Contents

require_relative 'exif_jpeg'
require 'set'
require_relative 'exif_tag_reader'
require_relative 'exif_data'

module FileData
  # Returns the exif data from a jpeg file
  class ExifReader
    def initialize(exif_stream)
      @exif_stream = exif_stream
    end

    def image_data_only
      exif_tags_internal(0).image
    end

    def thumbnail_data_only
      exif_tags_internal(1).thumbnail
    end

    def all_data
      exif_tags_internal(0, 1)
    end

    def only_image_tag(tag_id)
      exif_tag_internal(0, tag_id)
    end

    def only_thumbnail_tag(tag_id)
      exif_tag_internal(1, tag_id)
    end

    def tags(*ifds_to_include)
      return [] if @exif_stream.nil?

      @exif_stream.read_header
      ExifTagReader.new(@exif_stream, *ifds_to_include).tags
    end

    private

    def exif_tags_internal(*ifds_to_include)
      tags(@exif_stream, *ifds_to_include).each_with_object(ExifData.new) do |tag_info, data|
        data.add_tag(*tag_info, @exif_stream.read_tag_value)
      end
    end

    def exif_tag_internal(ifd_index, tag_to_find)
      @exif_stream.read_tag_value if find_tag(ifd_index, tag_to_find)
    end

    def find_tag(ifd_index, tag_to_find)
      tags(@exif_stream, ifd_index).find do |_, ifd_id, tag_num|
        tag_to_find == [ifd_id, tag_num]
      end
    end
  end
end

Version data entries

6 entries across 6 versions & 1 rubygems

Version	Path
file_data-6.0.0	lib/file_data/formats/exif/exif_reader.rb
file_data-5.2.3	lib/file_data/formats/exif/exif_reader.rb
file_data-5.2.2	lib/file_data/formats/exif/exif_reader.rb
file_data-5.2.1	lib/file_data/formats/exif/exif_reader.rb
file_data-5.2.0	lib/file_data/formats/exif/exif_reader.rb
file_data-5.0.0	lib/file_data/formats/exif/exif_reader.rb