Class: OpenC3::BinaryAccessor

Inherits:
Accessor show all
Defined in:
lib/openc3/accessors/binary_accessor.rb,
ext/openc3/ext/structure/structure.c

Overview

Provides methods for binary reading and writing

Constant Summary collapse

PACK_8_BIT_INT =

Constants for ruby packing directives

'c'
PACK_NATIVE_16_BIT_INT = 
's'
PACK_LITTLE_ENDIAN_16_BIT_UINT = 
'v'
PACK_BIG_ENDIAN_16_BIT_UINT = 
'n'
PACK_NATIVE_32_BIT_INT = 
'l'
PACK_NATIVE_32_BIT_UINT = 
'L'
PACK_NATIVE_64_BIT_INT = 
'q'
PACK_NATIVE_64_BIT_UINT = 
'Q'
PACK_LITTLE_ENDIAN_32_BIT_UINT = 
'V'
PACK_BIG_ENDIAN_32_BIT_UINT = 
'N'
PACK_LITTLE_ENDIAN_32_BIT_FLOAT = 
'e'
PACK_LITTLE_ENDIAN_64_BIT_FLOAT = 
'E'
PACK_BIG_ENDIAN_32_BIT_FLOAT = 
'g'
PACK_BIG_ENDIAN_64_BIT_FLOAT = 
'G'
PACK_NULL_TERMINATED_STRING = 
'Z*'
PACK_BLOCK = 
'a*'
PACK_8_BIT_INT_ARRAY = 
'c*'
PACK_8_BIT_UINT_ARRAY = 
'C*'
PACK_NATIVE_16_BIT_INT_ARRAY = 
's*'
PACK_BIG_ENDIAN_16_BIT_UINT_ARRAY = 
'n*'
PACK_LITTLE_ENDIAN_16_BIT_UINT_ARRAY = 
'v*'
PACK_NATIVE_32_BIT_INT_ARRAY = 
'l*'
PACK_BIG_ENDIAN_32_BIT_UINT_ARRAY = 
'N*'
PACK_LITTLE_ENDIAN_32_BIT_UINT_ARRAY = 
'V*'
PACK_NATIVE_64_BIT_INT_ARRAY = 
'q*'
PACK_NATIVE_64_BIT_UINT_ARRAY = 
'Q*'
PACK_LITTLE_ENDIAN_32_BIT_FLOAT_ARRAY = 
'e*'
PACK_LITTLE_ENDIAN_64_BIT_FLOAT_ARRAY = 
'E*'
PACK_BIG_ENDIAN_32_BIT_FLOAT_ARRAY = 
'g*'
PACK_BIG_ENDIAN_64_BIT_FLOAT_ARRAY = 
'G*'
MIN_INT8 = 
MIN_INT8
MAX_INT8 = 
MAX_INT8
MAX_UINT8 = 
MAX_UINT8
MIN_INT16 = 
MIN_INT16
MAX_INT16 = 
MAX_INT16
MAX_UINT16 = 
MAX_UINT16
MIN_INT32 = 
MIN_INT32
MAX_INT32 = 
MAX_INT32
MAX_UINT32 = 
MAX_UINT32
MIN_INT64 = 
MIN_INT64
MAX_INT64 = 
MAX_INT64
MAX_UINT64 = 
MAX_UINT64
ZERO_STRING =

Additional Constants

"\000"
DATA_TYPES =

Valid data types

[:INT, :UINT, :FLOAT, :STRING, :BLOCK]
OVERFLOW_TYPES =

Valid overflow types

[:TRUNCATE, :SATURATE, :ERROR, :ERROR_ALLOW_HEX]
HOST_ENDIANNESS =

Store the host endianness so that it only has to be determined once

get_host_endianness()
ENDIANNESS =

Valid endianess

[:BIG_ENDIAN, :LITTLE_ENDIAN]

Instance Attribute Summary

Attributes inherited from Accessor

#packet

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Accessor

#args, convert_to_type, #initialize, #read_items, read_items, #write_items, write_items

Constructor Details

This class inherits a constructor from OpenC3::Accessor

Class Method Details

.adjust_packed_size(num_bytes, packed) ⇒ Object

Adjusts the packed array to be the given number of bytes

Parameters:

  • num_bytes (Integer) —

    The desired number of bytes

  • packed (Array) —

    The packed data buffer



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# File 'lib/openc3/accessors/binary_accessor.rb', line 1302

def self.adjust_packed_size(num_bytes, packed)
  difference = num_bytes - packed.length
  if difference > 0
    packed << (ZERO_STRING * difference)
  elsif difference < 0
    packed = packed[0..(packed.length - 1 + difference)]
  end
  packed
end

.byte_aligned(value) ⇒ Object 



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# File 'lib/openc3/accessors/binary_accessor.rb', line 860

def self.byte_aligned(value)
  (value % 8) == 0
end

.byte_swap_buffer(buffer, num_bytes_per_word) ⇒ String

Byte swaps every X bytes of data in a buffer into a new buffer

Parameters:

  • buffer (String) —

    Buffer that will be copied then modified

  • num_bytes_per_word (Integer) —

    Number of bytes per word that will be swapped

Returns:

  • (String) —

    modified buffer



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# File 'lib/openc3/accessors/binary_accessor.rb', line 1333

def self.byte_swap_buffer(buffer, num_bytes_per_word)
  buffer = buffer.clone
  self.byte_swap_buffer!(buffer, num_bytes_per_word)
end

.byte_swap_buffer!(buffer, num_bytes_per_word) ⇒ String

Byte swaps every X bytes of data in a buffer overwriting the buffer

Parameters:

  • buffer (String) —

    Buffer to modify

  • num_bytes_per_word (Integer) —

    Number of bytes per word that will be swapped

Returns:

  • (String) —

    buffer passed in as a parameter



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# File 'lib/openc3/accessors/binary_accessor.rb', line 1317

def self.byte_swap_buffer!(buffer, num_bytes_per_word)
  num_swaps = buffer.length / num_bytes_per_word
  index = 0
  num_swaps.times do
    range = index..(index + num_bytes_per_word - 1)
    buffer[range] = buffer[range].reverse
    index += num_bytes_per_word
  end
  buffer
end

.check_bit_offset_and_size(read_or_write, given_bit_offset, given_bit_size, data_type, buffer) ⇒ Object

Check the bit size and bit offset for problems. Recalulate the bit offset and return back through the passed in pointer.



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# File 'lib/openc3/accessors/binary_accessor.rb', line 754

def self.check_bit_offset_and_size(read_or_write, given_bit_offset, given_bit_size, data_type, buffer)
  bit_offset = given_bit_offset

  if (given_bit_size <= 0) && (data_type != :STRING) && (data_type != :BLOCK)
    raise(ArgumentError, "bit_size #{given_bit_size} must be positive for data types other than :STRING and :BLOCK")
  end

  if (given_bit_size <= 0) && (given_bit_offset < 0)
    raise(ArgumentError, "negative or zero bit_sizes (#{given_bit_size}) cannot be given with negative bit_offsets (#{given_bit_offset})")
  end

  if given_bit_offset < 0
    bit_offset = (buffer.length * 8) + bit_offset
    if bit_offset < 0
      raise_buffer_error(read_or_write, buffer, data_type, given_bit_offset, given_bit_size)
    end
  end

  return bit_offset
end

.check_bounds_and_buffer_size(bit_offset, bit_size, buffer_length, endianness, data_type) ⇒ Object

Calculate the bounds of the string to access the item based on the bit_offset and bit_size. Also determine if the buffer size is sufficient.



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# File 'lib/openc3/accessors/binary_accessor.rb', line 777

def self.check_bounds_and_buffer_size(bit_offset, bit_size, buffer_length, endianness, data_type)
  result = true # Assume ok

  # Define bounds of string to access this item
  lower_bound = bit_offset / 8
  upper_bound = (bit_offset + bit_size - 1) / 8

  # Sanity check buffer size
  if upper_bound >= buffer_length
    # If it's not the special case of little endian bit field then we fail and return false
    if !((endianness == :LITTLE_ENDIAN) &&
           ((data_type == :INT) || (data_type == :UINT)) &&
           # Not byte aligned with an even bit size
           (!((byte_aligned(bit_offset)) && (even_bit_size(bit_size)))) &&
           (lower_bound < buffer_length)
        )
      result = false
    end
  end
  return result, lower_bound, upper_bound
end

.check_overflow(value, min_value, max_value, hex_max_value, bit_size, data_type, overflow) ⇒ Integer

Checks for overflow of an integer data type

Parameters:

  • value (Integer) —

    Value to write into the buffer

  • min_value (Integer) —

    Minimum allowed value

  • max_value (Integer) —

    Maximum allowed value

  • hex_max_value (Integer) —

    Maximum allowed value if specified in hex

  • bit_size (Integer) —

    Size of the item in bits

  • data_type (Symbol) —

    DATA_TYPES

  • overflow (Symbol) —

    OVERFLOW_TYPES

Returns:

  • (Integer) —

    Potentially modified value



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# File 'lib/openc3/accessors/binary_accessor.rb', line 1348

def self.check_overflow(value, min_value, max_value, hex_max_value, bit_size, data_type, overflow)
  if overflow == :TRUNCATE
    # Note this will always convert to unsigned equivalent for signed integers
    value = value % (hex_max_value + 1)
  else
    if value > max_value
      if overflow == :SATURATE
        value = max_value
      else
        if overflow == :ERROR or value > hex_max_value
          raise ArgumentError, "value of #{value} invalid for #{bit_size}-bit #{data_type}"
        end
      end
    elsif value < min_value
      if overflow == :SATURATE
        value = min_value
      else
        raise ArgumentError, "value of #{value} invalid for #{bit_size}-bit #{data_type}"
      end
    end
  end
  value
end

.check_overflow_array(values, min_value, max_value, hex_max_value, bit_size, data_type, overflow) ⇒ Array[Integer]

Checks for overflow of an array of integer data types

Parameters:

  • values (Array[Integer]) —

    Values to write into the buffer

  • min_value (Integer) —

    Minimum allowed value

  • max_value (Integer) —

    Maximum allowed value

  • hex_max_value (Integer) —

    Maximum allowed value if specified in hex

  • bit_size (Integer) —

    Size of the item in bits

  • data_type (Symbol) —

    DATA_TYPES

  • overflow (Symbol) —

    OVERFLOW_TYPES

Returns:

  • (Array[Integer]) —

    Potentially modified values



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# File 'lib/openc3/accessors/binary_accessor.rb', line 1382

def self.check_overflow_array(values, min_value, max_value, hex_max_value, bit_size, data_type, overflow)
  if overflow != :TRUNCATE
    values.each_with_index do |value, index|
      values[index] = check_overflow(value, min_value, max_value, hex_max_value, bit_size, data_type, overflow)
    end
  end
  values
end

.even_bit_size(bit_size) ⇒ Object 



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# File 'lib/openc3/accessors/binary_accessor.rb', line 864

def self.even_bit_size(bit_size)
  (bit_size == 8) || (bit_size == 16) || (bit_size == 32) || (bit_size == 64)
end

.get_check_overflow_ranges(bit_size, data_type) ⇒ Object 



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# File 'lib/openc3/accessors/binary_accessor.rb', line 799

def self.get_check_overflow_ranges(bit_size, data_type)
  min_value = 0 # Default for UINT cases

  case bit_size
  when 8
    hex_max_value = MAX_UINT8
    if data_type == :INT
      min_value = MIN_INT8
      max_value = MAX_INT8
    else
      max_value = MAX_UINT8
    end
  when 16
    hex_max_value = MAX_UINT16
    if data_type == :INT
      min_value = MIN_INT16
      max_value = MAX_INT16
    else
      max_value = MAX_UINT16
    end
  when 32
    hex_max_value = MAX_UINT32
    if data_type == :INT
      min_value = MIN_INT32
      max_value = MAX_INT32
    else
      max_value = MAX_UINT32
    end
  when 64
    hex_max_value = MAX_UINT64
    if data_type == :INT
      min_value = MIN_INT64
      max_value = MAX_INT64
    else
      max_value = MAX_UINT64
    end
  else # Bitfield
    if data_type == :INT
      # Note signed integers must allow up to the maximum unsigned value to support values given in hex
      if bit_size > 1
        max_value = 2**(bit_size - 1)
        # min_value = -(2 ** bit_size - 1)
        min_value = -max_value
        # max_value = (2 ** bit_size - 1) - 1
        max_value -= 1
        # hex_max_value = (2 ** bit_size) - 1
        hex_max_value = (2**bit_size) - 1
      else # 1-bit signed
        min_value = -1
        max_value = 1
        hex_max_value = 1
      end
    else
      max_value = (2**bit_size) - 1
      hex_max_value = max_value
    end
  end

  return min_value, max_value, hex_max_value
end

.get_host_endianness ⇒ Symbol

Determines the endianness of the host running this code

This method is protected to force the use of the constant HOST_ENDIANNESS rather than this method

Returns:

  • (Symbol) —

    :BIG_ENDIAN or :LITTLE_ENDIAN



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# File 'lib/openc3/accessors/binary_accessor.rb', line 94

def self.get_host_endianness
  value = 0x01020304
  packed = [value].pack(PACK_NATIVE_32_BIT_UINT)
  unpacked = packed.unpack(PACK_LITTLE_ENDIAN_32_BIT_UINT)[0]
  if unpacked == value
    :LITTLE_ENDIAN
  else
    :BIG_ENDIAN
  end
end

.raise_buffer_error(read_write, buffer, data_type, given_bit_offset, given_bit_size) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/openc3/accessors/binary_accessor.rb', line 105

def self.raise_buffer_error(read_write, buffer, data_type, given_bit_offset, given_bit_size)
  raise ArgumentError, "#{buffer.length} byte buffer insufficient to #{read_write} #{data_type} at bit_offset #{given_bit_offset} with bit_size #{given_bit_size}"
end

.read(param_bit_offset, param_bit_size, param_data_type, param_buffer, param_endianness) ⇒ Integer

Reads binary data of any data type from a buffer

Parameters:

  • bit_offset (Integer) —

    Bit offset to the start of the item. A negative number means to offset from the end of the buffer.

  • bit_size (Integer) —

    Size of the item in bits

  • data_type (Symbol) —

    DATA_TYPES

  • buffer (String) —

    Binary string buffer to read from

  • endianness (Symbol) —

    ENDIANNESS

Returns:

  • (Integer) —

    value read from the buffer



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# File 'lib/openc3/accessors/binary_accessor.rb', line 307

def self.read(bit_offset, bit_size, data_type, buffer, endianness)
  given_bit_offset = bit_offset
  given_bit_size = bit_size

  bit_offset = check_bit_offset_and_size(:read, given_bit_offset, given_bit_size, data_type, buffer)

  # If passed a negative bit size with strings or blocks
  # recalculate based on the buffer length
  if (bit_size <= 0) && ((data_type == :STRING) || (data_type == :BLOCK))
    bit_size = (buffer.length * 8) - bit_offset + bit_size
    if bit_size == 0
      return ""
    elsif bit_size < 0
      raise_buffer_error(:read, buffer, data_type, given_bit_offset, given_bit_size)
    end
  end

  result, lower_bound, upper_bound = check_bounds_and_buffer_size(bit_offset, bit_size, buffer.length, endianness, data_type)
  raise_buffer_error(:read, buffer, data_type, given_bit_offset, given_bit_size) unless result

  if (data_type == :STRING) || (data_type == :BLOCK)
    #######################################
    # Handle :STRING and :BLOCK data types
    #######################################

    if byte_aligned(bit_offset)
      if data_type == :STRING
        return buffer[lower_bound..upper_bound].unpack('Z*')[0]
      else
        return buffer[lower_bound..upper_bound].unpack('a*')[0]
      end
    else
      raise(ArgumentError, "bit_offset #{given_bit_offset} is not byte aligned for data_type #{data_type}")
    end

  elsif (data_type == :INT) || (data_type == :UINT)
    ###################################
    # Handle :INT and :UINT data types
    ###################################

    if byte_aligned(bit_offset) && even_bit_size(bit_size)

      if data_type == :INT
        ###########################################################
        # Handle byte-aligned 8, 16, 32, and 64 bit :INT
        ###########################################################

        case bit_size
        when 8
          return buffer[lower_bound].unpack(PACK_8_BIT_INT)[0]
        when 16
          if endianness == HOST_ENDIANNESS
            return buffer[lower_bound..upper_bound].unpack(PACK_NATIVE_16_BIT_INT)[0]
          else # endianness != HOST_ENDIANNESS
            temp = buffer[lower_bound..upper_bound].reverse
            return temp.unpack(PACK_NATIVE_16_BIT_INT)[0]
          end
        when 32
          if endianness == HOST_ENDIANNESS
            return buffer[lower_bound..upper_bound].unpack(PACK_NATIVE_32_BIT_INT)[0]
          else # endianness != HOST_ENDIANNESS
            temp = buffer[lower_bound..upper_bound].reverse
            return temp.unpack(PACK_NATIVE_32_BIT_INT)[0]
          end
        when 64
          if endianness == HOST_ENDIANNESS
            return buffer[lower_bound..upper_bound].unpack(PACK_NATIVE_64_BIT_INT)[0]
          else # endianness != HOST_ENDIANNESS
            temp = buffer[lower_bound..upper_bound].reverse
            return temp.unpack(PACK_NATIVE_64_BIT_INT)[0]
          end
        end
      else # data_type == :UINT
        ###########################################################
        # Handle byte-aligned 8, 16, 32, and 64 bit :UINT
        ###########################################################

        case bit_size
        when 8
          return buffer.getbyte(lower_bound)
        when 16
          if endianness == :BIG_ENDIAN
            return buffer[lower_bound..upper_bound].unpack(PACK_BIG_ENDIAN_16_BIT_UINT)[0]
          else # endianness == :LITTLE_ENDIAN
            return buffer[lower_bound..upper_bound].unpack(PACK_LITTLE_ENDIAN_16_BIT_UINT)[0]
          end
        when 32
          if endianness == :BIG_ENDIAN
            return buffer[lower_bound..upper_bound].unpack(PACK_BIG_ENDIAN_32_BIT_UINT)[0]
          else # endianness == :LITTLE_ENDIAN
            return buffer[lower_bound..upper_bound].unpack(PACK_LITTLE_ENDIAN_32_BIT_UINT)[0]
          end
        when 64
          if endianness == HOST_ENDIANNESS
            return buffer[lower_bound..upper_bound].unpack(PACK_NATIVE_64_BIT_UINT)[0]
          else # endianness != HOST_ENDIANNESS
            temp = buffer[lower_bound..upper_bound].reverse
            return temp.unpack(PACK_NATIVE_64_BIT_UINT)[0]
          end
        end
      end

    else
      ##########################
      # Handle :INT and :UINT Bitfields
      ##########################

      # Extract Data for Bitfield
      if endianness == :LITTLE_ENDIAN
        # Bitoffset always refers to the most significant bit of a bitfield
        num_bytes = (((bit_offset % 8) + bit_size - 1) / 8) + 1
        upper_bound = bit_offset / 8
        lower_bound = upper_bound - num_bytes + 1

        if lower_bound < 0
          raise(ArgumentError, "LITTLE_ENDIAN bitfield with bit_offset #{given_bit_offset} and bit_size #{given_bit_size} is invalid")
        end

        temp_data = buffer[lower_bound..upper_bound].reverse
      else
        temp_data = buffer[lower_bound..upper_bound]
      end

      # Determine temp upper bound
      temp_upper = upper_bound - lower_bound

      # Handle Bitfield
      start_bits = bit_offset % 8
      start_mask = ~(0xFF << (8 - start_bits))
      total_bits = (temp_upper + 1) * 8
      right_shift = total_bits - start_bits - bit_size

      # Mask off unwanted bits at beginning
      temp = temp_data.getbyte(0) & start_mask

      if upper_bound > lower_bound
        # Combine bytes into a FixNum
        temp_data[1..temp_upper].each_byte do |temp_value|
          temp = temp << 8
          temp = temp + temp_value
        end
      end

      # Shift off unwanted bits at end
      temp = temp >> right_shift

      if data_type == :INT
        # Convert to negative if necessary
        if (bit_size > 1) && (temp[bit_size - 1] == 1)
          temp = -((1 << bit_size) - temp)
        end
      end

      return temp
    end

  elsif data_type == :FLOAT
    ##########################
    # Handle :FLOAT data type
    ##########################

    if byte_aligned(bit_offset)
      case bit_size
      when 32
        if endianness == :BIG_ENDIAN
          return buffer[lower_bound..upper_bound].unpack(PACK_BIG_ENDIAN_32_BIT_FLOAT)[0]
        else # endianness == :LITTLE_ENDIAN
          return buffer[lower_bound..upper_bound].unpack(PACK_LITTLE_ENDIAN_32_BIT_FLOAT)[0]
        end
      when 64
        if endianness == :BIG_ENDIAN
          return buffer[lower_bound..upper_bound].unpack(PACK_BIG_ENDIAN_64_BIT_FLOAT)[0]
        else # endianness == :LITTLE_ENDIAN
          return buffer[lower_bound..upper_bound].unpack(PACK_LITTLE_ENDIAN_64_BIT_FLOAT)[0]
        end
      else
        raise(ArgumentError, "bit_size is #{given_bit_size} but must be 32 or 64 for data_type #{data_type}")
      end
    else
      raise(ArgumentError, "bit_offset #{given_bit_offset} is not byte aligned for data_type #{data_type}")
    end

  else
    ############################
    # Handle Unknown data types
    ############################

    raise(ArgumentError, "data_type #{data_type} is not recognized")
  end

  return return_value
end

.read_array(bit_offset, bit_size, data_type, array_size, buffer, endianness) ⇒ Array

Reads an array of binary data of any data type from a buffer

Parameters:

  • bit_offset (Integer) —

    Bit offset to the start of the array. A negative number means to offset from the end of the buffer.

  • bit_size (Integer) —

    Size of each item in the array in bits

  • data_type (Symbol) —

    DATA_TYPES

  • array_size (Integer) —

    Size in bits of the array. 0 or negative means fill the array with as many bit_size number of items that exist (negative means excluding the final X number of bits).

  • buffer (String) —

    Binary string buffer to read from

  • endianness (Symbol) —

    ENDIANNESS

Returns:

  • (Array) —

    Array created from reading the buffer

Raises:

  • (ArgumentError) 


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# File 'lib/openc3/accessors/binary_accessor.rb', line 883

def self.read_array(bit_offset, bit_size, data_type, array_size, buffer, endianness)
  # Save given values of bit offset, bit size, and array_size
  given_bit_offset = bit_offset
  given_bit_size = bit_size
  given_array_size = array_size

  # Handle negative and zero bit sizes
  raise ArgumentError, "bit_size #{given_bit_size} must be positive for arrays" if bit_size <= 0

  # Handle negative bit offsets
  if bit_offset < 0
    bit_offset = ((buffer.length * 8) + bit_offset)
    raise_buffer_error(:read, buffer, data_type, given_bit_offset, given_bit_size) if bit_offset < 0
  end

  # Handle negative and zero array sizes
  if array_size <= 0
    if given_bit_offset < 0
      raise ArgumentError, "negative or zero array_size (#{given_array_size}) cannot be given with negative bit_offset (#{given_bit_offset})"
    else
      array_size = ((buffer.length * 8) - bit_offset + array_size)
      if array_size == 0
        return []
      elsif array_size < 0
        raise_buffer_error(:read, buffer, data_type, given_bit_offset, given_bit_size)
      end
    end
  end

  # Calculate number of items in the array
  # If there is a remainder then we have a problem
  raise ArgumentError, "array_size #{given_array_size} not a multiple of bit_size #{given_bit_size}" if array_size % bit_size != 0

  num_items = array_size / bit_size

  # Define bounds of string to access this item
  lower_bound = bit_offset / 8
  upper_bound = (bit_offset + array_size - 1) / 8

  # Check for byte alignment
  byte_aligned = ((bit_offset % 8) == 0)

  case data_type
  when :STRING, :BLOCK
    #######################################
    # Handle :STRING and :BLOCK data types
    #######################################

    if byte_aligned
      value = []
      num_items.times do
        value << self.read(bit_offset, bit_size, data_type, buffer, endianness)
        bit_offset += bit_size
      end
    else
      raise ArgumentError, "bit_offset #{given_bit_offset} is not byte aligned for data_type #{data_type}"
    end

  when :INT, :UINT
    ###################################
    # Handle :INT and :UINT data types
    ###################################

    if byte_aligned and (bit_size == 8 or bit_size == 16 or bit_size == 32 or bit_size == 64)
      ###########################################################
      # Handle byte-aligned 8, 16, 32, and 64 bit :INT and :UINT
      ###########################################################

      case bit_size
      when 8
        if data_type == :INT
          value = buffer[lower_bound..upper_bound].unpack(PACK_8_BIT_INT_ARRAY)
        else # data_type == :UINT
          value = buffer[lower_bound..upper_bound].unpack(PACK_8_BIT_UINT_ARRAY)
        end

      when 16
        if data_type == :INT
          if endianness == HOST_ENDIANNESS
            value = buffer[lower_bound..upper_bound].unpack(PACK_NATIVE_16_BIT_INT_ARRAY)
          else # endianness != HOST_ENDIANNESS
            temp = self.byte_swap_buffer(buffer[lower_bound..upper_bound], 2)
            value = temp.to_s.unpack(PACK_NATIVE_16_BIT_INT_ARRAY)
          end
        else # data_type == :UINT
          if endianness == :BIG_ENDIAN
            value = buffer[lower_bound..upper_bound].unpack(PACK_BIG_ENDIAN_16_BIT_UINT_ARRAY)
          else # endianness == :LITTLE_ENDIAN
            value = buffer[lower_bound..upper_bound].unpack(PACK_LITTLE_ENDIAN_16_BIT_UINT_ARRAY)
          end
        end

      when 32
        if data_type == :INT
          if endianness == HOST_ENDIANNESS
            value = buffer[lower_bound..upper_bound].unpack(PACK_NATIVE_32_BIT_INT_ARRAY)
          else # endianness != HOST_ENDIANNESS
            temp = self.byte_swap_buffer(buffer[lower_bound..upper_bound], 4)
            value = temp.to_s.unpack(PACK_NATIVE_32_BIT_INT_ARRAY)
          end
        else # data_type == :UINT
          if endianness == :BIG_ENDIAN
            value = buffer[lower_bound..upper_bound].unpack(PACK_BIG_ENDIAN_32_BIT_UINT_ARRAY)
          else # endianness == :LITTLE_ENDIAN
            value = buffer[lower_bound..upper_bound].unpack(PACK_LITTLE_ENDIAN_32_BIT_UINT_ARRAY)
          end
        end

      when 64
        if data_type == :INT
          if endianness == HOST_ENDIANNESS
            value = buffer[lower_bound..upper_bound].unpack(PACK_NATIVE_64_BIT_INT_ARRAY)
          else # endianness != HOST_ENDIANNESS
            temp = self.byte_swap_buffer(buffer[lower_bound..upper_bound], 8)
            value = temp.to_s.unpack(PACK_NATIVE_64_BIT_INT_ARRAY)
          end
        else # data_type == :UINT
          if endianness == HOST_ENDIANNESS
            value = buffer[lower_bound..upper_bound].unpack(PACK_NATIVE_64_BIT_UINT_ARRAY)
          else # endianness != HOST_ENDIANNESS
            temp = self.byte_swap_buffer(buffer[lower_bound..upper_bound], 8)
            value = temp.to_s.unpack(PACK_NATIVE_64_BIT_UINT_ARRAY)
          end
        end
      end

    else
      ##################################
      # Handle :INT and :UINT Bitfields
      ##################################
      raise ArgumentError, "read_array does not support little endian bit fields with bit_size greater than 1-bit" if endianness == :LITTLE_ENDIAN and bit_size > 1

      value = []
      num_items.times do
        value << self.read(bit_offset, bit_size, data_type, buffer, endianness)
        bit_offset += bit_size
      end
    end

  when :FLOAT
    ##########################
    # Handle :FLOAT data type
    ##########################

    if byte_aligned
      case bit_size
      when 32
        if endianness == :BIG_ENDIAN
          value = buffer[lower_bound..upper_bound].unpack(PACK_BIG_ENDIAN_32_BIT_FLOAT_ARRAY)
        else # endianness == :LITTLE_ENDIAN
          value = buffer[lower_bound..upper_bound].unpack(PACK_LITTLE_ENDIAN_32_BIT_FLOAT_ARRAY)
        end

      when 64
        if endianness == :BIG_ENDIAN
          value = buffer[lower_bound..upper_bound].unpack(PACK_BIG_ENDIAN_64_BIT_FLOAT_ARRAY)
        else # endianness == :LITTLE_ENDIAN
          value = buffer[lower_bound..upper_bound].unpack(PACK_LITTLE_ENDIAN_64_BIT_FLOAT_ARRAY)
        end

      else
        raise ArgumentError, "bit_size is #{given_bit_size} but must be 32 or 64 for data_type #{data_type}"
      end

    else
      raise ArgumentError, "bit_offset #{given_bit_offset} is not byte aligned for data_type #{data_type}"
    end

  else
    ############################
    # Handle Unknown data types
    ############################

    raise ArgumentError, "data_type #{data_type} is not recognized"
  end

  value
end

.read_item(item, buffer) ⇒ Object

Note: do not use directly - use instance read_item



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# File 'lib/openc3/accessors/binary_accessor.rb', line 278

def self.read_item(item, buffer)
  return nil if item.data_type == :DERIVED
  if item.array_size
    return read_array(item.bit_offset, item.bit_size, item.data_type, item.array_size, buffer, item.endianness)
  else
    return read(item.bit_offset, item.bit_size, item.data_type, buffer, item.endianness)
  end
end

.write(value, param_bit_offset, param_bit_size, param_data_type, param_buffer, param_endianness, param_overflow) ⇒ Integer

Writes binary data of any data type to a buffer

Parameters:

  • bit_offset (Integer) —

    Bit offset to the start of the item. A negative number means to offset from the end of the buffer.

  • bit_size (Integer) —

    Size of the item in bits

  • data_type (Symbol) —

    DATA_TYPES

  • buffer (String) —

    Binary string buffer to read from

  • endianness (Symbol) —

    ENDIANNESS

Returns:

  • (Integer) —

    value read from the buffer



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# File 'lib/openc3/accessors/binary_accessor.rb', line 511

def self.write(value, bit_offset, bit_size, data_type, buffer, endianness, overflow)
  given_bit_offset = bit_offset
  given_bit_size = bit_size

  bit_offset = check_bit_offset_and_size(:write, given_bit_offset, given_bit_size, data_type, buffer)

  # If passed a negative bit size with strings or blocks
  # recalculate based on the value length in bytes
  if (bit_size <= 0) && ((data_type == :STRING) || (data_type == :BLOCK))
    value = value.to_s
    bit_size = value.length * 8
  end

  result, lower_bound, upper_bound = check_bounds_and_buffer_size(bit_offset, bit_size, buffer.length, endianness, data_type)
  raise_buffer_error(:write, buffer, data_type, given_bit_offset, given_bit_size) if !result && (given_bit_size > 0)

  # Check overflow type
  if (overflow != :TRUNCATE) && (overflow != :SATURATE) && (overflow != :ERROR) && (overflow != :ERROR_ALLOW_HEX)
    raise(ArgumentError, "unknown overflow type #{overflow}")
  end

  if (data_type == :STRING) || (data_type == :BLOCK)
    #######################################
    # Handle :STRING and :BLOCK data types
    #######################################
    value = value.to_s

    if byte_aligned(bit_offset)
      temp = value
      if given_bit_size <= 0
        end_bytes = -(given_bit_size / 8)
        old_upper_bound = buffer.length - 1 - end_bytes
        # Lower bound + end_bytes can never be more than 1 byte outside of the given buffer
        if (lower_bound + end_bytes) > buffer.length
          raise_buffer_error(:write, buffer, data_type, given_bit_offset, given_bit_size)
        end

        if old_upper_bound < lower_bound
          # String was completely empty
          if end_bytes > 0
            # Preserve bytes at end of buffer
            buffer << ("\000" * value.length)
            buffer[lower_bound + value.length, end_bytes] = buffer[lower_bound, end_bytes]
          end
        elsif bit_size == 0
          # Remove entire string
          buffer[lower_bound, old_upper_bound - lower_bound + 1] = ''
        elsif upper_bound < old_upper_bound
          # Remove extra bytes from old string
          buffer[upper_bound + 1, old_upper_bound - upper_bound] = ''
        elsif (upper_bound > old_upper_bound) && (end_bytes > 0)
          # Preserve bytes at end of buffer
          diff = upper_bound - old_upper_bound
          buffer << ("\000" * diff)
          buffer[upper_bound + 1, end_bytes] = buffer[old_upper_bound + 1, end_bytes]
        end
      else # given_bit_size > 0
        byte_size = bit_size / 8
        if value.length < byte_size
          # Pad the requested size with zeros
          temp = value.ljust(byte_size, "\000")
        elsif value.length > byte_size
          if overflow == :TRUNCATE
            # Resize the value to fit the field
            value[byte_size, value.length - byte_size] = ''
          else
            raise(ArgumentError, "value of #{value.length} bytes does not fit into #{byte_size} bytes for data_type #{data_type}")
          end
        end
      end
      if bit_size != 0
        buffer[lower_bound, temp.length] = temp
      end
    else
      raise(ArgumentError, "bit_offset #{given_bit_offset} is not byte aligned for data_type #{data_type}")
    end

  elsif (data_type == :INT) || (data_type == :UINT)
    ###################################
    # Handle :INT data type
    ###################################
    value = Integer(value)
    min_value, max_value, hex_max_value = get_check_overflow_ranges(bit_size, data_type)
    value = check_overflow(value, min_value, max_value, hex_max_value, bit_size, data_type, overflow)

    if byte_aligned(bit_offset) && even_bit_size(bit_size)
      ###########################################################
      # Handle byte-aligned 8, 16, 32, and 64 bit
      ###########################################################

      if data_type == :INT
        ###########################################################
        # Handle byte-aligned 8, 16, 32, and 64 bit :INT
        ###########################################################

        case bit_size
        when 8
          buffer.setbyte(lower_bound, value)
        when 16
          if endianness == HOST_ENDIANNESS
            buffer[lower_bound..upper_bound] = [value].pack(PACK_NATIVE_16_BIT_INT)
          else # endianness != HOST_ENDIANNESS
            buffer[lower_bound..upper_bound] = [value].pack(PACK_NATIVE_16_BIT_INT).reverse
          end
        when 32
          if endianness == HOST_ENDIANNESS
            buffer[lower_bound..upper_bound] = [value].pack(PACK_NATIVE_32_BIT_INT)
          else # endianness != HOST_ENDIANNESS
            buffer[lower_bound..upper_bound] = [value].pack(PACK_NATIVE_32_BIT_INT).reverse
          end
        when 64
          if endianness == HOST_ENDIANNESS
            buffer[lower_bound..upper_bound] = [value].pack(PACK_NATIVE_64_BIT_INT)
          else # endianness != HOST_ENDIANNESS
            buffer[lower_bound..upper_bound] = [value].pack(PACK_NATIVE_64_BIT_INT).reverse
          end
        end
      else # data_type == :UINT
        ###########################################################
        # Handle byte-aligned 8, 16, 32, and 64 bit :UINT
        ###########################################################

        case bit_size
        when 8
          buffer.setbyte(lower_bound, value)
        when 16
          if endianness == :BIG_ENDIAN
            buffer[lower_bound..upper_bound] = [value].pack(PACK_BIG_ENDIAN_16_BIT_UINT)
          else # endianness == :LITTLE_ENDIAN
            buffer[lower_bound..upper_bound] = [value].pack(PACK_LITTLE_ENDIAN_16_BIT_UINT)
          end
        when 32
          if endianness == :BIG_ENDIAN
            buffer[lower_bound..upper_bound] = [value].pack(PACK_BIG_ENDIAN_32_BIT_UINT)
          else # endianness == :LITTLE_ENDIAN
            buffer[lower_bound..upper_bound] = [value].pack(PACK_LITTLE_ENDIAN_32_BIT_UINT)
          end
        when 64
          if endianness == HOST_ENDIANNESS
            buffer[lower_bound..upper_bound] = [value].pack(PACK_NATIVE_64_BIT_UINT)
          else # endianness != HOST_ENDIANNESS
            buffer[lower_bound..upper_bound] = [value].pack(PACK_NATIVE_64_BIT_UINT).reverse
          end
        end
      end

    else
      ###########################################################
      # Handle bit fields
      ###########################################################

      # Extract Existing Data
      if endianness == :LITTLE_ENDIAN
        # Bitoffset always refers to the most significant bit of a bitfield
        num_bytes = (((bit_offset % 8) + bit_size - 1) / 8) + 1
        upper_bound = bit_offset / 8
        lower_bound = upper_bound - num_bytes + 1
        if lower_bound < 0
          raise(ArgumentError, "LITTLE_ENDIAN bitfield with bit_offset #{given_bit_offset} and bit_size #{given_bit_size} is invalid")
        end

        temp_data = buffer[lower_bound..upper_bound].reverse
      else
        temp_data = buffer[lower_bound..upper_bound]
      end

      # Determine temp upper bound
      temp_upper = upper_bound - lower_bound

      # Determine Values needed to Handle Bitfield
      start_bits = bit_offset % 8
      start_mask = (0xFF << (8 - start_bits))
      total_bits = (temp_upper + 1) * 8
      end_bits = total_bits - start_bits - bit_size
      end_mask = ~(0xFF << end_bits)

      # Add in Start Bits
      temp = temp_data.getbyte(0) & start_mask

      # Adjust value to correct number of bits
      temp_mask = (2**bit_size) - 1
      temp_value = value & temp_mask

      # Add in New Data
      temp = (temp << (bit_size - (8 - start_bits))) + temp_value

      # Add in Remainder of Existing Data
      temp = (temp << end_bits) + (temp_data.getbyte(temp_upper) & end_mask)

      # Extract into an array of bytes
      temp_array = []
      (0..temp_upper).each { temp_array.insert(0, (temp & 0xFF)); temp = temp >> 8 }

      # Store into data
      if endianness == :LITTLE_ENDIAN
        buffer[lower_bound..upper_bound] = temp_array.pack(PACK_8_BIT_UINT_ARRAY).reverse
      else
        buffer[lower_bound..upper_bound] = temp_array.pack(PACK_8_BIT_UINT_ARRAY)
      end

    end

  elsif data_type == :FLOAT
    ##########################
    # Handle :FLOAT data type
    ##########################
    value = Float(value)

    if byte_aligned(bit_offset)
      case bit_size
      when 32
        if endianness == :BIG_ENDIAN
          buffer[lower_bound..upper_bound] = [value].pack(PACK_BIG_ENDIAN_32_BIT_FLOAT)
        else # endianness == :LITTLE_ENDIAN
          buffer[lower_bound..upper_bound] = [value].pack(PACK_LITTLE_ENDIAN_32_BIT_FLOAT)
        end
      when 64
        if endianness == :BIG_ENDIAN
          buffer[lower_bound..upper_bound] = [value].pack(PACK_BIG_ENDIAN_64_BIT_FLOAT)
        else # endianness == :LITTLE_ENDIAN
          buffer[lower_bound..upper_bound] = [value].pack(PACK_LITTLE_ENDIAN_64_BIT_FLOAT)
        end
      else
        raise(ArgumentError, "bit_size is #{given_bit_size} but must be 32 or 64 for data_type #{data_type}")
      end
    else
      raise(ArgumentError, "bit_offset #{given_bit_offset} is not byte aligned for data_type #{data_type}")
    end

  else
    ############################
    # Handle Unknown data types
    ############################

    raise(ArgumentError, "data_type #{data_type} is not recognized")
  end

  return value
end

.write_array(values, bit_offset, bit_size, data_type, array_size, buffer, endianness, overflow) ⇒ Array

Writes an array of binary data of any data type to a buffer

Parameters:

  • values (Array) —

    Values to write into the buffer

  • bit_offset (Integer) —

    Bit offset to the start of the array. A negative number means to offset from the end of the buffer.

  • bit_size (Integer) —

    Size of each item in the array in bits

  • data_type (Symbol) —

    DATA_TYPES

  • array_size (Integer) —

    Size in bits of the array as represented in the buffer. Size 0 means to fill the buffer with as many bit_size number of items that exist (negative means excluding the final X number of bits).

  • buffer (String) —

    Binary string buffer to write to

  • endianness (Symbol) —

    ENDIANNESS

Returns:

  • (Array) —

    values passed in as a parameter

Raises:

  • (ArgumentError) 


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# File 'lib/openc3/accessors/binary_accessor.rb', line 1075

def self.write_array(values, bit_offset, bit_size, data_type, array_size, buffer, endianness, overflow)
  # Save given values of bit offset, bit size, and array_size
  given_bit_offset = bit_offset
  given_bit_size = bit_size
  given_array_size = array_size

  # Verify an array was given
  raise ArgumentError, "values must be an Array type class is #{values.class}" unless values.kind_of? Array

  # Handle negative and zero bit sizes
  raise ArgumentError, "bit_size #{given_bit_size} must be positive for arrays" if bit_size <= 0

  # Handle negative bit offsets
  if bit_offset < 0
    bit_offset = ((buffer.length * 8) + bit_offset)
    raise_buffer_error(:write, buffer, data_type, given_bit_offset, given_bit_size) if bit_offset < 0
  end

  # Handle negative and zero array sizes
  if array_size <= 0
    if given_bit_offset < 0
      raise ArgumentError, "negative or zero array_size (#{given_array_size}) cannot be given with negative bit_offset (#{given_bit_offset})"
    else
      end_bytes = -(given_array_size / 8)
      lower_bound = bit_offset / 8
      upper_bound = (bit_offset + (bit_size * values.length) - 1) / 8
      old_upper_bound = buffer.length - 1 - end_bytes

      if upper_bound < old_upper_bound
        # Remove extra bytes from old buffer
        buffer[(upper_bound + 1)..old_upper_bound] = ''
      elsif upper_bound > old_upper_bound
        # Grow buffer and preserve bytes at end of buffer if necesssary
        buffer_length = buffer.length
        diff = upper_bound - old_upper_bound
        buffer << (ZERO_STRING * diff)
        if end_bytes > 0
          buffer[(upper_bound + 1)..(buffer.length - 1)] = buffer[(old_upper_bound + 1)..(buffer_length - 1)]
        end
      end

      array_size = ((buffer.length * 8) - bit_offset + array_size)
    end
  end

  # Get data bounds for this array
  lower_bound = bit_offset / 8
  upper_bound = (bit_offset + array_size - 1) / 8
  num_bytes   = upper_bound - lower_bound + 1

  # Check for byte alignment
  byte_aligned = ((bit_offset % 8) == 0)

  # Calculate the number of writes
  num_writes = array_size / bit_size
  # Check for a negative array_size and adjust the number of writes
  # to simply be the number of values in the passed in array
  if given_array_size <= 0
    num_writes = values.length
  end

  # Ensure the buffer has enough room
  if bit_offset + (num_writes * bit_size) > buffer.length * 8
    raise_buffer_error(:write, buffer, data_type, given_bit_offset, given_bit_size)
  end

  # Ensure the given_array_size is an even multiple of bit_size
  raise ArgumentError, "array_size #{given_array_size} not a multiple of bit_size #{given_bit_size}" if array_size % bit_size != 0

  raise ArgumentError, "too many values #{values.length} for given array_size #{given_array_size} and bit_size #{given_bit_size}" if num_writes < values.length

  # Check overflow type
  raise "unknown overflow type #{overflow}" unless OVERFLOW_TYPES.include?(overflow)

  case data_type
  when :STRING, :BLOCK
    #######################################
    # Handle :STRING and :BLOCK data types
    #######################################

    if byte_aligned
      num_writes.times do |index|
        self.write(values[index], bit_offset, bit_size, data_type, buffer, endianness, overflow)
        bit_offset += bit_size
      end
    else
      raise ArgumentError, "bit_offset #{given_bit_offset} is not byte aligned for data_type #{data_type}"
    end

  when :INT, :UINT
    ###################################
    # Handle :INT and :UINT data types
    ###################################

    if byte_aligned and (bit_size == 8 or bit_size == 16 or bit_size == 32 or bit_size == 64)
      ###########################################################
      # Handle byte-aligned 8, 16, 32, and 64 bit :INT and :UINT
      ###########################################################

      case bit_size
      when 8
        if data_type == :INT
          values = self.check_overflow_array(values, MIN_INT8, MAX_INT8, MAX_UINT8, bit_size, data_type, overflow)
          packed = values.pack(PACK_8_BIT_INT_ARRAY)
        else # data_type == :UINT
          values = self.check_overflow_array(values, 0, MAX_UINT8, MAX_UINT8, bit_size, data_type, overflow)
          packed = values.pack(PACK_8_BIT_UINT_ARRAY)
        end

      when 16
        if data_type == :INT
          values = self.check_overflow_array(values, MIN_INT16, MAX_INT16, MAX_UINT16, bit_size, data_type, overflow)
          if endianness == HOST_ENDIANNESS
            packed = values.pack(PACK_NATIVE_16_BIT_INT_ARRAY)
          else # endianness != HOST_ENDIANNESS
            packed = values.pack(PACK_NATIVE_16_BIT_INT_ARRAY)
            self.byte_swap_buffer!(packed, 2)
          end
        else # data_type == :UINT
          values = self.check_overflow_array(values, 0, MAX_UINT16, MAX_UINT16, bit_size, data_type, overflow)
          if endianness == :BIG_ENDIAN
            packed = values.pack(PACK_BIG_ENDIAN_16_BIT_UINT_ARRAY)
          else # endianness == :LITTLE_ENDIAN
            packed = values.pack(PACK_LITTLE_ENDIAN_16_BIT_UINT_ARRAY)
          end
        end

      when 32
        if data_type == :INT
          values = self.check_overflow_array(values, MIN_INT32, MAX_INT32, MAX_UINT32, bit_size, data_type, overflow)
          if endianness == HOST_ENDIANNESS
            packed = values.pack(PACK_NATIVE_32_BIT_INT_ARRAY)
          else # endianness != HOST_ENDIANNESS
            packed = values.pack(PACK_NATIVE_32_BIT_INT_ARRAY)
            self.byte_swap_buffer!(packed, 4)
          end
        else # data_type == :UINT
          values = self.check_overflow_array(values, 0, MAX_UINT32, MAX_UINT32, bit_size, data_type, overflow)
          if endianness == :BIG_ENDIAN
            packed = values.pack(PACK_BIG_ENDIAN_32_BIT_UINT_ARRAY)
          else # endianness == :LITTLE_ENDIAN
            packed = values.pack(PACK_LITTLE_ENDIAN_32_BIT_UINT_ARRAY)
          end
        end

      when 64
        if data_type == :INT
          values = self.check_overflow_array(values, MIN_INT64, MAX_INT64, MAX_UINT64, bit_size, data_type, overflow)
          if endianness == HOST_ENDIANNESS
            packed = values.pack(PACK_NATIVE_64_BIT_INT_ARRAY)
          else # endianness != HOST_ENDIANNESS
            packed = values.pack(PACK_NATIVE_64_BIT_INT_ARRAY)
            self.byte_swap_buffer!(packed, 8)
          end
        else # data_type == :UINT
          values = self.check_overflow_array(values, 0, MAX_UINT64, MAX_UINT64, bit_size, data_type, overflow)
          if endianness == HOST_ENDIANNESS
            packed = values.pack(PACK_NATIVE_64_BIT_UINT_ARRAY)
          else # endianness != HOST_ENDIANNESS
            packed = values.pack(PACK_NATIVE_64_BIT_UINT_ARRAY)
            self.byte_swap_buffer!(packed, 8)
          end
        end
      end

      # Adjust packed size to hold number of items written
      buffer[lower_bound..upper_bound] = adjust_packed_size(num_bytes, packed) if num_bytes > 0

    else
      ##################################
      # Handle :INT and :UINT Bitfields
      ##################################

      raise ArgumentError, "write_array does not support little endian bit fields with bit_size greater than 1-bit" if endianness == :LITTLE_ENDIAN and bit_size > 1

      num_writes.times do |index|
        self.write(values[index], bit_offset, bit_size, data_type, buffer, endianness, overflow)
        bit_offset += bit_size
      end
    end

  when :FLOAT
    ##########################
    # Handle :FLOAT data type
    ##########################

    if byte_aligned
      case bit_size
      when 32
        if endianness == :BIG_ENDIAN
          packed = values.pack(PACK_BIG_ENDIAN_32_BIT_FLOAT_ARRAY)
        else # endianness == :LITTLE_ENDIAN
          packed = values.pack(PACK_LITTLE_ENDIAN_32_BIT_FLOAT_ARRAY)
        end

      when 64
        if endianness == :BIG_ENDIAN
          packed = values.pack(PACK_BIG_ENDIAN_64_BIT_FLOAT_ARRAY)
        else # endianness == :LITTLE_ENDIAN
          packed = values.pack(PACK_LITTLE_ENDIAN_64_BIT_FLOAT_ARRAY)
        end

      else
        raise ArgumentError, "bit_size is #{given_bit_size} but must be 32 or 64 for data_type #{data_type}"
      end

      # Adjust packed size to hold number of items written
      buffer[lower_bound..upper_bound] = adjust_packed_size(num_bytes, packed) if num_bytes > 0

    else
      raise ArgumentError, "bit_offset #{given_bit_offset} is not byte aligned for data_type #{data_type}"
    end

  else
    ############################
    # Handle Unknown data types
    ############################
    raise ArgumentError, "data_type #{data_type} is not recognized"
  end # case data_type

  values
end

.write_item(item, value, buffer) ⇒ Object

Note: do not use directly - use instance write_item



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# File 'lib/openc3/accessors/binary_accessor.rb', line 288

def self.write_item(item, value, buffer)
  return nil if item.data_type == :DERIVED
  if item.array_size
    return write_array(value, item.bit_offset, item.bit_size, item.data_type, item.array_size, buffer, item.endianness, item.overflow)
  else
    return write(value, item.bit_offset, item.bit_size, item.data_type, buffer, item.endianness, item.overflow)
  end
end

Instance Method Details

#enforce_derived_write_conversion(_item) ⇒ Object

If this is true it will enfore that COSMOS DERIVED items must have a write_conversion to be written



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# File 'lib/openc3/accessors/binary_accessor.rb', line 1413

def enforce_derived_write_conversion(_item)
  return true
end

#enforce_encoding ⇒ Object

If this is set it will enforce that buffer data is encoded in a specific encoding



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# File 'lib/openc3/accessors/binary_accessor.rb', line 1393

def enforce_encoding
  return 'ASCII-8BIT'.freeze
end

#enforce_length ⇒ Object

This affects whether the Packet class enforces the buffer length at all. Set to false to remove any correlation between buffer length and defined sizes of items in COSMOS



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# File 'lib/openc3/accessors/binary_accessor.rb', line 1400

def enforce_length
  return true
end

#enforce_short_buffer_allowed ⇒ Object

This sets the short_buffer_allowed flag in the Packet class which allows packets that have a buffer shorter than the defined size. Note that the buffer is still resized to the defined length



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# File 'lib/openc3/accessors/binary_accessor.rb', line 1407

def enforce_short_buffer_allowed
  return false
end

#handle_read_variable_bit_size(item, _buffer) ⇒ Object 



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# File 'lib/openc3/accessors/binary_accessor.rb', line 114

def handle_read_variable_bit_size(item, _buffer)
  length_value = @packet.read(item.variable_bit_size['length_item_name'], :CONVERTED)
  if item.array_size
    item.array_size = (length_value * item.variable_bit_size['length_bits_per_count']) + item.variable_bit_size['length_value_bit_offset']
  else
    if item.data_type == :INT or item.data_type == :UINT
      # QUIC encoding is currently assumed for individual variable sized integers
      # see https://datatracker.ietf.org/doc/html/rfc9000#name-variable-length-integer-enc
      case length_value
      when 0
        item.bit_size = 6
      when 1
        item.bit_size = 14
      when 2
        item.bit_size = 30
      else
        item.bit_size = 62
      end
    else
      item.bit_size = (length_value * item.variable_bit_size['length_bits_per_count']) + item.variable_bit_size['length_value_bit_offset']
    end
  end
end

#handle_write_variable_bit_size(item, value, buffer) ⇒ Object 



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# File 'lib/openc3/accessors/binary_accessor.rb', line 144

def handle_write_variable_bit_size(item, value, buffer)
  # Update length field to new size
  if (item.data_type == :INT or item.data_type == :UINT) and not item.original_array_size
    # QUIC encoding is currently assumed for individual variable sized integers
    # see https://datatracker.ietf.org/doc/html/rfc9000#name-variable-length-integer-enc

    # Calculate current bit size so we can preserve bytes after the item
    length_item_value = @packet.read(item.variable_bit_size['length_item_name'], :CONVERTED)
    case length_item_value
    when 0
      current_bit_size = 6
    when 1
      current_bit_size = 14
    when 2
      current_bit_size = 30
    when 3
      current_bit_size = 62
    else
      raise "Value #{item.variable_bit_size['length_item_name']} has unknown QUIC bit size encoding: #{length_item_value}"
    end

    if item.data_type == :UINT
      if value <= 63
        # Length = 0, value up to 6-bits
        new_bit_size = 6
        item.bit_size = new_bit_size
        @packet.write(item.variable_bit_size['length_item_name'], 0)
      elsif value <= 16383
        # Length = 1, value up to 14-bits
        new_bit_size = 14
        item.bit_size = new_bit_size
        @packet.write(item.variable_bit_size['length_item_name'], 1)
      elsif value <= 1073741823
        # Length = 2, value up to 30-bits
        new_bit_size = 30
        item.bit_size = new_bit_size
        @packet.write(item.variable_bit_size['length_item_name'], 2)
      else
        # Length = 3, value up to 62-bits
        new_bit_size = 62
        item.bit_size = new_bit_size
        @packet.write(item.variable_bit_size['length_item_name'], 3)
      end
    else
      if value <= 31 and value >= -32
        # Length = 0, value up to 6-bits
        new_bit_size = 6
        item.bit_size = new_bit_size
        @packet.write(item.variable_bit_size['length_item_name'], 0)
      elsif value <= 8191 and value >= -8192
        # Length = 1, value up to 14-bits
        new_bit_size = 14
        item.bit_size = new_bit_size
        @packet.write(item.variable_bit_size['length_item_name'], 1)
      elsif value <= 536870911 and value >= -536870912
        # Length = 2, value up to 30-bits
        new_bit_size = 30
        item.bit_size = new_bit_size
        @packet.write(item.variable_bit_size['length_item_name'], 2)
      else
        # Length = 3, value up to 62-bits
        new_bit_size = 62
        item.bit_size = new_bit_size
        @packet.write(item.variable_bit_size['length_item_name'], 3)
      end
    end

    # Later items need their bit_offset adjusted by the change in this item
    adjustment = new_bit_size - current_bit_size
    bytes = (adjustment / 8)
    item_offset = item.bit_offset / 8
    if bytes > 0
      original_length = buffer.length
      # Add extra bytes because we're adjusting larger
      buffer << ("\000" * bytes)
      # We added bytes to the end so now we have to shift the buffer over
      #   NOTE: buffer[offset, length]
      # We copy to the shifted offset location with the remaining buffer length
      buffer[item_offset + bytes, buffer.length - (item_offset + bytes)] =
          # We copy from the original offset location with the original length minus the offset
          buffer[item_offset, original_length - item_offset]
    elsif bytes < 0
      # Remove extra bytes because we're adjusting smaller
      buffer[item_offset + 1, -bytes] = ''
    end
  # Probably not possible to get this condition because we don't allow 0 sized floats
  # but check for it just to cover all the possible data_types
  elsif item.data_type == :FLOAT
    raise "Variable bit size not currently supported for FLOAT data type"
  else
    # STRING, BLOCK, or array types

    # Calculate current bit size so we can preserve bytes after the item
    length_item_value = @packet.read(item.variable_bit_size['length_item_name'], :CONVERTED)
    current_bit_size = (length_item_value * item.variable_bit_size['length_bits_per_count']) + item.variable_bit_size['length_value_bit_offset']

    # Calculate bits after this item
    bits_with_item = item.bit_offset + current_bit_size
    bits_after_item = (buffer.length * 8) - bits_with_item
    if item.original_array_size
      item.array_size = -bits_after_item
    else
      item.bit_size = -bits_after_item
    end

    new_bit_size = value.length * 8
    length_value = (new_bit_size - item.variable_bit_size['length_value_bit_offset']) / item.variable_bit_size['length_bits_per_count']
    @packet.write(item.variable_bit_size['length_item_name'], length_value)

    # Later items need their bit_offset adjusted by the change in this item
    adjustment = new_bit_size - current_bit_size
  end

  # Recalculate bit offsets after this item
  if adjustment != 0 and item.bit_offset >= 0
    @packet.sorted_items.each do |sitem|
      if sitem.data_type == :DERIVED or sitem.bit_offset < item.bit_offset
        # Skip items before this item and derived items and items with negative bit offsets
        next
      end
      if sitem != item
        sitem.bit_offset += adjustment
      end
    end
  end
end

#read_item(item, buffer) ⇒ Object 



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# File 'lib/openc3/accessors/binary_accessor.rb', line 138

def read_item(item, buffer)
  return nil if item.data_type == :DERIVED
  handle_read_variable_bit_size(item, buffer) if item.variable_bit_size
  self.class.read_item(item, buffer)
end

#write_item(item, value, buffer) ⇒ Object 



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# File 'lib/openc3/accessors/binary_accessor.rb', line 271

def write_item(item, value, buffer)
  return nil if item.data_type == :DERIVED
  handle_write_variable_bit_size(item, value, buffer) if item.variable_bit_size
  self.class.write_item(item, value, buffer)
end