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defmodule Boltex.PackStream do
@moduledoc """
The PackStream implementation for Bolt.
This module defines a decode function, that will take a binary stream of data
and recursively turn it into a list of Elixir data types.
It further defines a function for encoding Elixir data types into a binary
stream, using the Boltex.PackStream.Encoder protocol.
"""
@doc """
Encodes a list of items into their binary representation.
As developers tend to be lazy, single objects may be passed.
## Examples
iex> Boltex.PackStream.encode "hello world"
<<0x8B, 0x68, 0x65, 0x6C, 0x6C, 0x6F, 0x20, 0x77, 0x6F, 0x72, 0x6C, 0x64>>
"""
def encode(item), do: Boltex.PackStream.Encoder.encode(item)
##
# Decode
@doc "Decodes a binary stream recursively into Elixir data types"
# Null
def decode(<< 0xC0, rest :: binary >>), do: [nil| decode(rest)]
# Boolean
def decode(<< 0xC3, rest :: binary >>), do: [true | decode(rest)]
def decode(<< 0xC2, rest :: binary >>), do: [false | decode(rest)]
# Float
def decode(<< 0xC1, number :: float, rest :: binary >>) do
[number | decode(rest)]
end
# Strings
def decode(<< 0x8 :: 4, str_length :: 4, rest :: bytes >>) do
decode_text rest, str_length
end
def decode(<< 0xD0, str_length, rest :: bytes >>) do
decode_text rest, str_length
end
def decode(<< 0xD1, str_length :: 16, rest :: bytes >>) do
decode_text rest, str_length
end
def decode(<< 0xD2, str_length :: 32, rest :: binary >>) do
decode_text rest, str_length
end
# Lists
# FIXME: Make sure list size is correct, only collect items within list-size.
def decode(<< 0x9 :: 4, _list_size :: 4, list :: binary >>), do: [decode list]
def decode(<< 0xD4, _list_size :: 8, list :: binary >>), do: [decode list]
def decode(<< 0xD5, _list_size :: 16, list :: binary >>), do: [decode list]
def decode(<< 0xD6, _list_size :: 32, list :: binary >>), do: [decode list]
def decode(<< 0xD7, list :: binary >>) do
position =
for(<<byte <- list>>, do: byte)
|> Enum.find_index(&(&1 == 0xDF))
<< list :: binary-size(position), 0xDF, rest :: binary >> = list
[decode(list) | decode(rest)]
end
# Maps
# FIXME: Make sure map size is correct, only collect items within map-size.
def decode(<< 0xA :: 4, _entries :: 4, map :: binary>>), do: decode_map(map)
def decode(<< 0xD8, _entries, map :: binary >>), do: decode_map(map)
def decode(<< 0xD9, _entries :: 16, map :: binary >>), do: decode_map(map)
def decode(<< 0xDA, _entries :: 32, map :: binary >>), do: decode_map(map)
def decode(<< 0xDB, map :: binary >>) do
position =
for(<<byte <- map>>, do: byte)
|> Enum.find_index(&(&1 == 0xDF))
<< map:: binary-size(position), 0xDF, rest :: binary >> = map
decode_map(map) ++ decode(rest)
end
# Struct
def decode(<< 0xB :: 4, _struct_size :: 4, sig :: 8>> <> struct) do
[sig: sig, fields: decode(struct)]
end
def decode(<<0, 0>>), do: []
def decode(""), do: []
# Integers
def decode(<< 0xC8, int, rest :: binary >>), do: [int | decode(rest)]
def decode(<< 0xC9, int :: 16, rest :: binary >>), do: [int | decode(rest)]
def decode(<< 0xCA, int :: 32, rest :: binary >>), do: [int | decode(rest)]
def decode(<< 0xCB, int :: 64, rest :: binary >>), do: [int | decode(rest)]
def decode(<< int, rest :: binary >>), do: [int | decode(rest)]
defp decode_text(bytes, str_length) do
<< string :: binary-size(str_length), rest :: binary >> = bytes
[string | decode(rest)]
end
defp decode_map(map) do
decode(map)
|> Enum.chunk(2)
|> Enum.map(&List.to_tuple/1)
|> Enum.into(%{})
|> List.wrap
end
end
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