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/*
* Copyright (C) 2016 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.apkzlib.sign.v2;
import com.google.common.base.Preconditions;
import java.security.MessageDigest;
import javax.annotation.Nonnull;
/**
* {@code byte[]} which is fed into {@link MessageDigest} instances.
*/
public class ByteArrayDigestSource implements DigestSource {
private final byte[] mBuf;
/**
* Constructs a new {@code ByteArrayDigestSource} instance which obtains its data from the
* provided byte array. Changes to the byte array's contents are reflected visible in this
* source.
*/
public ByteArrayDigestSource(@Nonnull byte[] buf) {
mBuf = buf;
}
@Override
public long size() {
return mBuf.length;
}
@Override
public void feedDigests(long offset, int size, @Nonnull MessageDigest[] digests) {
Preconditions.checkArgument(offset >= 0, "offset: %s", offset);
Preconditions.checkArgument(size >= 0, "size: %s", size);
Preconditions.checkArgument(offset <= mBuf.length, "offset too large: %s", offset);
int offsetInBuf = (int) offset;
Preconditions.checkPositionIndex(offsetInBuf, mBuf.length, "offset out of range");
int availableSize = mBuf.length - offsetInBuf;
Preconditions.checkArgument(
size <= availableSize,
"offset (%s) + size (%s) > array length (%s)", offset, size, mBuf.length);
for (MessageDigest md : digests) {
md.update(mBuf, offsetInBuf, size);
}
}
}
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