Class: FormatParser::CR2Parser

Inherits:
Object
  • Object
show all
Includes:
EXIFParser, IOUtils
Defined in:
lib/parsers/cr2_parser.rb

Constant Summary collapse

TIFF_HEADER = 
[0x49, 0x49, 0x2a, 0x00]
CR2_HEADER = 
[0x43, 0x52, 0x02, 0x00]
CR2_MIME_TYPE = 
'image/x-canon-cr2'

Constants included from EXIFParser

EXIFParser::ORIENTATIONS

Constants included from IOUtils

IOUtils::INTEGER_DIRECTIVES

Instance Method Summary collapse

Methods included from EXIFParser

#exif_from_tiff_io

Methods included from IOUtils

#read_bytes, #read_fixed_point, #read_int, #safe_read, #safe_skip, #skip_bytes

Instance Method Details

#call(io) ⇒ Object 



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# File 'lib/parsers/cr2_parser.rb', line 15

def call(io)
  io = FormatParser::IOConstraint.new(io)

  tiff_header = safe_read(io, 8)

  # Check whether it's a CR2 file
  tiff_bytes = tiff_header[0..3].bytes
  magic_bytes = safe_read(io, 4).unpack('C4')

  return if !magic_bytes.eql?(CR2_HEADER) || !tiff_bytes.eql?(TIFF_HEADER)

  # The TIFF scanner in EXIFR is plenty good enough,
  # so why don't we use it? It does all the right skips
  # in all the right places.
  exif_data = exif_from_tiff_io(io)
  return unless exif_data

  w = exif_data.image_width
  h = exif_data.image_length

  FormatParser::Image.new(
    format: :cr2,
    width_px: w,
    height_px: h,
    display_width_px: exif_data.rotated? ? h : w,
    display_height_px: exif_data.rotated? ? w : h,
    orientation: exif_data.orientation_sym,
    intrinsics: {exif: exif_data},
    content_type: CR2_MIME_TYPE,
  )
rescue EXIFR::MalformedTIFF
  nil
end

#likely_match?(filename) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/parsers/cr2_parser.rb', line 11

def likely_match?(filename)
  filename =~ /\.cr2$/i
end