Module: LZWS::Option

Defined in:
lib/lzws/option.rb

Constant Summary collapse

DEFAULT_BUFFER_LENGTH =

Default options will be compatible with UNIX compress.

0
LOWEST_MAX_CODE_BIT_LENGTH = 
9
BIGGEST_MAX_CODE_BIT_LENGTH = 
16
DECOMPRESSOR_DEFAULTS = 
{
  :without_magic_header => false,
  :msb                  => false,
  :unaligned_bit_groups => false,
  :quiet                => false
}
.freeze
COMPRESSOR_DEFAULTS = 
DECOMPRESSOR_DEFAULTS.merge(
  :max_code_bit_length => BIGGEST_MAX_CODE_BIT_LENGTH,
  :block_mode          => true
)
.freeze

Class Method Summary collapse

Class Method Details

.get_compressor_options(options, buffer_length_names) ⇒ Object

Raises:



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# File 'lib/lzws/option.rb', line 31

def self.get_compressor_options(options, buffer_length_names)
  Validation.validate_hash options

  buffer_length_defaults = buffer_length_names.each_with_object({}) { |name, defaults| defaults[name] = DEFAULT_BUFFER_LENGTH }
  options                = COMPRESSOR_DEFAULTS.merge(buffer_length_defaults).merge options

  buffer_length_names.each { |name| Validation.validate_not_negative_integer options[name] }

  max_code_bit_length = options[:max_code_bit_length]
  Validation.validate_positive_integer max_code_bit_length

  raise ValidateError, "invalid max code bit length" if
    max_code_bit_length < LOWEST_MAX_CODE_BIT_LENGTH || max_code_bit_length > BIGGEST_MAX_CODE_BIT_LENGTH

  Validation.validate_bool options[:without_magic_header]
  Validation.validate_bool options[:block_mode]
  Validation.validate_bool options[:msb]
  Validation.validate_bool options[:unaligned_bit_groups]
  Validation.validate_bool options[:quiet]

  options
end

.get_decompressor_options(options, buffer_length_names) ⇒ Object 



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# File 'lib/lzws/option.rb', line 54

def self.get_decompressor_options(options, buffer_length_names)
  Validation.validate_hash options

  buffer_length_defaults = buffer_length_names.each_with_object({}) { |name, defaults| defaults[name] = DEFAULT_BUFFER_LENGTH }
  options                = DECOMPRESSOR_DEFAULTS.merge(buffer_length_defaults).merge options

  buffer_length_names.each { |name| Validation.validate_not_negative_integer options[name] }

  Validation.validate_bool options[:without_magic_header]
  Validation.validate_bool options[:msb]
  Validation.validate_bool options[:unaligned_bit_groups]
  Validation.validate_bool options[:quiet]

  options
end