// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
// http://code.google.com/p/protobuf/
//
// 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 com.google.protobuf;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
/**
* 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 CodedInputStream {
/**
* Create a new CodedInputStream wrapping the given InputStream.
*/
public static CodedInputStream newInstance(final InputStream input) {
return new CodedInputStream(input);
}
/**
* Create a new CodedInputStream wrapping the given byte array.
*/
public static CodedInputStream newInstance(final byte[] buf) {
return newInstance(buf, 0, buf.length);
}
/**
* Create a new CodedInputStream wrapping the given byte array slice.
*/
public static CodedInputStream newInstance(final byte[] buf, final int off,
final int len) {
CodedInputStream result = new CodedInputStream(buf, off, len);
try {
// Some uses of CodedInputStream can be more efficient if they know
// exactly how many bytes are available. By pushing the end point of the
// buffer as a limit, we allow them to get this information via
// getBytesUntilLimit(). Pushing a limit that we know is at the end of
// the stream can never hurt, since we can never past that point anyway.
result.pushLimit(len);
} catch (InvalidProtocolBufferException ex) {
// The only reason pushLimit() might throw an exception here is if len
// is negative. Normally pushLimit()'s parameter comes directly off the
// wire, so it's important to catch exceptions in case of corrupt or
// malicious data. However, in this case, we expect that len is not a
// user-supplied value, so we can assume that it being negative indicates
// a programming error. Therefore, throwing an unchecked exception is
// appropriate.
throw new IllegalArgumentException(ex);
}
return result;
}
// -----------------------------------------------------------------
/**
* 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 (WireFormat.getTagFieldNumber(lastTag) == 0) {
// If we actually read zero (or any tag number corresponding to field
// number zero), that's not a valid tag.
throw InvalidProtocolBufferException.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 InvalidProtocolBufferException {@code value} does not match the
* last tag.
*/
public void checkLastTagWas(final int value)
throws InvalidProtocolBufferException {
if (lastTag != value) {
throw InvalidProtocolBufferException.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 (WireFormat.getTagWireType(tag)) {
case WireFormat.WIRETYPE_VARINT:
readInt32();
return true;
case WireFormat.WIRETYPE_FIXED64:
readRawLittleEndian64();
return true;
case WireFormat.WIRETYPE_LENGTH_DELIMITED:
skipRawBytes(readRawVarint32());
return true;
case WireFormat.WIRETYPE_START_GROUP:
skipMessage();
checkLastTagWas(
WireFormat.makeTag(WireFormat.getTagFieldNumber(tag),
WireFormat.WIRETYPE_END_GROUP));
return true;
case WireFormat.WIRETYPE_END_GROUP:
return false;
case WireFormat.WIRETYPE_FIXED32:
readRawLittleEndian32();
return true;
default:
throw InvalidProtocolBufferException.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, "UTF-8");
bufferPos += size;
return result;
} else {
// Slow path: Build a byte array first then copy it.
return new String(readRawBytes(size), "UTF-8");
}
}
/** Read a {@code group} field value from the stream. */
public void readGroup(final int fieldNumber,
final MessageLite.Builder builder,
final ExtensionRegistryLite extensionRegistry)
throws IOException {
if (recursionDepth >= recursionLimit) {
throw InvalidProtocolBufferException.recursionLimitExceeded();
}
++recursionDepth;
builder.mergeFrom(this, extensionRegistry);
checkLastTagWas(
WireFormat.makeTag(fieldNumber, WireFormat.WIRETYPE_END_GROUP));
--recursionDepth;
}
/** Read a {@code group} field value from the stream. */
public <T extends MessageLite> T readGroup(
final int fieldNumber,
final Parser<T> parser,
final ExtensionRegistryLite extensionRegistry)
throws IOException {
if (recursionDepth >= recursionLimit) {
throw InvalidProtocolBufferException.recursionLimitExceeded();
}
++recursionDepth;
T result = parser.parsePartialFrom(this, extensionRegistry);
checkLastTagWas(
WireFormat.makeTag(fieldNumber, WireFormat.WIRETYPE_END_GROUP));
--recursionDepth;
return result;
}
/**
* Reads a {@code group} field value from the stream and merges it into the
* given {@link UnknownFieldSet}.
*
* @deprecated UnknownFieldSet.Builder now implements MessageLite.Builder, so
* you can just call {@link #readGroup}.
*/
@Deprecated
public void readUnknownGroup(final int fieldNumber,
final MessageLite.Builder builder)
throws IOException {
// We know that UnknownFieldSet will ignore any ExtensionRegistry so it
// is safe to pass null here. (We can't call
// ExtensionRegistry.getEmptyRegistry() because that would make this
// class depend on ExtensionRegistry, which is not part of the lite
// library.)
readGroup(fieldNumber, builder, null);
}
/** Read an embedded message field value from the stream. */
public void readMessage(final MessageLite.Builder builder,
final ExtensionRegistryLite extensionRegistry)
throws IOException {
final int length = readRawVarint32();
if (recursionDepth >= recursionLimit) {
throw InvalidProtocolBufferException.recursionLimitExceeded();
}
final int oldLimit = pushLimit(length);
++recursionDepth;
builder.mergeFrom(this, extensionRegistry);
checkLastTagWas(0);
--recursionDepth;
popLimit(oldLimit);
}
/** Read an embedded message field value from the stream. */
public <T extends MessageLite> T readMessage(
final Parser<T> parser,
final ExtensionRegistryLite extensionRegistry)
throws IOException {
int length = readRawVarint32();
if (recursionDepth >= recursionLimit) {
throw InvalidProtocolBufferException.recursionLimitExceeded();
}
final int oldLimit = pushLimit(length);
++recursionDepth;
T result = parser.parsePartialFrom(this, extensionRegistry);
checkLastTagWas(0);
--recursionDepth;
popLimit(oldLimit);
return result;
}
/** Read a {@code bytes} field value from the stream. */
public ByteString readBytes() throws IOException {
final int size = readRawVarint32();
if (size == 0) {
return ByteString.EMPTY;
} else if (size <= (bufferSize - bufferPos) && size > 0) {
// Fast path: We already have the bytes in a contiguous buffer, so
// just copy directly from it.
final ByteString result = ByteString.copyFrom(buffer, bufferPos, size);
bufferPos += size;
return result;
} else {
// Slow path: Build a byte array first then copy it.
return ByteString.copyFrom(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 InvalidProtocolBufferException.malformedVarint();
}
}
}
}
return result;
}
/**
* Reads a varint from the input one byte at a time, so that it does not
* read any bytes after the end of the varint. If you simply wrapped the
* stream in a CodedInputStream and used {@link #readRawVarint32(InputStream)}
* then you would probably end up reading past the end of the varint since
* CodedInputStream buffers its input.
*/
static int readRawVarint32(final InputStream input) throws IOException {
final int firstByte = input.read();
if (firstByte == -1) {
throw InvalidProtocolBufferException.truncatedMessage();
}
return readRawVarint32(firstByte, input);
}
/**
* Like {@link #readRawVarint32(InputStream)}, but expects that the caller
* has already read one byte. This allows the caller to determine if EOF
* has been reached before attempting to read.
*/
public static int readRawVarint32(
final int firstByte, final InputStream input) throws IOException {
if ((firstByte & 0x80) == 0) {
return firstByte;
}
int result = firstByte & 0x7f;
int offset = 7;
for (; offset < 32; offset += 7) {
final int b = input.read();
if (b == -1) {
throw InvalidProtocolBufferException.truncatedMessage();
}
result |= (b & 0x7f) << offset;
if ((b & 0x80) == 0) {
return result;
}
}
// Keep reading up to 64 bits.
for (; offset < 64; offset += 7) {
final int b = input.read();
if (b == -1) {
throw InvalidProtocolBufferException.truncatedMessage();
}
if ((b & 0x80) == 0) {
return result;
}
}
throw InvalidProtocolBufferException.malformedVarint();
}
/** 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 InvalidProtocolBufferException.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 (((int)b1 & 0xff) ) |
(((int)b2 & 0xff) << 8) |
(((int)b3 & 0xff) << 16) |
(((int)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 bufferSize;
private int bufferSizeAfterLimit;
private int bufferPos;
private final InputStream input;
private int lastTag;
/**
* The total number of bytes read before the current buffer. The total
* bytes read up to the current position can be computed as
* {@code totalBytesRetired + bufferPos}. This value may be negative if
* reading started in the middle of the current buffer (e.g. if the
* constructor that takes a byte array and an offset was used).
*/
private int totalBytesRetired;
/** 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 static final int BUFFER_SIZE = 4096;
private CodedInputStream(final byte[] buffer, final int off, final int len) {
this.buffer = buffer;
bufferSize = off + len;
bufferPos = off;
totalBytesRetired = -off;
input = null;
}
private CodedInputStream(final InputStream input) {
buffer = new byte[BUFFER_SIZE];
bufferSize = 0;
bufferPos = 0;
totalBytesRetired = 0;
this.input = input;
}
/**
* 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 (nor with
* {@link ByteString#newCodedInput}).
* <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() {
totalBytesRetired = -bufferPos;
}
/**
* Sets {@code currentLimit} to (current position) + {@code byteLimit}. This
* is called when descending into a length-delimited embedded message.
*
* <p>Note that {@code pushLimit()} does NOT affect how many bytes the
* {@code CodedInputStream} reads from an underlying {@code InputStream} when
* refreshing its buffer. If you need to prevent reading past a certain
* point in the underlying {@code InputStream} (e.g. because you expect it to
* contain more data after the end of the message which you need to handle
* differently) then you must place a wrapper around your {@code InputStream}
* which limits the amount of data that can be read from it.
*
* @return the old limit.
*/
public int pushLimit(int byteLimit) throws InvalidProtocolBufferException {
if (byteLimit < 0) {
throw InvalidProtocolBufferException.negativeSize();
}
byteLimit += totalBytesRetired + bufferPos;
final int oldLimit = currentLimit;
if (byteLimit > oldLimit) {
throw InvalidProtocolBufferException.truncatedMessage();
}
currentLimit = byteLimit;
recomputeBufferSizeAfterLimit();
return oldLimit;
}
private void recomputeBufferSizeAfterLimit() {
bufferSize += bufferSizeAfterLimit;
final int bufferEnd = totalBytesRetired + 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 = totalBytesRetired + 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() throws IOException {
return bufferPos == bufferSize && !refillBuffer(false);
}
/**
* The total bytes read up to the current position. Calling
* {@link #resetSizeCounter()} resets this value to zero.
*/
public int getTotalBytesRead() {
return totalBytesRetired + bufferPos;
}
/**
* Called with {@code this.buffer} is empty to read more bytes from the
* input. If {@code mustSucceed} is true, refillBuffer() guarantees that
* either there will be at least one byte in the buffer when it returns
* or it will throw an exception. If {@code mustSucceed} is false,
* refillBuffer() returns false if no more bytes were available.
*/
private boolean refillBuffer(final boolean mustSucceed) throws IOException {
if (bufferPos < bufferSize) {
throw new IllegalStateException(
"refillBuffer() called when buffer wasn't empty.");
}
if (totalBytesRetired + bufferSize == currentLimit) {
// Oops, we hit a limit.
if (mustSucceed) {
throw InvalidProtocolBufferException.truncatedMessage();
} else {
return false;
}
}
totalBytesRetired += bufferSize;
bufferPos = 0;
bufferSize = (input == null) ? -1 : input.read(buffer);
if (bufferSize == 0 || bufferSize < -1) {
throw new IllegalStateException(
"InputStream#read(byte[]) returned invalid result: " + bufferSize +
"\nThe InputStream implementation is buggy.");
}
if (bufferSize == -1) {
bufferSize = 0;
if (mustSucceed) {
throw InvalidProtocolBufferException.truncatedMessage();
} else {
return false;
}
} else {
recomputeBufferSizeAfterLimit();
final int totalBytesRead =
totalBytesRetired + bufferSize + bufferSizeAfterLimit;
if (totalBytesRead > sizeLimit || totalBytesRead < 0) {
throw InvalidProtocolBufferException.sizeLimitExceeded();
}
return true;
}
}
/**
* Read one byte from the input.
*
* @throws InvalidProtocolBufferException The end of the stream or the current
* limit was reached.
*/
public byte readRawByte() throws IOException {
if (bufferPos == bufferSize) {
refillBuffer(true);
}
return buffer[bufferPos++];
}
/**
* Read a fixed size of bytes from the input.
*
* @throws InvalidProtocolBufferException The end of the stream or the current
* limit was reached.
*/
public byte[] readRawBytes(final int size) throws IOException {
if (size < 0) {
throw InvalidProtocolBufferException.negativeSize();
}
if (totalBytesRetired + bufferPos + size > currentLimit) {
// Read to the end of the stream anyway.
skipRawBytes(currentLimit - totalBytesRetired - bufferPos);
// Then fail.
throw InvalidProtocolBufferException.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 if (size < BUFFER_SIZE) {
// Reading more bytes than are in the buffer, but not an excessive number
// of bytes. We can safely allocate the resulting array ahead of time.
// First copy what we have.
final byte[] bytes = new byte[size];
int pos = bufferSize - bufferPos;
System.arraycopy(buffer, bufferPos, bytes, 0, pos);
bufferPos = bufferSize;
// We want to use refillBuffer() and then copy from the buffer into our
// byte array rather than reading directly into our byte array because
// the input may be unbuffered.
refillBuffer(true);
while (size - pos > bufferSize) {
System.arraycopy(buffer, 0, bytes, pos, bufferSize);
pos += bufferSize;
bufferPos = bufferSize;
refillBuffer(true);
}
System.arraycopy(buffer, 0, bytes, pos, size - pos);
bufferPos = size - pos;
return bytes;
} else {
// The size is very large. For security reasons, we can't allocate the
// entire byte array yet. The size comes directly from the input, so a
// maliciously-crafted message could provide a bogus very large size in
// order to trick the app into allocating a lot of memory. We avoid this
// by allocating and reading only a small chunk at a time, so that the
// malicious message must actually *be* extremely large to cause
// problems. Meanwhile, we limit the allowed size of a message elsewhere.
// Remember the buffer markers since we'll have to copy the bytes out of
// it later.
final int originalBufferPos = bufferPos;
final int originalBufferSize = bufferSize;
// Mark the current buffer consumed.
totalBytesRetired += bufferSize;
bufferPos = 0;
bufferSize = 0;
// Read all the rest of the bytes we need.
int sizeLeft = size - (originalBufferSize - originalBufferPos);
final List<byte[]> chunks = new ArrayList<byte[]>();
while (sizeLeft > 0) {
final byte[] chunk = new byte[Math.min(sizeLeft, BUFFER_SIZE)];
int pos = 0;
while (pos < chunk.length) {
final int n = (input == null) ? -1 :
input.read(chunk, pos, chunk.length - pos);
if (n == -1) {
throw InvalidProtocolBufferException.truncatedMessage();
}
totalBytesRetired += n;
pos += n;
}
sizeLeft -= chunk.length;
chunks.add(chunk);
}
// OK, got everything. Now concatenate it all into one buffer.
final byte[] bytes = new byte[size];
// Start by copying the leftover bytes from this.buffer.
int pos = originalBufferSize - originalBufferPos;
System.arraycopy(buffer, originalBufferPos, bytes, 0, pos);
// And now all the chunks.
for (final byte[] chunk : chunks) {
System.arraycopy(chunk, 0, bytes, pos, chunk.length);
pos += chunk.length;
}
// Done.
return bytes;
}
}
/**
* Reads and discards {@code size} bytes.
*
* @throws InvalidProtocolBufferException The end of the stream or the current
* limit was reached.
*/
public void skipRawBytes(final int size) throws IOException {
if (size < 0) {
throw InvalidProtocolBufferException.negativeSize();
}
if (totalBytesRetired + bufferPos + size > currentLimit) {
// Read to the end of the stream anyway.
skipRawBytes(currentLimit - totalBytesRetired - bufferPos);
// Then fail.
throw InvalidProtocolBufferException.truncatedMessage();
}
if (size <= bufferSize - bufferPos) {
// We have all the bytes we need already.
bufferPos += size;
} else {
// Skipping more bytes than are in the buffer. First skip what we have.
int pos = bufferSize - bufferPos;
bufferPos = bufferSize;
// Keep refilling the buffer until we get to the point we wanted to skip
// to. This has the side effect of ensuring the limits are updated
// correctly.
refillBuffer(true);
while (size - pos > bufferSize) {
pos += bufferSize;
bufferPos = bufferSize;
refillBuffer(true);
}
bufferPos = size - pos;
}
}
}