Here are some small improvements when creating new BlockInputStream
instances. This reduces the size of the byte[] for the block header to
the actual size and replaces use of ByteArrayInputStream, which has
synchronized methods, with a ByteBuffer, which provides the same
functionality without synchronization.
diff --git a/src/org/tukaani/xz/BlockInputStream.java
b/src/org/tukaani/xz/BlockInputStream.java
index 1931bd6..94342e2 100644
--- a/src/org/tukaani/xz/BlockInputStream.java
+++ b/src/org/tukaani/xz/BlockInputStream.java
@@ -9,13 +9,15 @@
package org.tukaani.xz;
-import java.io.InputStream;
import java.io.DataInputStream;
-import java.io.ByteArrayInputStream;
import java.io.IOException;
+import java.io.InputStream;
+import java.nio.BufferUnderflowException;
+import java.nio.ByteBuffer;
import java.util.Arrays;
-import org.tukaani.xz.common.DecoderUtil;
+
import org.tukaani.xz.check.Check;
+import org.tukaani.xz.common.DecoderUtil;
class BlockInputStream extends InputStream {
private final DataInputStream inData;
@@ -44,17 +46,18 @@ class BlockInputStream extends InputStream {
this.verifyCheck = verifyCheck;
inData = new DataInputStream(in);
- byte[] buf = new byte[DecoderUtil.BLOCK_HEADER_SIZE_MAX];
-
// Block Header Size or Index Indicator
- inData.readFully(buf, 0, 1);
+ int b = inData.readUnsignedByte();
// See if this begins the Index field.
- if (buf[0] == 0x00)
+ if (b == 0x00)
throw new IndexIndicatorException();
// Read the rest of the Block Header.
- headerSize = 4 * ((buf[0] & 0xFF) + 1);
+ headerSize = ((b & 0xFF) + 1) << 2;
+
+ final byte[] buf = new byte[headerSize];
+ buf[0] = (byte) b;
inData.readFully(buf, 1, headerSize - 1);
// Validate the CRC32.
@@ -71,11 +74,9 @@ class BlockInputStream extends InputStream {
long[] filterIDs = new long[filterCount];
byte[][] filterProps = new byte[filterCount][];
- // Use a stream to parse the fields after the Block Flags field.
+ // Use a ByteBuffer to parse the fields after the Block Flags field.
// Exclude the CRC32 field at the end.
- ByteArrayInputStream bufStream = new ByteArrayInputStream(
- buf, 2, headerSize - 6);
-
+ final ByteBuffer bb = ByteBuffer.wrap(buf, 2, headerSize - 6);
try {
// Set the maximum valid compressed size. This is overriden
// by the value from the Compressed Size field if it is present.
@@ -85,7 +86,7 @@ class BlockInputStream extends InputStream {
// Decode and validate Compressed Size if the relevant flag
// is set in Block Flags.
if ((buf[1] & 0x40) != 0x00) {
- compressedSizeInHeader = DecoderUtil.decodeVLI(bufStream);
+ compressedSizeInHeader = DecoderUtil.decodeVLI(bb);
if (compressedSizeInHeader == 0
|| compressedSizeInHeader > compressedSizeLimit)
@@ -97,27 +98,27 @@ class BlockInputStream extends InputStream {
// Decode Uncompressed Size if the relevant flag is set
// in Block Flags.
if ((buf[1] & 0x80) != 0x00)
- uncompressedSizeInHeader = DecoderUtil.decodeVLI(bufStream);
+ uncompressedSizeInHeader = DecoderUtil.decodeVLI(bb);
// Decode Filter Flags.
for (int i = 0; i < filterCount; ++i) {
- filterIDs[i] = DecoderUtil.decodeVLI(bufStream);
+ filterIDs[i] = DecoderUtil.decodeVLI(bb);
- long filterPropsSize = DecoderUtil.decodeVLI(bufStream);
- if (filterPropsSize > bufStream.available())
+ long filterPropsSize = DecoderUtil.decodeVLI(bb);
+ if (filterPropsSize > bb.remaining())
throw new CorruptedInputException();
filterProps[i] = new byte[(int)filterPropsSize];
- bufStream.read(filterProps[i]);
+ bb.get(filterProps[i]);
}
- } catch (IOException e) {
+ } catch (IOException | BufferUnderflowException e) {
throw new CorruptedInputException("XZ Block Header is corrupt");
}
// Check that the remaining bytes are zero.
- for (int i = bufStream.available(); i > 0; --i)
- if (bufStream.read() != 0x00)
+ for (int i = bb.remaining(); i > 0; --i)
+ if (bb.get() != 0x00)
throw new UnsupportedOptionsException(
"Unsupported options in XZ Block Header");
diff --git a/src/org/tukaani/xz/common/DecoderUtil.java
b/src/org/tukaani/xz/common/DecoderUtil.java
index 77ba441..c3aa21d 100644
--- a/src/org/tukaani/xz/common/DecoderUtil.java
+++ b/src/org/tukaani/xz/common/DecoderUtil.java
@@ -9,14 +9,17 @@
package org.tukaani.xz.common;
-import java.io.InputStream;
-import java.io.IOException;
import java.io.EOFException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.BufferUnderflowException;
+import java.nio.ByteBuffer;
import java.util.zip.CRC32;
-import org.tukaani.xz.XZ;
-import org.tukaani.xz.XZFormatException;
+
import org.tukaani.xz.CorruptedInputException;
import org.tukaani.xz.UnsupportedOptionsException;
+import org.tukaani.xz.XZ;
+import org.tukaani.xz.XZFormatException;
public class DecoderUtil extends Util {
public static boolean isCRC32Valid(byte[] buf, int off, int len,
@@ -118,4 +121,27 @@ public class DecoderUtil extends Util {
return num;
}
+
+ public static long decodeVLI(ByteBuffer bb) throws IOException {
+ try {
+ int b = bb.get();
+ long num = b & 0x7F;
+ int i = 0;
+
+ while ((b & 0x80) != 0x00) {
+ if (++i >= VLI_SIZE_MAX)
+ throw new CorruptedInputException();
+
+ b = bb.get();
+ if (b == 0x00)
+ throw new CorruptedInputException();
+
+ num |= (long)(b & 0x7F) << (i * 7);
+ }
+
+ return num;
+ } catch (BufferUnderflowException e) {
+ throw new EOFException();
+ }
+ }
}
