Module: Protobug::BinaryEncoding

Defined in:
lib/protobug/binary_encoding.rb

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.decode_length(binary) ⇒ Object

Raises:

  • (EOFError) 


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# File 'lib/protobug/binary_encoding.rb', line 131

def decode_length(binary)
  length = decode_varint(binary) || raise(EOFError, "unexpected EOF")
  string = binary.read(length) || raise(EOFError, "unexpected EOF")
  raise EOFError, "expected #{length} bytes, got #{string.bytesize}" unless string.bytesize == length

  string
end

.decode_varint(binary) ⇒ Object 



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# File 'lib/protobug/binary_encoding.rb', line 58

def decode_varint(binary)
  # Only the first byte may legitimately be absent (clean EOF, signaled by
  # returning nil). Once a continuation bit is set, any subsequent missing
  # byte is a truncated varint and must be rejected.
  if (byte0 = binary.getbyte || return) < 0x80
    byte0
  elsif (byte1 = binary.getbyte || varint_eof!) < 0x80
    (byte1 << 7) | (byte0 & 0x7F)
  elsif (byte2 = binary.getbyte || varint_eof!) < 0x80
    (byte2 << 14) |
      ((byte1 & 0x7F) << 7) |
      (byte0 & 0x7F)
  elsif (byte3 = binary.getbyte || varint_eof!) < 0x80
    (byte3 << 21) |
      ((byte2 & 0x7F) << 14) |
      ((byte1 & 0x7F) << 7) |
      (byte0 & 0x7F)
  elsif (byte4 = binary.getbyte || varint_eof!) < 0x80
    (byte4 << 28) |
      ((byte3 & 0x7F) << 21) |
      ((byte2 & 0x7F) << 14) |
      ((byte1 & 0x7F) << 7) |
      (byte0 & 0x7F)
  elsif (byte5 = binary.getbyte || varint_eof!) < 0x80
    (byte5 << 35) |
      ((byte4 & 0x7F) << 28) |
      ((byte3 & 0x7F) << 21) |
      ((byte2 & 0x7F) << 14) |
      ((byte1 & 0x7F) << 7) |
      (byte0 & 0x7F)
  elsif (byte6 = binary.getbyte || varint_eof!) < 0x80
    (byte6 << 42) |
      ((byte5 & 0x7F) << 35) |
      ((byte4 & 0x7F) << 28) |
      ((byte3 & 0x7F) << 21) |
      ((byte2 & 0x7F) << 14) |
      ((byte1 & 0x7F) << 7) |
      (byte0 & 0x7F)
  elsif (byte7 = binary.getbyte || varint_eof!) < 0x80
    (byte7 << 49) |
      ((byte6 & 0x7F) << 42) |
      ((byte5 & 0x7F) << 35) |
      ((byte4 & 0x7F) << 28) |
      ((byte3 & 0x7F) << 21) |
      ((byte2 & 0x7F) << 14) |
      ((byte1 & 0x7F) << 7) |
      (byte0 & 0x7F)
  elsif (byte8 = binary.getbyte || varint_eof!) < 0x80
    (byte8 << 56) |
      ((byte7 & 0x7F) << 49) |
      ((byte6 & 0x7F) << 42) |
      ((byte5 & 0x7F) << 35) |
      ((byte4 & 0x7F) << 28) |
      ((byte3 & 0x7F) << 21) |
      ((byte2 & 0x7F) << 14) |
      ((byte1 & 0x7F) << 7) |
      (byte0 & 0x7F)
  elsif (byte9 = binary.getbyte || varint_eof!) < 0x80
    raise DecodeError, "varint overflow: 10th byte #{byte9} exceeds 64 bits" if byte9 > 1

    (byte9 << 63) |
      ((byte8 & 0x7F) << 56) |
      ((byte7 & 0x7F) << 49) |
      ((byte6 & 0x7F) << 42) |
      ((byte5 & 0x7F) << 35) |
      ((byte4 & 0x7F) << 28) |
      ((byte3 & 0x7F) << 21) |
      ((byte2 & 0x7F) << 14) |
      ((byte1 & 0x7F) << 7) |
      (byte0 & 0x7F)
  end
end

.decode_zigzag(size, value) ⇒ Object 



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# File 'lib/protobug/binary_encoding.rb', line 139

def decode_zigzag(size, value)
  negative = value & 1 == 1
  value %= 2**size
  value >>= 1
  value = -value - 1 if negative

  unless value.bit_length <= size
    raise DecodeError,
          "bitlength too large for #{size}-bit integer: #{value.bit_length}"
  end

  value
end

.encode_length(contents, outbuf) ⇒ Object 



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# File 'lib/protobug/binary_encoding.rb', line 49

def encode_length(contents, outbuf)
  encode_varint contents.bytesize, outbuf
  outbuf << contents
end

.encode_varint(value, outbuf) ⇒ Object

Raises:



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# File 'lib/protobug/binary_encoding.rb', line 9

def encode_varint(value, outbuf)
  raise EncodeError, "expected integer, got #{value.inspect}" unless value.is_a? Integer
  raise RangeError, "expected 64-bit integer" if value > (2**64) - 1 || value < -2**63

  value += 2**64 if value < 0
  loop do
    if value.bit_length > 7
      outbuf << (0b1000_0000 | (value & 0b0111_1111))
      value >>= 7
    else
      outbuf << (value & 0b0111_1111)
      break
    end
  end
end

.encode_zigzag(size, value, outbuf) ⇒ Object

Raises:



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# File 'lib/protobug/binary_encoding.rb', line 36

def encode_zigzag(size, value, outbuf)
  raise EncodeError, "expected integer, got #{value.inspect}" unless value.is_a? Integer

  unless value.bit_length <= size
    raise EncodeError,
          "bitlength too large for #{size}-bit integer: #{value.bit_length}"
  end

  encoded = 2 * value.abs
  encoded -= 1 if value < 0
  encode_varint encoded, outbuf
end

.read_field_value(binary, wire_type) ⇒ Object 



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# File 'lib/protobug/binary_encoding.rb', line 153

def read_field_value(binary, wire_type)
  case wire_type
  when 0
    decode_varint(binary) || raise(EOFError, "unexpected EOF")
  when 1
    value = binary.read(8)
    raise EOFError, "unexpected EOF" if value&.bytesize != 8

    value
  when 2
    decode_length(binary)
  when 3, 4
    raise UnsupportedFeatureError.new(:group, "reading groups from binary protos (in #{self})")
  when 5
    value = binary.read(4)
    raise EOFError, "unexpected EOF" if value&.bytesize != 4

    value
  else
    raise DecodeError, "unknown wire_type: #{wire_type}"
  end
end

.varint_eof! ⇒ Object

Raises:

  • (EOFError) 


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# File 'lib/protobug/binary_encoding.rb', line 54

def varint_eof!
  raise EOFError, "unexpected EOF in the middle of a varint"
end

Instance Method Details

#pack(ary, format, buffer:) ⇒ Object

see github.com/oracle/truffleruby/issues/3559



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# File 'lib/protobug/binary_encoding.rb', line 27

def pack(ary, format, buffer:)
  buffer.concat ary.pack(format)
end