Module: Sashite::Cell::Parser Private

Defined in:
lib/sashite/cell/parser.rb

Overview

This module is part of a private API. You should avoid using this module if possible, as it may be removed or be changed in the future.

Parses CELL coordinate strings into index arrays.

This module handles the conversion from CELL string representation to numeric indices, following the cyclic pattern:

  • Dimension 1, 4, 7…: lowercase letters (a-z, aa-iv)

  • Dimension 2, 5, 8…: positive integers (1-256)

  • Dimension 3, 6, 9…: uppercase letters (A-Z, AA-IV)

Security considerations:

  • Character-by-character parsing (no regex, no ReDoS risk)

  • Fail-fast on invalid input

  • Bounded iteration (max 7 characters)

  • Explicit ASCII validation

Examples:

Parser.parse_to_indices("e4")  # => [4, 3]
Parser.parse_to_indices("a1A") # => [0, 0, 0]

Class Method Summary collapse

Class Method Details

.parse_to_indices(string) ⇒ Array<Integer>

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Parses a CELL string into an array of indices.

Examples:

Parser.parse_to_indices("e4")      # => [4, 3]
Parser.parse_to_indices("iv256IV") # => [255, 255, 255]

Raises:



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# File 'lib/sashite/cell/parser.rb', line 37

def self.parse_to_indices(string)
  raise Errors::Argument, Errors::Argument::Messages::EMPTY_INPUT if string.empty?

  if string.length > Constants::MAX_STRING_LENGTH
    raise Errors::Argument, Errors::Argument::Messages::INPUT_TOO_LONG
  end

  first_byte = string.getbyte(0)
  unless lowercase?(first_byte)
    raise Errors::Argument, Errors::Argument::Messages::INVALID_START
  end

  indices = []
  pos = 0
  dimension_type = 0 # 0: lowercase, 1: integer, 2: uppercase

  while pos < string.length
    if indices.size >= Constants::MAX_DIMENSIONS
      raise Errors::Argument, Errors::Argument::Messages::TOO_MANY_DIMENSIONS
    end

    case dimension_type
    when 0
      value, consumed = parse_lowercase(string, pos)
      indices << value
      pos += consumed
      dimension_type = 1
    when 1
      value, consumed = parse_integer(string, pos)
      indices << value
      pos += consumed
      dimension_type = 2
    when 2
      value, consumed = parse_uppercase(string, pos)
      indices << value
      pos += consumed
      dimension_type = 0
    end
  end

  indices
end