Sha256: faff66df7f00877505bdf19e10752575144f214cc9ce0626197cec97d2ac3cdc
Contents?: true
Size: 1.33 KB
Versions: 9
Compression:
Stored size: 1.33 KB
Contents
# coding: utf-8
# typed: strict
# frozen_string_literal: true
#
class PDF::Reader # :nodoc:
module Filter # :nodoc:
# implementation of the run length stream filter
class RunLength
def initialize(options = {})
@options = options
end
################################################################################
# Decode the specified data with the RunLengthDecode compression algorithm
def filter(data)
pos = 0
out = "".dup
while pos < data.length
length = data.getbyte(pos)
pos += 1
unless length.nil?
case
# nothing
when length == 128
break
when length < 128
# When the length is < 128, we copy the following length+1 bytes
# literally.
out << data[pos, length + 1]
pos += length
else
# When the length is > 128, we copy the next byte (257 - length)
# times; i.e., "\xFA\x00" ([250, 0]) will expand to
# "\x00\x00\x00\x00\x00\x00\x00".
previous_byte = data[pos, 1] || ""
out << previous_byte * (257 - length)
end
end
pos += 1
end
Depredict.new(@options).filter(out)
end
end
end
end
Version data entries
9 entries across 9 versions & 1 rubygems