rubyzip · jspanjers · Nov 29, 2019 · Nov 29, 2019 · Dec 1, 2019 · Dec 1, 2019
diff --git a/README.md b/README.md
@@ -36,6 +36,13 @@ Or in your Gemfile:
 gem 'rubyzip'
 ```
 
+If you want to read zip files that use the bzip2 compression method,
+you must also install the optional dependency `ffi`:
+
+```ruby
+gem 'ffi'
+```
+
 ## Usage
 
 ### Basic zip archive creation

diff --git a/lib/zip.rb b/lib/zip.rb
@@ -26,6 +26,10 @@
 require 'zip/crypto/traditional_encryption'
 require 'zip/inflater'
 require 'zip/deflater'
+begin
+  require 'zip/bzip2_decompressor'
+rescue LoadError
+end
 require 'zip/streamable_stream'
 require 'zip/streamable_directory'
 require 'zip/constants'

diff --git a/lib/zip/bzip2/decompress.rb b/lib/zip/bzip2/decompress.rb
@@ -0,0 +1,104 @@
+require 'zip/bzip2/libbz2'
+require 'zip/bzip2/errors'
+
+module Zip
+  module Bzip2
+    class Decompress
+      OUT_BUFFER_SIZE = 4096
+
+      class << self
+        private
+
+        def finalize(stream)
+          -> (id) do
+            res = Libbz2::BZ2_bzDecompressEnd(stream)
+            check_error(res)
+          end
+        end
+      end
+
+      def initialize(options = {})
+        small = options[:small]
+
+        @stream = Libbz2::BzStream.new
+        @out_eof = false
+
+        res = Libbz2::BZ2_bzDecompressInit(stream, 0, small ? 1 : 0)
+        check_error(res)
+
+        ObjectSpace.define_finalizer(self, self.class.send(:finalize, stream))
+      end
+
+      def decompress(decompress_string)
+        return nil if @out_eof
+
+        out_buffer = nil
+        in_buffer = nil
+        begin
+          out_buffer = ::FFI::MemoryPointer.new(1, OUT_BUFFER_SIZE)
+          in_buffer = ::FFI::MemoryPointer.new(1, decompress_string.bytesize)
+
+          in_buffer.write_bytes(decompress_string)
+          stream[:next_in] = in_buffer
+          stream[:avail_in] = in_buffer.size
+
+          result = String.new
+          while stream[:avail_in].positive?
+            stream[:next_out] = out_buffer
+            stream[:avail_out] = out_buffer.size
+
+            res = Libbz2::BZ2_bzDecompress(stream)
+            check_error(res)
+
+            result += out_buffer.read_bytes(out_buffer.size - stream[:avail_out])
+
+            if res == Libbz2::BZ_STREAM_END
+              @out_eof = true
+
+              res = Libbz2::BZ2_bzDecompressEnd(stream)
+              ObjectSpace.undefine_finalizer(self)
+              check_error(res)
+
+              break
+            end
+          end
+          result
+        ensure
+          in_buffer.free if in_buffer
+          in_buffer = nil
+          out_buffer.free if out_buffer
+          out_buffer = nil
+        end
+      end
+
+      def finished?
+        @out_eof
+      end
+
+      protected
+
+      attr_reader :stream
+
+      private
+
+      def check_error(res)
+        return res if res >= 0
+
+        error_class = case res
+          when Libbz2::BZ_MEM_ERROR
+            MemError
+          when Libbz2::BZ_DATA_ERROR
+            DataError
+          when Libbz2::BZ_DATA_ERROR_MAGIC
+            MagicDataError
+          when Libbz2::BZ_CONFIG_ERROR
+            ConfigError
+          else
+            raise UnexpectedError.new(res)
+        end
+
+        raise error_class.new
+      end
+    end
+  end
+end
diff --git a/lib/zip/bzip2/errors.rb b/lib/zip/bzip2/errors.rb
@@ -0,0 +1,61 @@
+module Zip
+  module Bzip2
+    # Base class for Zip::Bzip2 exceptions.
+    class Error < IOError
+    end
+
+    # Raised if a failure occurred allocating memory to complete a request.
+    class MemError < Error
+      # Initializes a new instance of MemError.
+      #
+      # @private
+      def initialize #:nodoc:
+        super('Could not allocate enough memory to perform this request')
+      end
+    end
+
+    # Raised if a data integrity error is detected (a mismatch between
+    # stored and computed CRCs or another anomaly in the compressed data).
+    class DataError < Error
+      # Initializes a new instance of DataError.
+      #
+      # @param message [String] Exception message (overrides the default).
+      # @private
+      def initialize(message = nil) #:nodoc:
+        super(message || 'Data integrity error detected (mismatch between stored and computed CRCs, or other anomaly in the compressed data)')
+      end
+    end
+
+    # Raised if the compressed data does not start with the correct magic
+    # bytes ('BZh').
+    class MagicDataError < DataError
+      # Initializes a new instance of MagicDataError.
+      #
+      # @private
+      def initialize #:nodoc:
+        super('Compressed data does not start with the correct magic bytes (\'BZh\')')
+      end
+    end
+
+    # Raised if libbz2 detects that it has been improperly compiled.
+    class ConfigError < DataError
+      # Initializes a new instance of ConfigError.
+      #
+      # @private
+      def initialize #:nodoc:
+        super('libbz2 has been improperly compiled on your platform')
+      end
+    end
+
+    # Raised if libbz2 reported an unexpected error code.
+    class UnexpectedError < Error
+      # Initializes a new instance of UnexpectedError.
+      #
+      # @param error_code [Integer] The error_code reported by libbz2.
+      # @private
+      def initialize(error_code) #:nodoc:
+        super("An unexpected error was detected (error code: #{error_code})")
+      end
+    end
+  end
+end
diff --git a/lib/zip/bzip2/libbz2.rb b/lib/zip/bzip2/libbz2.rb
@@ -0,0 +1,100 @@
+# This file is copied from:
+#
+# https://github.com/philr/bzip2-ffi/raw/master/lib/bzip2/ffi/libbz2.rb
+#
+
+# Copyright (c) 2015-2016 Philip Ross
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy of
+# this software and associated documentation files (the "Software"), to deal in
+# the Software without restriction, including without limitation the rights to
+# use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+# of the Software, and to permit persons to whom the Software is furnished to do
+# so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+
+require 'ffi'
+
+module Zip
+  module Bzip2
+    # FFI bindings for the libbz2 low-level interface.
+    #
+    # See bzlib.h and http://bzip.org/docs.html.
+    #
+    # @private
+    module Libbz2 #:nodoc:
+      extend ::FFI::Library
+
+      ffi_lib ['bz2', 'libbz2.so.1', 'libbz2.dll']
+
+      BZ_RUN    = 0
+      BZ_FLUSH  = 1
+      BZ_FINISH = 2
+
+      BZ_OK               =  0
+      BZ_RUN_OK           =  1
+      BZ_FLUSH_OK         =  2
+      BZ_FINISH_OK        =  3
+      BZ_STREAM_END       =  4
+      BZ_SEQUENCE_ERROR   = -1
+      BZ_PARAM_ERROR      = -2
+      BZ_MEM_ERROR        = -3
+      BZ_DATA_ERROR       = -4
+      BZ_DATA_ERROR_MAGIC = -5
+      BZ_CONFIG_ERROR     = -9
+
+      # void *(*bzalloc)(void *,int,int);
+      callback :bzalloc, [:pointer, :int, :int], :pointer
+
+      # void (*bzfree)(void *,void *);
+      callback :bzfree, [:pointer, :pointer], :void
+
+      # typedef struct { ... } bz_stream;
+      class BzStream < ::FFI::Struct #:nodoc:
+        layout :next_in,       :pointer,
+               :avail_in,      :uint,
+               :total_in_lo32, :uint,
+               :total_in_hi32, :uint,
+
+               :next_out,       :pointer,
+               :avail_out,      :uint,
+               :total_out_lo32, :uint,
+               :total_out_hi32, :uint,
+
+               :state,          :pointer,
+
+               :bzalloc,        :bzalloc,
+               :bzfree,         :bzfree,
+               :opaque,         :pointer
+      end
+
+      # int BZ2_bzCompressInt(bz_stream* strm, int blockSize100k, int verbosity, int workFactor);
+      attach_function :BZ2_bzCompressInit, [BzStream.by_ref, :int, :int, :int], :int
+
+      # int BZ2_bzCompress (bz_stream* strm, int action);
+      attach_function :BZ2_bzCompress, [BzStream.by_ref, :int], :int
+
+      # int BZ2_bzCompressEnd (bz_stream* strm);
+      attach_function :BZ2_bzCompressEnd, [BzStream.by_ref], :int
+
+      # int BZ2_bzDecompressInit (bz_stream *strm, int verbosity, int small);
+      attach_function :BZ2_bzDecompressInit, [BzStream.by_ref, :int, :int], :int
+
+      # int BZ2_bzDecompress (bz_stream* strm);
+      attach_function :BZ2_bzDecompress, [BzStream.by_ref], :int
+
+      # int BZ2_bzDecompressEnd (bz_stream *strm);
+      attach_function :BZ2_bzDecompressEnd, [BzStream.by_ref], :int
+    end
+  end
+end
diff --git a/lib/zip/bzip2_decompressor.rb b/lib/zip/bzip2_decompressor.rb
@@ -0,0 +1,59 @@
+require 'zip/bzip2/decompress'
+
+module Zip
+  class Bzip2Decompressor < Decompressor #:nodoc:all
+    def initialize(input_stream, decrypter = NullDecrypter.new)
+      super(input_stream)
+      @bzip2_ffi_decompressor  = Bzip2::Decompress.new
+      @output_buffer           = ''.dup
+      @has_returned_empty_string = false
+      @decrypter = decrypter
+    end
+
+    def sysread(number_of_bytes = nil, buf = '')
+      readEverything = number_of_bytes.nil?
+      while readEverything || @output_buffer.bytesize < number_of_bytes
+        break if internal_input_finished?
+        @output_buffer << internal_produce_input(buf)
+      end
+      return value_when_finished if @output_buffer.bytesize == 0 && input_finished?
+      end_index = number_of_bytes.nil? ? @output_buffer.bytesize : number_of_bytes
+      @output_buffer.slice!(0...end_index)
+    end
+
+    def produce_input
+      if @output_buffer.empty?
+        internal_produce_input
+      else
+        @output_buffer.slice!(0...(@output_buffer.length))
+      end
+    end
+
+    # to be used with produce_input, not read (as read may still have more data cached)
+    # is data cached anywhere other than @outputBuffer?  the comment above may be wrong
+    def input_finished?
+      @output_buffer.empty? && internal_input_finished?
+    end
+
+    alias :eof input_finished?
+    alias :eof? input_finished?
+
+    private
+
+    def internal_produce_input(buf = '')
+      @bzip2_ffi_decompressor.decompress(@decrypter.decrypt(@input_stream.read(1024, buf)))
+    rescue Bzip2::Error => e
+      raise DecompressionError, e.message
+    end
+
+    def internal_input_finished?
+      @bzip2_ffi_decompressor.finished?
+    end
+
+    def value_when_finished # mimic behaviour of ruby File object.
+      return if @has_returned_empty_string
+      @has_returned_empty_string = true
+      ''
+    end
+  end
+end
diff --git a/lib/zip/entry.rb b/lib/zip/entry.rb
@@ -3,6 +3,7 @@ module Zip
   class Entry
     STORED   = 0
     DEFLATED = 8
+    BZIP2ED = 12
     # Language encoding flag (EFS) bit
     EFS = 0b100000000000
 

diff --git a/lib/zip/errors.rb b/lib/zip/errors.rb
@@ -7,6 +7,7 @@ class EntryNameError < Error; end
   class EntrySizeError < Error; end
   class InternalError < Error; end
   class GPFBit3Error < Error; end
+  class DecompressionError < Error; end
 
   # Backwards compatibility with v1 (delete in v2)
   ZipError = Error

diff --git a/lib/zip/input_stream.rb b/lib/zip/input_stream.rb
@@ -152,6 +152,10 @@ def get_decompressor
         header = @archive_io.read(@decrypter.header_bytesize)
         @decrypter.reset!(header)
         ::Zip::Inflater.new(@archive_io, @decrypter)
+      elsif @current_entry.compression_method == ::Zip::Entry::BZIP2ED && defined?(::Zip::Bzip2Decompressor)
+        header = @archive_io.read(@decrypter.header_bytesize)
+        @decrypter.reset!(header)
+        ::Zip::Bzip2Decompressor.new(@archive_io, @decrypter)
       else
         raise ::Zip::CompressionMethodError,
               "Unsupported compression method #{@current_entry.compression_method}"

diff --git a/rubyzip.gemspec b/rubyzip.gemspec
@@ -23,6 +23,7 @@ Gem::Specification.new do |s|
     'wiki_uri'          => 'https://github.com/rubyzip/rubyzip/wiki'
   }
   s.required_ruby_version = '>= 2.4'
+  s.add_development_dependency 'ffi', '~> 1.0'
   s.add_development_dependency 'rake', '~> 10.3'
   s.add_development_dependency 'pry', '~> 0.10'
   s.add_development_dependency 'minitest', '~> 5.4'