BaseDexBuffer.java

/*
 * Copyright 2012, Google Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.jf.dexlib2.dexbacked;

import org.jf.util.ExceptionWithContext;

import javax.annotation.Nonnull;

public class BaseDexBuffer {
	@Nonnull
	/* package private */final byte[] buf;
	private MemoryReader reader;
	private int baseAddr;

	public MemoryReader getReader() {
		return reader;
	}

	public int getBaseAddr() {
		return baseAddr;
	}

	public BaseDexBuffer(MemoryReader reader, int baseAddr) {
		this.buf = null;
		this.reader = reader;
		this.baseAddr = baseAddr;
	}

	public BaseDexBuffer(@Nonnull byte[] buf) {
		this.buf = buf;
		this.reader = null;
		this.baseAddr =0;
	}

	public int readSmallUint(int offset) {
		if (this.reader == null) {
			byte[] buf = this.buf;
			int result = (buf[offset] & 0xff) | ((buf[offset + 1] & 0xff) << 8)
					| ((buf[offset + 2] & 0xff) << 16)
					| ((buf[offset + 3]) << 24);
			if (result < 0) {
				throw new ExceptionWithContext(
						"Encountered small uint that is out of range at offset 0x%x",
						offset);
			}
			return result;
		} else {
			byte[] buf = this.reader.readBytes(this.baseAddr + offset, 4);
			int result = (buf[0] & 0xff) | ((buf[1] & 0xff) << 8)
					| ((buf[2] & 0xff) << 16) | ((buf[3]) << 24);
			if (result < 0) {
				throw new ExceptionWithContext(
						"Encountered small uint that is out of range at offset 0x%x",
						offset);
			}
			return result;
		}
	}

	public int readOptionalUint(int offset) {
		if (this.reader == null) {
			byte[] buf = this.buf;
			int result = (buf[offset] & 0xff) | ((buf[offset + 1] & 0xff) << 8)
					| ((buf[offset + 2] & 0xff) << 16)
					| ((buf[offset + 3]) << 24);
			if (result < -1) {
				throw new ExceptionWithContext(
						"Encountered optional uint that is out of range at offset 0x%x",
						offset);
			}
			return result;
		} else {
			byte[] buf = this.reader.readBytes(this.baseAddr + offset, 4);
			int result = (buf[0] & 0xff) | ((buf[1] & 0xff) << 8)
					| ((buf[2] & 0xff) << 16) | ((buf[3]) << 24);
			if (result < -1) {
				throw new ExceptionWithContext(
						"Encountered optional uint that is out of range at offset 0x%x",
						offset);
			}
			return result;
		}
	}

	public int readUshort(int offset) {
		if (this.reader == null) {
			byte[] buf = this.buf;
			return (buf[offset] & 0xff) | ((buf[offset + 1] & 0xff) << 8);
		} else {
			byte[] buf = this.reader.readBytes(this.baseAddr + offset, 2);
			return (buf[0] & 0xff) | ((buf[1] & 0xff) << 8);
		}
	}

	public int readUbyte(int offset) {
		if (this.reader == null) {
			return buf[offset] & 0xff;
		} else {
			return this.reader.readBytes(this.baseAddr + offset, 1)[0] & 0xff;
		}
	}

	public long readLong(int offset) {
		if (this.reader == null) {
			byte[] buf = this.buf;
			return (buf[offset] & 0xff) | ((buf[offset + 1] & 0xff) << 8)
					| ((buf[offset + 2] & 0xff) << 16)
					| ((buf[offset + 3] & 0xffL) << 24)
					| ((buf[offset + 4] & 0xffL) << 32)
					| ((buf[offset + 5] & 0xffL) << 40)
					| ((buf[offset + 6] & 0xffL) << 48)
					| (((long) buf[offset + 7]) << 56);
		} else {
			byte[] buf = this.reader.readBytes(this.baseAddr + offset, 8);
			return (buf[0] & 0xff) | ((buf[1] & 0xff) << 8)
					| ((buf[2] & 0xff) << 16) | ((buf[3] & 0xffL) << 24)
					| ((buf[4] & 0xffL) << 32) | ((buf[5] & 0xffL) << 40)
					| ((buf[6] & 0xffL) << 48) | (((long) buf[7]) << 56);
		}
	}

	public int readInt(int offset) {
		if (this.reader == null) {
			byte[] buf = this.buf;
			return (buf[offset] & 0xff) | ((buf[offset + 1] & 0xff) << 8)
					| ((buf[offset + 2] & 0xff) << 16)
					| (buf[offset + 3] << 24);
		} else {
			byte[] buf = this.reader.readBytes(this.baseAddr + offset, 4);
			return (buf[0] & 0xff) | ((buf[1] & 0xff) << 8)
					| ((buf[2] & 0xff) << 16) | (buf[3] << 24);
		}
	}

	public int readShort(int offset) {
		if (this.reader == null) {
			byte[] buf = this.buf;
			return (buf[offset] & 0xff) | (buf[offset + 1] << 8);
		} else {
			byte[] buf = this.reader.readBytes(this.baseAddr + offset, 2);
			return (buf[0] & 0xff) | (buf[1] << 8);
		}
	}

	public int readByte(int offset) {
		if (this.reader == null) {
			return buf[offset];
		} else {
			return this.reader.readBytes(this.baseAddr + offset, 1)[0];
		}
	}

	@Nonnull
	public BaseDexReader readerAt(int offset) {
		return new BaseDexReader<BaseDexBuffer>(this, offset);
	}

	@Nonnull
	protected byte[] getBuf() {
		return buf;
	}
}