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/* Copyright 2017 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.wrapper.common;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.util.Arrays;
/**
* JNI wrapper for brotli common.
*/
public class BrotliCommon {
public static final int RFC_DICTIONARY_SIZE = 122784;
/* 96cecd2ee7a666d5aa3627d74735b32a */
private static final byte[] RFC_DICTIONARY_MD5 = {
-106, -50, -51, 46, -25, -90, 102, -43, -86, 54, 39, -41, 71, 53, -77, 42
};
/* 72b41051cb61a9281ba3c4414c289da50d9a7640 */
private static final byte[] RFC_DICTIONARY_SHA_1 = {
114, -76, 16, 81, -53, 97, -87, 40, 27, -93, -60, 65, 76, 40, -99, -91, 13, -102, 118, 64
};
/* 20e42eb1b511c21806d4d227d07e5dd06877d8ce7b3a817f378f313653f35c70 */
private static final byte[] RFC_DICTIONARY_SHA_256 = {
32, -28, 46, -79, -75, 17, -62, 24, 6, -44, -46, 39, -48, 126, 93, -48,
104, 119, -40, -50, 123, 58, -127, 127, 55, -113, 49, 54, 83, -13, 92, 112
};
private static boolean isDictionaryDataSet;
private static final Object mutex = new Object();
/**
* Checks if the given checksum matches MD5 checksum of the RFC dictionary.
*/
public static boolean checkDictionaryDataMd5(byte[] digest) {
return Arrays.equals(RFC_DICTIONARY_MD5, digest);
}
/**
* Checks if the given checksum matches SHA-1 checksum of the RFC dictionary.
*/
public static boolean checkDictionaryDataSha1(byte[] digest) {
return Arrays.equals(RFC_DICTIONARY_SHA_1, digest);
}
/**
* Checks if the given checksum matches SHA-256 checksum of the RFC dictionary.
*/
public static boolean checkDictionaryDataSha256(byte[] digest) {
return Arrays.equals(RFC_DICTIONARY_SHA_256, digest);
}
/**
* Copy bytes to a new direct ByteBuffer.
*
* Direct byte buffers are used to supply native code with large data chunks.
*/
public static ByteBuffer makeNative(byte[] data) {
ByteBuffer result = ByteBuffer.allocateDirect(data.length);
result.put(data);
return result;
}
/**
* Copies data and sets it to be brotli dictionary.
*/
public static void setDictionaryData(byte[] data) {
if (data.length != RFC_DICTIONARY_SIZE) {
throw new IllegalArgumentException("invalid dictionary size");
}
synchronized (mutex) {
if (isDictionaryDataSet) {
return;
}
setDictionaryData(makeNative(data));
}
}
/**
* Reads data and sets it to be brotli dictionary.
*/
public static void setDictionaryData(InputStream src) throws IOException {
synchronized (mutex) {
if (isDictionaryDataSet) {
return;
}
ByteBuffer copy = ByteBuffer.allocateDirect(RFC_DICTIONARY_SIZE);
byte[] buffer = new byte[4096];
int readBytes;
while ((readBytes = src.read(buffer)) != -1) {
if (copy.remaining() < readBytes) {
throw new IllegalArgumentException("invalid dictionary size");
}
copy.put(buffer, 0, readBytes);
}
if (copy.remaining() != 0) {
throw new IllegalArgumentException("invalid dictionary size " + copy.remaining());
}
setDictionaryData(copy);
}
}
/**
* Sets data to be brotli dictionary.
*/
public static void setDictionaryData(ByteBuffer data) {
if (!data.isDirect()) {
throw new IllegalArgumentException("direct byte buffer is expected");
}
if (data.capacity() != RFC_DICTIONARY_SIZE) {
throw new IllegalArgumentException("invalid dictionary size");
}
synchronized (mutex) {
if (isDictionaryDataSet) {
return;
}
if (!CommonJNI.nativeSetDictionaryData(data)) {
throw new RuntimeException("setting dictionary failed");
}
isDictionaryDataSet = true;
}
}
}
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