/*
* Copyright 2016-present Facebook, Inc.
*
* 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.facebook.buck.macho;
import com.google.common.base.Preconditions;
import com.google.common.primitives.UnsignedInteger;
import java.nio.ByteBuffer;
import java.util.Optional;
public class MachoHeaderUtils {
private MachoHeaderUtils() {}
public static final int MAGIC_SIZE = 4;
public static int getHeaderSize(MachoHeader machoHeader) {
return machoHeader.getMagic().equals(MachoHeader.MH_MAGIC_64)
? MachoHeader.MACH_HEADER_SIZE_64
: MachoHeader.MACH_HEADER_SIZE_32;
}
public static MachoHeader create32BitFromBuffer(ByteBuffer buffer) {
return MachoHeader.of(
UnsignedInteger.fromIntBits(buffer.getInt()),
buffer.getInt(),
buffer.getInt(),
UnsignedInteger.fromIntBits(buffer.getInt()),
UnsignedInteger.fromIntBits(buffer.getInt()),
UnsignedInteger.fromIntBits(buffer.getInt()),
UnsignedInteger.fromIntBits(buffer.getInt()),
Optional.empty());
}
public static MachoHeader create64BitFromBuffer(ByteBuffer buffer) {
return MachoHeader.of(
UnsignedInteger.fromIntBits(buffer.getInt()),
buffer.getInt(),
buffer.getInt(),
UnsignedInteger.fromIntBits(buffer.getInt()),
UnsignedInteger.fromIntBits(buffer.getInt()),
UnsignedInteger.fromIntBits(buffer.getInt()),
UnsignedInteger.fromIntBits(buffer.getInt()),
Optional.of(UnsignedInteger.fromIntBits(buffer.getInt())));
}
/**
* Reads the Mach Header from the given buffer from current position.
*
* @param buffer Buffer that holds the data of the mach header
* @return MachoHeader for 32 or 64 bit Mach object.
*/
public static MachoHeader createFromBuffer(ByteBuffer buffer) {
int position = buffer.position();
UnsignedInteger magic = UnsignedInteger.fromIntBits(buffer.getInt());
buffer.position(position);
Preconditions.checkArgument(
magic.equals(MachoHeader.MH_MAGIC) || magic.equals(MachoHeader.MH_MAGIC_64));
if (magic.equals(MachoHeader.MH_MAGIC_64)) {
return create64BitFromBuffer(buffer);
} else {
return create32BitFromBuffer(buffer);
}
}
}