/*
* 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.apksig.apk;
import java.io.UnsupportedEncodingException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* XML pull style parser of Android binary XML resources, such as {@code AndroidManifest.xml}.
*
* <p>For an input document, the parser outputs an event stream (see {@code EVENT_... constants} via
* {@link #getEventType()} and {@link #next()} methods. Additional information about the current
* event can be obtained via an assortment of getters, for example, {@link #getName()} or
* {@link #getAttributeNameResourceId(int)}.
*/
class AndroidBinXmlParser {
/** Event: start of document. */
public static final int EVENT_START_DOCUMENT = 1;
/** Event: end of document. */
public static final int EVENT_END_DOCUMENT = 2;
/** Event: start of an element. */
public static final int EVENT_START_ELEMENT = 3;
/** Event: end of an document. */
public static final int EVENT_END_ELEMENT = 4;
/** Attribute value type is not supported by this parser. */
public static final int VALUE_TYPE_UNSUPPORTED = 0;
/** Attribute value is a string. Use {@link #getAttributeStringValue(int)} to obtain it. */
public static final int VALUE_TYPE_STRING = 1;
/** Attribute value is an integer. Use {@link #getAttributeIntValue(int)} to obtain it. */
public static final int VALUE_TYPE_INT = 2;
/**
* Attribute value is a resource reference. Use {@link #getAttributeIntValue(int)} to obtain it.
*/
public static final int VALUE_TYPE_REFERENCE = 3;
/** Attribute value is a boolean. Use {@link #getAttributeBooleanValue(int)} to obtain it. */
public static final int VALUE_TYPE_BOOLEAN = 4;
private static final long NO_NAMESPACE = 0xffffffffL;
private final ByteBuffer mXml;
private StringPool mStringPool;
private ResourceMap mResourceMap;
private int mDepth;
private int mCurrentEvent = EVENT_START_DOCUMENT;
private String mCurrentElementName;
private String mCurrentElementNamespace;
private int mCurrentElementAttributeCount;
private List<Attribute> mCurrentElementAttributes;
private ByteBuffer mCurrentElementAttributesContents;
private int mCurrentElementAttrSizeBytes;
/**
* Constructs a new parser for the provided document.
*/
public AndroidBinXmlParser(ByteBuffer xml) throws XmlParserException {
xml.order(ByteOrder.LITTLE_ENDIAN);
Chunk resXmlChunk = null;
while (xml.hasRemaining()) {
Chunk chunk = Chunk.get(xml);
if (chunk == null) {
break;
}
if (chunk.getType() == Chunk.TYPE_RES_XML) {
resXmlChunk = chunk;
break;
}
}
if (resXmlChunk == null) {
throw new XmlParserException("No XML chunk in file");
}
mXml = resXmlChunk.getContents();
}
/**
* Returns the depth of the current element. Outside of the root of the document the depth is
* {@code 0}. The depth is incremented by {@code 1} before each {@code start element} event and
* is decremented by {@code 1} after each {@code end element} event.
*/
public int getDepth() {
return mDepth;
}
/**
* Returns the type of the current event. See {@code EVENT_...} constants.
*/
public int getEventType() {
return mCurrentEvent;
}
/**
* Returns the local name of the current element or {@code null} if the current event does not
* pertain to an element.
*/
public String getName() {
if ((mCurrentEvent != EVENT_START_ELEMENT) && (mCurrentEvent != EVENT_END_ELEMENT)) {
return null;
}
return mCurrentElementName;
}
/**
* Returns the namespace of the current element or {@code null} if the current event does not
* pertain to an element. Returns an empty string if the element is not associated with a
* namespace.
*/
public String getNamespace() {
if ((mCurrentEvent != EVENT_START_ELEMENT) && (mCurrentEvent != EVENT_END_ELEMENT)) {
return null;
}
return mCurrentElementNamespace;
}
/**
* Returns the number of attributes of the element associated with the current event or
* {@code -1} if no element is associated with the current event.
*/
public int getAttributeCount() {
if (mCurrentEvent != EVENT_START_ELEMENT) {
return -1;
}
return mCurrentElementAttributeCount;
}
/**
* Returns the resource ID corresponding to the name of the specified attribute of the current
* element or {@code 0} if the name is not associated with a resource ID.
*
* @throws IndexOutOfBoundsException if the index is out of range or the current event is not a
* {@code start element} event
* @throws XmlParserException if a parsing error is occurred
*/
public int getAttributeNameResourceId(int index) throws XmlParserException {
return getAttribute(index).getNameResourceId();
}
/**
* Returns the value type of the specified attribute of the current element. See
* {@code VALUE_TYPE_...} constants.
*
* @throws IndexOutOfBoundsException if the index is out of range or the current event is not a
* {@code start element} event
* @throws XmlParserException if a parsing error is occurred
*/
public int getAttributeValueType(int index) throws XmlParserException {
int type = getAttribute(index).getValueType();
switch (type) {
case Attribute.TYPE_STRING:
return VALUE_TYPE_STRING;
case Attribute.TYPE_INT_DEC:
case Attribute.TYPE_INT_HEX:
case Attribute.TYPE_REFERENCE:
return VALUE_TYPE_INT;
case Attribute.TYPE_INT_BOOLEAN:
return VALUE_TYPE_BOOLEAN;
default:
return VALUE_TYPE_UNSUPPORTED;
}
}
/**
* Returns the integer value of the specified attribute of the current element. See
* {@code VALUE_TYPE_...} constants.
*
* @throws IndexOutOfBoundsException if the index is out of range or the current event is not a
* {@code start element} event.
* @throws XmlParserException if a parsing error is occurred
*/
public int getAttributeIntValue(int index) throws XmlParserException {
return getAttribute(index).getIntValue();
}
/**
* Returns the boolean value of the specified attribute of the current element. See
* {@code VALUE_TYPE_...} constants.
*
* @throws IndexOutOfBoundsException if the index is out of range or the current event is not a
* {@code start element} event.
* @throws XmlParserException if a parsing error is occurred
*/
public boolean getAttributeBooleanValue(int index) throws XmlParserException {
return getAttribute(index).getBooleanValue();
}
/**
* Returns the string value of the specified attribute of the current element. See
* {@code VALUE_TYPE_...} constants.
*
* @throws IndexOutOfBoundsException if the index is out of range or the current event is not a
* {@code start element} event.
* @throws XmlParserException if a parsing error is occurred
*/
public String getAttributeStringValue(int index) throws XmlParserException {
return getAttribute(index).getStringValue();
}
private Attribute getAttribute(int index) {
if (mCurrentEvent != EVENT_START_ELEMENT) {
throw new IndexOutOfBoundsException("Current event not a START_ELEMENT");
}
if (index < 0) {
throw new IndexOutOfBoundsException("index must be >= 0");
}
if (index >= mCurrentElementAttributeCount) {
throw new IndexOutOfBoundsException(
"index must be <= attr count (" + mCurrentElementAttributeCount + ")");
}
parseCurrentElementAttributesIfNotParsed();
return mCurrentElementAttributes.get(index);
}
/**
* Advances to the next parsing event and returns its type. See {@code EVENT_...} constants.
*/
public int next() throws XmlParserException {
// Decrement depth if the previous event was "end element".
if (mCurrentEvent == EVENT_END_ELEMENT) {
mDepth--;
}
// Read events from document, ignoring events that we don't report to caller. Stop at the
// earliest event which we report to caller.
while (mXml.hasRemaining()) {
Chunk chunk = Chunk.get(mXml);
if (chunk == null) {
break;
}
switch (chunk.getType()) {
case Chunk.TYPE_STRING_POOL:
if (mStringPool != null) {
throw new XmlParserException("Multiple string pools not supported");
}
mStringPool = new StringPool(chunk);
break;
case Chunk.RES_XML_TYPE_START_ELEMENT:
{
if (mStringPool == null) {
throw new XmlParserException(
"Named element encountered before string pool");
}
ByteBuffer contents = chunk.getContents();
if (contents.remaining() < 20) {
throw new XmlParserException(
"Start element chunk too short. Need at least 20 bytes. Available: "
+ contents.remaining() + " bytes");
}
long nsId = getUnsignedInt32(contents);
long nameId = getUnsignedInt32(contents);
int attrStartOffset = getUnsignedInt16(contents);
int attrSizeBytes = getUnsignedInt16(contents);
int attrCount = getUnsignedInt16(contents);
long attrEndOffset = attrStartOffset + ((long) attrCount) * attrSizeBytes;
contents.position(0);
if (attrStartOffset > contents.remaining()) {
throw new XmlParserException(
"Attributes start offset out of bounds: " + attrStartOffset
+ ", max: " + contents.remaining());
}
if (attrEndOffset > contents.remaining()) {
throw new XmlParserException(
"Attributes end offset out of bounds: " + attrEndOffset
+ ", max: " + contents.remaining());
}
mCurrentElementName = mStringPool.getString(nameId);
mCurrentElementNamespace =
(nsId == NO_NAMESPACE) ? "" : mStringPool.getString(nsId);
mCurrentElementAttributeCount = attrCount;
mCurrentElementAttributes = null;
mCurrentElementAttrSizeBytes = attrSizeBytes;
mCurrentElementAttributesContents =
sliceFromTo(contents, attrStartOffset, attrEndOffset);
mDepth++;
mCurrentEvent = EVENT_START_ELEMENT;
return mCurrentEvent;
}
case Chunk.RES_XML_TYPE_END_ELEMENT:
{
if (mStringPool == null) {
throw new XmlParserException(
"Named element encountered before string pool");
}
ByteBuffer contents = chunk.getContents();
if (contents.remaining() < 8) {
throw new XmlParserException(
"End element chunk too short. Need at least 8 bytes. Available: "
+ contents.remaining() + " bytes");
}
long nsId = getUnsignedInt32(contents);
long nameId = getUnsignedInt32(contents);
mCurrentElementName = mStringPool.getString(nameId);
mCurrentElementNamespace =
(nsId == NO_NAMESPACE) ? "" : mStringPool.getString(nsId);
mCurrentEvent = EVENT_END_ELEMENT;
mCurrentElementAttributes = null;
mCurrentElementAttributesContents = null;
return mCurrentEvent;
}
case Chunk.RES_XML_TYPE_RESOURCE_MAP:
if (mResourceMap != null) {
throw new XmlParserException("Multiple resource maps not supported");
}
mResourceMap = new ResourceMap(chunk);
break;
}
}
mCurrentEvent = EVENT_END_DOCUMENT;
return mCurrentEvent;
}
private void parseCurrentElementAttributesIfNotParsed() {
if (mCurrentElementAttributes != null) {
return;
}
mCurrentElementAttributes = new ArrayList<>(mCurrentElementAttributeCount);
for (int i = 0; i < mCurrentElementAttributeCount; i++) {
int startPosition = i * mCurrentElementAttrSizeBytes;
ByteBuffer attr =
sliceFromTo(
mCurrentElementAttributesContents,
startPosition,
startPosition + mCurrentElementAttrSizeBytes);
@SuppressWarnings("unused")
long nsId = getUnsignedInt32(attr);
long nameId = getUnsignedInt32(attr);
attr.position(attr.position() + 7); // skip ignored fields
int valueType = getUnsignedInt8(attr);
long valueData = getUnsignedInt32(attr);
mCurrentElementAttributes.add(
new Attribute(
nameId,
valueType,
(int) valueData,
mStringPool,
mResourceMap));
}
}
private static class Attribute {
private static final int TYPE_REFERENCE = 1;
private static final int TYPE_STRING = 3;
private static final int TYPE_INT_DEC = 0x10;
private static final int TYPE_INT_HEX = 0x11;
private static final int TYPE_INT_BOOLEAN = 0x12;
private final long mNameId;
private final int mValueType;
private final int mValueData;
private final StringPool mStringPool;
private final ResourceMap mResourceMap;
private Attribute(
long nameId,
int valueType,
int valueData,
StringPool stringPool,
ResourceMap resourceMap) {
mNameId = nameId;
mValueType = valueType;
mValueData = valueData;
mStringPool = stringPool;
mResourceMap = resourceMap;
}
public int getNameResourceId() {
return (mResourceMap != null) ? mResourceMap.getResourceId(mNameId) : 0;
}
public int getValueType() {
return mValueType;
}
public int getIntValue() throws XmlParserException {
switch (mValueType) {
case TYPE_REFERENCE:
case TYPE_INT_DEC:
case TYPE_INT_HEX:
case TYPE_INT_BOOLEAN:
return mValueData;
default:
throw new XmlParserException("Cannot coerce to int: value type " + mValueType);
}
}
public boolean getBooleanValue() throws XmlParserException {
switch (mValueType) {
case TYPE_INT_BOOLEAN:
return mValueData != 0;
default:
throw new XmlParserException(
"Cannot coerce to boolean: value type " + mValueType);
}
}
public String getStringValue() throws XmlParserException {
switch (mValueType) {
case TYPE_STRING:
return mStringPool.getString(mValueData & 0xffffffffL);
case TYPE_INT_DEC:
return Integer.toString(mValueData);
case TYPE_INT_HEX:
return "0x" + Integer.toHexString(mValueData);
case TYPE_INT_BOOLEAN:
return Boolean.toString(mValueData != 0);
case TYPE_REFERENCE:
return "@" + Integer.toHexString(mValueData);
default:
throw new XmlParserException(
"Cannot coerce to string: value type " + mValueType);
}
}
}
/**
* Chunk of a document. Each chunk is tagged with a type and consists of a header followed by
* contents.
*/
private static class Chunk {
public static final int TYPE_STRING_POOL = 1;
public static final int TYPE_RES_XML = 3;
public static final int RES_XML_TYPE_START_ELEMENT = 0x0102;
public static final int RES_XML_TYPE_END_ELEMENT = 0x0103;
public static final int RES_XML_TYPE_RESOURCE_MAP = 0x0180;
static final int HEADER_MIN_SIZE_BYTES = 8;
private final int mType;
private final ByteBuffer mHeader;
private final ByteBuffer mContents;
public Chunk(int type, ByteBuffer header, ByteBuffer contents) {
mType = type;
mHeader = header;
mContents = contents;
}
public ByteBuffer getContents() {
ByteBuffer result = mContents.slice();
result.order(mContents.order());
return result;
}
public ByteBuffer getHeader() {
ByteBuffer result = mHeader.slice();
result.order(mHeader.order());
return result;
}
public int getType() {
return mType;
}
/**
* Consumes the chunk located at the current position of the input and returns the chunk
* or {@code null} if there is no chunk left in the input.
*
* @throws XmlParserException if the chunk is malformed
*/
public static Chunk get(ByteBuffer input) throws XmlParserException {
if (input.remaining() < HEADER_MIN_SIZE_BYTES) {
// Android ignores the last chunk if its header is too big to fit into the file
input.position(input.limit());
return null;
}
int originalPosition = input.position();
int type = getUnsignedInt16(input);
int headerSize = getUnsignedInt16(input);
long chunkSize = getUnsignedInt32(input);
long chunkRemaining = chunkSize - 8;
if (chunkRemaining > input.remaining()) {
// Android ignores the last chunk if it's too big to fit into the file
input.position(input.limit());
return null;
}
if (headerSize < HEADER_MIN_SIZE_BYTES) {
throw new XmlParserException(
"Malformed chunk: header too short: " + headerSize + " bytes");
} else if (headerSize > chunkSize) {
throw new XmlParserException(
"Malformed chunk: header too long: " + headerSize + " bytes. Chunk size: "
+ chunkSize + " bytes");
}
int contentStartPosition = originalPosition + headerSize;
long chunkEndPosition = originalPosition + chunkSize;
Chunk chunk =
new Chunk(
type,
sliceFromTo(input, originalPosition, contentStartPosition),
sliceFromTo(input, contentStartPosition, chunkEndPosition));
input.position((int) chunkEndPosition);
return chunk;
}
}
/**
* String pool of a document. Strings are referenced by their {@code 0}-based index in the pool.
*/
private static class StringPool {
private static final int FLAG_UTF8 = 1 << 8;
private final ByteBuffer mChunkContents;
private final ByteBuffer mStringsSection;
private final int mStringCount;
private final boolean mUtf8Encoded;
private final Map<Integer, String> mCachedStrings = new HashMap<>();
/**
* Constructs a new string pool from the provided chunk.
*
* @throws XmlParserException if a parsing error occurred
*/
public StringPool(Chunk chunk) throws XmlParserException {
ByteBuffer header = chunk.getHeader();
int headerSizeBytes = header.remaining();
header.position(Chunk.HEADER_MIN_SIZE_BYTES);
if (header.remaining() < 20) {
throw new XmlParserException(
"XML chunk's header too short. Required at least 20 bytes. Available: "
+ header.remaining() + " bytes");
}
long stringCount = getUnsignedInt32(header);
if (stringCount > Integer.MAX_VALUE) {
throw new XmlParserException("Too many strings: " + stringCount);
}
mStringCount = (int) stringCount;
long styleCount = getUnsignedInt32(header);
if (styleCount > Integer.MAX_VALUE) {
throw new XmlParserException("Too many styles: " + styleCount);
}
long flags = getUnsignedInt32(header);
long stringsStartOffset = getUnsignedInt32(header);
long stylesStartOffset = getUnsignedInt32(header);
ByteBuffer contents = chunk.getContents();
if (mStringCount > 0) {
int stringsSectionStartOffsetInContents =
(int) (stringsStartOffset - headerSizeBytes);
int stringsSectionEndOffsetInContents;
if (styleCount > 0) {
// Styles section follows the strings section
if (stylesStartOffset < stringsStartOffset) {
throw new XmlParserException(
"Styles offset (" + stylesStartOffset + ") < strings offset ("
+ stringsStartOffset + ")");
}
stringsSectionEndOffsetInContents = (int) (stylesStartOffset - headerSizeBytes);
} else {
stringsSectionEndOffsetInContents = contents.remaining();
}
mStringsSection =
sliceFromTo(
contents,
stringsSectionStartOffsetInContents,
stringsSectionEndOffsetInContents);
} else {
mStringsSection = ByteBuffer.allocate(0);
}
mUtf8Encoded = (flags & FLAG_UTF8) != 0;
mChunkContents = contents;
}
/**
* Returns the string located at the specified {@code 0}-based index in this pool.
*
* @throws XmlParserException if the string does not exist or cannot be decoded
*/
public String getString(long index) throws XmlParserException {
if (index < 0) {
throw new XmlParserException("Unsuported string index: " + index);
} else if (index >= mStringCount) {
throw new XmlParserException(
"Unsuported string index: " + index + ", max: " + (mStringCount - 1));
}
int idx = (int) index;
String result = mCachedStrings.get(idx);
if (result != null) {
return result;
}
long offsetInStringsSection = getUnsignedInt32(mChunkContents, idx * 4);
if (offsetInStringsSection >= mStringsSection.capacity()) {
throw new XmlParserException(
"Offset of string idx " + idx + " out of bounds: " + offsetInStringsSection
+ ", max: " + (mStringsSection.capacity() - 1));
}
mStringsSection.position((int) offsetInStringsSection);
result =
(mUtf8Encoded)
? getLengthPrefixedUtf8EncodedString(mStringsSection)
: getLengthPrefixedUtf16EncodedString(mStringsSection);
mCachedStrings.put(idx, result);
return result;
}
private static String getLengthPrefixedUtf16EncodedString(ByteBuffer encoded)
throws XmlParserException {
// If the length (in uint16s) is 0x7fff or lower, it is stored as a single uint16.
// Otherwise, it is stored as a big-endian uint32 with highest bit set. Thus, the range
// of supported values is 0 to 0x7fffffff inclusive.
int lengthChars = getUnsignedInt16(encoded);
if ((lengthChars & 0x8000) != 0) {
lengthChars = ((lengthChars & 0x7fff) << 16) | getUnsignedInt16(encoded);
}
if (lengthChars > Integer.MAX_VALUE / 2) {
throw new XmlParserException("String too long: " + lengthChars + " uint16s");
}
int lengthBytes = lengthChars * 2;
byte[] arr;
int arrOffset;
if (encoded.hasArray()) {
arr = encoded.array();
arrOffset = encoded.arrayOffset() + encoded.position();
encoded.position(encoded.position() + lengthBytes);
} else {
arr = new byte[lengthBytes];
arrOffset = 0;
encoded.get(arr);
}
// Reproduce the behavior of Android runtime which requires that the UTF-16 encoded
// array of bytes is NULL terminated.
if ((arr[arrOffset + lengthBytes] != 0)
|| (arr[arrOffset + lengthBytes + 1] != 0)) {
throw new XmlParserException("UTF-16 encoded form of string not NULL terminated");
}
try {
return new String(arr, arrOffset, lengthBytes, "UTF-16LE");
} catch (UnsupportedEncodingException e) {
throw new RuntimeException("UTF-16LE character encoding not supported", e);
}
}
private static String getLengthPrefixedUtf8EncodedString(ByteBuffer encoded)
throws XmlParserException {
// If the length (in bytes) is 0x7f or lower, it is stored as a single uint8. Otherwise,
// it is stored as a big-endian uint16 with highest bit set. Thus, the range of
// supported values is 0 to 0x7fff inclusive.
// Skip UTF-16 encoded length (in uint16s)
int lengthBytes = getUnsignedInt8(encoded);
if ((lengthBytes & 0x80) != 0) {
lengthBytes = ((lengthBytes & 0x7f) << 8) | getUnsignedInt8(encoded);
}
// Read UTF-8 encoded length (in bytes)
lengthBytes = getUnsignedInt8(encoded);
if ((lengthBytes & 0x80) != 0) {
lengthBytes = ((lengthBytes & 0x7f) << 8) | getUnsignedInt8(encoded);
}
byte[] arr;
int arrOffset;
if (encoded.hasArray()) {
arr = encoded.array();
arrOffset = encoded.arrayOffset() + encoded.position();
encoded.position(encoded.position() + lengthBytes);
} else {
arr = new byte[lengthBytes];
arrOffset = 0;
encoded.get(arr);
}
// Reproduce the behavior of Android runtime which requires that the UTF-8 encoded array
// of bytes is NULL terminated.
if (arr[arrOffset + lengthBytes] != 0) {
throw new XmlParserException("UTF-8 encoded form of string not NULL terminated");
}
try {
return new String(arr, arrOffset, lengthBytes, "UTF-8");
} catch (UnsupportedEncodingException e) {
throw new RuntimeException("UTF-8 character encoding not supported", e);
}
}
}
/**
* Resource map of a document. Resource IDs are referenced by their {@code 0}-based index in the
* map.
*/
private static class ResourceMap {
private final ByteBuffer mChunkContents;
private final int mEntryCount;
/**
* Constructs a new resource map from the provided chunk.
*
* @throws XmlParserException if a parsing error occurred
*/
public ResourceMap(Chunk chunk) throws XmlParserException {
mChunkContents = chunk.getContents().slice();
mChunkContents.order(chunk.getContents().order());
// Each entry of the map is four bytes long, containing the int32 resource ID.
mEntryCount = mChunkContents.remaining() / 4;
}
/**
* Returns the resource ID located at the specified {@code 0}-based index in this pool or
* {@code 0} if the index is out of range.
*/
public int getResourceId(long index) {
if ((index < 0) || (index >= mEntryCount)) {
return 0;
}
int idx = (int) index;
// Each entry of the map is four bytes long, containing the int32 resource ID.
return mChunkContents.getInt(idx * 4);
}
}
/**
* Returns new byte buffer whose content is a shared subsequence of this buffer's content
* between the specified start (inclusive) and end (exclusive) positions. As opposed to
* {@link ByteBuffer#slice()}, the returned buffer's byte order is the same as the source
* buffer's byte order.
*/
private static ByteBuffer sliceFromTo(ByteBuffer source, long start, long end) {
if (start < 0) {
throw new IllegalArgumentException("start: " + start);
}
if (end < start) {
throw new IllegalArgumentException("end < start: " + end + " < " + start);
}
int capacity = source.capacity();
if (end > source.capacity()) {
throw new IllegalArgumentException("end > capacity: " + end + " > " + capacity);
}
return sliceFromTo(source, (int) start, (int) end);
}
/**
* Returns new byte buffer whose content is a shared subsequence of this buffer's content
* between the specified start (inclusive) and end (exclusive) positions. As opposed to
* {@link ByteBuffer#slice()}, the returned buffer's byte order is the same as the source
* buffer's byte order.
*/
private static ByteBuffer sliceFromTo(ByteBuffer source, int start, int end) {
if (start < 0) {
throw new IllegalArgumentException("start: " + start);
}
if (end < start) {
throw new IllegalArgumentException("end < start: " + end + " < " + start);
}
int capacity = source.capacity();
if (end > source.capacity()) {
throw new IllegalArgumentException("end > capacity: " + end + " > " + capacity);
}
int originalLimit = source.limit();
int originalPosition = source.position();
try {
source.position(0);
source.limit(end);
source.position(start);
ByteBuffer result = source.slice();
result.order(source.order());
return result;
} finally {
source.position(0);
source.limit(originalLimit);
source.position(originalPosition);
}
}
private static int getUnsignedInt8(ByteBuffer buffer) {
return buffer.get() & 0xff;
}
private static int getUnsignedInt16(ByteBuffer buffer) {
return buffer.getShort() & 0xffff;
}
private static long getUnsignedInt32(ByteBuffer buffer) {
return buffer.getInt() & 0xffffffffL;
}
private static long getUnsignedInt32(ByteBuffer buffer, int position) {
return buffer.getInt(position) & 0xffffffffL;
}
/**
* Indicates that an error occurred while parsing a document.
*/
static class XmlParserException extends Exception {
private static final long serialVersionUID = 1L;
public XmlParserException(String message) {
super(message);
}
public XmlParserException(String message, Throwable cause) {
super(message, cause);
}
}
}