Module: Wordmap::Access

Defined in:
lib/wordmap/access.rb

Class Method Summary collapse

Class Method Details

.bsearch_vec(file, value, meta, ltrim_regex, trace) ⇒ Object 



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# File 'lib/wordmap/access.rb', line 151

def bsearch_vec(file, value, meta, ltrim_regex, trace)
  subtrace = nil

  if trace
    subtrace = []
    trace << [__method__, value, subtrace]
  end

  (0..(meta[:cell_count] - 1)).bsearch { |i|
    cell = FileAccess.read_cells(file, i, 1, meta, subtrace)[0]
    value <=> extract_value(cell, ltrim_regex)
  }
end

.clause_to_index_value(clause, descriptors, indexes, ltrim_regex, trace) ⇒ Object 



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# File 'lib/wordmap/access.rb', line 165

def clause_to_index_value(clause, descriptors, indexes, ltrim_regex, trace)
  name, *keys = clause

  case name
  when Symbol
    raise "Unknown index: #{name}" unless indexes.key?(name)
    keys.map { |key| indexes[name][key, trace: trace].first || '' }
  else
    # For vector lookup, if keys are sorted, then positions are guaranteed
    # to be sorted too, which means we can get away with getting locations
    # lazily here.
    vec_iterator(descriptors, Array(clause), ltrim_regex, trace)
  end
end

.each(descriptors, indexes, vec_or_index, ltrim_regex, trace) ⇒ Object 



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# File 'lib/wordmap/access.rb', line 87

def each(descriptors, indexes, vec_or_index, ltrim_regex, trace)
  unless block_given?
    return enum_for(
      __method__,
      descriptors,
      indexes,
      vec_or_index,
      ltrim_regex,
      trace
    )
  end

  case vec_or_index
  when NilClass, Integer
    descriptor = vec_or_index.nil? ? 'data' : "vec#{vec_or_index}"
    file, meta = descriptors[descriptor].values_at(:file, :meta)

    subtrace = nil

    if trace
      subtrace = []
      trace << [:each, descriptor, subtrace]
    end

    FileAccess.each_cell(file, meta: meta, trace: subtrace) { |cell|
      value = extract_value(cell, ltrim_regex)
      yield(value) unless value.empty?
    }
  when Symbol
    raise "Unknown index: #{vec_or_index}" unless indexes.key?(vec_or_index)

    subtrace = nil

    if trace
      subtrace = []
      trace << [:each, vec_or_index, subtrace]
    end

    indexes[vec_or_index].each(0, trace: subtrace) { |cell| yield(cell) }
    subtrace.replace(subtrace.flat_map { |v| v[2] }) if trace
  else
    raise 'Invalid value passed into each'
  end
end

.each_by_key(descriptors, key, ltrim_regex, trace) ⇒ Object 



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# File 'lib/wordmap/access.rb', line 61

def each_by_key(descriptors, key, ltrim_regex, trace)
  unless block_given?
    return enum_for(__method__, descriptors, key, ltrim_regex, trace)
  end

  index_value = index_value_by_key(descriptors, key, ltrim_regex, trace)
  return [].to_enum if index_value == ''
  seq = IndexValue.each_seq_value(index_value).to_a

  subtrace = nil

  if trace
    subtrace = []
    trace << [:each_by_key, "#{seq.first}-#{seq.last}", subtrace]
  end

  FileAccess.each_cell(descriptors['data'][:file], seq[0],
    count: seq.size,
    meta: descriptors['data'][:meta],
    trace: subtrace
  ) { |cell|
    value = extract_value(cell, ltrim_regex)
    yield(value) unless value.empty?
  }
end

.each_by_query(descriptors, indexes, query, ltrim_regex, trace) ⇒ Object 



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# File 'lib/wordmap/access.rb', line 16

def each_by_query descriptors, indexes, query, ltrim_regex, trace
  unless block_given?
    return enum_for(
      __method__, descriptors, indexes, query, ltrim_regex, trace
    )
  end

  index_values =
    if query.none? { |clause| clause.is_a?(Array) }
      [
        clause_to_index_value(
          query, descriptors, indexes, ltrim_regex, trace
        )
      ]
    else
      # Proactively intersect all clauses of the same type to save on reads.
      map_normalized_clauses(query) { |clause|
        clause_to_index_value \
          clause, descriptors, indexes, ltrim_regex, trace
      }
    end

  IndexValue
    .each_seq_value(*index_values)
    .lazy
    .slice_when { |a, b| b > a.succ }
    .each { |seq|
      subtrace = nil
      if trace
        subtrace = []
        trace << [:each_by_query, "#{seq.first}-#{seq.last}", subtrace]
      end

      FileAccess
        .each_cell(descriptors['data'][:file], seq[0],
          count: seq.size,
          meta: descriptors['data'][:meta],
          trace: subtrace
        ) { |cell|
          value = extract_value(cell, ltrim_regex)
          yield(value) unless value.empty?
        }
    }
end

.extract_value(cell, regex) ⇒ Object 



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# File 'lib/wordmap/access.rb', line 206

def extract_value(cell, regex)
  cell.sub(regex, '').force_encoding('utf-8')
end

.index_value_by_key(descriptors, key, ltrim_regex, trace) ⇒ Object 



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# File 'lib/wordmap/access.rb', line 132

def index_value_by_key(descriptors, key, ltrim_regex, trace)
  key = Array(key)
  cell_count = descriptors['data'][:meta][:cell_count]

  cell_c, cell_i =
    0.upto(key.size - 1).reduce([cell_count, 0]) { |(cc, ci), vi|
      vec_desc = descriptors["vec#{vi}"]
      return '' unless vec_desc
      vmeta = vec_desc[:meta]
      vfile = vec_desc[:file]
      vec_index = bsearch_vec(vfile, key[vi], vmeta, ltrim_regex, trace)
      return '' unless vec_index
      page_size = cc / vmeta[:cell_count]
      [page_size, ci + (page_size * vec_index)]
    }

  cell_c > 1 ? "#{cell_i}+#{cell_c - 1}"  : "#{cell_i}"
end

.load_descriptors(paths, spacer) ⇒ Object 



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# File 'lib/wordmap/access.rb', line 8

def load_descriptors(paths, spacer)
  paths.reduce({}) { |hash, path|
    file = File.open(path, 'rb')
    meta = FileAccess.read_meta(file, spacer)
    hash.merge(File.basename(path) => { file: file, meta: meta })
  }
end

.map_normalized_clauses(query) ⇒ Object 



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# File 'lib/wordmap/access.rb', line 192

def map_normalized_clauses(query)
  query
    .reduce({}) { |normalized, clause|
      normalized.merge(
        clause[0].is_a?(Symbol) ?
          { clause[0] => clause[1..-1] } :
          { '_keys' => clause }
      ) { |_, oldv, newv| oldv & newv }
    }
    .map { |name, keys|
      name == '_keys' ? yield(keys) : yield([name, *keys])
    }
end

.vec_iterator(descriptors, keys, ltrim_regex, trace = nil) ⇒ Object 



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# File 'lib/wordmap/access.rb', line 180

def vec_iterator(descriptors, keys, ltrim_regex, trace = nil)
  unless block_given?
    return enum_for(__method__, descriptors, keys, ltrim_regex, trace)
  end

  keys.sort.each do |key|
    value = index_value_by_key(descriptors, key, ltrim_regex, trace)
    next if value.nil? || value == ''
    yield(value.to_i)
  end
end