#region Copyright notice and license
// Protocol Buffers - Google's data interchange format
// Copyright 2008 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
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#endregion
using Google.Protobuf.Collections;
using System;
using System.Collections.Generic;
using System.IO;
namespace Google.Protobuf
{
/// <summary>
/// Reads and decodes protocol message fields.
/// </summary>
/// <remarks>
/// <para>
/// This class is generally used by generated code to read appropriate
/// primitives from the stream. It effectively encapsulates the lowest
/// levels of protocol buffer format.
/// </para>
/// <para>
/// Repeated fields and map fields are not handled by this class; use <see cref="RepeatedField{T}"/>
/// and <see cref="MapField{TKey, TValue}"/> to serialize such fields.
/// </para>
/// </remarks>
public sealed class CodedInputStream : IDisposable
{
/// <summary>
/// Whether to leave the underlying stream open when disposing of this stream.
/// This is always true when there's no stream.
/// </summary>
private readonly bool leaveOpen;
/// <summary>
/// Buffer of data read from the stream or provided at construction time.
/// </summary>
private readonly byte[] buffer;
/// <summary>
/// The index of the buffer at which we need to refill from the stream (if there is one).
/// </summary>
private int bufferSize;
private int bufferSizeAfterLimit = 0;
/// <summary>
/// The position within the current buffer (i.e. the next byte to read)
/// </summary>
private int bufferPos = 0;
/// <summary>
/// The stream to read further input from, or null if the byte array buffer was provided
/// directly on construction, with no further data available.
/// </summary>
private readonly Stream input;
/// <summary>
/// The last tag we read. 0 indicates we've read to the end of the stream
/// (or haven't read anything yet).
/// </summary>
private uint lastTag = 0;
/// <summary>
/// The next tag, used to store the value read by PeekTag.
/// </summary>
private uint nextTag = 0;
private bool hasNextTag = false;
internal const int DefaultRecursionLimit = 64;
internal const int DefaultSizeLimit = 64 << 20; // 64MB
internal const int BufferSize = 4096;
/// <summary>
/// The total number of bytes read before the current buffer. The
/// total bytes read up to the current position can be computed as
/// totalBytesRetired + bufferPos.
/// </summary>
private int totalBytesRetired = 0;
/// <summary>
/// The absolute position of the end of the current message.
/// </summary>
private int currentLimit = int.MaxValue;
private int recursionDepth = 0;
private readonly int recursionLimit;
private readonly int sizeLimit;
#region Construction
// Note that the checks are performed such that we don't end up checking obviously-valid things
// like non-null references for arrays we've just created.
/// <summary>
/// Creates a new CodedInputStream reading data from the given byte array.
/// </summary>
public CodedInputStream(byte[] buffer) : this(null, ProtoPreconditions.CheckNotNull(buffer, "buffer"), 0, buffer.Length)
{
}
/// <summary>
/// Creates a new <see cref="CodedInputStream"/> that reads from the given byte array slice.
/// </summary>
public CodedInputStream(byte[] buffer, int offset, int length)
: this(null, ProtoPreconditions.CheckNotNull(buffer, "buffer"), offset, offset + length)
{
if (offset < 0 || offset > buffer.Length)
{
throw new ArgumentOutOfRangeException("offset", "Offset must be within the buffer");
}
if (length < 0 || offset + length > buffer.Length)
{
throw new ArgumentOutOfRangeException("length", "Length must be non-negative and within the buffer");
}
}
/// <summary>
/// Creates a new <see cref="CodedInputStream"/> reading data from the given stream, which will be disposed
/// when the returned object is disposed.
/// </summary>
/// <param name="input">The stream to read from.</param>
public CodedInputStream(Stream input) : this(input, false)
{
}
/// <summary>
/// Creates a new <see cref="CodedInputStream"/> reading data from the given stream.
/// </summary>
/// <param name="input">The stream to read from.</param>
/// <param name="leaveOpen"><c>true</c> to leave <paramref name="input"/> open when the returned
/// <c cref="CodedInputStream"/> is disposed; <c>false</c> to dispose of the given stream when the
/// returned object is disposed.</param>
public CodedInputStream(Stream input, bool leaveOpen)
: this(ProtoPreconditions.CheckNotNull(input, "input"), new byte[BufferSize], 0, 0)
{
this.leaveOpen = leaveOpen;
}
/// <summary>
/// Creates a new CodedInputStream reading data from the given
/// stream and buffer, using the default limits.
/// </summary>
internal CodedInputStream(Stream input, byte[] buffer, int bufferPos, int bufferSize)
{
this.input = input;
this.buffer = buffer;
this.bufferPos = bufferPos;
this.bufferSize = bufferSize;
this.sizeLimit = DefaultSizeLimit;
this.recursionLimit = DefaultRecursionLimit;
}
/// <summary>
/// Creates a new CodedInputStream reading data from the given
/// stream and buffer, using the specified limits.
/// </summary>
/// <remarks>
/// This chains to the version with the default limits instead of vice versa to avoid
/// having to check that the default values are valid every time.
/// </remarks>
internal CodedInputStream(Stream input, byte[] buffer, int bufferPos, int bufferSize, int sizeLimit, int recursionLimit)
: this(input, buffer, bufferPos, bufferSize)
{
if (sizeLimit <= 0)
{
throw new ArgumentOutOfRangeException("sizeLimit", "Size limit must be positive");
}
if (recursionLimit <= 0)
{
throw new ArgumentOutOfRangeException("recursionLimit!", "Recursion limit must be positive");
}
this.sizeLimit = sizeLimit;
this.recursionLimit = recursionLimit;
}
#endregion
/// <summary>
/// Creates a <see cref="CodedInputStream"/> with the specified size and recursion limits, reading
/// from an input stream.
/// </summary>
/// <remarks>
/// This method exists separately from the constructor to reduce the number of constructor overloads.
/// It is likely to be used considerably less frequently than the constructors, as the default limits
/// are suitable for most use cases.
/// </remarks>
/// <param name="input">The input stream to read from</param>
/// <param name="sizeLimit">The total limit of data to read from the stream.</param>
/// <param name="recursionLimit">The maximum recursion depth to allow while reading.</param>
/// <returns>A <c>CodedInputStream</c> reading from <paramref name="input"/> with the specified size
/// and recursion limits.</returns>
public static CodedInputStream CreateWithLimits(Stream input, int sizeLimit, int recursionLimit)
{
return new CodedInputStream(input, new byte[BufferSize], 0, 0, sizeLimit, recursionLimit);
}
/// <summary>
/// Returns the current position in the input stream, or the position in the input buffer
/// </summary>
public long Position
{
get
{
if (input != null)
{
return input.Position - ((bufferSize + bufferSizeAfterLimit) - bufferPos);
}
return bufferPos;
}
}
/// <summary>
/// Returns the last tag read, or 0 if no tags have been read or we've read beyond
/// the end of the stream.
/// </summary>
internal uint LastTag { get { return lastTag; } }
/// <summary>
/// Returns the size limit for this stream.
/// </summary>
/// <remarks>
/// This limit is applied when reading from the underlying stream, as a sanity check. It is
/// not applied when reading from a byte array data source without an underlying stream.
/// The default value is 64MB.
/// </remarks>
/// <value>
/// The size limit.
/// </value>
public int SizeLimit { get { return sizeLimit; } }
/// <summary>
/// Returns the recursion limit for this stream. This limit is applied whilst reading messages,
/// to avoid maliciously-recursive data.
/// </summary>
/// <remarks>
/// The default limit is 64.
/// </remarks>
/// <value>
/// The recursion limit for this stream.
/// </value>
public int RecursionLimit { get { return recursionLimit; } }
/// <summary>
/// Disposes of this instance, potentially closing any underlying stream.
/// </summary>
/// <remarks>
/// As there is no flushing to perform here, disposing of a <see cref="CodedInputStream"/> which
/// was constructed with the <c>leaveOpen</c> option parameter set to <c>true</c> (or one which
/// was constructed to read from a byte array) has no effect.
/// </remarks>
public void Dispose()
{
if (!leaveOpen)
{
input.Dispose();
}
}
#region Validation
/// <summary>
/// Verifies that the last call to ReadTag() returned tag 0 - in other words,
/// we've reached the end of the stream when we expected to.
/// </summary>
/// <exception cref="InvalidProtocolBufferException">The
/// tag read was not the one specified</exception>
internal void CheckReadEndOfStreamTag()
{
if (lastTag != 0)
{
throw InvalidProtocolBufferException.MoreDataAvailable();
}
}
#endregion
#region Reading of tags etc
/// <summary>
/// Peeks at the next field tag. This is like calling <see cref="ReadTag"/>, but the
/// tag is not consumed. (So a subsequent call to <see cref="ReadTag"/> will return the
/// same value.)
/// </summary>
public uint PeekTag()
{
if (hasNextTag)
{
return nextTag;
}
uint savedLast = lastTag;
nextTag = ReadTag();
hasNextTag = true;
lastTag = savedLast; // Undo the side effect of ReadTag
return nextTag;
}
/// <summary>
/// Reads a field tag, returning the tag of 0 for "end of stream".
/// </summary>
/// <remarks>
/// If this method returns 0, it doesn't necessarily mean the end of all
/// the data in this CodedInputStream; it may be the end of the logical stream
/// for an embedded message, for example.
/// </remarks>
/// <returns>The next field tag, or 0 for end of stream. (0 is never a valid tag.)</returns>
public uint ReadTag()
{
if (hasNextTag)
{
lastTag = nextTag;
hasNextTag = false;
return lastTag;
}
// Optimize for the incredibly common case of having at least two bytes left in the buffer,
// and those two bytes being enough to get the tag. This will be true for fields up to 4095.
if (bufferPos + 2 <= bufferSize)
{
int tmp = buffer[bufferPos++];
if (tmp < 128)
{
lastTag = (uint)tmp;
}
else
{
int result = tmp & 0x7f;
if ((tmp = buffer[bufferPos++]) < 128)
{
result |= tmp << 7;
lastTag = (uint) result;
}
else
{
// Nope, rewind and go the potentially slow route.
bufferPos -= 2;
lastTag = ReadRawVarint32();
}
}
}
else
{
if (IsAtEnd)
{
lastTag = 0;
return 0; // This is the only case in which we return 0.
}
lastTag = ReadRawVarint32();
}
if (lastTag == 0)
{
// If we actually read zero, that's not a valid tag.
throw InvalidProtocolBufferException.InvalidTag();
}
return lastTag;
}
/// <summary>
/// Skips the data for the field with the tag we've just read.
/// This should be called directly after <see cref="ReadTag"/>, when
/// the caller wishes to skip an unknown field.
/// </summary>
/// <remarks>
/// This method throws <see cref="InvalidProtocolBufferException"/> if the last-read tag was an end-group tag.
/// If a caller wishes to skip a group, they should skip the whole group, by calling this method after reading the
/// start-group tag. This behavior allows callers to call this method on any field they don't understand, correctly
/// resulting in an error if an end-group tag has not been paired with an earlier start-group tag.
/// </remarks>
/// <exception cref="InvalidProtocolBufferException">The last tag was an end-group tag</exception>
/// <exception cref="InvalidOperationException">The last read operation read to the end of the logical stream</exception>
public void SkipLastField()
{
if (lastTag == 0)
{
throw new InvalidOperationException("SkipLastField cannot be called at the end of a stream");
}
switch (WireFormat.GetTagWireType(lastTag))
{
case WireFormat.WireType.StartGroup:
SkipGroup(lastTag);
break;
case WireFormat.WireType.EndGroup:
throw new InvalidProtocolBufferException(
"SkipLastField called on an end-group tag, indicating that the corresponding start-group was missing");
case WireFormat.WireType.Fixed32:
ReadFixed32();
break;
case WireFormat.WireType.Fixed64:
ReadFixed64();
break;
case WireFormat.WireType.LengthDelimited:
var length = ReadLength();
SkipRawBytes(length);
break;
case WireFormat.WireType.Varint:
ReadRawVarint32();
break;
}
}
private void SkipGroup(uint startGroupTag)
{
// Note: Currently we expect this to be the way that groups are read. We could put the recursion
// depth changes into the ReadTag method instead, potentially...
recursionDepth++;
if (recursionDepth >= recursionLimit)
{
throw InvalidProtocolBufferException.RecursionLimitExceeded();
}
uint tag;
while (true)
{
tag = ReadTag();
if (tag == 0)
{
throw InvalidProtocolBufferException.TruncatedMessage();
}
// Can't call SkipLastField for this case- that would throw.
if (WireFormat.GetTagWireType(tag) == WireFormat.WireType.EndGroup)
{
break;
}
// This recursion will allow us to handle nested groups.
SkipLastField();
}
int startField = WireFormat.GetTagFieldNumber(startGroupTag);
int endField = WireFormat.GetTagFieldNumber(tag);
if (startField != endField)
{
throw new InvalidProtocolBufferException(
$"Mismatched end-group tag. Started with field {startField}; ended with field {endField}");
}
recursionDepth--;
}
/// <summary>
/// Reads a double field from the stream.
/// </summary>
public double ReadDouble()
{
return BitConverter.Int64BitsToDouble((long) ReadRawLittleEndian64());
}
/// <summary>
/// Reads a float field from the stream.
/// </summary>
public float ReadFloat()
{
if (BitConverter.IsLittleEndian && 4 <= bufferSize - bufferPos)
{
float ret = BitConverter.ToSingle(buffer, bufferPos);
bufferPos += 4;
return ret;
}
else
{
byte[] rawBytes = ReadRawBytes(4);
if (!BitConverter.IsLittleEndian)
{
ByteArray.Reverse(rawBytes);
}
return BitConverter.ToSingle(rawBytes, 0);
}
}
/// <summary>
/// Reads a uint64 field from the stream.
/// </summary>
public ulong ReadUInt64()
{
return ReadRawVarint64();
}
/// <summary>
/// Reads an int64 field from the stream.
/// </summary>
public long ReadInt64()
{
return (long) ReadRawVarint64();
}
/// <summary>
/// Reads an int32 field from the stream.
/// </summary>
public int ReadInt32()
{
return (int) ReadRawVarint32();
}
/// <summary>
/// Reads a fixed64 field from the stream.
/// </summary>
public ulong ReadFixed64()
{
return ReadRawLittleEndian64();
}
/// <summary>
/// Reads a fixed32 field from the stream.
/// </summary>
public uint ReadFixed32()
{
return ReadRawLittleEndian32();
}
/// <summary>
/// Reads a bool field from the stream.
/// </summary>
public bool ReadBool()
{
return ReadRawVarint32() != 0;
}
/// <summary>
/// Reads a string field from the stream.
/// </summary>
public string ReadString()
{
int length = ReadLength();
// No need to read any data for an empty string.
if (length == 0)
{
return "";
}
if (length <= bufferSize - bufferPos)
{
// Fast path: We already have the bytes in a contiguous buffer, so
// just copy directly from it.
String result = CodedOutputStream.Utf8Encoding.GetString(buffer, bufferPos, length);
bufferPos += length;
return result;
}
// Slow path: Build a byte array first then copy it.
return CodedOutputStream.Utf8Encoding.GetString(ReadRawBytes(length), 0, length);
}
/// <summary>
/// Reads an embedded message field value from the stream.
/// </summary>
public void ReadMessage(IMessage builder)
{
int length = ReadLength();
if (recursionDepth >= recursionLimit)
{
throw InvalidProtocolBufferException.RecursionLimitExceeded();
}
int oldLimit = PushLimit(length);
++recursionDepth;
builder.MergeFrom(this);
CheckReadEndOfStreamTag();
// Check that we've read exactly as much data as expected.
if (!ReachedLimit)
{
throw InvalidProtocolBufferException.TruncatedMessage();
}
--recursionDepth;
PopLimit(oldLimit);
}
/// <summary>
/// Reads a bytes field value from the stream.
/// </summary>
public ByteString ReadBytes()
{
int length = ReadLength();
if (length <= bufferSize - bufferPos && length > 0)
{
// Fast path: We already have the bytes in a contiguous buffer, so
// just copy directly from it.
ByteString result = ByteString.CopyFrom(buffer, bufferPos, length);
bufferPos += length;
return result;
}
else
{
// Slow path: Build a byte array and attach it to a new ByteString.
return ByteString.AttachBytes(ReadRawBytes(length));
}
}
/// <summary>
/// Reads a uint32 field value from the stream.
/// </summary>
public uint ReadUInt32()
{
return ReadRawVarint32();
}
/// <summary>
/// Reads an enum field value from the stream. If the enum is valid for type T,
/// then the ref value is set and it returns true. Otherwise the unknown output
/// value is set and this method returns false.
/// </summary>
public int ReadEnum()
{
// Currently just a pass-through, but it's nice to separate it logically from WriteInt32.
return (int) ReadRawVarint32();
}
/// <summary>
/// Reads an sfixed32 field value from the stream.
/// </summary>
public int ReadSFixed32()
{
return (int) ReadRawLittleEndian32();
}
/// <summary>
/// Reads an sfixed64 field value from the stream.
/// </summary>
public long ReadSFixed64()
{
return (long) ReadRawLittleEndian64();
}
/// <summary>
/// Reads an sint32 field value from the stream.
/// </summary>
public int ReadSInt32()
{
return DecodeZigZag32(ReadRawVarint32());
}
/// <summary>
/// Reads an sint64 field value from the stream.
/// </summary>
public long ReadSInt64()
{
return DecodeZigZag64(ReadRawVarint64());
}
/// <summary>
/// Reads a length for length-delimited data.
/// </summary>
/// <remarks>
/// This is internally just reading a varint, but this method exists
/// to make the calling code clearer.
/// </remarks>
public int ReadLength()
{
return (int) ReadRawVarint32();
}
/// <summary>
/// Peeks at the next tag in the stream. If it matches <paramref name="tag"/>,
/// the tag is consumed and the method returns <c>true</c>; otherwise, the
/// stream is left in the original position and the method returns <c>false</c>.
/// </summary>
public bool MaybeConsumeTag(uint tag)
{
if (PeekTag() == tag)
{
hasNextTag = false;
return true;
}
return false;
}
#endregion
#region Underlying reading primitives
/// <summary>
/// Same code as ReadRawVarint32, but read each byte individually, checking for
/// buffer overflow.
/// </summary>
private uint SlowReadRawVarint32()
{
int tmp = ReadRawByte();
if (tmp < 128)
{
return (uint) tmp;
}
int result = tmp & 0x7f;
if ((tmp = ReadRawByte()) < 128)
{
result |= tmp << 7;
}
else
{
result |= (tmp & 0x7f) << 7;
if ((tmp = ReadRawByte()) < 128)
{
result |= tmp << 14;
}
else
{
result |= (tmp & 0x7f) << 14;
if ((tmp = ReadRawByte()) < 128)
{
result |= tmp << 21;
}
else
{
result |= (tmp & 0x7f) << 21;
result |= (tmp = ReadRawByte()) << 28;
if (tmp >= 128)
{
// Discard upper 32 bits.
for (int i = 0; i < 5; i++)
{
if (ReadRawByte() < 128)
{
return (uint) result;
}
}
throw InvalidProtocolBufferException.MalformedVarint();
}
}
}
}
return (uint) result;
}
/// <summary>
/// Reads a raw Varint from the stream. If larger than 32 bits, discard the upper bits.
/// This method is optimised for the case where we've got lots of data in the buffer.
/// That means we can check the size just once, then just read directly from the buffer
/// without constant rechecking of the buffer length.
/// </summary>
internal uint ReadRawVarint32()
{
if (bufferPos + 5 > bufferSize)
{
return SlowReadRawVarint32();
}
int tmp = buffer[bufferPos++];
if (tmp < 128)
{
return (uint) tmp;
}
int result = tmp & 0x7f;
if ((tmp = buffer[bufferPos++]) < 128)
{
result |= tmp << 7;
}
else
{
result |= (tmp & 0x7f) << 7;
if ((tmp = buffer[bufferPos++]) < 128)
{
result |= tmp << 14;
}
else
{
result |= (tmp & 0x7f) << 14;
if ((tmp = buffer[bufferPos++]) < 128)
{
result |= tmp << 21;
}
else
{
result |= (tmp & 0x7f) << 21;
result |= (tmp = buffer[bufferPos++]) << 28;
if (tmp >= 128)
{
// Discard upper 32 bits.
// Note that this has to use ReadRawByte() as we only ensure we've
// got at least 5 bytes at the start of the method. This lets us
// use the fast path in more cases, and we rarely hit this section of code.
for (int i = 0; i < 5; i++)
{
if (ReadRawByte() < 128)
{
return (uint) result;
}
}
throw InvalidProtocolBufferException.MalformedVarint();
}
}
}
}
return (uint) result;
}
/// <summary>
/// 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 ReadRawVarint32(Stream)
/// then you would probably end up reading past the end of the varint since
/// CodedInputStream buffers its input.
/// </summary>
/// <param name="input"></param>
/// <returns></returns>
internal static uint ReadRawVarint32(Stream input)
{
int result = 0;
int offset = 0;
for (; offset < 32; offset += 7)
{
int b = input.ReadByte();
if (b == -1)
{
throw InvalidProtocolBufferException.TruncatedMessage();
}
result |= (b & 0x7f) << offset;
if ((b & 0x80) == 0)
{
return (uint) result;
}
}
// Keep reading up to 64 bits.
for (; offset < 64; offset += 7)
{
int b = input.ReadByte();
if (b == -1)
{
throw InvalidProtocolBufferException.TruncatedMessage();
}
if ((b & 0x80) == 0)
{
return (uint) result;
}
}
throw InvalidProtocolBufferException.MalformedVarint();
}
/// <summary>
/// Reads a raw varint from the stream.
/// </summary>
internal ulong ReadRawVarint64()
{
int shift = 0;
ulong result = 0;
while (shift < 64)
{
byte b = ReadRawByte();
result |= (ulong) (b & 0x7F) << shift;
if ((b & 0x80) == 0)
{
return result;
}
shift += 7;
}
throw InvalidProtocolBufferException.MalformedVarint();
}
/// <summary>
/// Reads a 32-bit little-endian integer from the stream.
/// </summary>
internal uint ReadRawLittleEndian32()
{
uint b1 = ReadRawByte();
uint b2 = ReadRawByte();
uint b3 = ReadRawByte();
uint b4 = ReadRawByte();
return b1 | (b2 << 8) | (b3 << 16) | (b4 << 24);
}
/// <summary>
/// Reads a 64-bit little-endian integer from the stream.
/// </summary>
internal ulong ReadRawLittleEndian64()
{
ulong b1 = ReadRawByte();
ulong b2 = ReadRawByte();
ulong b3 = ReadRawByte();
ulong b4 = ReadRawByte();
ulong b5 = ReadRawByte();
ulong b6 = ReadRawByte();
ulong b7 = ReadRawByte();
ulong b8 = ReadRawByte();
return b1 | (b2 << 8) | (b3 << 16) | (b4 << 24)
| (b5 << 32) | (b6 << 40) | (b7 << 48) | (b8 << 56);
}
/// <summary>
/// Decode a 32-bit value with ZigZag encoding.
/// </summary>
/// <remarks>
/// 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.)
/// </remarks>
internal static int DecodeZigZag32(uint n)
{
return (int)(n >> 1) ^ -(int)(n & 1);
}
/// <summary>
/// Decode a 32-bit value with ZigZag encoding.
/// </summary>
/// <remarks>
/// 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.)
/// </remarks>
internal static long DecodeZigZag64(ulong n)
{
return (long)(n >> 1) ^ -(long)(n & 1);
}
#endregion
#region Internal reading and buffer management
/// <summary>
/// Sets currentLimit to (current position) + byteLimit. This is called
/// when descending into a length-delimited embedded message. The previous
/// limit is returned.
/// </summary>
/// <returns>The old limit.</returns>
internal int PushLimit(int byteLimit)
{
if (byteLimit < 0)
{
throw InvalidProtocolBufferException.NegativeSize();
}
byteLimit += totalBytesRetired + bufferPos;
int oldLimit = currentLimit;
if (byteLimit > oldLimit)
{
throw InvalidProtocolBufferException.TruncatedMessage();
}
currentLimit = byteLimit;
RecomputeBufferSizeAfterLimit();
return oldLimit;
}
private void RecomputeBufferSizeAfterLimit()
{
bufferSize += bufferSizeAfterLimit;
int bufferEnd = totalBytesRetired + bufferSize;
if (bufferEnd > currentLimit)
{
// Limit is in current buffer.
bufferSizeAfterLimit = bufferEnd - currentLimit;
bufferSize -= bufferSizeAfterLimit;
}
else
{
bufferSizeAfterLimit = 0;
}
}
/// <summary>
/// Discards the current limit, returning the previous limit.
/// </summary>
internal void PopLimit(int oldLimit)
{
currentLimit = oldLimit;
RecomputeBufferSizeAfterLimit();
}
/// <summary>
/// Returns whether or not all the data before the limit has been read.
/// </summary>
/// <returns></returns>
internal bool ReachedLimit
{
get
{
if (currentLimit == int.MaxValue)
{
return false;
}
int currentAbsolutePosition = totalBytesRetired + bufferPos;
return currentAbsolutePosition >= currentLimit;
}
}
/// <summary>
/// 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
/// the stream has reached a limit created using PushLimit.
/// </summary>
public bool IsAtEnd
{
get { return bufferPos == bufferSize && !RefillBuffer(false); }
}
/// <summary>
/// Called when buffer is empty to read more bytes from the
/// input. If <paramref name="mustSucceed"/> is true, RefillBuffer() gurantees that
/// either there will be at least one byte in the buffer when it returns
/// or it will throw an exception. If <paramref name="mustSucceed"/> is false,
/// RefillBuffer() returns false if no more bytes were available.
/// </summary>
/// <param name="mustSucceed"></param>
/// <returns></returns>
private bool RefillBuffer(bool mustSucceed)
{
if (bufferPos < bufferSize)
{
throw new InvalidOperationException("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) ? 0 : input.Read(buffer, 0, buffer.Length);
if (bufferSize < 0)
{
throw new InvalidOperationException("Stream.Read returned a negative count");
}
if (bufferSize == 0)
{
if (mustSucceed)
{
throw InvalidProtocolBufferException.TruncatedMessage();
}
else
{
return false;
}
}
else
{
RecomputeBufferSizeAfterLimit();
int totalBytesRead =
totalBytesRetired + bufferSize + bufferSizeAfterLimit;
if (totalBytesRead > sizeLimit || totalBytesRead < 0)
{
throw InvalidProtocolBufferException.SizeLimitExceeded();
}
return true;
}
}
/// <summary>
/// Read one byte from the input.
/// </summary>
/// <exception cref="InvalidProtocolBufferException">
/// the end of the stream or the current limit was reached
/// </exception>
internal byte ReadRawByte()
{
if (bufferPos == bufferSize)
{
RefillBuffer(true);
}
return buffer[bufferPos++];
}
/// <summary>
/// Reads a fixed size of bytes from the input.
/// </summary>
/// <exception cref="InvalidProtocolBufferException">
/// the end of the stream or the current limit was reached
/// </exception>
internal byte[] ReadRawBytes(int size)
{
if (size < 0)
{
throw InvalidProtocolBufferException.NegativeSize();
}
if (totalBytesRetired + bufferPos + size > currentLimit)
{
// Read to the end of the stream (up to the current limit) anyway.
SkipRawBytes(currentLimit - totalBytesRetired - bufferPos);
// Then fail.
throw InvalidProtocolBufferException.TruncatedMessage();
}
if (size <= bufferSize - bufferPos)
{
// We have all the bytes we need already.
byte[] bytes = new byte[size];
ByteArray.Copy(buffer, bufferPos, bytes, 0, size);
bufferPos += size;
return bytes;
}
else if (size < buffer.Length)
{
// 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.
byte[] bytes = new byte[size];
int pos = bufferSize - bufferPos;
ByteArray.Copy(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)
{
Buffer.BlockCopy(buffer, 0, bytes, pos, bufferSize);
pos += bufferSize;
bufferPos = bufferSize;
RefillBuffer(true);
}
ByteArray.Copy(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.
int originalBufferPos = bufferPos;
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);
List<byte[]> chunks = new List<byte[]>();
while (sizeLeft > 0)
{
byte[] chunk = new byte[Math.Min(sizeLeft, buffer.Length)];
int pos = 0;
while (pos < chunk.Length)
{
int n = (input == null) ? -1 : input.Read(chunk, pos, chunk.Length - pos);
if (n <= 0)
{
throw InvalidProtocolBufferException.TruncatedMessage();
}
totalBytesRetired += n;
pos += n;
}
sizeLeft -= chunk.Length;
chunks.Add(chunk);
}
// OK, got everything. Now concatenate it all into one buffer.
byte[] bytes = new byte[size];
// Start by copying the leftover bytes from this.buffer.
int newPos = originalBufferSize - originalBufferPos;
ByteArray.Copy(buffer, originalBufferPos, bytes, 0, newPos);
// And now all the chunks.
foreach (byte[] chunk in chunks)
{
Buffer.BlockCopy(chunk, 0, bytes, newPos, chunk.Length);
newPos += chunk.Length;
}
// Done.
return bytes;
}
}
/// <summary>
/// Reads and discards <paramref name="size"/> bytes.
/// </summary>
/// <exception cref="InvalidProtocolBufferException">the end of the stream
/// or the current limit was reached</exception>
private void SkipRawBytes(int size)
{
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;
// ROK 5/7/2013 Issue #54: should retire all bytes in buffer (bufferSize)
// totalBytesRetired += pos;
totalBytesRetired += bufferSize;
bufferPos = 0;
bufferSize = 0;
// Then skip directly from the InputStream for the rest.
if (pos < size)
{
if (input == null)
{
throw InvalidProtocolBufferException.TruncatedMessage();
}
SkipImpl(size - pos);
totalBytesRetired += size - pos;
}
}
}
/// <summary>
/// Abstraction of skipping to cope with streams which can't really skip.
/// </summary>
private void SkipImpl(int amountToSkip)
{
if (input.CanSeek)
{
long previousPosition = input.Position;
input.Position += amountToSkip;
if (input.Position != previousPosition + amountToSkip)
{
throw InvalidProtocolBufferException.TruncatedMessage();
}
}
else
{
byte[] skipBuffer = new byte[Math.Min(1024, amountToSkip)];
while (amountToSkip > 0)
{
int bytesRead = input.Read(skipBuffer, 0, Math.Min(skipBuffer.Length, amountToSkip));
if (bytesRead <= 0)
{
throw InvalidProtocolBufferException.TruncatedMessage();
}
amountToSkip -= bytesRead;
}
}
}
#endregion
}
}