/// <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>
/// 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)
{
throw InvalidProtocolBufferException.TruncatedMessage();
}
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 (size > bufferSize - bufferPos)
{
throw InvalidProtocolBufferException.TruncatedMessage();
}
// We have all the bytes we need already.
byte[] bytes = new byte[size];
ByteArray.Copy(buffer, bufferPos, bytes, 0, size);
bufferPos += size;
return(bytes);
}
/// <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)
{
throw InvalidProtocolBufferException.TruncatedMessage();
}
// Fast path: We already have the bytes in a contiguous buffer, so
// just copy directly from it.
var result = CodedOutputStream.Utf8Encoding.GetString(buffer, bufferPos, length);
bufferPos += length;
return(result);
}