = 0;
+ for (int i = 0; i <= bbIndex; i++) {
+ Entry<byte[], Integer> bb = backBuffers
+ .remove(backBuffers.size() - 1);
+ byte[] bbBuffer = bb.getKey();
+ int bbOffset = bb.getValue();
+ int bbSize = bbBuffer.length - bbOffset;
+ System.arraycopy(bbBuffer, bbOffset, consolidatedBuffer,
+ consolidatedPos, bbSize);
+ }
+
+ pushback(consolidatedBuffer, 0);
+ }
+
+ return bbUpToSize;
+ }
+
/**
* Check if we still have some data in the buffer and, if not, fetch some.
*
boolean hasRead = false;
if (in != null && !eof && start >= stop) {
start = 0;
- if (buffer2 != null) {
- buffer = buffer2;
- start = pos2;
- stop = len2;
-
- buffer2 = null;
- pos2 = 0;
- len2 = 0;
- } else {
- buffer = originalBuffer;
-
- stop = read(in, buffer, 0, buffer.length);
- if (stop > 0) {
- bytesRead += stop;
- }
+ stop = read(in, buffer);
+ if (stop > 0) {
+ bytesRead += stop;
}
hasRead = true;
}
/**
- * Read the under-laying stream into the local buffer.
+ * Push back some data that will be read again at the next read call.
+ *
+ * @param buffer
+ * the buffer to push back
+ * @param offset
+ * the offset at which to start reading in the buffer
+ */
+ protected void pushback(byte[] buffer, int offset) {
+ backBuffers.add(
+ new AbstractMap.SimpleEntry<byte[], Integer>(buffer, offset));
+ }
+
+ /**
+ * Push back some data that will be read again at the next read call.
+ *
+ * @param buffer
+ * the buffer to push back
+ * @param offset
+ * the offset at which to start reading in the buffer
+ * @param len
+ * the length to copy
+ */
+ protected void pushback(byte[] buffer, int offset, int len) {
+ // TODO: not efficient!
+ if (buffer.length != len) {
+ byte[] lenNotSupportedYet = new byte[len];
+ System.arraycopy(buffer, offset, lenNotSupportedYet, 0, len);
+ buffer = lenNotSupportedYet;
+ offset = 0;
+ }
+
+ pushback(buffer, offset);
+ }
+
+ /**
+ * Read the under-laying stream into the given local buffer.
*
* @param in
* the under-laying {@link InputStream}
* @param buffer
* the buffer we use in this {@link BufferedInputStream}
- * @param off
- * the offset
- * @param len
- * the length in bytes
*
* @return the number of bytes read
*
* @throws IOException
* in case of I/O error
*/
- protected int read(InputStream in, byte[] buffer, int off, int len)
- throws IOException {
- return in.read(buffer, off, len);
+ protected int read(InputStream in, byte[] buffer) throws IOException {
+ return in.read(buffer, 0, buffer.length);
}
/**
return false;
}
- return (start < stop) || !eof;
+ return !backBuffers.isEmpty() || (start < stop) || !eof;
}
/**
git://git.nikiroo.be / nikiroo-utils.git / blobdiff