Class: Omnizip::Algorithms::LZMA::State

Inherits:
Object
  • Object
show all
Defined in:
lib/omnizip/algorithms/lzma/state.rb

Overview

LZMA State Machine for managing compression states

This class implements the state machine used by LZMA to track the current compression context. The state determines which probability models are used for encoding the next symbol.

LZMA uses 12 states that transition based on the type of symbol being encoded (literal, match, rep match, etc.). The state affects probability model selection for better compression.

Constant Summary collapse

NUM_STATES =

Total number of LZMA states

12
LIT_STATES =

State transition tables After encoding a literal

[0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 4, 5].freeze
MATCH_STATES =

After encoding a match

[7, 7, 7, 7, 7, 7, 7, 10, 10, 10, 10, 10].freeze
REP_STATES =

After encoding a rep match

[8, 8, 8, 8, 8, 8, 8, 11, 11, 11, 11, 11].freeze
SHORT_REP_STATES =

After encoding a short rep

[9, 9, 9, 9, 9, 9, 9, 11, 11, 11, 11, 11].freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(initial_state = 0) ⇒ State

Initialize the state machine

Parameters:

  • initial_state (Integer) (defaults to: 0) —

    Initial state index (default: 0)



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# File 'lib/omnizip/algorithms/lzma/state.rb', line 58

def initialize(initial_state = 0)
  @index = initial_state
end

Instance Attribute Details

#index ⇒ Object (readonly)

Returns the value of attribute index.



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# File 'lib/omnizip/algorithms/lzma/state.rb', line 53

def index
  @index
end

Instance Method Details

#dup ⇒ State

Create a copy of this state

Returns:

  • (State) —

    A new State with the same index



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# File 'lib/omnizip/algorithms/lzma/state.rb', line 114

def dup
  State.new(@index)
end

#literal? ⇒ Boolean

Check if current state is a literal state

Returns:

  • (Boolean) —

    True if state < 7



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# File 'lib/omnizip/algorithms/lzma/state.rb', line 93

def literal?
  @index < 7
end

#match? ⇒ Boolean

Check if current state is a match state

Returns:

  • (Boolean) —

    True if state >= 7



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# File 'lib/omnizip/algorithms/lzma/state.rb', line 100

def match?
  @index >= 7
end

#reset ⇒ void

This method returns an undefined value.

Reset state to initial value



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# File 'lib/omnizip/algorithms/lzma/state.rb', line 107

def reset
  @index = 0
end

#to_i ⇒ Integer

Get state index for probability model selection

Returns:

  • (Integer) —

    Current state index



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# File 'lib/omnizip/algorithms/lzma/state.rb', line 121

def to_i
  @index
end

#update_literal ⇒ void

This method returns an undefined value.

Update state after encoding a literal



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# File 'lib/omnizip/algorithms/lzma/state.rb', line 65

def update_literal
  @index = LIT_STATES[@index]
end

#update_match ⇒ void

This method returns an undefined value.

Update state after encoding a match



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# File 'lib/omnizip/algorithms/lzma/state.rb', line 72

def update_match
  @index = MATCH_STATES[@index]
end

#update_rep ⇒ void

This method returns an undefined value.

Update state after encoding a repeat match



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# File 'lib/omnizip/algorithms/lzma/state.rb', line 79

def update_rep
  @index = REP_STATES[@index]
end

#update_short_rep ⇒ void

This method returns an undefined value.

Update state after encoding a short repeat match



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# File 'lib/omnizip/algorithms/lzma/state.rb', line 86

def update_short_rep
  @index = SHORT_REP_STATES[@index]
end