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- get_chars

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This commit is contained in:
Marc-Andre Lafortune 2014-01-29 09:19:24 -05:00
parent 77670ff6d4
commit a909410cdd
1 changed files with 22 additions and 26 deletions
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48
lib/fastimage.rb
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@ -330,16 +330,12 @@ class FastImage
end
end
def get_chars(n)
@stream.read(n)
end
def get_byte
get_chars(1).unpack("C")[0]
@stream.read(1).unpack("C")[0]
end
def get_int
get_chars(2).unpack('n')[0]
@stream.read(2).unpack('n')[0]
end
def parse_type
@ -362,18 +358,18 @@ class FastImage
end
def parse_size_for_gif
get_chars(11)[6..10].unpack('SS')
@stream.read(11)[6..10].unpack('SS')
end
def parse_size_for_png
get_chars(25)[16..24].unpack('NN')
@stream.read(25)[16..24].unpack('NN')
end
def parse_size_for_jpeg
loop do
@state = case @state
when nil
get_chars(2)
@stream.read(2)
:started
when :started
get_byte == 0xFF ? :sof : :started
@ -382,11 +378,11 @@ class FastImage
when 0xe1 # APP1
skip_chars = get_int - 2
skip_from = @stream.bytes_delivered
if get_chars(4) == "Exif"
get_chars(2)
if @stream.read(4) == "Exif"
@stream.read(2)
parse_exif
end
get_chars(skip_chars - (@stream.bytes_delivered - skip_from))
@stream.read(skip_chars - (@stream.bytes_delivered - skip_from))
:started
when 0xe0..0xef
:skipframe
@ -399,10 +395,10 @@ class FastImage
end
when :skipframe
skip_chars = get_int - 2
get_chars(skip_chars)
@stream.read(skip_chars)
:started
when :readsize
s = get_chars(3)
s = @stream.read(3)
height = get_int
width = get_int
width, height = height, width if @exif_orientation && @exif_orientation >= 5
@ -412,7 +408,7 @@ class FastImage
end
def parse_size_for_bmp
d = get_chars(32)[14..28]
d = @stream.read(32)[14..28]
header = d.unpack("C")[0]
result = if header == 40
@ -426,7 +422,7 @@ class FastImage
end
def get_exif_byte_order
byte_order = get_chars(2)
byte_order = @stream.read(2)
case byte_order
when 'II'
@short, @long = 'v', 'V'
@ -438,11 +434,11 @@ class FastImage
end
def parse_exif_ifd
tag_count = get_chars(2).unpack(@short)[0]
tag_count = @stream.read(2).unpack(@short)[0]
tag_count.downto(1) do
type = get_chars(2).unpack(@short)[0]
get_chars(6)
data = get_chars(2).unpack(@short)[0]
type = @stream.read(2).unpack(@short)[0]
@stream.read(6)
data = @stream.read(2).unpack(@short)[0]
case type
when 0x0100 # image width
@exif_width = data
@ -454,13 +450,13 @@ class FastImage
if @type == :tiff && @exif_width && @exif_height && @exif_orientation
return # no need to parse more
end
get_chars(2)
@stream.read(2)
end
next_offset = get_chars(4).unpack(@long)[0]
next_offset = @stream.read(4).unpack(@long)[0]
relative_offset = next_offset - (@stream.bytes_delivered - @exif_start_byte)
if relative_offset >= 0
get_chars(relative_offset)
@stream.read(relative_offset)
parse_exif_ifd
end
end
@ -470,10 +466,10 @@ class FastImage
get_exif_byte_order
get_chars(2) # 42
@stream.read(2) # 42
offset = get_chars(4).unpack(@long)[0]
get_chars(offset - 8)
offset = @stream.read(4).unpack(@long)[0]
@stream.read(offset - 8)
parse_exif_ifd
end