lib/icns/reader.rb in icns-0.1.0 vs lib/icns/reader.rb in icns-0.2.0

@@ -1,14 +1,15 @@
 # frozen_string_literal: true
 
 require 'icns/errors'
 
 module Icns
+  # Read an ICNS file’s metadata and extract images.
   class Reader
     # Initialize with a path to a valid ICNS file
     def initialize(path)
-      throw FileNotFound unless File.exists?(path)
+      throw FileNotFound unless File.exist?(path)
 
       @path = path
       @parts = {}
 
       read_metadata
@@ -18,12 +19,12 @@
     def types
       @parts.keys
     end
 
     # Raw data for a type
-    def data_for_type(type)
-      return nil unless part = @parts[type.to_s]
+    def data(type:)
+      return nil unless (part = @parts[type.to_s])
 
       File.open(@path) do |file|
         # Seek to the image data position
         file.pos = part[:offset]
 
@@ -31,26 +32,26 @@
         file.read(part[:length])
       end
     end
 
     # PNG or JPEG-2000 data for a size
-    def image_for_size(size)
-      return nil unless types = SIZE_TO_TYPE[size.to_i]
+    def image(size:)
+      return nil unless (types = SIZE_TO_TYPE[size.to_i])
 
       data = nil
       types.each do |type|
-        break if data = data_for_type(type)
+        break if (data = self.data(type: type))
       end
 
       data
     end
 
     # Available image sizes
     def sizes
       types = SIZE_TO_TYPE.values.flatten
-      @parts.keys.select { |k| types.include?(k) }.
-        map { |k| TYPE_TO_SIZE[k] }.sort.uniq
+      @parts.keys.select { |k| types.include?(k) }
+            .map { |k| TYPE_TO_SIZE[k] }.sort.uniq
     end
 
     private
 
     # These types are just metadata and not images.
@@ -72,26 +73,30 @@
 
         # The next 4 bytes are the total length of the file. Skip ahead.
         file.pos += 4
 
         # Keep reading until we hit the end
-        while true
-          # If we can't read the icon type and length, we’re at the end
-          break unless (type = file.read(4)) && (length = file.read(4))
+        loop do
+          break unless read_part(file)
+        end
+      end
+    end
 
-          # Convert the length into an integer. The length includes the icon
-          # header. We just want the length of the image data.
-          length = length.unpack('N')[0] - 8
+    def read_part(file)
+      # If we can't read the icon type and length, we’re at the end
+      return false unless (type = file.read(4)) && (length = file.read(4))
 
-          unless TYPES_BLACKLIST.include?(type)
-            # Add to our hash of type name to image data locations
-            puts "WARNING: duplicate part '#{type}'" if @parts[type]
-            @parts[type] = { offset: file.pos, length: length }
-          end
+      # Convert the length into an integer. The length includes the icon
+      # header. We just want the length of the image data.
+      length = length.unpack1('N') - 8
 
-          # Advance past the image data
-          file.pos += length
-        end
+      unless TYPES_BLACKLIST.include?(type)
+        # Add to our hash of type name to image data locations
+        puts "WARNING: duplicate part '#{type}'" if @parts[type]
+        @parts[type] = { offset: file.pos, length: length }
       end
+
+      # Advance past the image data
+      file.pos += length
     end
   end
 end