Class: Cabriolet::HLP::QuickHelp::OffsetCalculator

Inherits:
Object
  • Object
show all
Defined in:
lib/cabriolet/hlp/quickhelp/offset_calculator.rb

Overview

Calculates file offsets for QuickHelp structure

Class Method Summary collapse

Class Method Details

.calculate(topics:, contexts:, context_map:) ⇒ Hash

Calculate all offsets in the file

Parameters:

  • topics (Array<Hash>) —

    Compressed topics

  • contexts (Array<String>) —

    Context strings

  • context_map (Array<Integer>) —

    Context topic indices

Returns:

  • (Hash) —

    Calculated offsets



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# File 'lib/cabriolet/hlp/quickhelp/offset_calculator.rb', line 14

def self.calculate(topics:, contexts:, context_map:)
  offsets = {}

  # Start after file header (70 bytes = 2 signature + 68 header)
  current_offset = 70

  # Topic index: (topic_count + 1) * 4 bytes
  offsets[:topic_index] = current_offset
  topic_count = topics.size
  current_offset += (topic_count + 1) * 4

  # Context strings: sum of string lengths + null terminators
  offsets[:context_strings] = current_offset
  contexts.each do |ctx|
    current_offset += ctx.bytesize + 1 # +1 for null terminator
  end

  # Context map: context_count * 2 bytes
  offsets[:context_map] = current_offset
  current_offset += context_map.size * 2

  # Keywords: not implemented yet, set to 0
  offsets[:keywords] = 0

  # Huffman tree: not implemented yet, set to 0
  offsets[:huffman_tree] = 0

  # Topic text: starts after context map
  offsets[:topic_text] = current_offset

  # Calculate topic text offsets
  offsets[:topic_offsets] = []
  topics.each do |topic|
    offsets[:topic_offsets] << (current_offset - offsets[:topic_text])
    current_offset += topic[:compressed_length]
  end
  # Add end marker
  offsets[:topic_offsets] << (current_offset - offsets[:topic_text])

  # Total database size
  offsets[:database_size] = current_offset

  offsets
end