/*
* 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 org.jf.util.Utf8Utils;
import javax.annotation.Nonnull;
public class BaseDexReader<T extends BaseDexBuffer> {
@Nonnull public final T dexBuf;
private int offset;
public BaseDexReader(@Nonnull T dexBuf, int offset) {
this.dexBuf = dexBuf;
this.offset = offset;
}
public int getOffset() { return offset; }
public void setOffset(int offset) { this.offset = offset; }
/** {@inheritDoc} */
public int readSleb128() {
int end = offset;
int currentByteValue;
int result;
byte[] buf = dexBuf.buf;
result = buf[end++] & 0xff;
if (result <= 0x7f) {
result = (result << 25) >> 25;
} else {
currentByteValue = buf[end++] & 0xff;
result = (result & 0x7f) | ((currentByteValue & 0x7f) << 7);
if (currentByteValue <= 0x7f) {
result = (result << 18) >> 18;
} else {
currentByteValue = buf[end++] & 0xff;
result |= (currentByteValue & 0x7f) << 14;
if (currentByteValue <= 0x7f) {
result = (result << 11) >> 11;
} else {
currentByteValue = buf[end++] & 0xff;
result |= (currentByteValue & 0x7f) << 21;
if (currentByteValue <= 0x7f) {
result = (result << 4) >> 4;
} else {
currentByteValue = buf[end++] & 0xff;
if (currentByteValue > 0x7f) {
throw new ExceptionWithContext(
"Invalid sleb128 integer encountered at offset 0x%x", offset);
}
result |= currentByteValue << 28;
}
}
}
}
offset = end;
return result;
}
public int readSmallUleb128() {
return readUleb128(false);
}
private int readUleb128(boolean allowLarge) {
int end = offset;
int currentByteValue;
int result;
byte[] buf = dexBuf.buf;
result = buf[end++] & 0xff;
if (result > 0x7f) {
currentByteValue = buf[end++] & 0xff;
result = (result & 0x7f) | ((currentByteValue & 0x7f) << 7);
if (currentByteValue > 0x7f) {
currentByteValue = buf[end++] & 0xff;
result |= (currentByteValue & 0x7f) << 14;
if (currentByteValue > 0x7f) {
currentByteValue = buf[end++] & 0xff;
result |= (currentByteValue & 0x7f) << 21;
if (currentByteValue > 0x7f) {
currentByteValue = buf[end++];
// MSB shouldn't be set on last byte
if (currentByteValue < 0) {
throw new ExceptionWithContext(
"Invalid uleb128 integer encountered at offset 0x%x", offset);
} else if ((currentByteValue & 0xf) > 0x07) {
if (!allowLarge) {
// for non-large uleb128s, we assume most significant bit of the result will not be
// set, so that it can fit into a signed integer without wrapping
throw new ExceptionWithContext(
"Encountered valid uleb128 that is out of range at offset 0x%x", offset);
}
}
result |= currentByteValue << 28;
}
}
}
}
offset = end;
return result;
}
/**
* Reads a "large" uleb128. That is, one that may legitimately be greater than a signed int.
*
* The value is returned as if it were signed. i.e. a value of 0xFFFFFFFF would be returned as -1. It is up to the
* caller to handle the value appropriately.
*/
public int readLargeUleb128() {
return readUleb128(true);
}
/**
* Reads a "big" uleb128 that can legitimately be > 2^31. The value is returned as a signed integer, with the
* expected semantics of re-interpreting an unsigned value as a signed value.
*
* @return The unsigned value, reinterpreted as a signed int
*/
public int readBigUleb128() {
int end = offset;
int currentByteValue;
int result;
byte[] buf = dexBuf.buf;
result = buf[end++] & 0xff;
if (result > 0x7f) {
currentByteValue = buf[end++] & 0xff;
result = (result & 0x7f) | ((currentByteValue & 0x7f) << 7);
if (currentByteValue > 0x7f) {
currentByteValue = buf[end++] & 0xff;
result |= (currentByteValue & 0x7f) << 14;
if (currentByteValue > 0x7f) {
currentByteValue = buf[end++] & 0xff;
result |= (currentByteValue & 0x7f) << 21;
if (currentByteValue > 0x7f) {
currentByteValue = buf[end++];
// MSB shouldn't be set on last byte
if (currentByteValue < 0) {
throw new ExceptionWithContext(
"Invalid uleb128 integer encountered at offset 0x%x", offset);
}
result |= currentByteValue << 28;
}
}
}
}
offset = end;
return result;
}
public void skipUleb128() {
int end = offset;
byte currentByteValue;
byte[] buf = dexBuf.buf;
currentByteValue = buf[end++];
if (currentByteValue < 0) { // if the MSB is set
currentByteValue = buf[end++];
if (currentByteValue < 0) { // if the MSB is set
currentByteValue = buf[end++];
if (currentByteValue < 0) { // if the MSB is set
currentByteValue = buf[end++];
if (currentByteValue < 0) { // if the MSB is set
currentByteValue = buf[end++];
if (currentByteValue < 0) {
throw new ExceptionWithContext(
"Invalid uleb128 integer encountered at offset 0x%x", offset);
}
}
}
}
}
offset = end;
}
public int readSmallUint() {
int o = offset;
int result = dexBuf.readSmallUint(o);
offset = o + 4;
return result;
}
public int readOptionalUint() {
int o = offset;
int result = dexBuf.readOptionalUint(o);
offset = o + 4;
return result;
}
public int peekUshort() {
return dexBuf.readUshort(offset);
}
public int readUshort() {
int o = offset;
int result = dexBuf.readUshort(offset);
offset = o + 2;
return result;
}
public int peekUbyte() {
return dexBuf.readUbyte(offset);
}
public int readUbyte() {
int o = offset;
int result = dexBuf.readUbyte(offset);
offset = o + 1;
return result;
}
public long readLong() {
int o = offset;
long result = dexBuf.readLong(offset);
offset = o + 8;
return result;
}
public int readInt() {
int o = offset;
int result = dexBuf.readInt(offset);
offset = o + 4;
return result;
}
public int readShort() {
int o = offset;
int result = dexBuf.readShort(offset);
offset = o + 2;
return result;
}
public int readByte() {
int o = offset;
int result = dexBuf.readByte(offset);
offset = o + 1;
return result;
}
public void skipByte() { offset++; }
public void moveRelative(int i) { offset += i; }
public int readSmallUint(int offset) { return dexBuf.readSmallUint(offset); }
public int readUshort(int offset) { return dexBuf.readUshort(offset); }
public int readUbyte(int offset) { return dexBuf.readUbyte(offset); }
public long readLong(int offset) { return dexBuf.readLong(offset); }
public int readInt(int offset) { return dexBuf.readInt(offset); }
public int readShort(int offset) { return dexBuf.readShort(offset); }
public int readByte(int offset) { return dexBuf.readByte(offset); }
public int readSizedInt(int bytes) {
int o = offset;
byte[] buf = dexBuf.buf;
int result;
switch (bytes) {
case 4:
result = (buf[o] & 0xff) |
((buf[o+1] & 0xff) << 8) |
((buf[o+2] & 0xff) << 16) |
(buf[o+3] << 24);
break;
case 3:
result = (buf[o] & 0xff) |
((buf[o+1] & 0xff) << 8) |
((buf[o+2]) << 16);
break;
case 2:
result = (buf[o] & 0xff) |
((buf[o+1]) << 8);
break;
case 1:
result = buf[o];
break;
default:
throw new ExceptionWithContext("Invalid size %d for sized int at offset 0x%x", bytes, offset);
}
offset = o + bytes;
return result;
}
public int readSizedSmallUint(int bytes) {
int o = offset;
byte[] buf = dexBuf.buf;
int result = 0;
switch (bytes) {
case 4:
int b = buf[o+3];
if (b < 0) {
throw new ExceptionWithContext(
"Encountered valid sized uint that is out of range at offset 0x%x", offset);
}
result = b << 24;
// fall-through
case 3:
result |= (buf[o+2] & 0xff) << 16;
// fall-through
case 2:
result |= (buf[o+1] & 0xff) << 8;
// fall-through
case 1:
result |= (buf[o] & 0xff);
break;
default:
throw new ExceptionWithContext("Invalid size %d for sized uint at offset 0x%x", bytes, offset);
}
offset = o + bytes;
return result;
}
public int readSizedRightExtendedInt(int bytes) {
int o = offset;
byte[] buf = dexBuf.buf;
int result;
switch (bytes) {
case 4:
result = (buf[o] & 0xff) |
((buf[o+1] & 0xff) << 8) |
((buf[o+2] & 0xff) << 16) |
(buf[o+3] << 24);
break;
case 3:
result = (buf[o] & 0xff) << 8 |
((buf[o+1] & 0xff) << 16) |
(buf[o+2] << 24);
break;
case 2:
result = (buf[o] & 0xff) << 16 |
(buf[o+1] << 24);
break;
case 1:
result = buf[o] << 24;
break;
default:
throw new ExceptionWithContext(
"Invalid size %d for sized, right extended int at offset 0x%x", bytes, offset);
}
offset = o + bytes;
return result;
}
public long readSizedRightExtendedLong(int bytes) {
int o = offset;
byte[] buf = dexBuf.buf;
long result;
switch (bytes) {
case 8:
result = (buf[o] & 0xff) |
((buf[o+1] & 0xff) << 8) |
((buf[o+2] & 0xff) << 16) |
((buf[o+3] & 0xffL) << 24) |
((buf[o+4] & 0xffL) << 32) |
((buf[o+5] & 0xffL) << 40) |
((buf[o+6] & 0xffL) << 48) |
(((long)buf[o+7]) << 56);
break;
case 7:
result = ((buf[o] & 0xff)) << 8 |
((buf[o+1] & 0xff) << 16) |
((buf[o+2] & 0xffL) << 24) |
((buf[o+3] & 0xffL) << 32) |
((buf[o+4] & 0xffL) << 40) |
((buf[o+5] & 0xffL) << 48) |
(((long)buf[o+6]) << 56);
break;
case 6:
result = ((buf[o] & 0xff)) << 16 |
((buf[o+1] & 0xffL) << 24) |
((buf[o+2] & 0xffL) << 32) |
((buf[o+3] & 0xffL) << 40) |
((buf[o+4] & 0xffL) << 48) |
(((long)buf[o+5]) << 56);
break;
case 5:
result = ((buf[o] & 0xffL)) << 24 |
((buf[o+1] & 0xffL) << 32) |
((buf[o+2] & 0xffL) << 40) |
((buf[o+3] & 0xffL) << 48) |
(((long)buf[o+4]) << 56);
break;
case 4:
result = ((buf[o] & 0xffL)) << 32 |
((buf[o+1] & 0xffL) << 40) |
((buf[o+2] & 0xffL) << 48) |
(((long)buf[o+3]) << 56);
break;
case 3:
result = ((buf[o] & 0xffL)) << 40 |
((buf[o+1] & 0xffL) << 48) |
(((long)buf[o+2]) << 56);
break;
case 2:
result = ((buf[o] & 0xffL)) << 48 |
(((long)buf[o+1]) << 56);
break;
case 1:
result = ((long)buf[o]) << 56;
break;
default:
throw new ExceptionWithContext(
"Invalid size %d for sized, right extended long at offset 0x%x", bytes, offset);
}
offset = o + bytes;
return result;
}
public long readSizedLong(int bytes) {
int o = offset;
byte[] buf = dexBuf.buf;
long result;
switch (bytes) {
case 8:
result = (buf[o] & 0xff) |
((buf[o+1] & 0xff) << 8) |
((buf[o+2] & 0xff) << 16) |
((buf[o+3] & 0xffL) << 24) |
((buf[o+4] & 0xffL) << 32) |
((buf[o+5] & 0xffL) << 40) |
((buf[o+6] & 0xffL) << 48) |
(((long)buf[o+7]) << 56);
break;
case 7:
result = (buf[o] & 0xff) |
((buf[o+1] & 0xff) << 8) |
((buf[o+2] & 0xff) << 16) |
((buf[o+3] & 0xffL) << 24) |
((buf[o+4] & 0xffL) << 32) |
((buf[o+5] & 0xffL) << 40) |
((long)(buf[o+6]) << 48);
break;
case 6:
result = (buf[o] & 0xff) |
((buf[o+1] & 0xff) << 8) |
((buf[o+2] & 0xff) << 16) |
((buf[o+3] & 0xffL) << 24) |
((buf[o+4] & 0xffL) << 32) |
((long)(buf[o+5]) << 40);
break;
case 5:
result = (buf[o] & 0xff) |
((buf[o+1] & 0xff) << 8) |
((buf[o+2] & 0xff) << 16) |
((buf[o+3] & 0xffL) << 24) |
((long)(buf[o+4]) << 32);
break;
case 4:
result = (buf[o] & 0xff) |
((buf[o+1] & 0xff) << 8) |
((buf[o+2] & 0xff) << 16) |
(((long)buf[o+3]) << 24);
break;
case 3:
result = (buf[o] & 0xff) |
((buf[o+1] & 0xff) << 8) |
(buf[o+2] << 16);
break;
case 2:
result = (buf[o] & 0xff) |
(buf[o+1] << 8);
break;
case 1:
result = buf[o];
break;
default:
throw new ExceptionWithContext("Invalid size %d for sized long at offset 0x%x", bytes, offset);
}
offset = o + bytes;
return result;
}
public String readString(int utf16Length) {
int[] ret = new int[1];
String value = Utf8Utils.utf8BytesWithUtf16LengthToString(dexBuf.buf, offset, utf16Length, ret);
offset += ret[0];
return value;
}
}