// Protocol Buffers - Google's data interchange format
// Copyright 2013 Google Inc. All rights reserved.
// https://developers.google.com/protocol-buffers/
//
// 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
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
package com.google.protobuf.nano;
import java.io.IOException;
/**
* Reads and decodes protocol message fields.
*
* This class contains two kinds of methods: methods that read specific
* protocol message constructs and field types (e.g. {@link #readTag()} and
* {@link #readInt32()}) and methods that read low-level values (e.g.
* {@link #readRawVarint32()} and {@link #readRawBytes}). If you are reading
* encoded protocol messages, you should use the former methods, but if you are
* reading some other format of your own design, use the latter.
*
* @author kenton@google.com Kenton Varda
*/
public final class CodedInputByteBufferNano {
/**
* Create a new CodedInputStream wrapping the given byte array.
*/
public static CodedInputByteBufferNano newInstance(final byte[] buf) {
return newInstance(buf, 0, buf.length);
}
/**
* Create a new CodedInputStream wrapping the given byte array slice.
*/
public static CodedInputByteBufferNano newInstance(final byte[] buf, final int off,
final int len) {
return new CodedInputByteBufferNano(buf, off, len);
}
// -----------------------------------------------------------------
/**
* Attempt to read a field tag, returning zero if we have reached EOF.
* Protocol message parsers use this to read tags, since a protocol message
* may legally end wherever a tag occurs, and zero is not a valid tag number.
*/
public int readTag() throws IOException {
if (isAtEnd()) {
lastTag = 0;
return 0;
}
lastTag = readRawVarint32();
if (lastTag == 0) {
// If we actually read zero, that's not a valid tag.
throw InvalidProtocolBufferNanoException.invalidTag();
}
return lastTag;
}
/**
* Verifies that the last call to readTag() returned the given tag value.
* This is used to verify that a nested group ended with the correct
* end tag.
*
* @throws InvalidProtocolBufferNanoException {@code value} does not match the
* last tag.
*/
public void checkLastTagWas(final int value)
throws InvalidProtocolBufferNanoException {
if (lastTag != value) {
throw InvalidProtocolBufferNanoException.invalidEndTag();
}
}
/**
* Reads and discards a single field, given its tag value.
*
* @return {@code false} if the tag is an endgroup tag, in which case
* nothing is skipped. Otherwise, returns {@code true}.
*/
public boolean skipField(final int tag) throws IOException {
switch (WireFormatNano.getTagWireType(tag)) {
case WireFormatNano.WIRETYPE_VARINT:
readInt32();
return true;
case WireFormatNano.WIRETYPE_FIXED64:
readRawLittleEndian64();
return true;
case WireFormatNano.WIRETYPE_LENGTH_DELIMITED:
skipRawBytes(readRawVarint32());
return true;
case WireFormatNano.WIRETYPE_START_GROUP:
skipMessage();
checkLastTagWas(
WireFormatNano.makeTag(WireFormatNano.getTagFieldNumber(tag),
WireFormatNano.WIRETYPE_END_GROUP));
return true;
case WireFormatNano.WIRETYPE_END_GROUP:
return false;
case WireFormatNano.WIRETYPE_FIXED32:
readRawLittleEndian32();
return true;
default:
throw InvalidProtocolBufferNanoException.invalidWireType();
}
}
/**
* Reads and discards an entire message. This will read either until EOF
* or until an endgroup tag, whichever comes first.
*/
public void skipMessage() throws IOException {
while (true) {
final int tag = readTag();
if (tag == 0 || !skipField(tag)) {
return;
}
}
}
// -----------------------------------------------------------------
/** Read a {@code double} field value from the stream. */
public double readDouble() throws IOException {
return Double.longBitsToDouble(readRawLittleEndian64());
}
/** Read a {@code float} field value from the stream. */
public float readFloat() throws IOException {
return Float.intBitsToFloat(readRawLittleEndian32());
}
/** Read a {@code uint64} field value from the stream. */
public long readUInt64() throws IOException {
return readRawVarint64();
}
/** Read an {@code int64} field value from the stream. */
public long readInt64() throws IOException {
return readRawVarint64();
}
/** Read an {@code int32} field value from the stream. */
public int readInt32() throws IOException {
return readRawVarint32();
}
/** Read a {@code fixed64} field value from the stream. */
public long readFixed64() throws IOException {
return readRawLittleEndian64();
}
/** Read a {@code fixed32} field value from the stream. */
public int readFixed32() throws IOException {
return readRawLittleEndian32();
}
/** Read a {@code bool} field value from the stream. */
public boolean readBool() throws IOException {
return readRawVarint32() != 0;
}
/** Read a {@code string} field value from the stream. */
public String readString() throws IOException {
final int size = readRawVarint32();
if (size <= (bufferSize - bufferPos) && size > 0) {
// Fast path: We already have the bytes in a contiguous buffer, so
// just copy directly from it.
final String result = new String(buffer, bufferPos, size, InternalNano.UTF_8);
bufferPos += size;
return result;
} else {
// Slow path: Build a byte array first then copy it.
return new String(readRawBytes(size), InternalNano.UTF_8);
}
}
/** Read a {@code group} field value from the stream. */
public void readGroup(final MessageNano msg, final int fieldNumber)
throws IOException {
if (recursionDepth >= recursionLimit) {
throw InvalidProtocolBufferNanoException.recursionLimitExceeded();
}
++recursionDepth;
msg.mergeFrom(this);
checkLastTagWas(
WireFormatNano.makeTag(fieldNumber, WireFormatNano.WIRETYPE_END_GROUP));
--recursionDepth;
}
public void readMessage(final MessageNano msg)
throws IOException {
final int length = readRawVarint32();
if (recursionDepth >= recursionLimit) {
throw InvalidProtocolBufferNanoException.recursionLimitExceeded();
}
final int oldLimit = pushLimit(length);
++recursionDepth;
msg.mergeFrom(this);
checkLastTagWas(0);
--recursionDepth;
popLimit(oldLimit);
}
/** Read a {@code bytes} field value from the stream. */
public byte[] readBytes() throws IOException {
final int size = readRawVarint32();
if (size <= (bufferSize - bufferPos) && size > 0) {
// Fast path: We already have the bytes in a contiguous buffer, so
// just copy directly from it.
final byte[] result = new byte[size];
System.arraycopy(buffer, bufferPos, result, 0, size);
bufferPos += size;
return result;
} else if (size == 0) {
return WireFormatNano.EMPTY_BYTES;
} else {
// Slow path: Build a byte array first then copy it.
return readRawBytes(size);
}
}
/** Read a {@code uint32} field value from the stream. */
public int readUInt32() throws IOException {
return readRawVarint32();
}
/**
* Read an enum field value from the stream. Caller is responsible
* for converting the numeric value to an actual enum.
*/
public int readEnum() throws IOException {
return readRawVarint32();
}
/** Read an {@code sfixed32} field value from the stream. */
public int readSFixed32() throws IOException {
return readRawLittleEndian32();
}
/** Read an {@code sfixed64} field value from the stream. */
public long readSFixed64() throws IOException {
return readRawLittleEndian64();
}
/** Read an {@code sint32} field value from the stream. */
public int readSInt32() throws IOException {
return decodeZigZag32(readRawVarint32());
}
/** Read an {@code sint64} field value from the stream. */
public long readSInt64() throws IOException {
return decodeZigZag64(readRawVarint64());
}
// =================================================================
/**
* Read a raw Varint from the stream. If larger than 32 bits, discard the
* upper bits.
*/
public int readRawVarint32() throws IOException {
byte tmp = readRawByte();
if (tmp >= 0) {
return tmp;
}
int result = tmp & 0x7f;
if ((tmp = readRawByte()) >= 0) {
result |= tmp << 7;
} else {
result |= (tmp & 0x7f) << 7;
if ((tmp = readRawByte()) >= 0) {
result |= tmp << 14;
} else {
result |= (tmp & 0x7f) << 14;
if ((tmp = readRawByte()) >= 0) {
result |= tmp << 21;
} else {
result |= (tmp & 0x7f) << 21;
result |= (tmp = readRawByte()) << 28;
if (tmp < 0) {
// Discard upper 32 bits.
for (int i = 0; i < 5; i++) {
if (readRawByte() >= 0) {
return result;
}
}
throw InvalidProtocolBufferNanoException.malformedVarint();
}
}
}
}
return result;
}
/** Read a raw Varint from the stream. */
public long readRawVarint64() throws IOException {
int shift = 0;
long result = 0;
while (shift < 64) {
final byte b = readRawByte();
result |= (long)(b & 0x7F) << shift;
if ((b & 0x80) == 0) {
return result;
}
shift += 7;
}
throw InvalidProtocolBufferNanoException.malformedVarint();
}
/** Read a 32-bit little-endian integer from the stream. */
public int readRawLittleEndian32() throws IOException {
final byte b1 = readRawByte();
final byte b2 = readRawByte();
final byte b3 = readRawByte();
final byte b4 = readRawByte();
return ((b1 & 0xff) ) |
((b2 & 0xff) << 8) |
((b3 & 0xff) << 16) |
((b4 & 0xff) << 24);
}
/** Read a 64-bit little-endian integer from the stream. */
public long readRawLittleEndian64() throws IOException {
final byte b1 = readRawByte();
final byte b2 = readRawByte();
final byte b3 = readRawByte();
final byte b4 = readRawByte();
final byte b5 = readRawByte();
final byte b6 = readRawByte();
final byte b7 = readRawByte();
final byte b8 = readRawByte();
return (((long)b1 & 0xff) ) |
(((long)b2 & 0xff) << 8) |
(((long)b3 & 0xff) << 16) |
(((long)b4 & 0xff) << 24) |
(((long)b5 & 0xff) << 32) |
(((long)b6 & 0xff) << 40) |
(((long)b7 & 0xff) << 48) |
(((long)b8 & 0xff) << 56);
}
/**
* Decode a ZigZag-encoded 32-bit value. ZigZag encodes signed integers
* into values that can be efficiently encoded with varint. (Otherwise,
* negative values must be sign-extended to 64 bits to be varint encoded,
* thus always taking 10 bytes on the wire.)
*
* @param n An unsigned 32-bit integer, stored in a signed int because
* Java has no explicit unsigned support.
* @return A signed 32-bit integer.
*/
public static int decodeZigZag32(final int n) {
return (n >>> 1) ^ -(n & 1);
}
/**
* Decode a ZigZag-encoded 64-bit value. ZigZag encodes signed integers
* into values that can be efficiently encoded with varint. (Otherwise,
* negative values must be sign-extended to 64 bits to be varint encoded,
* thus always taking 10 bytes on the wire.)
*
* @param n An unsigned 64-bit integer, stored in a signed int because
* Java has no explicit unsigned support.
* @return A signed 64-bit integer.
*/
public static long decodeZigZag64(final long n) {
return (n >>> 1) ^ -(n & 1);
}
// -----------------------------------------------------------------
private final byte[] buffer;
private int bufferStart;
private int bufferSize;
private int bufferSizeAfterLimit;
private int bufferPos;
private int lastTag;
/** The absolute position of the end of the current message. */
private int currentLimit = Integer.MAX_VALUE;
/** See setRecursionLimit() */
private int recursionDepth;
private int recursionLimit = DEFAULT_RECURSION_LIMIT;
/** See setSizeLimit() */
private int sizeLimit = DEFAULT_SIZE_LIMIT;
private static final int DEFAULT_RECURSION_LIMIT = 64;
private static final int DEFAULT_SIZE_LIMIT = 64 << 20; // 64MB
private CodedInputByteBufferNano(final byte[] buffer, final int off, final int len) {
this.buffer = buffer;
bufferStart = off;
bufferSize = off + len;
bufferPos = off;
}
/**
* Set the maximum message recursion depth. In order to prevent malicious
* messages from causing stack overflows, {@code CodedInputStream} limits
* how deeply messages may be nested. The default limit is 64.
*
* @return the old limit.
*/
public int setRecursionLimit(final int limit) {
if (limit < 0) {
throw new IllegalArgumentException(
"Recursion limit cannot be negative: " + limit);
}
final int oldLimit = recursionLimit;
recursionLimit = limit;
return oldLimit;
}
/**
* Set the maximum message size. In order to prevent malicious
* messages from exhausting memory or causing integer overflows,
* {@code CodedInputStream} limits how large a message may be.
* The default limit is 64MB. You should set this limit as small
* as you can without harming your app's functionality. Note that
* size limits only apply when reading from an {@code InputStream}, not
* when constructed around a raw byte array.
* <p>
* If you want to read several messages from a single CodedInputStream, you
* could call {@link #resetSizeCounter()} after each one to avoid hitting the
* size limit.
*
* @return the old limit.
*/
public int setSizeLimit(final int limit) {
if (limit < 0) {
throw new IllegalArgumentException(
"Size limit cannot be negative: " + limit);
}
final int oldLimit = sizeLimit;
sizeLimit = limit;
return oldLimit;
}
/**
* Resets the current size counter to zero (see {@link #setSizeLimit(int)}).
*/
public void resetSizeCounter() {
}
/**
* Sets {@code currentLimit} to (current position) + {@code byteLimit}. This
* is called when descending into a length-delimited embedded message.
*
* @return the old limit.
*/
public int pushLimit(int byteLimit) throws InvalidProtocolBufferNanoException {
if (byteLimit < 0) {
throw InvalidProtocolBufferNanoException.negativeSize();
}
byteLimit += bufferPos;
final int oldLimit = currentLimit;
if (byteLimit > oldLimit) {
throw InvalidProtocolBufferNanoException.truncatedMessage();
}
currentLimit = byteLimit;
recomputeBufferSizeAfterLimit();
return oldLimit;
}
private void recomputeBufferSizeAfterLimit() {
bufferSize += bufferSizeAfterLimit;
final int bufferEnd = bufferSize;
if (bufferEnd > currentLimit) {
// Limit is in current buffer.
bufferSizeAfterLimit = bufferEnd - currentLimit;
bufferSize -= bufferSizeAfterLimit;
} else {
bufferSizeAfterLimit = 0;
}
}
/**
* Discards the current limit, returning to the previous limit.
*
* @param oldLimit The old limit, as returned by {@code pushLimit}.
*/
public void popLimit(final int oldLimit) {
currentLimit = oldLimit;
recomputeBufferSizeAfterLimit();
}
/**
* Returns the number of bytes to be read before the current limit.
* If no limit is set, returns -1.
*/
public int getBytesUntilLimit() {
if (currentLimit == Integer.MAX_VALUE) {
return -1;
}
final int currentAbsolutePosition = bufferPos;
return currentLimit - currentAbsolutePosition;
}
/**
* Returns true if the stream has reached the end of the input. This is the
* case if either the end of the underlying input source has been reached or
* if the stream has reached a limit created using {@link #pushLimit(int)}.
*/
public boolean isAtEnd() {
return bufferPos == bufferSize;
}
/**
* Get current position in buffer relative to beginning offset.
*/
public int getPosition() {
return bufferPos - bufferStart;
}
/**
* Retrieves a subset of data in the buffer. The returned array is not backed by the original
* buffer array.
*
* @param offset the position (relative to the buffer start position) to start at.
* @param length the number of bytes to retrieve.
*/
public byte[] getData(int offset, int length) {
if (length == 0) {
return WireFormatNano.EMPTY_BYTES;
}
byte[] copy = new byte[length];
int start = bufferStart + offset;
System.arraycopy(buffer, start, copy, 0, length);
return copy;
}
/**
* Rewind to previous position. Cannot go forward.
*/
public void rewindToPosition(int position) {
if (position > bufferPos - bufferStart) {
throw new IllegalArgumentException(
"Position " + position + " is beyond current " + (bufferPos - bufferStart));
}
if (position < 0) {
throw new IllegalArgumentException("Bad position " + position);
}
bufferPos = bufferStart + position;
}
/**
* Read one byte from the input.
*
* @throws InvalidProtocolBufferNanoException The end of the stream or the current
* limit was reached.
*/
public byte readRawByte() throws IOException {
if (bufferPos == bufferSize) {
throw InvalidProtocolBufferNanoException.truncatedMessage();
}
return buffer[bufferPos++];
}
/**
* Read a fixed size of bytes from the input.
*
* @throws InvalidProtocolBufferNanoException The end of the stream or the current
* limit was reached.
*/
public byte[] readRawBytes(final int size) throws IOException {
if (size < 0) {
throw InvalidProtocolBufferNanoException.negativeSize();
}
if (bufferPos + size > currentLimit) {
// Read to the end of the stream anyway.
skipRawBytes(currentLimit - bufferPos);
// Then fail.
throw InvalidProtocolBufferNanoException.truncatedMessage();
}
if (size <= bufferSize - bufferPos) {
// We have all the bytes we need already.
final byte[] bytes = new byte[size];
System.arraycopy(buffer, bufferPos, bytes, 0, size);
bufferPos += size;
return bytes;
} else {
throw InvalidProtocolBufferNanoException.truncatedMessage();
}
}
/**
* Reads and discards {@code size} bytes.
*
* @throws InvalidProtocolBufferNanoException The end of the stream or the current
* limit was reached.
*/
public void skipRawBytes(final int size) throws IOException {
if (size < 0) {
throw InvalidProtocolBufferNanoException.negativeSize();
}
if (bufferPos + size > currentLimit) {
// Read to the end of the stream anyway.
skipRawBytes(currentLimit - bufferPos);
// Then fail.
throw InvalidProtocolBufferNanoException.truncatedMessage();
}
if (size <= bufferSize - bufferPos) {
// We have all the bytes we need already.
bufferPos += size;
} else {
throw InvalidProtocolBufferNanoException.truncatedMessage();
}
}
// Read a primitive type.
Object readPrimitiveField(int type) throws IOException {
switch (type) {
case InternalNano.TYPE_DOUBLE:
return readDouble();
case InternalNano.TYPE_FLOAT:
return readFloat();
case InternalNano.TYPE_INT64:
return readInt64();
case InternalNano.TYPE_UINT64:
return readUInt64();
case InternalNano.TYPE_INT32:
return readInt32();
case InternalNano.TYPE_FIXED64:
return readFixed64();
case InternalNano.TYPE_FIXED32:
return readFixed32();
case InternalNano.TYPE_BOOL:
return readBool();
case InternalNano.TYPE_STRING:
return readString();
case InternalNano.TYPE_BYTES:
return readBytes();
case InternalNano.TYPE_UINT32:
return readUInt32();
case InternalNano.TYPE_ENUM:
return readEnum();
case InternalNano.TYPE_SFIXED32:
return readSFixed32();
case InternalNano.TYPE_SFIXED64:
return readSFixed64();
case InternalNano.TYPE_SINT32:
return readSInt32();
case InternalNano.TYPE_SINT64:
return readSInt64();
default:
throw new IllegalArgumentException("Unknown type " + type);
}
}
}