Module: ZSTDS::Option

Defined in:
lib/zstds/option.rb

Overview

ZSTDS::Option module.

Constant Summary collapse

DEFAULT_BUFFER_LENGTH =

Current default buffer length.

0
COMPRESSOR_DEFAULTS =

Current compressor defaults.

{
  # Enables global VM lock where possible.
  :gvl                           => false,
  # Compression level.
  :compression_level             => nil,
  # Maximum back-reference distance (power of 2).
  :window_log                    => nil,
  # Size of the initial probe table (power of 2).
  :hash_log                      => nil,
  # Size of the multi-probe search table (power of 2).
  :chain_log                     => nil,
  # Number of search attempts (power of 2).
  :search_log                    => nil,
  # Minimum size of searched matches.
  :min_match                     => nil,
  # Distance between match sampling (for :fast strategy),
  #   length of match considered "good enough" for (for other strategies).
  :target_length                 => nil,
  # Choses strategy.
  :strategy                      => nil,
  # Enables long distance matching.
  :enable_long_distance_matching => nil,
  # Size of the table for long distance matching (power of 2).
  :ldm_hash_log                  => nil,
  # Minimum match size for long distance matcher.
  :ldm_min_match                 => nil,
  # Log size of each bucket in the LDM hash table for collision resolution.
  :ldm_bucket_size_log           => nil,
  # Frequency of inserting/looking up entries into the LDM hash table.
  :ldm_hash_rate_log             => nil,
  # Enables writing of content size into frame header (if known).
  :content_size_flag             => nil,
  # Enables writing of 32-bits checksum of content at end of frame.
  :checksum_flag                 => nil,
  # Enables writing of dictionary id into frame header.
  :dict_id_flag                  => nil,
  # Number of threads spawned in parallel.
  :nb_workers                    => nil,
  # Size of job (nb_workers >= 1).
  :job_size                      => nil,
  # Overlap size, as a fraction of window size.
  :overlap_log                   => nil,
  # Chose dictionary.
  :dictionary                    => nil
}
.freeze
DECOMPRESSOR_DEFAULTS =

Current decompressor defaults.

{
  # Enables global VM lock where possible.
  :gvl            => false,
  # Size limit (power of 2).
  :window_log_max => nil,
  # Chose dictionary.
  :dictionary     => nil
}
.freeze

Class Method Summary collapse

Class Method Details

.get_compressor_options(options, buffer_length_names) ⇒ Object

Processes compressor options and buffer_length_names. Option: :source_buffer_length source buffer length. Option: :destination_buffer_length destination buffer length. Option: :gvl enables global VM lock where possible. Option: :compression_level compression level. Option: :window_log maximum back-reference distance (power of 2). Option: :hash_log size of the initial probe table (power of 2). Option: :chain_log size of the multi-probe search table (power of 2). Option: :search_log number of search attempts (power of 2). Option: :min_match minimum size of searched matches. Option: :target_length distance between match sampling (for :fast strategy),

length of match considered "good enough" for (for other strategies).

Option: :strategy choses strategy. Option: :ldm_hash_log size of the table for long distance matching (power of 2). Option: :ldm_min_match minimum match size for long distance matcher. Option: :ldm_bucket_size_log log size of each bucket in the LDM hash table for collision resolution. Option: :ldm_hash_rate_log frequency of inserting/looking up entries into the LDM hash table. Option: :content_size_flag enables writing of content size into frame header (if known). Option: :checksum_flag enables writing of 32-bits checksum of content at end of frame. Option: :dict_id_flag enables writing of dictionary id into frame header. Option: :nb_workers number of threads spawned in parallel. Option: :job_size size of job (nb_workers >= 1). Option: :overlap_log overlap size, as a fraction of window size. Option: :dictionary chose dictionary. Returns processed compressor options.

Raises:



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# File 'lib/zstds/option.rb', line 100

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

  buffer_length_defaults = buffer_length_names.each_with_object({}) do |name, defaults|
    defaults[name] = DEFAULT_BUFFER_LENGTH
  end

  options = COMPRESSOR_DEFAULTS.merge(buffer_length_defaults).merge options

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

  Validation.validate_bool options[:gvl]

  compression_level = options[:compression_level]
  unless compression_level.nil?
    Validation.validate_integer compression_level
    raise ValidateError, "invalid compression level" if
      compression_level < MIN_COMPRESSION_LEVEL || compression_level > MAX_COMPRESSION_LEVEL
  end

  window_log = options[:window_log]
  unless window_log.nil?
    Validation.validate_not_negative_integer window_log
    raise ValidateError, "invalid window log" if
      window_log < MIN_WINDOW_LOG || window_log > MAX_WINDOW_LOG
  end

  hash_log = options[:hash_log]
  unless hash_log.nil?
    Validation.validate_not_negative_integer hash_log
    raise ValidateError, "invalid hash log" if
      hash_log < MIN_HASH_LOG || hash_log > MAX_HASH_LOG
  end

  chain_log = options[:chain_log]
  unless chain_log.nil?
    Validation.validate_not_negative_integer chain_log
    raise ValidateError, "invalid chain log" if
      chain_log < MIN_CHAIN_LOG || chain_log > MAX_CHAIN_LOG
  end

  search_log = options[:search_log]
  unless search_log.nil?
    Validation.validate_not_negative_integer search_log
    raise ValidateError, "invalid search log" if
      search_log < MIN_SEARCH_LOG || search_log > MAX_SEARCH_LOG
  end

  min_match = options[:min_match]
  unless min_match.nil?
    Validation.validate_not_negative_integer min_match
    raise ValidateError, "invalid min match" if
      min_match < MIN_MIN_MATCH || min_match > MAX_MIN_MATCH
  end

  target_length = options[:target_length]
  unless target_length.nil?
    Validation.validate_not_negative_integer target_length
    raise ValidateError, "invalid target length" if
      target_length < MIN_TARGET_LENGTH || target_length > MAX_TARGET_LENGTH
  end

  strategy = options[:strategy]
  unless strategy.nil?
    Validation.validate_symbol strategy
    raise ValidateError, "invalid strategy" unless STRATEGIES.include? strategy
  end

  enable_long_distance_matching = options[:enable_long_distance_matching]
  Validation.validate_bool enable_long_distance_matching unless enable_long_distance_matching.nil?

  ldm_hash_log = options[:ldm_hash_log]
  unless ldm_hash_log.nil?
    Validation.validate_not_negative_integer ldm_hash_log
    raise ValidateError, "invalid ldm hash log" if
      ldm_hash_log < MIN_LDM_HASH_LOG || ldm_hash_log > MAX_LDM_HASH_LOG
  end

  ldm_min_match = options[:ldm_min_match]
  unless ldm_min_match.nil?
    Validation.validate_not_negative_integer ldm_min_match
    raise ValidateError, "invalid ldm min match" if
      ldm_min_match < MIN_LDM_MIN_MATCH || ldm_min_match > MAX_LDM_MIN_MATCH
  end

  ldm_bucket_size_log = options[:ldm_bucket_size_log]
  unless ldm_bucket_size_log.nil?
    Validation.validate_not_negative_integer ldm_bucket_size_log
    raise ValidateError, "invalid ldm bucket size log" if
      ldm_bucket_size_log < MIN_LDM_BUCKET_SIZE_LOG || ldm_bucket_size_log > MAX_LDM_BUCKET_SIZE_LOG
  end

  ldm_hash_rate_log = options[:ldm_hash_rate_log]
  unless ldm_hash_rate_log.nil?
    Validation.validate_not_negative_integer ldm_hash_rate_log
    raise ValidateError, "invalid ldm hash rate log" if
      ldm_hash_rate_log < MIN_LDM_HASH_RATE_LOG || ldm_hash_rate_log > MAX_LDM_HASH_RATE_LOG
  end

  content_size_flag = options[:content_size_flag]
  Validation.validate_bool content_size_flag unless content_size_flag.nil?

  checksum_flag = options[:checksum_flag]
  Validation.validate_bool checksum_flag unless checksum_flag.nil?

  dict_id_flag = options[:dict_id_flag]
  Validation.validate_bool dict_id_flag unless dict_id_flag.nil?

  nb_workers = options[:nb_workers]
  unless nb_workers.nil?
    Validation.validate_not_negative_integer nb_workers
    raise ValidateError, "invalid nb workers" if
      nb_workers < MIN_NB_WORKERS || nb_workers > MAX_NB_WORKERS
  end

  job_size = options[:job_size]
  unless job_size.nil?
    Validation.validate_not_negative_integer job_size
    raise ValidateError, "invalid job size" if
      job_size < MIN_JOB_SIZE || job_size > MAX_JOB_SIZE
  end

  overlap_log = options[:overlap_log]
  unless overlap_log.nil?
    Validation.validate_not_negative_integer overlap_log
    raise ValidateError, "invalid overlap log" if
      overlap_log < MIN_OVERLAP_LOG || overlap_log > MAX_OVERLAP_LOG
  end

  dictionary = options[:dictionary]
  raise ValidateError, "invalid dictionary" unless
    dictionary.nil? || dictionary.is_a?(Dictionary)

  options
end

.get_decompressor_options(options, buffer_length_names) ⇒ Object

Processes decompressor options and buffer_length_names. Option: :source_buffer_length source buffer length. Option: :destination_buffer_length destination buffer length. Option: :gvl enables global VM lock where possible. Option: :window_log_max size limit (power of 2). Returns processed decompressor options.



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# File 'lib/zstds/option.rb', line 242

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

  buffer_length_defaults = buffer_length_names.each_with_object({}) do |name, defaults|
    defaults[name] = DEFAULT_BUFFER_LENGTH
  end

  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[:gvl]

  window_log_max = options[:window_log_max]
  unless window_log_max.nil?
    Validation.validate_not_negative_integer window_log_max
    raise ValidateError, "invalid window log max" if
      window_log_max < MIN_WINDOW_LOG_MAX || window_log_max > MAX_WINDOW_LOG_MAX
  end

  options
end