1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
|
module FastImageParsing
class FiberStream # :nodoc:
include StreamUtil
attr_reader :pos
# read_fiber should return nil if it no longer has anything to return when resumed
# so the result of the whole Fiber block should be set to be nil in case yield is no
# longer called
def initialize(read_fiber)
@read_fiber = read_fiber
@pos = 0
@strpos = 0
@str = ''
end
# Peeking beyond the end of the input will raise
def peek(n)
while @strpos + n > @str.size
unused_str = @str[@strpos..-1]
new_string = @read_fiber.resume
raise FastImage::CannotParseImage if !new_string
# we are dealing with bytes here, so force the encoding
new_string.force_encoding("ASCII-8BIT") if new_string.respond_to? :force_encoding
@str = unused_str + new_string
@strpos = 0
end
@str[@strpos, n]
end
def read(n)
result = peek(n)
@strpos += n
@pos += n
result
end
def skip(n)
discarded = 0
fetched = @str[@strpos..-1].size
while n > fetched
discarded += @str[@strpos..-1].size
new_string = @read_fiber.resume
raise FastImage::CannotParseImage if !new_string
new_string.force_encoding("ASCII-8BIT") if new_string.respond_to? :force_encoding
fetched += new_string.size
@str = new_string
@strpos = 0
end
@strpos = @strpos + n - discarded
@pos += n
end
end
end
|
