Class: BTC::BlockHeader

Inherits:
Object
  • Object
show all
Defined in:
lib/btcruby/block_header.rb

Overview

Block header is the 80-byte prefix of the block. Nodes collect new transactions into a block, hash them into a hash tree, and scan through nonce values to make the block’s hash satisfy proof-of-work requirements. When they solve the proof-of-work, they broadcast the block to everyone and the block is added to the block chain. The first transaction in the block is a special one that creates a new coin owned by the creator of the block.

Direct Known Subclasses

Block

Constant Summary collapse

CURRENT_VERSION = 
2
ZERO_HASH256 = 
"\x00".b*32

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(data: nil, stream: nil, version: CURRENT_VERSION, previous_block_hash: nil, previous_block_id: nil, merkle_root: nil, timestamp: 0, time: nil, bits: 0, nonce: 0, height: nil, confirmations: nil) ⇒ BlockHeader

Returns a new instance of BlockHeader.



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# File 'lib/btcruby/block_header.rb', line 78

def initialize(data: nil,
               stream: nil,
               version: CURRENT_VERSION,
               previous_block_hash: nil,
               previous_block_id: nil,
               merkle_root: nil,
               timestamp: 0,
               time: nil,
               bits: 0,
               nonce: 0,

               # optional attributes
               height: nil,
               confirmations: nil)

  if stream || data
    init_with_stream(stream || StringIO.new(data))
  else
    @version = version || CURRENT_VERSION
    @previous_block_hash = previous_block_hash || ZERO_HASH256
    @previous_block_hash = BTC.hash_from_id(previous_block_id) if previous_block_id
    @merkle_root = merkle_root || ZERO_HASH256
    @timestamp   = timestamp   || 0
    @timestamp   = time.to_i if time
    @bits        = bits        || 0
    @nonce       = nonce       || 0
  end

  @height = height
  @confirmations = confirmations
end

Instance Attribute Details

#bits ⇒ Object

uint32 proof-of-work in compact format



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# File 'lib/btcruby/block_header.rb', line 39

def bits
  @bits
end

#block_hash ⇒ Object (readonly)

Binary hash of the block



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# File 'lib/btcruby/block_header.rb', line 15

def block_hash
  @block_hash
end

#block_id ⇒ Object (readonly)

Hex big-endian hash of the block



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# File 'lib/btcruby/block_header.rb', line 18

def block_id
  @block_id
end

#confirmations ⇒ Object

The number of blocks that have been processed since the previous block (including the block itself).



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# File 'lib/btcruby/block_header.rb', line 52

def confirmations
  @confirmations
end

#height ⇒ Object

The distance from the first block in the chain (genesis block has height 0).



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# File 'lib/btcruby/block_header.rb', line 49

def height
  @height
end

#merkle_root ⇒ Object

Raw binary root hash of the transaction merkle tree.



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# File 'lib/btcruby/block_header.rb', line 30

def merkle_root
  @merkle_root
end

#nonce ⇒ Object

uint32 nonce (used for mining iterations)



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# File 'lib/btcruby/block_header.rb', line 42

def nonce
  @nonce
end

#previous_block_hash ⇒ Object

Binary hash of the previous block



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# File 'lib/btcruby/block_header.rb', line 24

def previous_block_hash
  @previous_block_hash
end

#previous_block_id ⇒ Object

Hex big-endian hash of the previous block



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# File 'lib/btcruby/block_header.rb', line 27

def previous_block_id
  @previous_block_id
end

#time ⇒ Object

Time object derived from timestamp



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# File 'lib/btcruby/block_header.rb', line 36

def time
  @time
end

#timestamp ⇒ Object

uint32 unix timestamp



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# File 'lib/btcruby/block_header.rb', line 33

def timestamp
  @timestamp
end

#version ⇒ Object

Block version.



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# File 'lib/btcruby/block_header.rb', line 21

def version
  @version
end

Class Method Details

.genesis_mainnet ⇒ Object 



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# File 'lib/btcruby/block_header.rb', line 54

def self.genesis_mainnet
  self.new(
    version:             1,
    previous_block_hash: ZERO_HASH256,
    merkle_root:         BTC.from_hex("3ba3edfd7a7b12b27ac72c3e67768f617fc81bc3888a51323a9fb8aa4b1e5e4a"),
    timestamp:           1231006505,
    bits:                0x1d00ffff,
    nonce:               0x7c2bac1d,
    height:              0
  )
end

.genesis_testnet ⇒ Object 



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# File 'lib/btcruby/block_header.rb', line 66

def self.genesis_testnet
  self.new(
    version:             1,
    previous_block_hash: ZERO_HASH256,
    merkle_root:         BTC.from_hex("3ba3edfd7a7b12b27ac72c3e67768f617fc81bc3888a51323a9fb8aa4b1e5e4a"),
    timestamp:           1296688602,
    bits:                0x1d00ffff,
    nonce:               0x18aea41a,
    height:              0
  )
end

Instance Method Details

#==(other) ⇒ Object Also known as: eql? 



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# File 'lib/btcruby/block_header.rb', line 187

def ==(other)
              @version == other.version &&
  @previous_block_hash == other.previous_block_hash &&
          @merkle_root == other.merkle_root &&
            @timestamp == other.timestamp &&
                 @bits == other.bits &&
                @nonce == other.nonce
end

#data ⇒ Object 



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# File 'lib/btcruby/block_header.rb', line 172

def data
  header_data
end

#dup ⇒ Object 



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# File 'lib/btcruby/block_header.rb', line 197

def dup
  self.class.new(
    version:             self.version,
    previous_block_hash: self.previous_block_hash,
    merkle_root:         self.merkle_root,
    timestamp:           self.timestamp,
    bits:                self.bits,
    nonce:               self.nonce,
    height:              self.height,
    confirmations:       self.confirmations)
end

#header_data ⇒ Object

so that in subclass Block we don’t hash the entire block



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# File 'lib/btcruby/block_header.rb', line 176

def header_data # so that in subclass Block we don't hash the entire block
  data = "".b
  data << BTC::WireFormat.encode_int32le(self.version)
  data << self.previous_block_hash
  data << self.merkle_root
  data << BTC::WireFormat.encode_uint32le(self.timestamp)
  data << BTC::WireFormat.encode_uint32le(self.bits)
  data << BTC::WireFormat.encode_uint32le(self.nonce)
  data
end

#init_with_stream(stream) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/btcruby/block_header.rb', line 110

def init_with_stream(stream)
  raise ArgumentError, "Stream is missing" if !stream
  if stream.eof?
    raise ArgumentError, "Can't parse block header from stream because it is already closed."
  end

  if !(version = BTC::WireFormat.read_int32le(stream: stream).first)
    raise ArgumentError, "Failed to read block version prefix from the stream."
  end

  if !(prevhash = stream.read(32)) || prevhash.bytesize != 32
    raise ArgumentError, "Failed to read 32-byte previous_block_hash from the stream."
  end

  if !(mrklroot = stream.read(32)) || mrklroot.bytesize != 32
    raise ArgumentError, "Failed to read 32-byte block merkle_root from the stream."
  end

  if !(timestamp = BTC::WireFormat.read_uint32le(stream: stream).first)
    raise ArgumentError, "Failed to read 32-byte block timestamp from the stream."
  end

  if !(bits = BTC::WireFormat.read_uint32le(stream: stream).first)
    raise ArgumentError, "Failed to read 32-byte proof-of-work bits from the stream."
  end

  if !(nonce = BTC::WireFormat.read_uint32le(stream: stream).first)
    raise ArgumentError, "Failed to read 32-byte nonce from the stream."
  end

  @version = version
  @previous_block_hash = prevhash
  @merkle_root = mrklroot
  @timestamp = timestamp
  @bits = bits
  @nonce = nonce
end

#inspect ⇒ Object 



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# File 'lib/btcruby/block_header.rb', line 209

def inspect
  %{#<#{self.class.name}:#{self.block_id[0,24]}} +
  %{ ver:#{self.version}} +
  %{ prev:#{self.previous_block_id[0,24]}} +
  %{ merkle_root:#{BTC.id_from_hash(self.merkle_root)[0,16]}} +
  %{ timestamp:#{self.timestamp}} +
  %{ bits:0x#{self.bits.to_s(16)}} +
  %{ nonce:0x#{self.nonce.to_s(16)}} +
  %{>}
end