forked from rubyzip/rubyzip
/
input_stream.rb
169 lines (152 loc) · 5.29 KB
/
input_stream.rb
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module Zip
# InputStream is the basic class for reading zip entries in a
# zip file. It is possible to create a InputStream object directly,
# passing the zip file name to the constructor, but more often than not
# the InputStream will be obtained from a File (perhaps using the
# ZipFileSystem interface) object for a particular entry in the zip
# archive.
#
# A InputStream inherits IOExtras::AbstractInputStream in order
# to provide an IO-like interface for reading from a single zip
# entry. Beyond methods for mimicking an IO-object it contains
# the method get_next_entry for iterating through the entries of
# an archive. get_next_entry returns a Entry object that describes
# the zip entry the InputStream is currently reading from.
#
# Example that creates a zip archive with ZipOutputStream and reads it
# back again with a InputStream.
#
# require 'zip'
#
# Zip::OutputStream.open("my.zip") do |io|
#
# io.put_next_entry("first_entry.txt")
# io.write "Hello world!"
#
# io.put_next_entry("adir/first_entry.txt")
# io.write "Hello again!"
# end
#
#
# Zip::InputStream.open("my.zip") do |io|
#
# while (entry = io.get_next_entry)
# puts "Contents of #{entry.name}: '#{io.read}'"
# end
# end
#
# java.util.zip.ZipInputStream is the original inspiration for this
# class.
class InputStream
include ::Zip::IOExtras::AbstractInputStream
# Opens the indicated zip file. An exception is thrown
# if the specified offset in the specified filename is
# not a local zip entry header.
#
# @param context [String||IO||StringIO] file path or IO/StringIO object
# @param offset [Integer] offset in the IO/StringIO
def initialize(context, offset = 0, decrypter = nil)
super()
@archive_io = get_io(context, offset)
@decompressor = ::Zip::NullDecompressor
@decrypter = decrypter || ::Zip::NullDecrypter.new
@current_entry = nil
end
def close
@archive_io.close
end
# Returns a Entry object. It is necessary to call this
# method on a newly created InputStream before reading from
# the first entry in the archive. Returns nil when there are
# no more entries.
def get_next_entry
@archive_io.seek(@current_entry.next_header_offset, IO::SEEK_SET) if @current_entry
open_entry
end
# Rewinds the stream to the beginning of the current entry
def rewind
return if @current_entry.nil?
@lineno = 0
@pos = 0
@archive_io.seek(@current_entry.local_header_offset, IO::SEEK_SET)
open_entry
end
# Modeled after IO.sysread
def sysread(number_of_bytes = nil, buf = nil)
@decompressor.sysread(number_of_bytes, buf)
end
def eof
@output_buffer.empty? && @decompressor.eof
end
alias :eof? eof
class << self
# Same as #initialize but if a block is passed the opened
# stream is passed to the block and closed when the block
# returns.
def open(filename_or_io, offset = 0, decrypter = nil)
zio = new(filename_or_io, offset, decrypter)
return zio unless block_given?
begin
yield zio
ensure
zio.close if zio
end
end
def open_buffer(filename_or_io, offset = 0)
puts 'open_buffer is deprecated!!! Use open instead!'
open(filename_or_io, offset)
end
end
protected
def get_io(io_or_file, offset = 0)
if io_or_file.respond_to?(:seek)
io = io_or_file.dup
io.seek(offset, ::IO::SEEK_SET)
io
else
file = ::File.open(io_or_file, 'rb')
file.seek(offset, ::IO::SEEK_SET)
file
end
end
def open_entry
@current_entry = ::Zip::Entry.read_local_entry(@archive_io)
if @current_entry && @current_entry.gp_flags & 1 == 1 && @decrypter.is_a?(NullEncrypter)
raise Error, 'password required to decode zip file'
end
if @current_entry && @current_entry.gp_flags & 8 == 8 && @current_entry.crc == 0 \
&& @current_entry.compressed_size == 0 \
&& @current_entry.size == 0 && !@internal
raise GPFBit3Error,
'General purpose flag Bit 3 is set so not possible to get proper info from local header.' \
'Please use ::Zip::File instead of ::Zip::InputStream'
end
@decompressor = get_decompressor
flush
@current_entry
end
def get_decompressor
if @current_entry.nil?
::Zip::NullDecompressor
elsif @current_entry.compression_method == ::Zip::Entry::STORED
::Zip::PassThruDecompressor.new(@archive_io, @current_entry.size)
elsif @current_entry.compression_method == ::Zip::Entry::DEFLATED
header = @archive_io.read(@decrypter.header_bytesize)
@decrypter.reset!(header)
::Zip::Inflater.new(@archive_io, @decrypter)
else
raise ::Zip::CompressionMethodError,
"Unsupported compression method #{@current_entry.compression_method}"
end
end
def produce_input
@decompressor.produce_input
end
def input_finished?
@decompressor.input_finished?
end
end
end
# Copyright (C) 2002, 2003 Thomas Sondergaard
# rubyzip is free software; you can redistribute it and/or
# modify it under the terms of the ruby license.