/* Copyright 2016 Google Inc. All Rights Reserved. Distributed under MIT license. See file LICENSE for detail or copy at https://opensource.org/licenses/MIT */ package org.brotli.integration; import org.brotli.dec.BrotliInputStream; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FilterInputStream; import java.io.IOException; import java.io.InputStream; import java.math.BigInteger; import java.util.concurrent.atomic.AtomicInteger; import java.util.zip.ZipEntry; import java.util.zip.ZipInputStream; /** * Decompress files and (optionally) checks their checksums. * *
File are read from ZIP archive passed as an array of bytes. Multiple checkers negotiate about * task distribution via shared AtomicInteger counter. *
All entries are expected to be valid brotli compressed streams and output CRC64 checksum * is expected to match the checksum hex-encoded in the first part of entry name. */ public class BundleChecker implements Runnable { private final AtomicInteger nextJob; private final InputStream input; private final boolean sanityCheck; /** * @param sanityCheck do not calculate checksum and ignore {@link IOException}. */ public BundleChecker(InputStream input, AtomicInteger nextJob, boolean sanityCheck) { this.input = input; this.nextJob = nextJob; this.sanityCheck = sanityCheck; } /** ECMA CRC64 polynomial. */ private static final long CRC_64_POLY = new BigInteger("C96C5795D7870F42", 16).longValue(); /** * Rolls CRC64 calculation. * *
{@code CRC64(data) = -1 ^ updateCrc64((... updateCrc64(-1, firstBlock), ...), lastBlock);} *
This simple and reliable checksum is chosen to make is easy to calculate the same value
* across the variety of languages (C++, Java, Go, ...).
*/
private static long updateCrc64(long crc, byte[] data, int offset, int length) {
for (int i = offset; i < offset + length; ++i) {
long c = (crc ^ (long) (data[i] & 0xFF)) & 0xFF;
for (int k = 0; k < 8; k++) {
c = ((c & 1) == 1) ? CRC_64_POLY ^ (c >>> 1) : c >>> 1;
}
crc = c ^ (crc >>> 8);
}
return crc;
}
private long decompressAndCalculateCrc(ZipInputStream input) throws IOException {
/* Do not allow entry readers to close the whole ZipInputStream. */
FilterInputStream entryStream = new FilterInputStream(input) {
@Override
public void close() {}
};
long crc = -1;
byte[] buffer = new byte[65536];
BrotliInputStream decompressedStream = new BrotliInputStream(entryStream);
while (true) {
int len = decompressedStream.read(buffer);
if (len <= 0) {
break;
}
crc = updateCrc64(crc, buffer, 0, len);
}
decompressedStream.close();
return ~crc;
}
@Override
public void run() {
String entryName = "";
ZipInputStream zis = new ZipInputStream(input);
try {
int entryIndex = 0;
ZipEntry entry;
int jobIndex = nextJob.getAndIncrement();
while ((entry = zis.getNextEntry()) != null) {
if (entry.isDirectory()) {
continue;
}
if (entryIndex++ != jobIndex) {
zis.closeEntry();
continue;
}
entryName = entry.getName();
int dotIndex = entryName.indexOf('.');
String entryCrcString = (dotIndex == -1) ? entryName : entryName.substring(0, dotIndex);
long entryCrc = new BigInteger(entryCrcString, 16).longValue();
try {
if (entryCrc != decompressAndCalculateCrc(zis) && !sanityCheck) {
throw new RuntimeException("CRC mismatch");
}
} catch (IOException iox) {
if (!sanityCheck) {
throw new RuntimeException("Decompression failed", iox);
}
}
zis.closeEntry();
entryName = "";
jobIndex = nextJob.getAndIncrement();
}
zis.close();
input.close();
} catch (Throwable ex) {
throw new RuntimeException(entryName, ex);
}
}
public static void main(String[] args) throws FileNotFoundException {
int argsOffset = 0;
boolean sanityCheck = false;
if (args.length != 0) {
if (args[0].equals("-s")) {
sanityCheck = true;
argsOffset = 1;
}
}
if (args.length == argsOffset) {
throw new RuntimeException("Usage: BundleChecker [-s]