Class: BinaryCodec::Amount

Inherits:
SerializedType show all
Defined in:
lib/binary-codec/types/amount.rb

Constant Summary collapse

DEFAULT_AMOUNT_HEX = 
"4000000000000000".freeze
ZERO_CURRENCY_AMOUNT_HEX = 
"8000000000000000".freeze
NATIVE_AMOUNT_BYTE_LENGTH = 
8
CURRENCY_AMOUNT_BYTE_LENGTH = 
48
MAX_IOU_PRECISION = 
16
MIN_IOU_EXPONENT = 
-96
MAX_IOU_EXPONENT = 
80
MAX_DROPS = 
BigDecimal("1e17")
MIN_XRP = 
BigDecimal("1e-6")
MIN_XRP_DROPS = 
1
MAX_XRP_DROPS = 
10**17

Instance Attribute Summary

Attributes inherited from SerializedType

#bytes

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from SerializedType

from_bytes, from_hex, from_json, get_type_by_name, #to_byte_sink, #to_bytes, #to_hex, #value_of

Constructor Details

#initialize(bytes = nil) ⇒ Amount

Returns a new instance of Amount.



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# File 'lib/binary-codec/types/amount.rb', line 22

def initialize(bytes = nil)
  if bytes.nil?
    bytes = hex_to_bytes(DEFAULT_AMOUNT_HEX)
  end

  @bytes = bytes
end

Class Method Details

.assert_iou_is_valid(decimal) ⇒ Object

Validate IOU.value amount

Parameters:

  • decimal (BigDecimal) —

    object representing IOU.value

Raises:

  • (ArgumentError) —

    if the amount is invalid



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# File 'lib/binary-codec/types/amount.rb', line 251

def self.assert_iou_is_valid(decimal)
  return if decimal.zero?

  p = decimal.precision
  e = (decimal.exponent || 0) - 15

  if p > MAX_IOU_PRECISION || e > MAX_IOU_EXPONENT || e < MIN_IOU_EXPONENT
    raise ArgumentError, 'Decimal precision out of range'
  end

  verify_no_decimal(decimal)
end

.assert_mpt_is_valid(amount) ⇒ void

This method returns an undefined value.

Validate MPT.value amount

Parameters:

  • amount (String) —

    representing MPT.value



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# File 'lib/binary-codec/types/amount.rb', line 268

def self.assert_mpt_is_valid(amount)
  if amount.include?('.')
    raise "#{amount} is an illegal amount"
  end

  decimal = BigDecimal(amount)
  unless decimal.zero?
    if decimal < BigDecimal("0")
      raise "#{amount} is an illegal amount"
    end

    if (amount.to_i & mpt_mask) != 0
      raise "#{amount} is an illegal amount"
    end
  end
end

.assert_xrp_is_valid(amount) ⇒ void

This method returns an undefined value.

Validate XRP amount

Parameters:

  • amount (String) —

    representing XRP amount



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# File 'lib/binary-codec/types/amount.rb', line 234

def self.assert_xrp_is_valid(amount)
  if amount.include?('.')
    raise "#{amount} is an illegal amount"
  end

  decimal = amount.to_i
  unless decimal.zero?
    if decimal < MIN_XRP_DROPS || decimal > MAX_XRP_DROPS
      raise "#{amount} is an illegal amount"
    end
  end
end

.from(value) ⇒ Amount

Construct an amount from an IOU, MPT, or string amount

Creates a new Amount instance from a value.

Parameters:

  • value (Amount, Hash, String) —

    representing the amount

  • value (Amount, String, Hash, Integer) —

    The value to convert.

Returns:

  • (Amount) —

    an Amount object

  • (Amount) —

    The created instance.

Raises:

  • (ArgumentError) 


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# File 'lib/binary-codec/types/amount.rb', line 37

def self.from(value)
  return value if value.is_a?(Amount)

  if value.is_a?(String)
    Amount.assert_xrp_is_valid(value)
    number = value.to_i
    amount_bytes = int_to_bytes(number, 8)
    amount_bytes[0] |= 0x40
    return Amount.new(amount_bytes)
  end

  if value.respond_to?(:key?)
    val = value[:value] || value['value']
    cur = value[:currency] || value['currency']
    iss = value[:issuer] || value['issuer']

    if val && cur && iss
      number = BigDecimal(val.to_s)
      
      if number.precision > MAX_IOU_PRECISION
        raise ArgumentError, 'Decimal precision out of range'
      end

      currency_inst = Currency.from(cur)
      issuer_inst = AccountId.from(iss)

      if number.zero?
        iou_bytes = [0x80, 0, 0, 0, 0, 0, 0, 0]
        return Amount.new(iou_bytes + currency_inst.to_bytes + issuer_inst.to_bytes)
      end

      is_positive = number >= 0
      abs_value = number.abs
      
      exponent = (Math.log10(abs_value.to_f).floor) - 15
      mantissa = (abs_value / (BigDecimal(10)**exponent)).to_i

      while mantissa < 1000000000000000
        mantissa *= 10
        exponent -= 1
      end
      while mantissa > 9999999999999999
        mantissa /= 10
        exponent += 1
      end

      exponent_byte = exponent + 97
      b1 = (is_positive ? 0x40 : 0) | 0x80 | (exponent_byte >> 2)
      b2 = ((exponent_byte & 0x03) << 6) | (mantissa >> 48)

      iou_bytes = [
        b1, b2,
        (mantissa >> 40) & 0xff,
        (mantissa >> 32) & 0xff,
        (mantissa >> 24) & 0xff,
        (mantissa >> 16) & 0xff,
        (mantissa >> 8) & 0xff,
        mantissa & 0xff
      ]
      return Amount.new(iou_bytes + currency_inst.to_bytes + issuer_inst.to_bytes)
    end
  end

  if value.is_a?(Integer)
    Amount.assert_xrp_is_valid(value.to_s)
    amount_bytes = int_to_bytes(value, 8)
    amount_bytes[0] |= 0x40
    return Amount.new(amount_bytes)
  end

  raise ArgumentError, "Cannot construct Amount from the value given"
end

.from_parser(parser, _size_hint = nil) ⇒ Amount

Read an amount from a BinaryParser

Creates an Amount instance from a parser.

Parameters:

  • parser (BinaryParser) —

    The BinaryParser to read the Amount from

  • parser (BinaryParser) —

    The parser to read from.

  • _size_hint (Integer, nil) (defaults to: nil) —

    Optional size hint (unused).

Returns:

  • (Amount) —

    An Amount bundle exec rspec spec/binary-codec/types/st_object_spec.rb object

  • (Amount) —

    The created instance.



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# File 'lib/binary-codec/types/amount.rb', line 118

def self.from_parser(parser, _size_hint = nil)
  is_iou = parser.peek & 0x80 != 0
  return Amount.new(parser.read(48)) if is_iou

  # The amount can be either MPT or XRP at this point
  is_mpt = parser.peek & 0x20 != 0
  num_bytes = is_mpt ? 33 : 8
  Amount.new(parser.read(num_bytes))
end

.is_amount_object_iou?(arg) ⇒ Boolean

Type guard for AmountObjectIOU

Returns:

  • (Boolean) 


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# File 'lib/binary-codec/types/amount.rb', line 206

def self.is_amount_object_iou?(arg)
  return false unless arg.is_a?(::Hash)
  
  # Handle both string and symbol keys
  processed = arg.transform_keys(&:to_s)
  
  # Log for debugging
  # puts "DEBUG: Checking if #{processed.keys.inspect} is IOU"

  processed.key?('currency') &&
    processed.key?('issuer') &&
    processed.key?('value')
end

.is_amount_object_mpt?(arg) ⇒ Boolean

Type guard for AmountObjectMPT

Returns:

  • (Boolean) 


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# File 'lib/binary-codec/types/amount.rb', line 221

def self.is_amount_object_mpt?(arg)
  return false unless arg.is_a?(::Hash)
  keys = arg.transform_keys(&:to_s).keys.sort

  keys.length == 2 &&
    keys[0] == 'mpt_issuance_id' &&
    keys[1] == 'value'
end

.verify_no_decimal(decimal) ⇒ String

Ensure that the value, after being multiplied by the exponent, does not contain a decimal. This function is typically used to validate numbers that need to be represented as precise integers after scaling, such as amounts in financial transactions. Example failure:1.1234567891234567

Parameters:

  • decimal (BigDecimal) —

    A BigDecimal object

Returns:

  • (String) —

    The decimal converted to a string without a decimal point

Raises:

  • (ArgumentError) —

    if the value contains a decimal



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# File 'lib/binary-codec/types/amount.rb', line 293

def self.verify_no_decimal(decimal)
  # p is the number of significant digits
  # e is the power of 10 to multiply by the mantissa to get the number
  # BigDecimal('1.1234567891234567').precision => 17
  if decimal.precision > MAX_IOU_PRECISION
    raise ArgumentError, 'Decimal precision out of range'
  end
end

Instance Method Details

#to_json(_definitions = nil, _field_name = nil) ⇒ Hash, String

The JSON representation of this Amount

Returns the JSON representation of the Amount.

Parameters:

  • _definitions (Definitions, nil) (defaults to: nil) —

    Unused.

  • _field_name (String, nil) (defaults to: nil) —

    Optional field name.

Returns:

  • (Hash, String) —

    The JSON interpretation of this.bytes

  • (String, Hash) —

    The JSON representation.



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# File 'lib/binary-codec/types/amount.rb', line 135

def to_json(_definitions = nil, _field_name = nil)
  if is_native?
    bytes = @bytes.dup
    is_positive = (bytes[0] & 0x40) != 0
    sign = is_positive ? '' : '-'
    bytes[0] &= 0x3f

    msb = BinaryCodec.read_uint32be(bytes[0, 4])
    lsb = BinaryCodec.read_uint32be(bytes[4, 4])
    num = (msb << 32) | lsb

    return "#{sign}#{num}"
  end

  if is_iou?
    parser = BinaryParser.new(to_hex)
    mantissa_bytes = parser.read(8)
    currency = Currency.from_parser(parser)
    issuer = AccountId.from_parser(parser)

    b1 = mantissa_bytes[0]
    b2 = mantissa_bytes[1]

    is_positive = (b1 & 0x40) != 0
    exponent = ((b1 & 0x3f) << 2) + ((b2 & 0xff) >> 6) - 97

    mantissa_bytes[0] = 0
    mantissa_bytes[1] &= 0x3f
    
    # Convert mantissa bytes to integer
    mantissa_int = mantissa_bytes.reduce(0) { |acc, b| (acc << 8) + b }
    
    # value = mantissa * 10^exponent
    value = BigDecimal(mantissa_int) * (BigDecimal(10)**exponent)
    value = -value unless is_positive
    
    # Format the value string to match xrpl.js (stripping trailing .0)
    formatted_value = value.to_s('F').sub(/\.0$/, '')

    return {
      "value" => formatted_value,
      "currency" => currency.to_json,
      "issuer" => issuer.to_json
    }
  end

  if is_mpt?
    parser = BinaryParser.new(to_hex)
    leading_byte = parser.read(1)
    amount_bytes = parser.read(8)
    mpt_id = Hash192.from_parser(parser)

    is_positive = (leading_byte[0] & 0x40) != 0
    sign = is_positive ? '' : '-'

    msb = BinaryCodec.read_uint32be(amount_bytes[0, 4])
    lsb = BinaryCodec.read_uint32be(amount_bytes[4, 4])
    num = (msb << 32) | lsb

    return {
      "value" => "#{sign}#{num}",
      "mpt_issuance_id" => mpt_id.to_hex
    }
  end

  raise 'Invalid amount to construct JSON'
end