LatinIME/java/src/com/android/inputmethod/dictionarypack/MD5Calculator.java

47 lines
1.7 KiB
Java

/**
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.android.inputmethod.dictionarypack;
import java.io.InputStream;
import java.io.IOException;
import java.security.MessageDigest;
final class MD5Calculator {
private MD5Calculator() {} // This helper class is not instantiable
public static String checksum(final InputStream in) throws IOException {
// This code from the Android documentation for MessageDigest. Nearly verbatim.
MessageDigest digester;
try {
digester = MessageDigest.getInstance("MD5");
} catch (java.security.NoSuchAlgorithmException e) {
return null; // Platform does not support MD5 : can't check, so return null
}
final byte[] bytes = new byte[8192];
int byteCount;
while ((byteCount = in.read(bytes)) > 0) {
digester.update(bytes, 0, byteCount);
}
final byte[] digest = digester.digest();
final StringBuilder s = new StringBuilder();
for (int i = 0; i < digest.length; ++i) {
s.append(String.format("%1$02x", digest[i]));
}
return s.toString();
}
}