Chapters support

.gitignore

@@ -3,3 +3,5 @@ Session.vim
 pkg/
 fusil/fusil
 coverage/
+Gemfile.lock
+test/silence_copy.mp3

.travis.yml

@@ -1,14 +1,6 @@
 language: ruby
 rvm:
-  - 1.8.7
-  - 1.9.3
-  - 2.0.0
-  - 2.1.0
-  - 2.1.2
-  - ruby-head
-  - jruby
-  - rbx
-matrix:
-  allow_failures:
-    - rvm: 1.8.7
+  - 2.4
+  - 2.5
+  - 2.6
 script: ruby test/test_ruby-mp3info.rb

Gemfile

@@ -1,3 +1,6 @@
 source "https://rubygems.org"
 
 gem "minitest", "~> 5.4.1"
+gem "pry-byebug"
+
+gemspec

lib/mp3info.rb

@@ -6,6 +6,7 @@
 require "stringio"
 require "mp3info/id3v2"
 require "mp3info/extension_modules"
+require "mp3info/chapters_parser"
 
 # ruby -d to display debugging infos
 

lib/mp3info/chapters_parser.rb

@@ -0,0 +1,88 @@
+require 'date'
+require 'mp3info/frame'
+
+class Mp3Info
+  # accepts list of
+  # [['00:00:00.000', 'text'], ..]
+  self.send(:remove_const, :ChaptersParser) rescue nil
+  class ChaptersParser
+
+    self.send(:remove_const, :Chapter) rescue nil
+    class Chapter
+      attr_reader :start, :finish, :title
+
+      def initialize(id, start, finish, title)
+        @id, @start, @finish, @title = id, start, finish, title
+      end
+
+      def chap
+        Mp3Info::Frame::Chapter.new(
+          :id => id,
+          :start => start,
+          :finish => finish,
+          :sub_frames => sub_frames
+        )
+      end
+
+      private
+
+      def id
+        Mp3Info::Frame::StringzToSym.new(@id)
+      end
+
+      def sub_frames
+        [tit2]
+      end
+
+      def tit2
+        Mp3Info::Frame::SubFrame.new(
+          :name => "TIT2".encode("ASCII-8BIT"),
+          :body => Mp3Info::Frame::Tit2.new(
+            :encoding_index => 1,
+            :title => Mp3Info::Frame::StringUtf16.new(title))
+        )
+      end
+    end
+
+    attr_reader :tlen, :chapters, :ctocs, :chaps
+    TOC = :toc
+
+    def initialize(tlen, chapters)
+      @tlen, @chapters = tlen.to_i, chapters
+      @chaps = {}
+      @ctocs = { TOC => top_ctoc }
+      parse!
+    end
+
+    private
+
+    def parse!
+      return unless @chaps.empty?
+      (chapters + [nil]).each_cons(2).each_with_index do |((start, title), (finish, _)), i|
+        id = "chp#{i}".to_sym
+        finish_ms = finish ? to_ms(finish) : tlen
+        chapter = Chapter.new(id, to_ms(start), finish_ms, title)
+        @chaps[id] = chapter.chap
+        add_to_top_ctoc!(id)
+      end
+    end
+
+    def add_to_top_ctoc!(sym_id)
+      @ctocs[TOC][:children_ids] << Mp3Info::Frame::StringzToSym.new(sym_id)
+    end
+
+    def top_ctoc
+      Mp3Info::Frame::Toc.new(
+        :id => Mp3Info::Frame::StringzToSym.new(TOC),
+        :flags => Mp3Info::Frame::TocFlags.new(:top => true, :ordered => true),
+        :children_ids => []
+      )
+    end
+
+    def to_ms(hh_mm_ss_ms)
+      DateTime.strptime("1970-01-01 #{hh_mm_ss_ms}", "%Y-%m-%d %H:%M:%S.%L").strftime("%Q").to_i
+    rescue => e
+      binding.pry
+    end
+  end
+end

lib/mp3info/frame.rb

@@ -0,0 +1,180 @@
+require 'bindata'
+require 'mp3info/frame/apic'
+
+class Mp3Info
+  # IDv3 standart has different types of strings with same structure of the body under some
+  # header tag or chapter subtag
+  #
+  # Text encoding           $xx
+  # ... various fields. e.g. ULST/COMM (3 bytes for lang); TIT2 (0 bytes)
+  # Short content descrip.  <text string according to encoding> $00 (00)
+  # The actual text         <full text string according to encoding>
+  class Frame
+    self.send(:remove_const, :Mp3ChapterOffset) rescue nil
+    class Mp3ChapterOffset < BinData::Uint32be
+      def sensible_default
+        4294967295 # same as no offset, default for writes
+      end
+    end
+
+    self.send(:remove_const, :TocFlags) rescue nil
+    class TocFlags < BinData::Uint8
+      def assign(val)
+        @value = value
+      end
+
+      def value_to_binary_string(val)
+        super((val[:top] ? 1 : 0) + (val[:ordered] ? 2 : 0))
+      end
+
+      def read_and_return_value(io)
+        flags = super
+        top = flags & 1 == 1
+        ordered = (flags >> 1) & 1 == 1
+        { :top => top, :ordered => ordered }
+      end
+
+      def sensible_default
+        { :top => true, :ordered => true }
+      end
+    end
+
+    self.send(:remove_const, :SubFrame) rescue nil
+    class SubFrame < BinData::Record
+      # hide :sub_frame_len, :flags
+
+      string :name, :length => 4
+      uint32be :sub_frame_len, :value => lambda {
+        if reading?
+          @obj.instance_variable_get(:@value)
+        else
+          require 'pry'; binding.pry if $DEBUG && $DEBUG_WRITE
+          was =  @obj.instance_variable_get(:@value)
+          now = body.num_bytes
+          if now != was
+            puts "SubFrame #{name} changed length #{was.inspect} -> #{now.inspect}" if $DEBUG_WRITE
+          end
+          now
+        end
+      }
+      string :flags, :length => 2
+      choice :body, :choices => {
+               'WXXX' => [:link, :read_length => :sub_frame_len],
+               'APIC' => [:apic, :read_length => :sub_frame_len],
+               'TIT2' => [:tit2, :read_length => :sub_frame_len]
+             }, :selection => :name
+    end
+
+    self.send(:remove_const, :SubFrames) rescue nil
+    class SubFrames < BinData::Array
+      optional_parameters :read_if
+      def initialize_shared_instance
+        super
+        if has_parameter?(:read_until)
+          extend ReadIfPlugin
+        end
+      end
+
+      module ReadIfPlugin
+        def do_read(io)
+          loop do
+            variables = { index: self.length - 1, element: self.last, array: self }
+            require 'pry'; binding.pry if $DEBUG && $DEBUG_READ
+            break unless eval_parameter(:read_if, variables)
+            element = append_new_element
+            element.do_read(io)
+            break if eval_parameter(:read_until, variables)
+          end
+        end
+      end
+    end
+
+    self.send(:remove_const, :Chapter) rescue nil
+    class Chapter < BinData::Record
+      # hide :chap_len, :flags, :start_offset, :finish_offset
+      # mandatory_parameters :id, :start, :finish # cannot parse with that o_O
+
+      uint32be :chap_len, :value => lambda {
+        if reading?
+          @obj.instance_variable_get(:@value)
+        else
+          require 'pry'; binding.pry if $DEBUG && $DEBUG_WRITE
+          # 131067
+          was =  @obj.instance_variable_get(:@value)
+          now = id.num_bytes + start.num_bytes + finish.num_bytes + start_offset.num_bytes + finish_offset.num_bytes + sub_frames.map(&:num_bytes).reduce(:+).to_i
+          if now != was
+            puts "Chapter #{id} changed length #{was} -> #{now}" if $DEBUG_WRITE
+          end
+          now
+        end
+      }
+      string :flags, :length => 2
+
+      stringz_to_sym :id
+      uint32be :start
+      uint32be :finish
+      mp3_chapter_offset :start_offset
+      mp3_chapter_offset :finish_offset
+
+      # fix upstream: without :read_until it sets zero length
+      # https://github.com/dmendel/bindata/blob/v2.4.4/lib/bindata/array.rb#L278L281
+      sub_frames :sub_frames, :type => :sub_frame, :read_until => lambda {
+        require 'pry'; binding.pry if $DEBUG && $DEBUG_READ
+        bytes_left = (chap_len - id.num_bytes - start.num_bytes - finish.num_bytes - start_offset.num_bytes - finish_offset.num_bytes)
+        bytes_read = array.map(&:num_bytes).reduce(:+).to_i
+        bytes_read >= bytes_left
+      }, :read_if => lambda {
+        require 'pry'; binding.pry if $DEBUG && $DEBUG_READ
+        bytes_left = (chap_len - id.num_bytes - start.num_bytes - finish.num_bytes - start_offset.num_bytes - finish_offset.num_bytes)
+        # bytes_left = (chap_len - id.num_bytes - 16 - 4 - 4 - 2 - len)
+        bytes_read = array.map(&:num_bytes).reduce(:+).to_i
+        bytes_read < bytes_left
+      }
+    end
+
+    self.send(:remove_const, :Toc) rescue nil
+    class Toc < BinData::Record
+      stringz_to_sym :id
+      toc_flags :flags
+      uint8 :children_count, :value => lambda {
+        if reading?
+          @obj.instance_variable_get(:@value)
+        else
+          require 'pry'; binding.pry if $DEBUG && $DEBUG_WRITE
+          was =  @obj.instance_variable_get(:@value)
+          now = children_ids.size
+          if now != was
+            puts "TOC #{id} changed length #{was.inspect} -> #{now.inspect}" if $DEBUG_WRITE
+          end
+          now
+        end
+      }
+      array :children_ids, type: :stringz_to_sym, :initial_length => :children_count
+    end
+
+    # main wrapper
+    self.send(:remove_const, :Frame) rescue nil
+    class Frame < BinData::Record
+      default_parameter :flags => "\x00\x00"
+
+      string :name, :length => 4 # TODO: must be ascii
+      uint32be :frame_len, :value => lambda {
+        if reading?
+          @obj.instance_variable_get(:@value)
+        else
+          require 'pry'; binding.pry if $DEBUG && $DEBUG_WRITE
+          was =  @obj.instance_variable_get(:@value)
+          now = body.num_bytes
+          if now != was
+            puts "Frame #{name} changed length #{was.inspect} -> #{now.inspect}" if $DEBUG_WRITE
+          end
+          now
+        end
+      }
+      string :flags, :length => 2
+
+      # now for build/writes, TODO: use for reads
+      rest :body
+    end
+  end
+end