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# frozen_string_literal: true
# prawn/core/stream.rb : Implements Stream objects
#
# Copyright February 2013, Alexander Mankuta. All Rights Reserved.
#
# This is free software. Please see the LICENSE and COPYING files for details.
module PDF
module Core
# PDF Stream object
class Stream
# Stream filters
# @return [PDF::Core::FilterList]
attr_reader :filters
# @param io [String] must be mutable
def initialize(io = nil)
@filtered_stream = ''
@stream = io
@filters = FilterList.new
end
# Append data to stream.
#
# @param io [String]
# @return [self]
def <<(io)
(@stream ||= +'') << io
@filtered_stream = nil
self
end
# Set up stream to be compressed when serialized.
#
# @return [void]
def compress!
unless @filters.names.include?(:FlateDecode)
@filtered_stream = nil
@filters << :FlateDecode
end
end
# Is this stream compressed?
#
# @return [Boolean]
def compressed?
@filters.names.include?(:FlateDecode)
end
# Is there any data in this stream?
#
# @return [Boolean]
def empty?
@stream.nil?
end
# Stream data with filters applied.
#
# @return [Stream]
def filtered_stream
if @stream
if @filtered_stream.nil?
@filtered_stream = @stream.dup
@filters.each do |(filter_name, params)|
filter = PDF::Core::Filters.const_get(filter_name)
if filter
@filtered_stream = filter.encode(@filtered_stream, params)
end
end
end
@filtered_stream
end
end
# Size of data in the stream
#
# @return [Integer]
def length
@stream.length
end
# Serialized stream data
#
# @return [String]
def object
if filtered_stream
"stream\n#{filtered_stream}\nendstream\n"
else
''
end
end
# Stream dictionary
#
# @return [Hash]
def data
if @stream
filter_names = @filters.names
filter_params = @filters.decode_params
d = {
Length: filtered_stream.length,
}
if filter_names.any?
d[:Filter] = filter_names
end
if filter_params.any? { |f| !f.nil? }
d[:DecodeParms] = filter_params
end
d
else
{}
end
end
# String representation of the stream for debugging purposes.
#
# @return [String]
def inspect
format(
'#<%<class>s:0x%<object_id>014x @stream=%<stream>s, @filters=%<filters>s>',
class: self.class.name,
object_id: object_id,
stream: @stream.inspect,
filters: @filters.inspect,
)
end
end
end
end
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