Add bin and edit workflow

bin/gems/ttfunk-1.8.0/lib/ttfunk/subset/code_page.rb

@@ -0,0 +1,133 @@
+# frozen_string_literal: true
+
+require 'set'
+
+require_relative 'base'
+
+module TTFunk
+  module Subset
+    # A subset that uses standard code page encoding.
+    class CodePage < Base
+      class << self
+        # Get a mapping from an encoding to Unicode
+        #
+        # @param encoding [Encoding, String, Symbol]
+        # @return [Hash{Integer => Integer}]
+        def unicode_mapping_for(encoding)
+          mapping_cache[encoding] ||=
+            (0..255).each_with_object({}) do |c, ret|
+              codepoint =
+                c.chr(encoding)
+                  .encode(Encoding::UTF_8, undef: :replace, replace: '')
+                  .codepoints
+                  .first
+              ret[c] = codepoint if codepoint
+            end
+        end
+
+        private
+
+        def mapping_cache
+          @mapping_cache ||= {}
+        end
+      end
+
+      # Code page used in this subset.
+      # This is used for proper `OS/2` table encoding.
+      # @return [Integer]
+      attr_reader :code_page
+
+      # Encoding used in this subset.
+      # @return [Encoding, String, Symbol]
+      attr_reader :encoding
+
+      # @param original [TTFunk::File]
+      # @param code_page [Integer]
+      # @param encoding [Encoding, String, Symbol]
+      def initialize(original, code_page, encoding)
+        super(original)
+        @code_page = code_page
+        @encoding = encoding
+        @subset = Array.new(256)
+        @from_unicode_cache = {}
+        use(space_char_code)
+      end
+
+      # Get a mapping from this subset to Unicode.
+      #
+      # @return [Hash]
+      def to_unicode_map
+        self.class.unicode_mapping_for(encoding)
+          .select { |codepoint, _unicode| @subset[codepoint] }
+      end
+
+      # Add a character to subset.
+      #
+      # @param character [Integer] Unicode codepoint
+      # @return [void]
+      def use(character)
+        @subset[from_unicode(character)] = character
+      end
+
+      # Can this subset include the character? This depends on the encoding used
+      # in this subset.
+      #
+      # @param character [Integer] Unicode codepoint
+      # @return [Boolean]
+      def covers?(character)
+        !from_unicode(character).nil?
+      end
+
+      # Does this subset actually has the character?
+      #
+      # @param character [Integer] Unicode codepoint
+      # @return [Boolean]
+      def includes?(character)
+        code = from_unicode(character)
+        code && @subset[code]
+      end
+
+      # Get character code for Unicode codepoint.
+      #
+      # @param character [Integer] Unicode codepoint
+      # @return [Integer, nil]
+      def from_unicode(character)
+        @from_unicode_cache[character] ||= (+'' << character).encode!(encoding).ord
+      rescue Encoding::UndefinedConversionError
+        nil
+      end
+
+      # Get `cmap` table for this subset.
+      #
+      # @return [TTFunk::Table::Cmap]
+      def new_cmap_table
+        @new_cmap_table ||=
+          begin
+            mapping = {}
+
+            @subset.each_with_index do |unicode, roman|
+              mapping[roman] = unicode_cmap[unicode]
+            end
+
+            TTFunk::Table::Cmap.encode(mapping, :mac_roman)
+          end
+      end
+
+      # Get the list of Glyph IDs from the original font that are in this
+      # subset.
+      #
+      # @return [Array<Integer>]
+      def original_glyph_ids
+        ([0] + @subset.map { |unicode| unicode && unicode_cmap[unicode] })
+          .compact.uniq.sort
+      end
+
+      # Get a chacter code for Space in this subset
+      #
+      # @return [Integer, nil]
+      def space_char_code
+        @space_char_code ||= from_unicode(Unicode::SPACE_CHAR)
+      end
+    end
+  end
+end