Class: Tapyrus::Message::HeaderAndShortIDs

Inherits:
Object
  • Object
show all
Defined in:
lib/tapyrus/message/header_and_short_ids.rb

Overview

BIP-152 Compact Block’s data format. github.com/bitcoin/bips/blob/master/bip-0152.mediawiki#HeaderAndShortIDs

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(header, nonce, short_ids = [], prefilled_txn = []) ⇒ HeaderAndShortIDs

Returns a new instance of HeaderAndShortIDs.



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# File 'lib/tapyrus/message/header_and_short_ids.rb', line 13

def initialize(header, nonce, short_ids = [], prefilled_txn = [])
  @header = header
  @nonce = nonce
  @short_ids = short_ids
  @prefilled_txn = prefilled_txn
  @siphash_key = Tapyrus.sha256(header.to_payload << [nonce].pack("q*"))[0...16]
end

Instance Attribute Details

#header ⇒ Object

Returns the value of attribute header.



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# File 'lib/tapyrus/message/header_and_short_ids.rb', line 7

def header
  @header
end

#nonce ⇒ Object

Returns the value of attribute nonce.



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# File 'lib/tapyrus/message/header_and_short_ids.rb', line 8

def nonce
  @nonce
end

#prefilled_txn ⇒ Object

Returns the value of attribute prefilled_txn.



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# File 'lib/tapyrus/message/header_and_short_ids.rb', line 10

def prefilled_txn
  @prefilled_txn
end

#short_ids ⇒ Object

Returns the value of attribute short_ids.



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# File 'lib/tapyrus/message/header_and_short_ids.rb', line 9

def short_ids
  @short_ids
end

#siphash_key ⇒ Object

Returns the value of attribute siphash_key.



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# File 'lib/tapyrus/message/header_and_short_ids.rb', line 11

def siphash_key
  @siphash_key
end

Class Method Details

.parse_from_payload(payload) ⇒ Object 



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# File 'lib/tapyrus/message/header_and_short_ids.rb', line 21

def self.parse_from_payload(payload)
  buf = StringIO.new(payload)
  header = Tapyrus::BlockHeader.parse_from_payload(buf)
  nonce = buf.read(8).unpack("q*").first
  short_ids_len = Tapyrus.unpack_var_int_from_io(buf)
  short_ids = short_ids_len.times.map { buf.read(6).reverse.bth.to_i(16) }
  prefilled_txn_len = Tapyrus.unpack_var_int_from_io(buf)
  prefilled_txn = prefilled_txn_len.times.map { PrefilledTx.parse_from_io(buf) }
  self.new(header, nonce, short_ids, prefilled_txn)
end

Instance Method Details

#short_id(txid) ⇒ Integer

calculate short transaction id which specified by BIP-152.

Parameters:

  • txid (String) —

    a transaction id

Returns:

  • (Integer) —

    6 bytes short transaction id.



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# File 'lib/tapyrus/message/header_and_short_ids.rb', line 45

def short_id(txid)
  hash = SipHash.digest(siphash_key, txid.htb.reverse).to_even_length_hex
  [hash].pack("H*")[2...8].bth.to_i(16)
end

#to_payload ⇒ Object 



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# File 'lib/tapyrus/message/header_and_short_ids.rb', line 32

def to_payload
  p = header.to_payload
  p << [nonce].pack("q*")
  p << Tapyrus.pack_var_int(short_ids.size)
  p << short_ids.map { |id| sprintf("%12x", id).htb.reverse }.join
  p << Tapyrus.pack_var_int(prefilled_txn.size)
  p << prefilled_txn.map(&:to_payload).join
  p
end