Module: ScaleRb::Decode

Extended by:
TypeEnforcer
Includes:
Types
Included in:
Codec
Defined in:
lib/scale_rb/decode.rb

Constant Summary

Constants included from Types

Types::DecodeResult, Types::HashMap, Types::Hex, Types::PortableType, Types::Primitive, Types::Registry, Types::Ti, Types::TypedArray, Types::U8, Types::U8Array, Types::UnsignedInteger, Types::VariantKind

Instance Method Summary collapse

Methods included from TypeEnforcer

__, extended, method_added

Instance Method Details

#decode(id, bytes, registry) ⇒ Object

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# File 'lib/scale_rb/decode.rb', line 12

def decode(id, bytes, registry)
  ScaleRb.logger.debug("Decoding #{id}, bytes: #{bytes.length} bytes")
  type = registry[id]
  raise Codec::TypeNotFound, "id: #{id}" if type.nil?

  case type
  when PrimitiveType then decode_primitive(type, bytes)
  when CompactType then decode_compact(bytes)
  when ArrayType then decode_array(type, bytes, registry)
  when SequenceType then decode_sequence(type, bytes, registry)
  when TupleType then decode_tuple(type, bytes, registry)
  when StructType then decode_struct(type, bytes, registry)
  when UnitType then [[], bytes]
  when VariantType then decode_variant(type, bytes, registry)
  else raise Codec::TypeNotImplemented, "id: #{id}, type: #{type}"
  end
end

#decode_array(type, bytes, registry) ⇒ Object 



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# File 'lib/scale_rb/decode.rb', line 51

def decode_array(type, bytes, registry)
  ScaleRb.logger.debug("Decoding array: #{type}, bytes: #{bytes.length} bytes")

  len = type.len
  inner_type_id = type.type

  _decode_types([inner_type_id] * len, bytes, registry)
end

#decode_compact(bytes) ⇒ Object 



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# File 'lib/scale_rb/decode.rb', line 44

def decode_compact(bytes)
  ScaleRb.logger.debug("Decoding compact: bytes: #{bytes.length} bytes")

  CodecUtils.decode_compact(bytes)
end

#decode_primitive(type, bytes) ⇒ Object

Raises:



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# File 'lib/scale_rb/decode.rb', line 31

def decode_primitive(type, bytes)
  primitive = type.primitive.to_s
  ScaleRb.logger.debug("Decoding primitive: #{primitive}, bytes: #{bytes.length} bytes")

  return CodecUtils.decode_uint(primitive, bytes) if primitive.start_with?('U')
  return CodecUtils.decode_int(primitive, bytes) if primitive.start_with?('I')
  return CodecUtils.decode_str(bytes) if primitive == 'Str'
  return CodecUtils.decode_boolean(bytes) if primitive == 'Bool'

  raise Codec::TypeNotImplemented, "decoding primitive: #{primitive}"
end

#decode_sequence(sequence_type, bytes, registry) ⇒ Object 



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# File 'lib/scale_rb/decode.rb', line 61

def decode_sequence(sequence_type, bytes, registry)
  ScaleRb.logger.debug("Decoding sequence: #{sequence_type}, bytes: #{bytes.length} bytes")

  len, remaining_bytes = decode_compact(bytes)
  _decode_types([sequence_type.type] * len, remaining_bytes, registry)
end

#decode_struct(struct_type, bytes, registry) ⇒ Object 



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# File 'lib/scale_rb/decode.rb', line 84

def decode_struct(struct_type, bytes, registry)
  ScaleRb.logger.debug("Decoding struct: #{struct_type}, bytes: #{bytes.length} bytes")

  fields = struct_type.fields

  names = fields.map { |f| f.name.to_sym }
  type_ids = fields.map(&:type)

  values, remaining_bytes = _decode_types(type_ids, bytes, registry)
  [
    [names, values].transpose.to_h,
    remaining_bytes
  ]
end

#decode_tuple(tuple_type, bytes, registry) ⇒ Object 



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# File 'lib/scale_rb/decode.rb', line 69

def decode_tuple(tuple_type, bytes, registry)
  ScaleRb.logger.debug("Decoding tuple: #{tuple_type}, bytes: #{bytes.length} bytes")

  type_ids = tuple_type.tuple

  # NOTE: If the tuple has only one element, decode that element directly.
  # This is to make the structure of the decoded result clear.
  if type_ids.length == 1
    decode(type_ids.first, bytes, registry)
  else
    _decode_types(type_ids, bytes, registry)
  end
end

#decode_variant(variant_type, bytes, registry) ⇒ Object

Raises:



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# File 'lib/scale_rb/decode.rb', line 100

def decode_variant(variant_type, bytes, registry)
  ScaleRb.logger.debug("Decoding variant: #{variant_type}, bytes: #{bytes.length} bytes")

  # find the variant by the index
  index = bytes[0].to_i
  variant = variant_type.variants.find { |v| v.index == index }
  raise Codec::VariantIndexOutOfRange, "type: #{variant_type}, index: #{index}, bytes: #{bytes}" if variant.nil?

  # decode the variant
  case variant
  when SimpleVariant
    if variant.name == :None
      [nil, bytes[1..]]
    else
      [
        variant.name,
        bytes[1..]
      ]
    end
  when TupleVariant
    value, remainning_bytes = decode_tuple(variant.tuple, bytes[1..], registry)
    if variant.name == :Some
      [value, remainning_bytes]
    else
      [
        { variant.name => value },
        remainning_bytes
      ]
    end
  when StructVariant
    value, remainning_bytes = decode_struct(variant.struct, bytes[1..], registry)
    [
      { variant.name => value },
      remainning_bytes
    ]
  else raise 'Unreachable'
  end
end