Import Ruby/zlib from rough.

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+MANIFEST
+extconf.rb
+zlib.c
+doc/zlib.rd
diff --git a/ext/zlib/doc/zlib.rd b/ext/zlib/doc/zlib.rd
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+=begin
+#
+# zlib.rd.src
+#
+#   Copyright (C) UENO Katsuhiro 2000-2003
+#
+# $Id$
+#
+
+= Ruby/zlib version 0.6.0
+
+Ruby/zlib is an extension library to use zlib from Ruby.
+Ruby/zlib also provides the features for accessing gzipped files.
+
+You can modify or redistribute Ruby/zlib in the same manner of
+Ruby interpreter. The latest version of Ruby/zlib would be found
+at ((<URL:http://www.blue.sky.or.jp/>)).
+
+Any comments and suggestions are always welcome. Please send
+them to ruby-list ML, ruby-ext ML, ruby-talk ML, or the author's
+mail address ((<URL:mailto:katsu@blue.sky.or.jp>)).
+
+This document is experimental and broken English version.
+If you find some mistakes or strange expressions (including
+kidding or unnatural ones) in this document, please let me know
+for my study.
+
+* ((<Zlib>))
+
+  * ((<Zlib::Error>))
+  * ((<Zlib::ZStream>))
+  * ((<Zlib::Deflate>))
+  * ((<Zlib::Inflate>))
+  * ((<Zlib::GzipFile>))
+  * ((<Zlib::GzipFile::Error>))
+  * ((<Zlib::GzipWriter>))
+  * ((<Zlib::GzipReader>))
+
+* ((<Changes from 0.5 to 0.6>))
+* ((<Changes from 0.4 to 0.5>))
+
+== Zlib
+
+Zlib is the module which provides the other features in zlib C
+library. See zlib.h for detail of each module function.
+
+=== Module Functions:
+
+--- Zlib.zlib_version
+
+    Returns the string which represents the version of zlib
+    library.
+
+--- Zlib.adler32([string[, adler]])
+
+    Calculates Alder-32 checksum for ((|string|)),
+    and returns updated value of ((|alder|)).
+    If ((|string|)) is omitted, it returns the Adler-32 initial
+    value. If ((|alder|)) is omitted, it assumes that the initial
+    value is given to ((|alder|)).
+
+--- Zlib.crc32([string[, crc]])
+
+    Calculates CRC checksum for ((|string|)), and returns
+    updated value of ((|crc|)). If ((|string|)) is omitted,
+    it returns the CRC initial value. ((|crc|)) is omitted,
+    it assumes that the initial value is given to ((|crc|)).
+
+--- Zlib.crc_table
+
+    Returns the table for calculating CRC checksum as an array.
+
+=== Constants:
+
+--- Zlib::VERSION
+
+    The Ruby/zlib version string.
+
+--- Zlib::ZLIB_VERSION
+
+    The string which represents the version of zlib.h.
+
+--- Zlib::BINARY
+--- Zlib::ASCII
+--- Zlib::UNKNOWN
+
+    The integers representing data types which
+    ((<Zlib::ZStream#data_type>)) method returns.
+
+--- Zlib::NO_COMPRESSION
+--- Zlib::BEST_SPEED
+--- Zlib::BEST_COMPRESSION
+--- Zlib::DEFAULT_COMPRESSION
+
+    The integers representing compression levels which are
+    an argument for ((<Zlib::Deflate.new>)),
+    ((<Zlib::Deflate#deflate>)), and so on.
+
+--- Zlib::FILTERED
+--- Zlib::HUFFMAN_ONLY
+--- Zlib::DEFAULT_STRATEGY
+
+    The integers representing compression methods which are
+    an argument for ((<Zlib::Deflate.new>)) and
+    ((<Zlib::Deflate#params>)).
+
+--- Zlib::DEF_MEM_LEVEL
+--- Zlib::MAX_MEM_LEVEL
+
+    The integers representing memory levels which are an
+    argument for ((<Zlib::Deflate.new>)),
+    ((<Zlib::Deflate#params>)), and so on.
+
+--- Zlib::MAX_WBITS
+
+    The default value of ((|windowBits|)) which is an argument for
+    ((<Zlib::Deflate.new>)) and ((<Zlib::Inflate.new>)).
+
+--- Zlib::NO_FLUSH
+--- Zlib::SYNC_FLUSH
+--- Zlib::FULL_FLUSH
+--- Zlib::FINISH
+
+    The integers to control the output of the deflate stream,
+    which are an argument for ((<Zlib::Deflate#deflate>)) and so on.
+
+--- Zlib::OS_CODE
+--- Zlib::OS_MSDOS
+--- Zlib::OS_AMIGA
+--- Zlib::OS_VMS
+--- Zlib::OS_UNIX
+--- Zlib::OS_VMCMS
+--- Zlib::OS_ATARI
+--- Zlib::OS_OS2
+--- Zlib::OS_MACOS
+--- Zlib::OS_ZSYSTEM
+--- Zlib::OS_CPM
+--- Zlib::OS_TOPS20
+--- Zlib::OS_WIN32
+--- Zlib::OS_QDOS
+--- Zlib::OS_RISCOS
+--- Zlib::OS_UNKNOWN
+
+    The return values of ((<Zlib::GzipFile#os_code>)) method.
+
+
+== Zlib::Error
+
+The superclass for all exceptions raised by Ruby/zlib.
+
+The following exceptions are defined as subclasses of Zlib::Error.
+These exceptions are raised when zlib library functions return
+with an error status.
+
+  * Zlib::StreamEnd
+  * Zlib::NeedDict
+  * Zlib::DataError
+  * Zlib::StreamError
+  * Zlib::MemError
+  * Zlib::BufError
+  * Zlib::VersionError
+
+=== SuperClass:
+
+* StandardError
+
+
+== Zlib::ZStream
+
+The abstract class for the stream which handles the compressed
+data. The operations are defined in the subclasses,
+((<Zlib::Deflate>)) for compression, and ((<Zlib::Inflate>))
+for decompression.
+
+An instance of Zlib::ZStream has one stream (struct zstream) and
+two variable-length buffers which associated to the input
+(next_in) of the stream and the output (next_out) of the stream.
+In this document, "input buffer" means the buffer for input, and
+"output buffer" means the buffer for output.
+
+Data inputed into an instance of Zlib::ZStream are temporally
+stored into the end of input buffer, and then data in input buffer
+are processed from the beginning of the buffer until no more
+output from the stream is produced (i.e. until avail_out > 0
+after processing). During processing, output buffer is allocated
+and expanded automatically to hold all output data.
+
+Some particular instance methods consume the data in output buffer
+and return them as a String.
+
+Here is an ascii art for describing above:
+
+     +================ an instance of Zlib::ZStream ================+
+     ||                                                            ||
+     ||     +--------+          +-------+          +--------+      ||
+     ||  +--| output |<---------|zstream|<---------| input  |<--+  ||
+     ||  |  | buffer |  next_out+-------+next_in   | buffer |   |  ||
+     ||  |  +--------+                             +--------+   |  ||
+     ||  |                                                      |  ||
+     +===|======================================================|===+
+         |                                                      |
+         v                                                      |
+     "output data"                                         "input data"
+
+If an error is occurred during processing input buffer,
+an exception which is a subclass of ((<Zlib::Error>)) is raised.
+At that time, both input and output buffer keeps their conditions
+at the time when the error is occurred.
+
+=== SuperClass:
+
+* Object
+
+=== Class Methods:
+
+--- Zlib::ZStream.new
+
+    See ((<Zlib::Deflate.new>)) and ((<Zlib::Inflate.new>)).
+
+=== Methods:
+
+--- Zlib::ZStream#avail_in
+
+    Returns bytes of data in input buffer.
+    Normally, returns 0.
+
+--- Zlib::ZStream#avail_out
+
+    Returns bytes of free spaces in output buffer.
+    Because the free spaces are allocated automatically,
+    this method returns 0 normally.
+
+--- Zlib::ZStream#avail_out = size
+
+    Allocates free spaces of ((|size|)) bytes in output buffer.
+    If there are more than ((|size|)) bytes spaces in the buffer,
+    the buffer is truncated.
+    Because the free spaces are allocated automatically,
+    you usually need not to use this method.
+
+--- Zlib::ZStream#flush_next_in
+
+    Flushes input buffer and returns all data in that buffer.
+
+--- Zlib::ZStream#flush_next_out
+
+    Flushes output buffer and returns all data in that buffer.
+
+--- Zlib::ZStream#total_in
+
+    Returns the total bytes of the input data to the stream.
+
+--- Zlib::ZStream#total_out
+
+    Returns the total bytes of the output data from the stream.
+
+--- Zlib::ZStream#data_type
+
+    Guesses the type of the data which have been inputed into
+    the stream. The returned value is either ((<Zlib::BINARY>)),
+    ((<Zlib::ASCII>)), or ((<Zlib::UNKNOWN>)).
+
+--- Zlib::ZStream#adler
+
+    Returns the alder-32 checksum.
+
+--- Zlib::ZStream#reset
+
+    Resets and initializes the stream. All data in both
+    input and output buffer are discarded.
+
+--- Zlib::ZStream#finish
+
+    Finishes the stream and flushes output buffer.
+    See ((<Zlib::Deflate#finish>)) and ((<Zlib::Inflate#finish>))
+    for detail of the behavior.
+
+--- Zlib::ZStream#finished?
+--- Zlib::ZStream#stream_end?
+
+    Returns true if the stream is finished.
+
+--- Zlib::ZStream#close
+--- Zlib::ZStream#end
+
+    Closes the stream. All operations on the closed stream
+    will raise an exception.
+
+--- Zlib::ZStream#closed?
+--- Zlib::ZStream#ended?
+
+    Returns true if the stream closed.
+
+
+== Zlib::Deflate
+
+The class for compressing string data.
+
+=== SuperClass:
+
+* ((<Zlib::ZStream>))
+
+=== Class Methods:
+
+--- Zlib::Deflate.deflate(string[, level])
+
+    Compresses ((|string|)). The avail values of ((|level|)) are
+    ((<Zlib::NO_COMPRESSION>)), ((<Zlib::BEST_SPEED>)),
+    ((<Zlib::BEST_COMPRESSION>)), ((<Zlib::DEFAULT_COMPRESSION>)),
+    and the integer from 0 to 9.
+
+    This method is almost equivalent to the following code:
+
+      def deflate(string, level)
+        z = Zlib::Deflate.new(level)
+        dst = z.deflate(string, Zlib::FINISH)
+        z.close
+        dst
+      end
+
+--- Zlib::Deflate.new([level[, windowBits[, memlevel[, strategy]]]])
+
+    Creates a new deflate stream for compression.
+    See zlib.h for details of each argument.
+    If an argument is nil, the default value of that
+    argument is used.
+
+=== Methods:
+
+--- Zlib::Deflate#clone
+
+    Duplicates the deflate stream.
+
+--- Zlib::Deflate#deflate(string[, flush])
+
+    Inputs ((|string|)) into the deflate stream and returns
+    the output from the stream. Calling this method,
+    both input and output buffer of the stream are flushed.
+    If ((|string|)) is nil, this method finishes the stream,
+    just like ((<Zlib::ZStream#finish>)).
+    The value of ((|flush|)) should be either ((<Zlib::NO_FLUSH>)),
+    ((<Zlib::SYNC_FLUSH>)), ((<Zlib::FULL_FLUSH>)), or
+    ((<Zlib::FINISH>)).
+    See zlib.h for details.
+
+--- Zlib::Deflate#<< string
+
+    Inputs ((|string|)) into the deflate stream just like
+    ((<Zlib::Deflate#deflate>)), but returns Zlib::Deflate object
+    itself. The output from the stream is preserved in output
+    buffer.
+
+--- Zlib::Deflate#flush([flush])
+
+    This method is equivalent to (({deflate('', ((|flush|)))})).
+    If ((|flush|)) is omitted, ((<Zlib::SYNC_FLUSH>)) is used
+    as ((|flush|)). This method is just provided for
+    readability of your Ruby script.
+
+--- Zlib::Deflate#finish
+
+    Finishes the stream. This method is equivalent to
+    (({deflate('', Zlib::FINISH)})).
+
+--- Zlib::Deflate#params(level, strategy)
+
+    Changes the parameters of the deflate stream.
+    See zlib.h for details. The output from the stream
+    by changing the params is preserved in output buffer.
+
+--- Zlib::Deflate#set_dictionary(string)
+
+    Sets the preset dictionary and returns ((|string|)).
+    This method is available just only after
+    ((<Zlib::Deflate.new>)) or ((<Zlib::ZStream#reset>)) method
+    was called. See zlib.h for details.
+
+
+== Zlib::Inflate
+
+The class for decompressing compressed data.
+Unlike ((<Zlib::Deflate>)), an instance of this class is not able
+to duplicate (clone, dup) itself.
+
+=== SuperClass:
+
+* ((<Zlib::ZStream>))
+
+=== Class Methods:
+
+--- Zlib::Inflate.inflate(string)
+
+    Decompresses ((|string|)). Raises a ((<Zlib::NeedDict>))
+    exception if a preset dictionary is needed for decompression.
+
+    This method is almost equivalent to the following code:
+
+      def inflate(string)
+        zstream = Zlib::Inflate.new
+        buf = zstream.inflate(string)
+        zstream.finish
+        zstream.close
+        buf
+      end
+
+--- Zlib::Inflate.new([windowBits])
+
+    Creates a new inflate stream for decompression.
+    See zlib.h for details of the argument.
+    If ((|windowBits|)) is nil, the default value is used.
+
+=== Methods:
+
+--- Zlib::Inflate#inflate(string)
+
+    Inputs ((|string|)) into the inflate stream and returns
+    the output from the stream. Calling this method,
+    both input and output buffer of the stream are flushed.
+    If ((|string|)) is nil, this method finishes the stream,
+    just like ((<Zlib::ZStream#finish>)).
+
+    Raises a ((<Zlib::NeedDict>)) exception if a preset
+    dictionary is needed to decompress. Set the dictionary
+    by ((<Zlib::Inflate#set_dictionary>)) and then call
+    this method again with an empty string.
+
+--- Zlib::Inflate#<< string
+
+    Inputs ((|string|)) into the inflate stream just like
+    ((<Zlib::Inflate#inflate>)), but returns Zlib::Inflate object
+    itself. The output from the stream is preserved in output
+    buffer.
+
+--- Zlib::Inflate#finish
+
+    Finishes the inflate stream and returns the garbage
+    following the compressed data. Raises an exception
+    if the stream is not finished
+    (i.e. ((<Zlib::ZStream#finished?>)) doesn't returns true).
+
+    The inflate stream finishes itself as soon as it meets
+    the end code of the compressed data, you need not to call
+    this method explicitly. However, this method is useful
+    for checking whether the data is correctly ended or not.
+
+--- Zlib::Inflate#set_dictionary(string)
+
+    Sets the preset dictionary and returns ((|string|))
+    This method is available just only after a ((<Zlib::NeedDict>))
+    exception was raised. See zlib.h for details.
+
+--- Zlib::Inflate#sync(string)
+
+    Inputs ((|string|)) into the end of input buffer and
+    skips data until a full flush point can be found.
+    If the point is found in the buffer, this method flushes
+    the buffer and returns false. Otherwise it returns true
+    and the following data of full flush point is preserved
+    in the buffer.
+
+--- Zlib::Inflate#sync_point?
+
+    What is this?
+
+
+== Zlib::GzipFile
+
+The abstruct class for handling a gzip formatted compressed file.
+The operations are defined in the subclasses,
+((<Zlib::GzipReader>)) for reading, and ((<Zlib::GzipWriter>))
+for writing.
+
+GzipReader should be used with associating an instance of IO class
+(or an object which has the same methods as IO has).
+
+=== SuperClass:
+
+* Object
+
+=== Class Methods:
+
+--- Zlib::GzipFile.new(args...)
+
+    See ((<Zlib::GzipReader.new>)) and ((<Zlib::GzipWriter.new>)).
+
+--- Zlib::GzipFile.wrap(args...) {|gz| ... }
+
+    See ((<Zlib::GzipReader.wrap>)) and ((<Zlib::GzipWriter.wrap>)).
+
+--- Zlib::GzipFile.open(args...) {|gz| ... }
+
+    See ((<Zlib::GzipReader.open>)) and ((<Zlib::GzipWriter.open>)).
+
+=== Methods:
+
+--- Zlib::GzipFile#closed?
+--- Zlib::GzipFile#to_io
+
+    Same as IO.
+
+--- Zlib::GzipFile#close
+
+    Closes the GzipFile object. This method calls close method
+    of the associated IO object. Returns the associated IO object.
+
+--- Zlib::GzipFile#finish
+
+    Closes the GzipFile object. Unlike ((<Zlib::GzipFile#close>)),
+    this method ((*never*)) calls close method of the associated IO
+    object. Returns the associated IO object.
+
+--- Zlib::GzipFile#crc
+
+    Returns CRC value of the uncompressed data.
+
+--- Zlib::GzipFile#level
+
+    Returns compression level.
+
+--- Zlib::GzipFile#mtime
+
+    Returns last modification time recorded in the gzip
+    file header.
+
+--- Zlib::GzipFile#os_code
+
+    Returns OS code number recorded in the gzip file header.
+
+--- Zlib::GzipFile#orig_name
+
+    Returns original filename recorded in the gzip file header,
+    or nil if original filename is not present.
+
+--- Zlib::GzipFile#comment
+
+    Returns comments recorded in the gzip file header, or
+    nil if the comments is not present.
+
+--- Zlib::GzipFile#sync
+--- Zlib::GzipFile#sync= flag
+
+    Same as IO. If ((|flag|)) is true, the associated IO object
+    must respond to flush method. While `sync' mode is true,
+    the compression ratio decreases sharply.
+
+
+== Zlib::GzipFile::Error
+
+The superclass for all exceptions raised during processing a gzip
+file.
+
+The following exceptions are defined as subclasses of
+Zlib::GzipFile::Error.
+
+: Zlib::GzipFile::NoFooter
+
+    Raised when gzip file footer has not found.
+
+: Zlib::GzipFile::CRCError
+
+    Raised when the CRC checksum recorded in gzip file footer
+    is not equivalent to CRC checksum of the actually
+    uncompressed data.
+
+: Zlib::GzipFile::LengthError
+
+    Raised when the data length recorded in gzip file footer
+    is not equivalent to length of the actually uncompressed data.
+
+=== SuperClass:
+
+* ((<Zlib::Error>))
+
+
+== Zlib::GzipReader
+
+The class for reading a gzipped file. GzipReader should be used
+with associating an instance of IO class (or an object which has
+the same methods as IO has).
+
+    Zlib::GzipReader.open('hoge.gz') {|gz|
+      print gz.read
+    }
+
+    f = File.open('hoge.gz')
+    gz = Zlib::GzipReader.new(f)
+    print gz.read
+    gz.close
+
+=== SuperClass:
+
+* ((<Zlib::GzipFile>))
+
+=== Included Modules:
+
+* Enumerable
+
+=== Class Methods:
+
+--- Zlib::GzipReader.new(io)
+
+    Creates a GzipReader object associated with ((|io|)).
+    The GzipReader object reads gzipped data from ((|io|)),
+    and parses/decompresses them. At least, ((|io|)) must have
+    read method that behaves same as read method in IO class.
+
+    If the gzip file header is incorrect, raises an
+    ((<Zlib::GzipFile::Error>)) exception.
+
+--- Zlib::GzipReader.wrap(io) {|gz| ... }
+
+    Creates a GzipReader object associated with ((|io|)), and
+    executes the block with the newly created GzipReader object,
+    just like File::open. The GzipReader object will be closed
+    automatically after executing the block. If you want to keep
+    the associated IO object opening, you may call
+    ((<Zlib::GzipFile#finish>)) method in the block.
+
+--- Zlib::GzipReader.open(filename)
+--- Zlib::GzipReader.open(filename) {|gz| ... }
+
+    Opens a file specified by ((|filename|)) as a gzipped file,
+    and returns a GzipReader object associated with that file.
+    Further details of this method are same as
+    ((<Zlib::GzipReader.new>)) and ((<ZLib::GzipReader.wrap>)).
+
+=== ¥á¥½¥Ã¥É:
+
+--- Zlib::GzipReader#eof
+--- Zlib::GzipReader#eof?
+
+    Returns true if the object reaches the end of compressed data.
+    Note that eof? does ((*not*)) return true when reaches the
+    end of ((*file*)).
+
+--- Zlib::GzipReader#pos
+--- Zlib::GzipReader#tell
+
+    Returns the total bytes of data decompressed until now.
+    Not that it does ((*not*)) the position of file pointer.
+
+--- Zlib::GzipReader#each([rs])
+--- Zlib::GzipReader#each_line([rs])
+--- Zlib::GzipReader#each_byte([rs])
+--- Zlib::GzipReader#gets([rs])
+--- Zlib::GzipReader#getc
+--- Zlib::GzipReader#lineno
+--- Zlib::GzipReader#lineno=
+--- Zlib::GzipReader#read([length])
+--- Zlib::GzipReader#readchar
+--- Zlib::GzipReader#readline([rs])
+--- Zlib::GzipReader#readlines([rs])
+--- Zlib::GzipReader#ungetc(char)
+
+    Same as IO, but raises ((<Zlib::Error>)) or
+    ((<Zlib::GzipFile::Error>)) exception if an error was found
+    in the gzip file.
+
+    Be careful of the footer of gzip file. A gzip file has
+    the checksum of pre-compressed data in its footer.
+    GzipReader checks all uncompressed data against that checksum
+    at the following cases, and if failed, raises
+    ((<Zlib::GzipFile::NoFooter>)), ((<Zlib::GzipFile::CRCError>)),
+    or ((<Zlib::GzipFile::LengthError>)) exception.
+
+    * When an reading request is received beyond the end of file
+      (the end of compressed data).
+      That is, when ((<Zlib::GzipReader#read>)),
+      ((<Zlib::GzipReader#gets>)), or some other methods for reading
+      returns nil.
+
+    * When ((<Zlib::GzipFile#close>)) method is called after
+      the object reaches the end of file.
+
+    * When ((<Zlib::GzipReader#unused>)) method is called after
+      the object reaches the end of file.
+
+--- Zlib::GzipReader#rewind
+
+    Resets the position of the file pointer to the point
+    created the GzipReader object.
+    The associated IO object need to respond to seek method.
+
+--- Zlib::GzipReader#unused
+
+    Returns the rest of the data which had read for parsing gzip
+    format, or nil if the whole gzip file is not parsed yet.
+
+
+== Zlib::GzipWriter
+
+The class for writing a gzipped file. GzipWriter should be used
+with associate with an instance of IO class (or an object which
+has the same methods as IO has).
+
+    Zlib::GzipWriter.open('hoge.gz') {|gz|
+      gz.write 'jugemu jugemu gokou no surikire...'
+    }
+
+    f = File.open('hoge.gz', 'w')
+    gz = Zlib::GzipWriter.new(f)
+    gz.write 'jugemu jugemu gokou no surikire...'
+    gz.close
+
+NOTE: Due to the limitation in finalizer of Ruby, you must close
+explicitly GzipWriter object by ((<Zlib::GzipWriter#close>)) etc.
+Otherwise, GzipWriter should be not able to write gzip footer and
+generate broken gzip file.
+
+=== SuperClass:
+
+* ((<Zlib::GzipFile>))
+
+=== Class Methods:
+
+--- Zlib::GzipWriter.new(io[, level[, strategy]])
+
+    Creates a GzipWriter object associated with ((|io|)).
+    ((|level|)) and ((|strategy|)) should be same as the
+    arguments of ((<Zlib::Deflate.new>)). The GzipWriter object
+    writes gzipped data to ((|io|)). At least, ((|io|)) must
+    respond to write method that behaves same as write method
+    in IO class.
+
+--- Zlib::GzipWriter.wrap(io[, level[, strategy]]) {|gz| ... }
+
+    Creates a GzipWriter object associated with ((|io|)), and
+    executes the block with the newly created GzipWriter object,
+    just like File::open. The GzipWriter object will be closed
+    automatically after executing the block. If you want to keep
+    the associated IO object opening, you may call
+    ((<Zlib::GzipFile#finish>)) method in the block.
+
+--- Zlib::GzipWriter.open(filename[, level[, strategy]])
+--- Zlib::GzipWriter.open(filename[, level[, strategy]]) {|gz| ... }
+
+    Opens a file specified by ((|filename|)) for writing
+    gzip compressed data, and returns a GzipWriter object
+    associated with that file. Further details of this method
+    are same as ((<Zlib::GzipWriter.new>)) and
+    ((<Zlib::GzipWriter#wrap>)).
+
+
+=== Methods:
+
+--- Zlib::GzipWriter#close
+--- Zlib::GzipWriter#finish
+
+    Closes the GzipFile object. This method calls close method
+    of the associated IO object. Returns the associated IO object.
+    See ((<Zlib::GzipFile#close>)) and ((<Zlib::GzipFile#finish>))
+    for the difference between close and finish.
+
+    ((*NOTE: Due to the limitation in finalizer of Ruby, you must
+    close GzipWriter object explicitly. Otherwise, GzipWriter
+    should be not able to write gzip footer and generate broken
+    gzip file.*))
+
+--- Zlib::GzipWriter#pos
+--- Zlib::GzipWriter#tell
+
+    Returns the total bytes of data compressed until now.
+    Note that it does ((*not*)) the position of file pointer.
+
+--- Zlib::GzipWriter#<< str
+--- Zlib::GzipWriter#putc(ch)
+--- Zlib::GzipWriter#puts(obj...)
+--- Zlib::GzipWriter#print(arg...)
+--- Zlib::GzipWriter#printf(format, arg...)
+--- Zlib::GzipWriter#write(str)
+
+    Same as IO.
+
+--- Zlib::GzipWriter#flush([flush])
+
+    Flushes all the internal buffers of the GzipWriter object.
+    The meaning of ((|flush|)) is same as one of the argument of
+    ((<Zlib::Deflate#deflate>)).
+    ((<Zlib::SYNC_FLUSH>)) is used if ((|flush|)) is omitted.
+    It is no use giving ((|flush|)) ((<Zlib::NO_FLUSH>)).
+
+--- Zlib::GzipWriter#mtime= time
+
+    Sets last modification time to be stored in the gzip file
+    header. ((<Zlib::GzipFile::Error>)) exception will be raised
+    if this method is called after writing method (like
+    ((<Zlib::GzipWriter#write>))) was called.
+
+--- Zlib::GzipWriter#orig_name= filename
+
+    Sets original filename to be stored in the gzip file header.
+    ((<Zlib::GzipFile::Error>)) exception will be raised
+    if this method is called after writing method (like
+    ((<Zlib::GzipWriter#write>))) was called.
+
+--- Zlib::GzipWriter#comment= string
+
+    Sets comments to be stored in the gzip file header.
+    ((<Zlib::GzipFile::Error>)) exception will be raised
+    if this method is called after writing method (like
+    ((<Zlib::GzipWriter#write>))) was called.
+
+
+== Changes from 0.5 to 0.6
+
+* New methods:
+
+  * ((<Zlib::GzipFile.wrap>))
+  * ((<Zlib::GzipFile#finish>))
+
+* New constants:
+
+  * ((<Zlib::ZLIB_VERSION>))
+  * ((<Zlib::OS_VMCMS>))
+  * ((<Zlib::OS_ZSYSTEM>))
+  * ((<Zlib::OS_CPM>))
+  * ((<Zlib::OS_QDOS>))
+  * ((<Zlib::OS_RISCOS>))
+  * ((<Zlib::OS_UNKNOWN>))
+
+* Changed methods:
+
+  * ((<Zlib::GzipFile.new>)) now takes no block. Use
+    ((<Zlib::GzipFile.wrap>)) instead.
+
+  * ((<Zlib::GzipFile#close>)) now takes no argument. Use
+    ((<Zlib::GzipFile#finish>)) instead.
+
+* Renamed methods:
+
+  * Zlib.version is renamed to ((<Zlib.zlib_version>)).
+
+* Changed constants:
+
+  * ((<Zlib::VERSION>)) indicates the version of Ruby/zlib.
+    The zlib.h version is now in ((<Zlib::ZLIB_VERSION>)).
+
+* Backward compatibility:
+
+  * For backward compatibility for 0.5, the obsoleted methods and
+    arguments are still available.
+
+  * Obsoleted classes, methods, and constants for backward
+    compatibility for 0.4 or earlier are removed.
+
+== Changes from 0.4 to 0.5
+
+Almost all the code are rewritten.
+I hope all changes are enumerated below :-)
+
+* The names of almost classes and some methods are changed.
+  All classes and constants are now defined under module
+  ((<Zlib>)). The obsoleted names are also available for backward
+  compatibility.
+
+  * Classes
+
+    * Deflate -> ((<Zlib::Deflate>))
+    * Inflate -> ((<Zlib::Inflate>))
+    * Zlib::Gzip -> ((<Zlib::GzipFile>))
+    * GzipReader -> ((<Zlib::GzipReader>))
+    * GzipWriter -> ((<Zlib::GzipWriter>))
+    * Zlib::Gzip::Error -> ((<Zlib::GzipFile::Error>))
+    * Zlib::GzipReader::NoFooter -> ((<Zlib::GzipFile::NoFooter>))
+    * Zlib::GzipReader::CRCError -> ((<Zlib::GzipFile::CRCError>))
+    * Zlib::GzipReader::LengthError -> ((<Zlib::GzipFile::LengthError>))
+
+  * Constants
+
+    * Zlib::ZStream::BINARY -> ((<Zlib::BINARY>))
+    * Zlib::ZStream::ASCII -> ((<Zlib::ASCII>))
+    * Zlib::ZStream::UNKNOWN -> ((<Zlib::UNKNOWN>))
+    * Zlib::Deflate::NO_COMPRESSION -> ((<Zlib::NO_COMPRESSION>))
+    * Zlib::Deflate::BEST_SPEED -> ((<Zlib::BEST_SPEED>))
+    * Zlib::Deflate::BEST_COMPRESSION -> ((<Zlib::BEST_COMPRESSION>))
+    * Zlib::Deflate::DEFAULT_COMPRESSION -> ((<Zlib::DEFAULT_COMPRESSION>))
+    * Zlib::Deflate::FILTERED -> ((<Zlib::FILTERED>))
+    * Zlib::Deflate::HUFFMAN_ONLY -> ((<Zlib::HUFFMAN_ONLY>))
+    * Zlib::Deflate::DEFAULT_STRATEGY -> ((<Zlib::DEFAULT_STRATEGY>))
+    * Zlib::Deflate::MAX_WBITS -> ((<Zlib::MAX_WBITS>))
+    * Zlib::Deflate::DEF_MEM_LEVEL -> ((<Zlib::DEF_MEM_LEVEL>))
+    * Zlib::Deflate::MAX_MEM_LEVEL -> ((<Zlib::MAX_MEM_LEVEL>))
+    * Zlib::Deflate::NO_FLUSH -> ((<Zlib::NO_FLUSH>))
+    * Zlib::Deflate::SYNC_FLUSH -> ((<Zlib::SYNC_FLUSH>))
+    * Zlib::Deflate::FULL_FLUSH -> ((<Zlib::FULL_FLUSH>))
+    * Zlib::Inflate::MAX_WBITS -> ((<Zlib::MAX_WBITS>))
+    * Zlib::GzipReader::OS_* -> ((<Zlib::OS_*|Zlib::OS_CODE>))
+
+  * Methods
+
+    * Zlib::ZStream#flush_out -> ((<Zlib::ZStream#flush_next_out>))
+
+* Made buffer for input (next_in).
+
+* ((<Zlib::GzipReader#unused>)) returns nil after closing.
+
+* Now you are up to call ((<Zlib::GzipWriter#close>)) explicitly
+to avoid segv in finalizer.
+((<[ruby-dev:11915]|URL:http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-dev/11915>))
+
+* divided initialize from new.
+
+* remove sanity checks for arguments for deflateInit2 and
+  inflateInit2.
+
+* adapted the behavior of ((<Zlib::GzipWriter#puts>)) to Ruby-1.7.
+
+* Made all functions static.
+
+
+=end
diff --git a/ext/zlib/extconf.rb b/ext/zlib/extconf.rb
new file mode 100644
index 0000000000..a1a28bb078
--- /dev/null
+++ b/ext/zlib/extconf.rb
@@ -0,0 +1,66 @@
+#
+# extconf.rb
+#
+# $Id$
+#
+
+require 'mkmf'
+require 'rbconfig'
+
+dir_config 'zlib'
+
+
+if %w'z libz zlib'.find {|z| have_library(z, 'deflateReset')} and
+    have_header('zlib.h') then
+
+  defines = []
+
+  message 'checking for kind of operating system... '
+  os_code = with_config('os-code') ||
+    case RUBY_PLATFORM.split('-',2)[1]
+    when 'amigaos' then
+      os_code = 'AMIGA'
+    when /\Aos2[\-_]emx\z/ then
+      os_code = 'OS2'
+    when 'mswin32', 'mingw32' then
+      # NOTE: cygwin should be regarded as Unix.
+      os_code = 'WIN32'
+    else
+      os_code = 'UNIX'
+    end
+  os_code = 'OS_' + os_code.upcase
+
+  OS_NAMES = {
+    'OS_MSDOS'   => 'MS-DOS',
+    'OS_AMIGA'   => 'Amiga',
+    'OS_VMS'     => 'VMS',
+    'OS_UNIX'    => 'Unix',
+    'OS_ATARI'   => 'Atari',
+    'OS_OS2'     => 'OS/2',
+    'OS_MACOS'   => 'MacOS',
+    'OS_TOPS20'  => 'TOPS20',
+    'OS_WIN32'   => 'Win32',
+    'OS_VMCMS'   => 'VM/CMS',
+    'OS_ZSYSTEM' => 'Z-System',
+    'OS_CPM'     => 'CP/M',
+    'OS_QDOS'    => 'QDOS',
+    'OS_RISCOS'  => 'RISCOS',
+    'OS_UNKNOWN' => 'Unknown',
+  }
+  unless OS_NAMES.key? os_code then
+    puts "invalid OS_CODE `#{os_code}'"
+    exit
+  end
+  message "#{OS_NAMES[os_code]}\n"
+  defines << "OS_CODE=#{os_code}"
+
+  defines = defines.collect{|d|' -D'+d}.join
+  if $CPPFLAGS then
+    $CPPFLAGS += defines
+  else
+    $CFLAGS += defines
+  end
+
+  create_makefile('zlib')
+
+end
diff --git a/ext/zlib/zlib.c b/ext/zlib/zlib.c
new file mode 100644
index 0000000000..b89738de89
--- /dev/null
+++ b/ext/zlib/zlib.c
@@ -0,0 +1,2768 @@
+/*
+ * zlib.c - An interface for zlib.
+ *
+ *   Copyright (C) UENO Katsuhiro 2000-2003
+ *
+ * $Id$
+ */
+
+#include <ruby.h>
+#include <zlib.h>
+#include <time.h>
+
+#define RUBY_ZLIB_VERSION  "0.6.0"
+
+
+#define OBJ_IS_FREED(val)  (RBASIC(val)->flags == 0)
+
+#ifndef GZIP_SUPPORT
+#define GZIP_SUPPORT  1
+#endif
+
+/* from zutil.h */
+#ifndef DEF_MEM_LEVEL
+#if MAX_MEM_LEVEL >= 8
+#define DEF_MEM_LEVEL  8
+#else
+#define DEF_MEM_LEVEL  MAX_MEM_LEVEL
+#endif
+#endif
+
+
+
+/*--------- Prototypes --------*/
+
+static NORETURN(void raise_zlib_error _((int, const char *)));
+static VALUE rb_zlib_version _((VALUE));
+static VALUE do_checksum _((int, VALUE*, uLong (*) _((uLong, const Bytef*, uInt))));
+static VALUE rb_zlib_adler32 _((int, VALUE*, VALUE));
+static VALUE rb_zlib_crc32 _((int, VALUE*, VALUE));
+static VALUE rb_zlib_crc_table _((VALUE));
+static voidpf zlib_mem_alloc _((voidpf, uInt, uInt));
+static void zlib_mem_free _((voidpf, voidpf));
+
+struct zstream;
+struct zstream_funcs;
+static void zstream_init _((struct zstream*, const struct zstream_funcs *));
+static void zstream_expand_buffer _((struct zstream*));
+static void zstream_expand_buffer_into _((struct zstream*, int));
+static void zstream_append_buffer _((struct zstream*, const char*, int));
+static VALUE zstream_detach_buffer _((struct zstream*));
+static VALUE zstream_shift_buffer _((struct zstream*, int));
+static void zstream_buffer_ungetc _((struct zstream*, int));
+static void zstream_append_input _((struct zstream*, const char*, unsigned int));
+static void zstream_discard_input _((struct zstream*, unsigned int));
+static void zstream_reset_input _((struct zstream*));
+static void zstream_passthrough_input _((struct zstream*));
+static VALUE zstream_detach_input _((struct zstream*));
+static void zstream_reset _((struct zstream*));
+static void zstream_end _((struct zstream*));
+static void zstream_run _((struct zstream*, Bytef*, uInt, int));
+static VALUE zstream_sync _((struct zstream*, Bytef*, uInt));
+static void zstream_mark _((struct zstream*));
+static void zstream_free _((struct zstream*));
+static VALUE zstream_new _((VALUE, const struct zstream_funcs*));
+static struct zstream *get_zstream _((VALUE));
+
+static VALUE rb_zstream_end _((VALUE));
+static VALUE rb_zstream_reset _((VALUE));
+static VALUE rb_zstream_finish _((VALUE));
+static VALUE rb_zstream_flush_next_in _((VALUE));
+static VALUE rb_zstream_flush_next_out _((VALUE));
+static VALUE rb_zstream_avail_out _((VALUE));
+static VALUE rb_zstream_set_avail_out _((VALUE, VALUE));
+static VALUE rb_zstream_avail_in _((VALUE));
+static VALUE rb_zstream_total_in _((VALUE));
+static VALUE rb_zstream_total_out _((VALUE));
+static VALUE rb_zstream_data_type _((VALUE));
+static VALUE rb_zstream_adler _((VALUE));
+static VALUE rb_zstream_finished_p _((VALUE));
+static VALUE rb_zstream_closed_p _((VALUE));
+
+static VALUE rb_deflate_s_allocate _((VALUE));
+static VALUE rb_deflate_initialize _((int, VALUE*, VALUE));
+static VALUE rb_deflate_clone _((VALUE));
+static VALUE rb_deflate_s_deflate _((int, VALUE*, VALUE));
+static void do_deflate _((struct zstream*, VALUE, int));
+static VALUE rb_deflate_deflate _((int, VALUE*, VALUE));
+static VALUE rb_deflate_addstr _((VALUE, VALUE));
+static VALUE rb_deflate_flush _((int, VALUE*, VALUE));
+static VALUE rb_deflate_params _((VALUE, VALUE, VALUE));
+static VALUE rb_deflate_set_dictionary _((VALUE, VALUE));
+
+static VALUE rb_inflate_s_allocate _((VALUE));
+static VALUE rb_inflate_initialize _((int, VALUE*, VALUE));
+static VALUE rb_inflate_s_inflate _((VALUE, VALUE));
+static void do_inflate _((struct zstream*, VALUE));
+static VALUE rb_inflate_inflate _((VALUE, VALUE));
+static VALUE rb_inflate_addstr _((VALUE, VALUE));
+static VALUE rb_inflate_sync _((VALUE, VALUE));
+static VALUE rb_inflate_sync_point_p _((VALUE));
+static VALUE rb_inflate_set_dictionary _((VALUE, VALUE));
+
+#if GZIP_SUPPORT
+struct gzfile;
+static void gzfile_mark _((struct gzfile*));
+static void gzfile_free _((struct gzfile*));
+static VALUE gzfile_new _((VALUE, const struct zstream_funcs*, void (*) _((struct gzfile*))));
+static void gzfile_reset _((struct gzfile*));
+static void gzfile_close _((struct gzfile*, int));
+static void gzfile_write_raw _((struct gzfile*));
+static VALUE gzfile_read_raw _((struct gzfile*));
+static int gzfile_read_raw_ensure _((struct gzfile*, int));
+static char *gzfile_read_raw_until_zero _((struct gzfile*, long));
+static unsigned int gzfile_get16 _((const unsigned char*));
+static unsigned long gzfile_get32 _((const unsigned char*));
+static void gzfile_set32 _((unsigned long n, unsigned char*));
+static void gzfile_make_header _((struct gzfile*));
+static void gzfile_make_footer _((struct gzfile*));
+static void gzfile_read_header _((struct gzfile*));
+static void gzfile_check_footer _((struct gzfile*));
+static void gzfile_write _((struct gzfile*, Bytef*, uInt));
+static long gzfile_read_more _((struct gzfile*));
+static VALUE gzfile_read _((struct gzfile*, int));
+static VALUE gzfile_read_all _((struct gzfile*));
+static void gzfile_ungetc _((struct gzfile*, int));
+static VALUE gzfile_finalize _((VALUE));
+static void gzfile_writer_end _((struct gzfile*));
+static void gzfile_reader_end _((struct gzfile*));
+static void gzfile_reader_rewind _((struct gzfile*));
+static VALUE gzfile_reader_get_unused _((struct gzfile*));
+static struct gzfile *get_gzfile _((VALUE));
+static VALUE gzfile_ensure_close _((VALUE));
+static VALUE rb_gzfile_s_wrap _((int, VALUE*, VALUE));
+static VALUE gzfile_s_open _((int, VALUE*, VALUE, const char*));
+
+static VALUE rb_gzfile_to_io _((VALUE));
+static VALUE rb_gzfile_crc _((VALUE));
+static VALUE rb_gzfile_mtime _((VALUE));
+static VALUE rb_gzfile_level _((VALUE));
+static VALUE rb_gzfile_os_code _((VALUE));
+static VALUE rb_gzfile_orig_name _((VALUE));
+static VALUE rb_gzfile_comment _((VALUE));
+static VALUE rb_gzfile_lineno _((VALUE));
+static VALUE rb_gzfile_set_lineno _((VALUE, VALUE));
+static VALUE rb_gzfile_set_mtime _((VALUE, VALUE));
+static VALUE rb_gzfile_set_orig_name _((VALUE, VALUE));
+static VALUE rb_gzfile_set_comment _((VALUE, VALUE));
+static VALUE rb_gzfile_close _((VALUE));
+static VALUE rb_gzfile_finish _((VALUE));
+static VALUE rb_gzfile_closed_p _((VALUE));
+static VALUE rb_gzfile_eof_p _((VALUE));
+static VALUE rb_gzfile_sync _((VALUE));
+static VALUE rb_gzfile_set_sync _((VALUE, VALUE));
+static VALUE rb_gzfile_total_in _((VALUE));
+static VALUE rb_gzfile_total_out _((VALUE));
+
+static VALUE rb_gzwriter_s_allocate _((VALUE));
+static VALUE rb_gzwriter_s_open _((int, VALUE*, VALUE));
+static VALUE rb_gzwriter_initialize _((int, VALUE*, VALUE));
+static VALUE rb_gzwriter_flush _((int, VALUE*, VALUE));
+static VALUE rb_gzwriter_write _((VALUE, VALUE));
+static VALUE rb_gzwriter_putc _((VALUE, VALUE));
+
+static VALUE rb_gzreader_s_allocate _((VALUE));
+static VALUE rb_gzreader_s_open _((int, VALUE*, VALUE));
+static VALUE rb_gzreader_initialize _((VALUE, VALUE));
+static VALUE rb_gzreader_rewind _((VALUE));
+static VALUE rb_gzreader_unused _((VALUE));
+static VALUE rb_gzreader_read _((int, VALUE*, VALUE));
+static VALUE rb_gzreader_getc _((VALUE));
+static VALUE rb_gzreader_readchar _((VALUE));
+static VALUE rb_gzreader_each_byte _((VALUE));
+static VALUE rb_gzreader_ungetc _((VALUE, VALUE));
+static void gzreader_skip_linebreaks _((struct gzfile*));
+static VALUE gzreader_gets _((int, VALUE*, VALUE));
+static VALUE rb_gzreader_gets _((int, VALUE*, VALUE));
+static VALUE rb_gzreader_readline _((int, VALUE*, VALUE));
+static VALUE rb_gzreader_each _((int, VALUE*, VALUE));
+static VALUE rb_gzreader_readlines _((int, VALUE*, VALUE));
+#endif /* GZIP_SUPPORT */
+
+
+void Init_zlib _((void));
+
+
+
+/*--------- Exceptions --------*/
+
+static VALUE cZError, cStreamEnd, cNeedDict;
+static VALUE cStreamError, cDataError, cMemError, cBufError, cVersionError;
+
+static void
+raise_zlib_error(err, msg)
+    int err;
+    const char *msg;
+{
+    VALUE exc;
+
+    if (!msg) {
+	msg = zError(err);
+    }
+
+    switch(err) {
+      case Z_STREAM_END:
+	exc = rb_exc_new2(cStreamEnd, msg);
+	break;
+      case Z_NEED_DICT:
+	exc = rb_exc_new2(cNeedDict, msg);
+	break;
+      case Z_STREAM_ERROR:
+	exc = rb_exc_new2(cStreamError, msg);
+	break;
+      case Z_DATA_ERROR:
+	exc = rb_exc_new2(cDataError, msg);
+	break;
+      case Z_BUF_ERROR:
+	exc = rb_exc_new2(cBufError, msg);
+	break;
+      case Z_VERSION_ERROR:
+	exc = rb_exc_new2(cVersionError, msg);
+	break;
+      case Z_MEM_ERROR:
+	exc = rb_exc_new2(cMemError, msg);
+	break;
+      case Z_ERRNO:
+	rb_sys_fail(msg);
+	/* no return */
+      default:
+      {
+	  char buf[BUFSIZ];
+	  snprintf(buf, BUFSIZ, "unknown zlib error %d: %s", err, msg);
+	  exc = rb_exc_new2(cZError, buf);
+      }
+    }
+
+    rb_exc_raise(exc);
+}
+
+
+
+/*-------- module Zlib --------*/
+
+static VALUE
+rb_zlib_version(klass)
+    VALUE klass;
+{
+    VALUE str;
+
+    str = rb_str_new2(zlibVersion());
+    OBJ_TAINT(str);  /* for safe */
+    return str;
+}
+
+static VALUE
+do_checksum(argc, argv, func)
+    int argc;
+    VALUE *argv;
+    uLong (*func) _((uLong, const Bytef *, uInt));
+{
+    VALUE str, vsum;
+    unsigned long sum;
+
+    rb_scan_args(argc, argv, "02", &str, &vsum);
+
+    if (!NIL_P(vsum)) {
+	sum = NUM2ULONG(vsum);
+    }
+    else if (NIL_P(str)) {
+	sum = 0;
+    }
+    else {
+	sum = func(0, Z_NULL, 0);
+    }
+
+    if (NIL_P(str)) {
+	sum = func(sum, Z_NULL, 0);
+    }
+    else {
+	StringValue(str);
+	sum = func(sum, RSTRING(str)->ptr, RSTRING(str)->len);
+    }
+    return rb_uint2inum(sum);
+}
+
+static VALUE
+rb_zlib_adler32(argc, argv, klass)
+    int argc;
+    VALUE *argv;
+    VALUE klass;
+{
+    return do_checksum(argc, argv, adler32);
+}
+
+static VALUE
+rb_zlib_crc32(argc, argv, klass)
+    int argc;
+    VALUE *argv;
+    VALUE klass;
+{
+    return do_checksum(argc, argv, crc32);
+}
+
+static VALUE
+rb_zlib_crc_table(obj)
+    VALUE obj;
+{
+    const unsigned long *crctbl;
+    VALUE dst;
+    int i;
+
+    crctbl = get_crc_table();
+    dst = rb_ary_new2(256);
+
+    for (i = 0; i < 256; i++) {
+	rb_ary_push(dst, rb_uint2inum(crctbl[i]));
+    }
+    return dst;
+}
+
+
+
+/*-------- zstream - internal APIs --------*/
+
+struct zstream {
+    unsigned long flags;
+    VALUE buf;
+    long buf_filled;
+    VALUE input;
+    z_stream stream;
+    const struct zstream_funcs {
+	int (*reset) _((z_streamp));
+	int (*end) _((z_streamp));
+	int (*run) _((z_streamp, int));
+    } *func;
+};
+
+#define ZSTREAM_FLAG_READY      0x1
+#define ZSTREAM_FLAG_IN_STREAM  0x2
+#define ZSTREAM_FLAG_FINISHED   0x4
+#define ZSTREAM_FLAG_FINALIZE   0x8
+#define ZSTREAM_FLAG_UNUSED     0x10
+
+#define ZSTREAM_READY(z)       ((z)->flags |= ZSTREAM_FLAG_READY)
+#define ZSTREAM_IS_READY(z)    ((z)->flags & ZSTREAM_FLAG_READY)
+#define ZSTREAM_IS_FINISHED(z) ((z)->flags & ZSTREAM_FLAG_FINISHED)
+#define ZSTREAM_IS_FINALIZE(z) ((z)->flags & ZSTREAM_FLAG_FINALIZE)
+
+/* I think that more better value should be found,
+   but I gave up finding it. B) */
+#define ZSTREAM_INITIAL_BUFSIZE       1024
+#define ZSTREAM_AVAIL_OUT_STEP_MAX   16384
+#define ZSTREAM_AVAIL_OUT_STEP_MIN    2048
+
+static const struct zstream_funcs deflate_funcs = {
+    deflateReset, deflateEnd, deflate,
+};
+
+static const struct zstream_funcs inflate_funcs = {
+    inflateReset, inflateEnd, inflate,
+};
+
+
+static voidpf
+zlib_mem_alloc(opaque, items, size)
+    voidpf opaque;
+    uInt items, size;
+{
+    return xmalloc(items * size);
+}
+
+static void
+zlib_mem_free(opaque, address)
+    voidpf opaque, address;
+{
+    free(address);
+}
+
+static void
+zstream_init(z, func)
+    struct zstream *z;
+    const struct zstream_funcs *func;
+{
+    z->flags = 0;
+    z->buf = Qnil;
+    z->buf_filled = 0;
+    z->input = Qnil;
+    z->stream.zalloc = zlib_mem_alloc;
+    z->stream.zfree = zlib_mem_free;
+    z->stream.opaque = Z_NULL;
+    z->stream.msg = Z_NULL;
+    z->stream.next_in = Z_NULL;
+    z->stream.avail_in = 0;
+    z->stream.next_out = Z_NULL;
+    z->stream.avail_out = 0;
+    z->func = func;
+}
+
+#define zstream_init_deflate(z)   zstream_init((z), &deflate_funcs)
+#define zstream_init_inflate(z)   zstream_init((z), &inflate_funcs)
+
+static void
+zstream_expand_buffer(z)
+    struct zstream *z;
+{
+    long inc;
+
+    if (NIL_P(z->buf)) {
+	    /* I uses rb_str_new here not rb_str_buf_new because
+	       rb_str_buf_new makes a zero-length string. */
+	z->buf = rb_str_new(0, ZSTREAM_INITIAL_BUFSIZE);
+	z->buf_filled = 0;
+	z->stream.next_out = RSTRING(z->buf)->ptr;
+	z->stream.avail_out = ZSTREAM_INITIAL_BUFSIZE;
+	return;
+    }
+
+    if (RSTRING(z->buf)->len - z->buf_filled >= ZSTREAM_AVAIL_OUT_STEP_MAX) {
+	/* to keep other threads from freezing */
+	z->stream.avail_out = ZSTREAM_AVAIL_OUT_STEP_MAX;
+    }
+    else {
+	inc = z->buf_filled / 2;
+	if (inc < ZSTREAM_AVAIL_OUT_STEP_MIN) {
+	    inc = ZSTREAM_AVAIL_OUT_STEP_MIN;
+	}
+	rb_str_resize(z->buf, z->buf_filled + inc);
+	z->stream.avail_out = (inc < ZSTREAM_AVAIL_OUT_STEP_MAX) ?
+	    inc : ZSTREAM_AVAIL_OUT_STEP_MAX;
+    }
+    z->stream.next_out = RSTRING(z->buf)->ptr + z->buf_filled;
+}
+
+static void
+zstream_expand_buffer_into(z, size)
+    struct zstream *z;
+    int size;
+{
+    if (NIL_P(z->buf)) {
+	/* I uses rb_str_new here not rb_str_buf_new because
+	   rb_str_buf_new makes a zero-length string. */
+	z->buf = rb_str_new(0, size);
+	z->buf_filled = 0;
+	z->stream.next_out = RSTRING(z->buf)->ptr;
+	z->stream.avail_out = size;
+    }
+    else if (z->stream.avail_out != size) {
+	rb_str_resize(z->buf, z->buf_filled + size);
+	z->stream.next_out = RSTRING(z->buf)->ptr + z->buf_filled;
+	z->stream.avail_out = size;
+    }
+}
+
+static void
+zstream_append_buffer(z, src, len)
+    struct zstream *z;
+    const char *src;
+    int len;
+{
+    if (NIL_P(z->buf)) {
+	z->buf = rb_str_buf_new(len);
+	rb_str_buf_cat(z->buf, src, len);
+	z->buf_filled = len;
+	z->stream.next_out = RSTRING(z->buf)->ptr;
+	z->stream.avail_out = 0;
+	return;
+    }
+
+    if (RSTRING(z->buf)->len < z->buf_filled + len) {
+	rb_str_resize(z->buf, z->buf_filled + len);
+	z->stream.avail_out = 0;
+    }
+    else {
+	if (z->stream.avail_out >= len) {
+	    z->stream.avail_out -= len;
+	}
+	else {
+	    z->stream.avail_out = 0;
+	}
+    }
+    memcpy(RSTRING(z->buf)->ptr + z->buf_filled, src, len);
+    z->buf_filled += len;
+    z->stream.next_out = RSTRING(z->buf)->ptr + z->buf_filled;
+}
+
+#define zstream_append_buffer2(z,v) \
+    zstream_append_buffer((z),RSTRING(v)->ptr,RSTRING(v)->len)
+
+static VALUE
+zstream_detach_buffer(z)
+    struct zstream *z;
+{
+    VALUE dst;
+
+    if (NIL_P(z->buf)) {
+	dst = rb_str_new(0, 0);
+    }
+    else {
+	dst = z->buf;
+	rb_str_resize(dst, z->buf_filled);
+    }
+
+    z->buf = Qnil;
+    z->buf_filled = 0;
+    z->stream.next_out = 0;
+    z->stream.avail_out = 0;
+    return dst;
+}
+
+static VALUE
+zstream_shift_buffer(z, len)
+    struct zstream *z;
+    int len;
+{
+    VALUE dst;
+
+    if (z->buf_filled <= len) {
+	return zstream_detach_buffer(z);
+    }
+
+    dst = rb_str_substr(z->buf, 0, len);
+    z->buf_filled -= len;
+    memmove(RSTRING(z->buf)->ptr, RSTRING(z->buf)->ptr + len,
+	    z->buf_filled);
+    z->stream.next_out = RSTRING(z->buf)->ptr + z->buf_filled;
+    z->stream.avail_out = RSTRING(z->buf)->len - z->buf_filled;
+    if (z->stream.avail_out > ZSTREAM_AVAIL_OUT_STEP_MAX) {
+	z->stream.avail_out = ZSTREAM_AVAIL_OUT_STEP_MAX;
+    }
+
+    return dst;
+}
+
+static void
+zstream_buffer_ungetc(z, c)
+    struct zstream *z;
+    int c;
+{
+    if (NIL_P(z->buf) || RSTRING(z->buf)->len - z->buf_filled == 0) {
+	zstream_expand_buffer(z);
+    }
+
+    memmove(RSTRING(z->buf)->ptr + 1, RSTRING(z->buf)->ptr, z->buf_filled);
+    RSTRING(z->buf)->ptr[0] = (char)c;
+    z->buf_filled++;
+    if (z->stream.avail_out > 0) {
+	z->stream.next_out++;
+	z->stream.avail_out--;
+    }
+}
+
+static void
+zstream_append_input(z, src, len)
+    struct zstream *z;
+    const char *src;
+    unsigned int len;
+{
+    if (len <= 0) return;
+
+    if (NIL_P(z->input)) {
+	z->input = rb_str_buf_new(len);
+	rb_str_buf_cat(z->input, src, len);
+    }
+    else {
+	rb_str_buf_cat(z->input, src, len);
+    }
+}
+
+#define zstream_append_input2(z,v)\
+    zstream_append_input((z), RSTRING(v)->ptr, RSTRING(v)->len)
+
+static void
+zstream_discard_input(z, len)
+    struct zstream *z;
+    unsigned int len;
+{
+    if (NIL_P(z->input) || RSTRING(z->input)->len <= len) {
+	z->input = Qnil;
+    }
+    else {
+	memmove(RSTRING(z->input)->ptr, RSTRING(z->input)->ptr + len,
+		RSTRING(z->input)->len - len);
+	rb_str_resize(z->input, RSTRING(z->input)->len - len);
+    }
+}
+
+static void
+zstream_reset_input(z)
+    struct zstream *z;
+{
+    z->input = Qnil;
+}
+
+static void
+zstream_passthrough_input(z)
+    struct zstream *z;
+{
+    if (!NIL_P(z->input)) {
+	zstream_append_buffer2(z, z->input);
+	z->input = Qnil;
+    }
+}
+
+static VALUE
+zstream_detach_input(z)
+    struct zstream *z;
+{
+    VALUE dst;
+
+    dst = NIL_P(z->input) ? rb_str_new(0, 0) : z->input;
+    z->input = Qnil;
+    return dst;
+}
+
+static void
+zstream_reset(z)
+    struct zstream *z;
+{
+    int err;
+
+    err = z->func->reset(&z->stream);
+    if (err != Z_OK && !ZSTREAM_IS_FINALIZE(z)) {
+	raise_zlib_error(err, z->stream.msg);
+    }
+    z->flags = ZSTREAM_FLAG_READY;
+    z->buf = Qnil;
+    z->buf_filled = 0;
+    z->stream.next_out = 0;
+    z->stream.avail_out = 0;
+    zstream_reset_input(z);
+}
+
+static void
+zstream_end(z)
+    struct zstream *z;
+{
+    int err;
+
+    if (!ZSTREAM_IS_READY(z) && !ZSTREAM_IS_FINALIZE(z)) {
+	if (RTEST(ruby_debug)) {
+	    rb_warning("attempt to close uninitialized zstream; ignored.");
+	}
+	return;
+    }
+    if (z->flags & ZSTREAM_FLAG_IN_STREAM) {
+	if (RTEST(ruby_debug)) {
+	    rb_warning("attempt to close unfinished zstream; reset forced.");
+	}
+	zstream_reset(z);
+    }
+
+    zstream_reset_input(z);
+    err = z->func->end(&z->stream);
+    if (err != Z_OK && !ZSTREAM_IS_FINALIZE(z)) {
+	raise_zlib_error(err, z->stream.msg);
+    }
+    z->flags = 0;
+}
+
+static void
+zstream_run(z, src, len, flush)
+    struct zstream *z;
+    Bytef *src;
+    uInt len;
+    int flush;
+{
+    uInt n;
+    int err;
+
+    if (NIL_P(z->input)) {
+	z->stream.next_in = src;
+	z->stream.avail_in = len;
+    }
+    else {
+	zstream_append_input(z, src, len);
+	z->stream.next_in = RSTRING(z->input)->ptr;
+	z->stream.avail_in = RSTRING(z->input)->len;
+    }
+
+    if (z->stream.avail_out == 0) {
+	zstream_expand_buffer(z);
+    }
+
+    for (;;) {
+	n = z->stream.avail_out;
+	err = z->func->run(&z->stream, flush);
+	z->buf_filled += n - z->stream.avail_out;
+	rb_thread_schedule();
+
+	if (err == Z_STREAM_END) {
+	    z->flags &= ~ZSTREAM_FLAG_IN_STREAM;
+	    z->flags |= ZSTREAM_FLAG_FINISHED;
+	    break;
+	}
+	if (err != Z_OK) {
+	    zstream_reset_input(z);
+	    if (z->stream.avail_in > 0) {
+		zstream_append_input(z, z->stream.next_in, z->stream.avail_in);
+	    }
+	    raise_zlib_error(err, z->stream.msg);
+	}
+	if (z->stream.avail_out > 0) {
+	    z->flags |= ZSTREAM_FLAG_IN_STREAM;
+	    break;
+	}
+	zstream_expand_buffer(z);
+    }
+
+    zstream_reset_input(z);
+    if (z->stream.avail_in > 0) {
+	zstream_append_input(z, z->stream.next_in, z->stream.avail_in);
+    }
+}
+
+static VALUE
+zstream_sync(z, src, len)
+    struct zstream *z;
+    Bytef *src;
+    uInt len;
+{
+    VALUE rest;
+    int err;
+
+    if (!NIL_P(z->input)) {
+	z->stream.next_in = RSTRING(z->input)->ptr;
+	z->stream.avail_in = RSTRING(z->input)->len;
+	err = inflateSync(&z->stream);
+	if (err == Z_OK) {
+	    zstream_discard_input(z,
+				  RSTRING(z->input)->len - z->stream.avail_in);
+	    zstream_append_input(z, src, len);
+	    return Qtrue;
+	}
+	zstream_reset_input(z);
+	if (err != Z_DATA_ERROR) {
+	    rest = rb_str_new(z->stream.next_in, z->stream.avail_in);
+	    raise_zlib_error(err, z->stream.msg);
+	}
+    }
+
+    if (len <= 0) return Qfalse;
+
+    z->stream.next_in = src;
+    z->stream.avail_in = len;
+    err = inflateSync(&z->stream);
+    if (err == Z_OK) {
+	zstream_append_input(z, z->stream.next_in, z->stream.avail_in);
+	return Qtrue;
+    }
+    if (err != Z_DATA_ERROR) {
+	rest = rb_str_new(z->stream.next_in, z->stream.avail_in);
+	raise_zlib_error(err, z->stream.msg);
+    }
+    return Qfalse;
+}
+
+static void
+zstream_mark(z)
+    struct zstream *z;
+{
+    rb_gc_mark(z->buf);
+    rb_gc_mark(z->input);
+}
+
+static void
+zstream_free(z)
+    struct zstream *z;
+{
+    z->flags |= ZSTREAM_FLAG_FINALIZE;
+    zstream_end(z);
+    free(z);
+}
+
+static VALUE
+zstream_new(klass, funcs)
+    VALUE klass;
+    const struct zstream_funcs *funcs;
+{
+    VALUE obj;
+    struct zstream *z;
+
+    obj = Data_Make_Struct(klass, struct zstream,
+			   zstream_mark, zstream_free, z);
+    zstream_init(z, funcs);
+    return obj;
+}
+
+#define zstream_deflate_new(klass)  zstream_new((klass), &deflate_funcs)
+#define zstream_inflate_new(klass)  zstream_new((klass), &inflate_funcs)
+
+static struct zstream *
+get_zstream(obj)
+    VALUE obj;
+{
+    struct zstream *z;
+
+    Data_Get_Struct(obj, struct zstream, z);
+    if (!ZSTREAM_IS_READY(z)) {
+	rb_raise(cZError, "stream is not ready");
+    }
+    return z;
+}
+
+
+
+/*-------- class Zlib::ZStream ---------*/
+
+static VALUE
+rb_zstream_end(obj)
+    VALUE obj;
+{
+    zstream_end(get_zstream(obj));
+    return Qnil;
+}
+
+static VALUE
+rb_zstream_reset(obj)
+    VALUE obj;
+{
+    zstream_reset(get_zstream(obj));
+    return Qnil;
+}
+
+static VALUE
+rb_zstream_finish(obj)
+    VALUE obj;
+{
+    struct zstream *z = get_zstream(obj);
+    VALUE dst;
+
+    zstream_run(z, "", 0, Z_FINISH);
+    dst = zstream_detach_buffer(z);
+
+    OBJ_INFECT(dst, obj);
+    return dst;
+}
+
+static VALUE
+rb_zstream_flush_next_in(obj)
+    VALUE obj;
+{
+    struct zstream *z;
+    VALUE dst;
+
+    Data_Get_Struct(obj, struct zstream, z);
+    dst = zstream_detach_input(z);
+    OBJ_INFECT(dst, obj);
+    return dst;
+}
+
+static VALUE
+rb_zstream_flush_next_out(obj)
+    VALUE obj;
+{
+    struct zstream *z;
+    VALUE dst;
+
+    Data_Get_Struct(obj, struct zstream, z);
+    dst = zstream_detach_buffer(z);
+    OBJ_INFECT(dst, obj);
+    return dst;
+}
+
+static VALUE
+rb_zstream_avail_out(obj)
+    VALUE obj;
+{
+    struct zstream *z;
+    Data_Get_Struct(obj, struct zstream, z);
+    return rb_uint2inum(z->stream.avail_out);
+}
+
+static VALUE
+rb_zstream_set_avail_out(obj, size)
+    VALUE obj, size;
+{
+    struct zstream *z = get_zstream(obj);
+
+    Check_Type(size, T_FIXNUM);
+    zstream_expand_buffer_into(z, FIX2INT(size));
+    return size;
+}
+
+static VALUE
+rb_zstream_avail_in(obj)
+    VALUE obj;
+{
+    struct zstream *z;
+    Data_Get_Struct(obj, struct zstream, z);
+    return INT2FIX(NIL_P(z->input) ? 0 : (int)(RSTRING(z->input)->len));
+}
+
+static VALUE
+rb_zstream_total_in(obj)
+    VALUE obj;
+{
+    return rb_uint2inum(get_zstream(obj)->stream.total_in);
+}
+
+static VALUE
+rb_zstream_total_out(obj)
+    VALUE obj;
+{
+    return rb_uint2inum(get_zstream(obj)->stream.total_out);
+}
+
+static VALUE
+rb_zstream_data_type(obj)
+    VALUE obj;
+{
+    return INT2FIX(get_zstream(obj)->stream.data_type);
+}
+
+static VALUE
+rb_zstream_adler(obj)
+    VALUE obj;
+{
+	return rb_uint2inum(get_zstream(obj)->stream.adler);
+}
+
+static VALUE
+rb_zstream_finished_p(obj)
+    VALUE obj;
+{
+    return ZSTREAM_IS_FINISHED(get_zstream(obj)) ? Qtrue : Qfalse;
+}
+
+static VALUE
+rb_zstream_closed_p(obj)
+    VALUE obj;
+{
+    struct zstream *z;
+    Data_Get_Struct(obj, struct zstream, z);
+    return ZSTREAM_IS_READY(z) ? Qfalse : Qtrue;
+}
+
+
+
+/*-------- class Zlib::Deflate --------*/
+
+#define FIXNUMARG(val, ifnil) \
+    (NIL_P((val)) ? (ifnil) \
+    : ((void)Check_Type((val), T_FIXNUM), FIX2INT((val))))
+
+#define ARG_LEVEL(val)     FIXNUMARG((val), Z_DEFAULT_COMPRESSION)
+#define ARG_WBITS(val)     FIXNUMARG((val), MAX_WBITS)
+#define ARG_MEMLEVEL(val)  FIXNUMARG((val), DEF_MEM_LEVEL)
+#define ARG_STRATEGY(val)  FIXNUMARG((val), Z_DEFAULT_STRATEGY)
+#define ARG_FLUSH(val)     FIXNUMARG((val), Z_NO_FLUSH)
+
+
+static VALUE
+rb_deflate_s_allocate(klass)
+    VALUE klass;
+{
+	return zstream_deflate_new(klass);
+}
+
+static VALUE
+rb_deflate_initialize(argc, argv, obj)
+    int argc;
+    VALUE *argv;
+    VALUE obj;
+{
+    struct zstream *z;
+    VALUE level, wbits, memlevel, strategy;
+    int err;
+
+    rb_scan_args(argc, argv, "04", &level, &wbits, &memlevel, &strategy);
+    Data_Get_Struct(obj, struct zstream, z);
+
+    err = deflateInit2(&z->stream, ARG_LEVEL(level), Z_DEFLATED,
+		       ARG_WBITS(wbits), ARG_MEMLEVEL(memlevel),
+		       ARG_STRATEGY(strategy));
+    if (err != Z_OK) {
+	raise_zlib_error(err, z->stream.msg);
+    }
+    ZSTREAM_READY(z);
+
+    return obj;
+}
+
+static VALUE
+rb_deflate_clone(obj)
+    VALUE obj;
+{
+    struct zstream *z = get_zstream(obj);
+    struct zstream *z2;
+    VALUE clone;
+    int err;
+
+    clone = zstream_deflate_new(rb_class_of(obj));
+    Data_Get_Struct(clone, struct zstream, z2);
+
+    err = deflateCopy(&z2->stream, &z->stream);
+    if (err != Z_OK) {
+	raise_zlib_error(err, 0);
+    }
+
+    z2->flags = z->flags;
+    CLONESETUP(clone, obj);
+    OBJ_INFECT(clone, obj);
+    return clone;
+}
+
+static VALUE
+rb_deflate_s_deflate(argc, argv, klass)
+    int argc;
+    VALUE *argv;
+    VALUE klass;
+{
+    struct zstream z;
+    VALUE src, level, dst;
+    int err;
+
+    rb_scan_args(argc, argv, "11", &src, &level);
+
+    zstream_init_deflate(&z);
+    err = deflateInit(&z.stream, ARG_LEVEL(level));
+    if (err != Z_OK) {
+	raise_zlib_error(err, z.stream.msg);
+    }
+    ZSTREAM_READY(&z);
+
+    StringValue(src);
+    zstream_run(&z, RSTRING(src)->ptr, RSTRING(src)->len, Z_FINISH);
+    dst = zstream_detach_buffer(&z);
+    zstream_end(&z);
+
+    OBJ_INFECT(dst, src);
+    return dst;
+}
+
+static void
+do_deflate(z, src, flush)
+    struct zstream *z;
+    VALUE src;
+    int flush;
+{
+    if (NIL_P(src)) {
+	zstream_run(z, "", 0, Z_FINISH);
+	return;
+    }
+    StringValue(src);
+    if (flush != Z_NO_FLUSH || RSTRING(src)->len > 0) { /* prevent BUF_ERROR */
+	zstream_run(z, RSTRING(src)->ptr, RSTRING(src)->len, flush);
+    }
+}
+
+static VALUE
+rb_deflate_deflate(argc, argv, obj)
+    int argc;
+    VALUE *argv;
+    VALUE obj;
+{
+    struct zstream *z = get_zstream(obj);
+    VALUE src, flush, dst;
+
+    rb_scan_args(argc, argv, "11", &src, &flush);
+    OBJ_INFECT(obj, src);
+    do_deflate(z, src, ARG_FLUSH(flush));
+    dst = zstream_detach_buffer(z);
+
+    OBJ_INFECT(dst, obj);
+    return dst;
+}
+
+static VALUE
+rb_deflate_addstr(obj, src)
+    VALUE obj, src;
+{
+    OBJ_INFECT(obj, src);
+    do_deflate(get_zstream(obj), src, Z_NO_FLUSH);
+    return obj;
+}
+
+static VALUE
+rb_deflate_flush(argc, argv, obj)
+    int argc;
+    VALUE *argv;
+    VALUE obj;
+{
+    struct zstream *z = get_zstream(obj);
+    VALUE v_flush, dst;
+    int flush;
+
+    rb_scan_args(argc, argv, "01", &v_flush);
+    flush = FIXNUMARG(v_flush, Z_SYNC_FLUSH);
+    if (flush != Z_NO_FLUSH) {  /* prevent Z_BUF_ERROR */
+	zstream_run(z, "", 0, flush);
+    }
+    dst = zstream_detach_buffer(z);
+
+    OBJ_INFECT(dst, obj);
+    return dst;
+}
+
+static VALUE
+rb_deflate_params(obj, v_level, v_strategy)
+    VALUE obj, v_level, v_strategy;
+{
+    struct zstream *z = get_zstream(obj);
+    int level, strategy;
+    int err;
+
+    level = ARG_LEVEL(v_level);
+    strategy = ARG_STRATEGY(v_strategy);
+
+    err = deflateParams(&z->stream, level, strategy);
+    while (err == Z_BUF_ERROR) {
+	if (RTEST(ruby_debug)) {
+	    rb_warning("deflateParams() returned Z_BUF_ERROR");
+	}
+	zstream_expand_buffer(z);
+	err = deflateParams(&z->stream, level, strategy);
+    }
+    if (err != Z_OK) {
+	raise_zlib_error(err, z->stream.msg);
+    }
+
+    return Qnil;
+}
+
+static VALUE
+rb_deflate_set_dictionary(obj, dic)
+    VALUE obj, dic;
+{
+    struct zstream *z = get_zstream(obj);
+    VALUE src = dic;
+    int err;
+
+    OBJ_INFECT(obj, dic);
+    StringValue(src);
+    err = deflateSetDictionary(&z->stream,
+			       RSTRING(src)->ptr, RSTRING(src)->len);
+    if (err != Z_OK) {
+	raise_zlib_error(err, z->stream.msg);
+    }
+
+    return dic;
+}
+
+
+
+/*-------- class Zlib::Inflate --------*/
+
+static VALUE
+rb_inflate_s_allocate(klass)
+    VALUE klass;
+{
+    return zstream_inflate_new(klass);
+}
+
+static VALUE
+rb_inflate_initialize(argc, argv, obj)
+    int argc;
+    VALUE *argv;
+    VALUE obj;
+{
+    struct zstream *z;
+    VALUE wbits;
+    int err;
+
+    rb_scan_args(argc, argv, "01", &wbits);
+    Data_Get_Struct(obj, struct zstream, z);
+
+    err = inflateInit2(&z->stream, ARG_WBITS(wbits));
+    if (err != Z_OK) {
+	raise_zlib_error(err, z->stream.msg);
+    }
+    ZSTREAM_READY(z);
+
+    return obj;
+}
+
+static VALUE
+rb_inflate_s_inflate(obj, src)
+    VALUE obj, src;
+{
+    struct zstream z;
+    VALUE dst;
+    int err;
+
+    zstream_init_inflate(&z);
+    err = inflateInit(&z.stream);
+    if (err != Z_OK) {
+	raise_zlib_error(err, z.stream.msg);
+    }
+    ZSTREAM_READY(&z);
+
+    StringValue(src);
+    zstream_run(&z, RSTRING(src)->ptr, RSTRING(src)->len, Z_SYNC_FLUSH);
+    zstream_run(&z, "", 0, Z_FINISH);  /* for checking errors */
+    dst = zstream_detach_buffer(&z);
+    zstream_end(&z);
+
+    OBJ_INFECT(dst, src);
+    return dst;
+}
+
+static void
+do_inflate(z, src)
+    struct zstream *z;
+    VALUE src;
+{
+    if (NIL_P(src)) {
+	zstream_run(z, "", 0, Z_FINISH);
+	return;
+    }
+    StringValue(src);
+    if (RSTRING(src)->len > 0) { /* prevent Z_BUF_ERROR */
+	zstream_run(z, RSTRING(src)->ptr, RSTRING(src)->len, Z_SYNC_FLUSH);
+    }
+}
+
+static VALUE
+rb_inflate_inflate(obj, src)
+    VALUE obj, src;
+{
+    struct zstream *z = get_zstream(obj);
+    VALUE dst;
+
+    OBJ_INFECT(obj, src);
+
+    if (ZSTREAM_IS_FINISHED(z)) {
+	if (NIL_P(src)) {
+	    dst = zstream_detach_buffer(z);
+	}
+	else {
+	    StringValue(src);
+	    zstream_append_buffer2(z, src);
+	    dst = rb_str_new(0, 0);
+	}
+    }
+    else {
+	do_inflate(z, src);
+	dst = zstream_detach_buffer(z);
+	if (ZSTREAM_IS_FINISHED(z)) {
+	    zstream_passthrough_input(z);
+	}
+    }
+
+    OBJ_INFECT(dst, obj);
+    return dst;
+}
+
+static VALUE
+rb_inflate_addstr(obj, src)
+    VALUE obj, src;
+{
+    struct zstream *z = get_zstream(obj);
+
+    OBJ_INFECT(obj, src);
+
+    if (ZSTREAM_IS_FINISHED(z)) {
+	if (!NIL_P(src)) {
+	    StringValue(src);
+	    zstream_append_buffer2(z, src);
+	}
+    }
+    else {
+	do_inflate(z, src);
+	if (ZSTREAM_IS_FINISHED(z)) {
+	    zstream_passthrough_input(z);
+	}
+    }
+
+    return obj;
+}
+
+static VALUE
+rb_inflate_sync(obj, src)
+    VALUE obj, src;
+{
+    struct zstream *z = get_zstream(obj);
+
+    OBJ_INFECT(obj, src);
+    StringValue(src);
+    return zstream_sync(z, RSTRING(src)->ptr, RSTRING(src)->len);
+}
+
+static VALUE
+rb_inflate_sync_point_p(obj)
+    VALUE obj;
+{
+    struct zstream *z = get_zstream(obj);
+    int err;
+
+    err = inflateSyncPoint(&z->stream);
+    if (err == 1) {
+	return Qtrue;
+    }
+    if (err != Z_OK) {
+	raise_zlib_error(err, z->stream.msg);
+    }
+    return Qfalse;
+}
+
+static VALUE
+rb_inflate_set_dictionary(obj, dic)
+    VALUE obj, dic;
+{
+    struct zstream *z = get_zstream(obj);
+    VALUE src = dic;
+    int err;
+
+    OBJ_INFECT(obj, dic);
+    StringValue(src);
+    err = inflateSetDictionary(&z->stream,
+			       RSTRING(src)->ptr, RSTRING(src)->len);
+    if (err != Z_OK) {
+	raise_zlib_error(err, z->stream.msg);
+    }
+
+    return dic;
+}
+
+
+
+#if GZIP_SUPPORT
+
+/* NOTE: Features for gzip files of Ruby/zlib are written from scratch
+ *       and using undocumented feature of zlib, negative wbits.
+ *       I don't think gzFile APIs of zlib are good for Ruby.
+ */
+
+/*------- .gz file header --------*/
+
+#define GZ_MAGIC1             0x1f
+#define GZ_MAGIC2             0x8b
+#define GZ_METHOD_DEFLATE     8
+#define GZ_FLAG_MULTIPART     0x2
+#define GZ_FLAG_EXTRA         0x4
+#define GZ_FLAG_ORIG_NAME     0x8
+#define GZ_FLAG_COMMENT       0x10
+#define GZ_FLAG_ENCRYPT       0x20
+#define GZ_FLAG_UNKNOWN_MASK  0xc0
+
+#define GZ_EXTRAFLAG_FAST     0x4
+#define GZ_EXTRAFLAG_SLOW     0x2
+
+/* from zutil.h */
+#define OS_MSDOS    0x00
+#define OS_AMIGA    0x01
+#define OS_VMS      0x02
+#define OS_UNIX     0x03
+#define OS_ATARI    0x05
+#define OS_OS2      0x06
+#define OS_MACOS    0x07
+#define OS_TOPS20   0x0a
+#define OS_WIN32    0x0b
+
+#define OS_VMCMS    0x04
+#define OS_ZSYSTEM  0x08
+#define OS_CPM      0x09
+#define OS_QDOS     0x0c
+#define OS_RISCOS   0x0d
+#define OS_UNKNOWN  0xff
+
+#ifndef OS_CODE
+#define OS_CODE  OS_UNIX
+#endif
+
+static ID id_write, id_read, id_flush, id_seek, id_close;
+static VALUE cGzError, cNoFooter, cCRCError, cLengthError;
+
+
+
+/*-------- gzfile internal APIs --------*/
+
+struct gzfile {
+    struct zstream z;
+    VALUE io;
+    int level;
+    time_t mtime;       /* for header */
+    int os_code;        /* for header */
+    VALUE orig_name;    /* for header; must be a String */
+    VALUE comment;      /* for header; must be a String */
+    unsigned long crc;
+    int lineno;
+    int ungetc;
+    void (*end)(struct gzfile *);
+};
+
+#define GZFILE_FLAG_SYNC             ZSTREAM_FLAG_UNUSED
+#define GZFILE_FLAG_HEADER_FINISHED  (ZSTREAM_FLAG_UNUSED << 1)
+#define GZFILE_FLAG_FOOTER_FINISHED  (ZSTREAM_FLAG_UNUSED << 2)
+
+#define GZFILE_IS_FINISHED(gz) \
+    (ZSTREAM_IS_FINISHED(&gz->z) && (gz)->z.buf_filled == 0)
+
+#define GZFILE_READ_SIZE  2048
+
+
+static void
+gzfile_mark(gz)
+    struct gzfile *gz;
+{
+    rb_gc_mark(gz->io);
+    rb_gc_mark(gz->orig_name);
+    rb_gc_mark(gz->comment);
+    zstream_mark(&gz->z);
+}
+
+static void
+gzfile_free(gz)
+    struct gzfile *gz;
+{
+    gz->z.flags |= ZSTREAM_FLAG_FINALIZE;
+    if (ZSTREAM_IS_READY(&gz->z)) {
+	gz->end(gz);
+    }
+    free(gz);
+}
+
+static VALUE
+gzfile_new(klass, funcs, endfunc)
+    VALUE klass;
+    const struct zstream_funcs *funcs;
+    void (*endfunc) _((struct gzfile *));
+{
+    VALUE obj;
+    struct gzfile *gz;
+
+    obj = Data_Make_Struct(klass, struct gzfile, gzfile_mark, gzfile_free, gz);
+    zstream_init(&gz->z, funcs);
+    gz->io = Qnil;
+    gz->level = 0;
+    gz->mtime = 0;
+    gz->os_code = OS_CODE;
+    gz->orig_name = Qnil;
+    gz->comment = Qnil;
+    gz->crc = crc32(0, Z_NULL, 0);
+    gz->lineno = 0;
+    gz->ungetc = 0;
+    gz->end = endfunc;
+
+    return obj;
+}
+
+#define gzfile_writer_new(gz) gzfile_new((gz),&deflate_funcs,gzfile_writer_end)
+#define gzfile_reader_new(gz) gzfile_new((gz),&inflate_funcs,gzfile_reader_end)
+
+static void
+gzfile_reset(gz)
+    struct gzfile *gz;
+{
+    zstream_reset(&gz->z);
+    gz->crc = crc32(0, Z_NULL, 0);
+    gz->lineno = 0;
+    gz->ungetc = 0;
+}
+
+static void
+gzfile_close(gz, closeflag)
+    struct gzfile *gz;
+    int closeflag;
+{
+    VALUE io = gz->io;
+    gz->end(gz);
+    gz->io = Qnil;
+    gz->orig_name = Qnil;
+    gz->comment = Qnil;
+    if (closeflag && rb_respond_to(io, id_close)) {
+	rb_funcall(io, id_close, 0);
+    }
+}
+
+static void
+gzfile_write_raw(gz)
+    struct gzfile *gz;
+{
+    VALUE str;
+
+    if (gz->z.buf_filled > 0) {
+	str = zstream_detach_buffer(&gz->z);
+	OBJ_TAINT(str);  /* for safe */
+	rb_funcall(gz->io, id_write, 1, str);
+	if ((gz->z.flags & GZFILE_FLAG_SYNC)
+	    && rb_respond_to(gz->io, id_flush))
+	    rb_funcall(gz->io, id_flush, 0);
+    }
+}
+
+static VALUE
+gzfile_read_raw(gz)
+    struct gzfile *gz;
+{
+    VALUE str;
+
+    str = rb_funcall(gz->io, id_read, 1, INT2FIX(GZFILE_READ_SIZE));
+    if (!NIL_P(str)) {
+	Check_Type(str, T_STRING);
+    }
+    return str;
+}
+
+static int
+gzfile_read_raw_ensure(gz, size)
+    struct gzfile *gz;
+    int size;
+{
+    VALUE str;
+
+    while (NIL_P(gz->z.input) || RSTRING(gz->z.input)->len < size) {
+	str = gzfile_read_raw(gz);
+	if (NIL_P(str)) return Qfalse;
+	zstream_append_input2(&gz->z, str);
+    }
+    return Qtrue;
+}
+
+static char *
+gzfile_read_raw_until_zero(gz, offset)
+    struct gzfile *gz;
+    long offset;
+{
+    VALUE str;
+    char *p;
+
+    for (;;) {
+	p = memchr(RSTRING(gz->z.input)->ptr + offset, '\0',
+		   RSTRING(gz->z.input)->len - offset);
+	if (p) break;
+	str = gzfile_read_raw(gz);
+	if (NIL_P(str)) {
+	    rb_raise(cGzError, "unexpected end of file");
+	}
+	offset = RSTRING(gz->z.input)->len;
+	zstream_append_input2(&gz->z, str);
+    }
+    return p;
+}
+
+static unsigned int
+gzfile_get16(src)
+    const unsigned char *src;
+{
+    unsigned int n;
+    n  = *(src++) & 0xff;
+    n |= (*(src++) & 0xff) << 8;
+    return n;
+}
+
+static unsigned long
+gzfile_get32(src)
+    const unsigned char *src;
+{
+    unsigned long n;
+    n  = *(src++) & 0xff;
+    n |= (*(src++) & 0xff) << 8;
+    n |= (*(src++) & 0xff) << 16;
+    n |= (*(src++) & 0xff) << 24;
+    return n;
+}
+
+static void
+gzfile_set32(n, dst)
+    unsigned long n;
+    unsigned char *dst;
+{
+    *(dst++) = n & 0xff;
+    *(dst++) = (n >> 8) & 0xff;
+    *(dst++) = (n >> 16) & 0xff;
+    *dst     = (n >> 24) & 0xff;
+}
+
+static void
+gzfile_make_header(gz)
+    struct gzfile *gz;
+{
+    unsigned char buf[10];  /* the size of gzip header */
+    unsigned char flags = 0, extraflags = 0;
+
+    if (!NIL_P(gz->orig_name)) {
+	flags |= GZ_FLAG_ORIG_NAME;
+    }
+    if (!NIL_P(gz->comment)) {
+	flags |= GZ_FLAG_COMMENT;
+    }
+    if (gz->mtime == 0) {
+	gz->mtime = time(0);
+    }
+
+    if (gz->level == Z_BEST_SPEED) {
+	extraflags |= GZ_EXTRAFLAG_FAST;
+    }
+    else if (gz->level == Z_BEST_COMPRESSION) {
+	extraflags |= GZ_EXTRAFLAG_SLOW;
+    }
+
+    buf[0] = GZ_MAGIC1;
+    buf[1] = GZ_MAGIC2;
+    buf[2] = GZ_METHOD_DEFLATE;
+    buf[3] = flags;
+    gzfile_set32(gz->mtime, &buf[4]);
+    buf[8] = extraflags;
+    buf[9] = gz->os_code;
+    zstream_append_buffer(&gz->z, buf, sizeof(buf));
+
+    if (!NIL_P(gz->orig_name)) {
+	zstream_append_buffer2(&gz->z, gz->orig_name);
+	zstream_append_buffer(&gz->z, "\0", 1);
+    }
+    if (!NIL_P(gz->comment)) {
+	zstream_append_buffer2(&gz->z, gz->comment);
+	zstream_append_buffer(&gz->z, "\0", 1);
+    }
+
+    gz->z.flags |= GZFILE_FLAG_HEADER_FINISHED;
+}
+
+static void
+gzfile_make_footer(gz)
+    struct gzfile *gz;
+{
+    unsigned char buf[8];  /* 8 is the size of gzip footer */
+
+    gzfile_set32(gz->crc, buf);
+    gzfile_set32(gz->z.stream.total_in, &buf[4]);
+    zstream_append_buffer(&gz->z, buf, sizeof(buf));
+    gz->z.flags |= GZFILE_FLAG_FOOTER_FINISHED;
+}
+
+static void
+gzfile_read_header(gz)
+    struct gzfile *gz;
+{
+    const unsigned char *head;
+    long len;
+    char flags, *p;
+
+    if (!gzfile_read_raw_ensure(gz, 10)) {  /* 10 is the size of gzip header */
+	rb_raise(cGzError, "not in gzip format");
+    }
+
+    head = RSTRING(gz->z.input)->ptr;
+
+    if (head[0] != GZ_MAGIC1 || head[1] != GZ_MAGIC2) {
+	rb_raise(cGzError, "not in gzip format");
+    }
+    if (head[2] != GZ_METHOD_DEFLATE) {
+	rb_raise(cGzError, "unsupported compression method %d", head[2]);
+    }
+
+    flags = head[3];
+    if (flags & GZ_FLAG_MULTIPART) {
+	rb_raise(cGzError, "multi-part gzip file is not supported");
+    }
+    else if (flags & GZ_FLAG_ENCRYPT) {
+	rb_raise(cGzError, "encrypted gzip file is not supported");
+    }
+    else if (flags & GZ_FLAG_UNKNOWN_MASK) {
+	rb_raise(cGzError, "unknown flags 0x%02x", flags);
+    }
+
+    if (head[8] & GZ_EXTRAFLAG_FAST) {
+	gz->level = Z_BEST_SPEED;
+    }
+    else if (head[8] & GZ_EXTRAFLAG_SLOW) {
+	gz->level = Z_BEST_COMPRESSION;
+    }
+    else {
+	gz->level = Z_DEFAULT_COMPRESSION;
+    }
+
+    gz->mtime = gzfile_get32(&head[4]);
+    gz->os_code = head[9];
+    zstream_discard_input(&gz->z, 10);
+
+    if (flags & GZ_FLAG_EXTRA) {
+	if (!gzfile_read_raw_ensure(gz, 2)) {
+	    rb_raise(cGzError, "unexpected end of file");
+	}
+	len = gzfile_get16(RSTRING(gz->z.input)->ptr);
+	if (!gzfile_read_raw_ensure(gz, 2 + len)) {
+	    rb_raise(cGzError, "unexpected end of file");
+	}
+	zstream_discard_input(&gz->z, 2 + len);
+    }
+    if (flags & GZ_FLAG_ORIG_NAME) {
+	p = gzfile_read_raw_until_zero(gz, 0);
+	len = p - RSTRING(gz->z.input)->ptr;
+	gz->orig_name = rb_str_new(RSTRING(gz->z.input)->ptr, len);
+	OBJ_TAINT(gz->orig_name);  /* for safe */
+	zstream_discard_input(&gz->z, len + 1);
+    }
+    if (flags & GZ_FLAG_COMMENT) {
+	p = gzfile_read_raw_until_zero(gz, 0);
+	len = p - RSTRING(gz->z.input)->ptr;
+	gz->comment = rb_str_new(RSTRING(gz->z.input)->ptr, len);
+	OBJ_TAINT(gz->comment);  /* for safe */
+	zstream_discard_input(&gz->z, len + 1);
+    }
+
+    if (RSTRING(gz->z.input)->len > 0) {
+	zstream_run(&gz->z, 0, 0, Z_SYNC_FLUSH);
+    }
+}
+
+static void
+gzfile_check_footer(gz)
+    struct gzfile *gz;
+{
+    unsigned long crc, length;
+
+    gz->z.flags |= GZFILE_FLAG_FOOTER_FINISHED;
+
+    if (!gzfile_read_raw_ensure(gz, 8)) { /* 8 is the size of gzip footer */
+	rb_raise(cNoFooter, "footer is not found");
+    }
+
+    crc = gzfile_get32(RSTRING(gz->z.input)->ptr);
+    length = gzfile_get32(RSTRING(gz->z.input)->ptr + 4);
+
+    gz->z.stream.total_in += 8;  /* to rewind correctly */
+    zstream_discard_input(&gz->z, 8);
+
+    if (gz->crc != crc) {
+	rb_raise(cCRCError, "invalid compressed data -- crc error");
+    }
+    if (gz->z.stream.total_out != length) {
+	rb_raise(cLengthError, "invalid compressed data -- length error");
+    }
+}
+
+static void
+gzfile_write(gz, str, len)
+    struct gzfile *gz;
+    Bytef *str;
+    uInt len;
+{
+    if (!(gz->z.flags & GZFILE_FLAG_HEADER_FINISHED)) {
+	gzfile_make_header(gz);
+    }
+
+    if (len > 0 || (gz->z.flags & GZFILE_FLAG_SYNC)) {
+	gz->crc = crc32(gz->crc, str, len);
+	zstream_run(&gz->z, str, len, (gz->z.flags & GZFILE_FLAG_SYNC)
+		    ? Z_SYNC_FLUSH : Z_NO_FLUSH);
+    }
+    gzfile_write_raw(gz);
+}
+
+static long
+gzfile_read_more(gz)
+    struct gzfile *gz;
+{
+    VALUE str;
+
+    while (!ZSTREAM_IS_FINISHED(&gz->z)) {
+	str = gzfile_read_raw(gz);
+	if (NIL_P(str)) {
+	    if (!ZSTREAM_IS_FINISHED(&gz->z)) {
+		rb_raise(cGzError, "unexpected end of file");
+	    }
+	    break;
+	}
+	if (RSTRING(str)->len > 0) { /* prevent Z_BUF_ERROR */
+	    zstream_run(&gz->z, RSTRING(str)->ptr, RSTRING(str)->len,
+			Z_SYNC_FLUSH);
+	}
+	if (gz->z.buf_filled > 0) break;
+    }
+    return gz->z.buf_filled;
+}
+
+static VALUE
+gzfile_read(gz, len)
+    struct gzfile *gz;
+    int len;
+{
+    VALUE dst;
+
+    if (len <= 0) return Qnil;
+    while (!ZSTREAM_IS_FINISHED(&gz->z) && gz->z.buf_filled < len) {
+	gzfile_read_more(gz);
+    }
+    if (GZFILE_IS_FINISHED(gz)) {
+	if (!(gz->z.flags & GZFILE_FLAG_FOOTER_FINISHED)) {
+	    gzfile_check_footer(gz);
+	}
+	return Qnil;
+    }
+
+    dst = zstream_shift_buffer(&gz->z, len);
+    if (RSTRING(dst)->len <= gz->ungetc) {
+	gz->ungetc -= RSTRING(dst)->len;
+    }
+    else {
+	gz->crc = crc32(gz->crc, RSTRING(dst)->ptr + gz->ungetc,
+			RSTRING(dst)->len - gz->ungetc);
+    }
+
+    OBJ_TAINT(dst);  /* for safe */
+    return dst;
+}
+
+static VALUE
+gzfile_read_all(gz)
+    struct gzfile *gz;
+{
+    VALUE dst;
+
+    while (!ZSTREAM_IS_FINISHED(&gz->z)) {
+	gzfile_read_more(gz);
+    }
+    if (GZFILE_IS_FINISHED(gz)) {
+	if (!(gz->z.flags & GZFILE_FLAG_FOOTER_FINISHED)) {
+	    gzfile_check_footer(gz);
+	}
+	return Qnil;
+    }
+
+    dst = zstream_detach_buffer(&gz->z);
+    if (RSTRING(dst)->len <= gz->ungetc) {
+	gz->ungetc -= RSTRING(dst)->len;
+    }
+    else {
+	gz->crc = crc32(gz->crc, RSTRING(dst)->ptr + gz->ungetc,
+			RSTRING(dst)->len - gz->ungetc);
+    }
+
+    OBJ_TAINT(dst);  /* for safe */
+    return dst;
+}
+
+static void
+gzfile_ungetc(gz, c)
+    struct gzfile *gz;
+    int c;
+{
+    zstream_buffer_ungetc(&gz->z, c);
+    gz->ungetc++;
+}
+
+static VALUE
+gzfile_finalize(obj)
+    VALUE obj;
+{
+    struct gzfile *gz = (struct gzfile *)obj;
+    gzfile_write_raw(gz);
+    return Qnil;
+}
+
+static void
+gzfile_writer_end(gz)
+    struct gzfile *gz;
+{
+    int aborted;
+
+    if (!(gz->z.flags & GZFILE_FLAG_HEADER_FINISHED)) {
+	gzfile_make_header(gz);
+    }
+
+    zstream_run(&gz->z, "", 0, Z_FINISH);
+    gzfile_make_footer(gz);
+
+    if (ZSTREAM_IS_FINALIZE(&gz->z)) {
+	rb_warn("Zlib::GzipWriter object must be closed explicitly.");
+	if (OBJ_IS_FREED(gz->io)) {
+	    aborted = 1;
+	}
+	else {
+	    rb_protect(gzfile_finalize, (VALUE)gz, &aborted);
+	}
+	if (aborted) {
+	    rb_warn("gzip footer is not written; broken gzip file");
+	}
+	zstream_end(&gz->z);
+	return;
+    }
+    gzfile_write_raw(gz);
+    zstream_end(&gz->z);
+}
+
+static void
+gzfile_reader_end(gz)
+    struct gzfile *gz;
+{
+    if (GZFILE_IS_FINISHED(gz)
+	&& !ZSTREAM_IS_FINALIZE(&gz->z)
+	&& !(gz->z.flags & GZFILE_FLAG_FOOTER_FINISHED)) {
+	gzfile_check_footer(gz);
+    }
+
+    zstream_end(&gz->z);
+}
+
+static void
+gzfile_reader_rewind(gz)
+    struct gzfile *gz;
+{
+    long n;
+
+    n = gz->z.stream.total_in;
+    if (!NIL_P(gz->z.input)) {
+	n += RSTRING(gz->z.input)->len;
+    }
+
+    rb_funcall(gz->io, id_seek, 2, rb_int2inum(-n), INT2FIX(1));
+    gzfile_reset(gz);
+}
+
+static VALUE
+gzfile_reader_get_unused(gz)
+    struct gzfile *gz;
+{
+    VALUE str;
+
+    if (!ZSTREAM_IS_READY(&gz->z)) return Qnil;
+    if (!GZFILE_IS_FINISHED(gz)) return Qnil;
+    if (!(gz->z.flags & GZFILE_FLAG_FOOTER_FINISHED)) {
+	gzfile_check_footer(gz);
+    }
+    if (NIL_P(gz->z.input)) return Qnil;
+
+    str = rb_str_dup(gz->z.input);
+    OBJ_TAINT(str);  /* for safe */
+    return str;
+}
+
+static struct gzfile *
+get_gzfile(obj)
+    VALUE obj;
+{
+    struct gzfile *gz;
+
+    Data_Get_Struct(obj, struct gzfile, gz);
+    if (!ZSTREAM_IS_READY(&gz->z)) {
+	rb_raise(cGzError, "closed gzip stream");
+    }
+    return gz;
+}
+
+
+
+/*-------- class Zlib::GzipFile --------*/
+
+static VALUE
+gzfile_ensure_close(obj)
+    VALUE obj;
+{
+    struct gzfile *gz;
+
+    Data_Get_Struct(obj, struct gzfile, gz);
+    if (ZSTREAM_IS_READY(&gz->z)) {
+	gzfile_close(gz, 1);
+    }
+    return Qnil;
+}
+
+static VALUE
+rb_gzfile_s_wrap(argc, argv, klass)
+    int argc;
+    VALUE *argv;
+    VALUE klass;
+{
+    VALUE obj = rb_class_new_instance(argc, argv, klass);
+
+    if (rb_block_given_p()) {
+	return rb_ensure(rb_yield, obj, gzfile_ensure_close, obj);
+    }
+    else {
+	return obj;
+    }
+}
+
+static VALUE
+gzfile_s_open(argc, argv, klass, mode)
+    int argc;
+    VALUE *argv;
+    VALUE klass;
+    const char *mode;
+{
+    VALUE io, filename;
+
+    if (argc < 1) {
+	rb_raise(rb_eArgError, "wrong number of arguments (0 for 1)");
+    }
+    filename = argv[0];
+    SafeStringValue(filename);
+    io = rb_file_open(RSTRING(filename)->ptr, mode);
+
+    argv[0] = io;
+    return rb_gzfile_s_wrap(argc, argv, klass);
+}
+
+static VALUE
+rb_gzfile_to_io(obj)
+    VALUE obj;
+{
+    return get_gzfile(obj)->io;
+}
+
+static VALUE
+rb_gzfile_crc(obj)
+    VALUE obj;
+{
+    return rb_uint2inum(get_gzfile(obj)->crc);
+}
+
+static VALUE
+rb_gzfile_mtime(obj)
+    VALUE obj;
+{
+    return rb_time_new(get_gzfile(obj)->mtime, (time_t)0);
+}
+
+static VALUE
+rb_gzfile_level(obj)
+    VALUE obj;
+{
+    return INT2FIX(get_gzfile(obj)->level);
+}
+
+static VALUE
+rb_gzfile_os_code(obj)
+    VALUE obj;
+{
+    return INT2FIX(get_gzfile(obj)->os_code);
+}
+
+static VALUE
+rb_gzfile_orig_name(obj)
+    VALUE obj;
+{
+    VALUE str = get_gzfile(obj)->orig_name;
+    if (!NIL_P(str)) {
+	str = rb_str_dup(str);
+    }
+    OBJ_TAINT(str);  /* for safe */
+    return str;
+}
+
+static VALUE
+rb_gzfile_comment(obj)
+    VALUE obj;
+{
+    VALUE str = get_gzfile(obj)->comment;
+    if (!NIL_P(str)) {
+	str = rb_str_dup(str);
+    }
+    OBJ_TAINT(str);  /* for safe */
+    return str;
+}
+
+static VALUE
+rb_gzfile_lineno(obj)
+    VALUE obj;
+{
+    return INT2NUM(get_gzfile(obj)->lineno);
+}
+
+static VALUE
+rb_gzfile_set_lineno(obj, lineno)
+    VALUE obj, lineno;
+{
+    struct gzfile *gz = get_gzfile(obj);
+    gz->lineno = NUM2INT(lineno);
+    return lineno;
+}
+
+static VALUE
+rb_gzfile_set_mtime(obj, mtime)
+    VALUE obj, mtime;
+{
+    struct gzfile *gz = get_gzfile(obj);
+    VALUE val;
+
+    if (gz->z.flags & GZFILE_FLAG_HEADER_FINISHED) {
+	rb_raise(cGzError, "header is already written");
+    }
+
+    if (FIXNUM_P(time)) {
+	gz->mtime = FIX2INT(mtime);
+    }
+    else {
+	val = rb_Integer(mtime);
+	gz->mtime = FIXNUM_P(val) ? FIX2INT(val) : rb_big2ulong(val);
+    }
+    return mtime;
+}
+
+static VALUE
+rb_gzfile_set_orig_name(obj, str)
+    VALUE obj, str;
+{
+    struct gzfile *gz = get_gzfile(obj);
+    VALUE s;
+    char *p;
+
+    if (gz->z.flags & GZFILE_FLAG_HEADER_FINISHED) {
+	rb_raise(cGzError, "header is already written");
+    }
+    s = rb_str_dup(rb_str_to_str(str));
+    p = memchr(RSTRING(s)->ptr, '\0', RSTRING(s)->len);
+    if (p) {
+	rb_str_resize(s, p - RSTRING(s)->ptr);
+    }
+    gz->orig_name = s;
+    return str;
+}
+
+static VALUE
+rb_gzfile_set_comment(obj, str)
+    VALUE obj, str;
+{
+    struct gzfile *gz = get_gzfile(obj);
+    VALUE s;
+    char *p;
+
+    if (gz->z.flags & GZFILE_FLAG_HEADER_FINISHED) {
+	rb_raise(cGzError, "header is already written");
+    }
+    s = rb_str_dup(rb_str_to_str(str));
+    p = memchr(RSTRING(s)->ptr, '\0', RSTRING(s)->len);
+    if (p) {
+	rb_str_resize(s, p - RSTRING(s)->ptr);
+    }
+    gz->comment = s;
+    return str;
+}
+
+static VALUE
+rb_gzfile_close(obj)
+    VALUE obj;
+{
+    struct gzfile *gz = get_gzfile(obj);
+    VALUE io;
+
+    io = gz->io;
+    gzfile_close(gz, 1);
+    return io;
+}
+
+static VALUE
+rb_gzfile_finish(obj)
+    VALUE obj;
+{
+    struct gzfile *gz = get_gzfile(obj);
+    VALUE io;
+
+    io = gz->io;
+    gzfile_close(gz, 0);
+    return io;
+}
+
+static VALUE
+rb_gzfile_closed_p(obj)
+    VALUE obj;
+{
+    struct gzfile *gz;
+    Data_Get_Struct(obj, struct gzfile, gz);
+    return NIL_P(gz->io) ? Qtrue : Qfalse;
+}
+
+static VALUE
+rb_gzfile_eof_p(obj)
+    VALUE obj;
+{
+    struct gzfile *gz = get_gzfile(obj);
+    return GZFILE_IS_FINISHED(gz) ? Qtrue : Qfalse;
+}
+
+static VALUE
+rb_gzfile_sync(obj)
+    VALUE obj;
+{
+    return (get_gzfile(obj)->z.flags & GZFILE_FLAG_SYNC) ? Qtrue : Qfalse;
+}
+
+static VALUE
+rb_gzfile_set_sync(obj, mode)
+    VALUE obj, mode;
+{
+    struct gzfile *gz = get_gzfile(obj);
+
+    if (RTEST(mode)) {
+	gz->z.flags |= GZFILE_FLAG_SYNC;
+    }
+    else {
+	gz->z.flags &= ~GZFILE_FLAG_SYNC;
+    }
+    return mode;
+}
+
+static VALUE
+rb_gzfile_total_in(obj)
+    VALUE obj;
+{
+    return rb_uint2inum(get_gzfile(obj)->z.stream.total_in);
+}
+
+static VALUE
+rb_gzfile_total_out(obj)
+    VALUE obj;
+{
+    struct gzfile *gz = get_gzfile(obj);
+    return rb_uint2inum(gz->z.stream.total_out - gz->z.buf_filled);
+}
+
+
+
+/*-------- class Zlib::GzipWriter --------*/
+
+static VALUE
+rb_gzwriter_s_allocate(klass)
+    VALUE klass;
+{
+    return gzfile_writer_new(klass);
+}
+
+static VALUE
+rb_gzwriter_s_open(argc, argv, klass)
+    int argc;
+    VALUE *argv;
+    VALUE klass;
+{
+    return gzfile_s_open(argc, argv, klass, "wb");
+}
+
+static VALUE
+rb_gzwriter_initialize(argc, argv, obj)
+    int argc;
+    VALUE *argv;
+    VALUE obj;
+{
+    struct gzfile *gz;
+    VALUE io, level, strategy;
+    int err;
+
+    rb_scan_args(argc, argv, "12", &io, &level, &strategy);
+    Data_Get_Struct(obj, struct gzfile, gz);
+
+    /* this is undocumented feature of zlib */
+    gz->level = ARG_LEVEL(level);
+    err = deflateInit2(&gz->z.stream, gz->level, Z_DEFLATED,
+		       -MAX_WBITS, DEF_MEM_LEVEL, ARG_STRATEGY(strategy));
+    if (err != Z_OK) {
+	raise_zlib_error(err, gz->z.stream.msg);
+    }
+    gz->io = io;
+    ZSTREAM_READY(&gz->z);
+
+    return obj;
+}
+
+static VALUE
+rb_gzwriter_flush(argc, argv, obj)
+    int argc;
+    VALUE *argv;
+    VALUE obj;
+{
+    struct gzfile *gz = get_gzfile(obj);
+    VALUE v_flush;
+    int flush;
+
+    rb_scan_args(argc, argv, "01", &v_flush);
+
+    flush = FIXNUMARG(v_flush, Z_SYNC_FLUSH);
+    if (flush != Z_NO_FLUSH) {  /* prevent Z_BUF_ERROR */
+	zstream_run(&gz->z, "", 0, flush);
+    }
+
+    gzfile_write_raw(gz);
+    if (rb_respond_to(gz->io, id_flush)) {
+	rb_funcall(gz->io, id_flush, 0);
+    }
+    return obj;
+}
+
+static VALUE
+rb_gzwriter_write(obj, str)
+    VALUE obj, str;
+{
+    struct gzfile *gz = get_gzfile(obj);
+
+    if (TYPE(str) != T_STRING) {
+	str = rb_obj_as_string(str);
+    }
+    gzfile_write(gz, RSTRING(str)->ptr, RSTRING(str)->len);
+    return INT2FIX(RSTRING(str)->len);
+}
+
+static VALUE
+rb_gzwriter_putc(obj, ch)
+    VALUE obj, ch;
+{
+    struct gzfile *gz = get_gzfile(obj);
+    char c = NUM2CHR(ch);
+
+    gzfile_write(gz, &c, 1);
+    return ch;
+}
+
+#define rb_gzwriter_addstr  rb_io_addstr
+#define rb_gzwriter_printf  rb_io_printf
+#define rb_gzwriter_print  rb_io_print
+#define rb_gzwriter_puts  rb_io_puts
+
+
+/*-------- class Zlib::GzipReader --------*/
+
+static VALUE
+rb_gzreader_s_allocate(klass)
+    VALUE klass;
+{
+    return gzfile_reader_new(klass);
+}
+
+static VALUE
+rb_gzreader_s_open(argc, argv, klass)
+    int argc;
+    VALUE *argv;
+    VALUE klass;
+{
+    return gzfile_s_open(argc, argv, klass, "rb");
+}
+
+static VALUE
+rb_gzreader_initialize(obj, io)
+    VALUE obj, io;
+{
+    struct gzfile *gz;
+    int err;
+
+    Data_Get_Struct(obj, struct gzfile, gz);
+
+    /* this is undocumented feature of zlib */
+    err = inflateInit2(&gz->z.stream, -MAX_WBITS);
+    if (err != Z_OK) {
+	raise_zlib_error(err, gz->z.stream.msg);
+    }
+    gz->io = io;
+    ZSTREAM_READY(&gz->z);
+    gzfile_read_header(gz);
+
+    return obj;
+}
+
+static VALUE
+rb_gzreader_rewind(obj)
+    VALUE obj;
+{
+    struct gzfile *gz = get_gzfile(obj);
+    gzfile_reader_rewind(gz);
+    return INT2FIX(0);
+}
+
+static VALUE
+rb_gzreader_unused(obj)
+    VALUE obj;
+{
+    struct gzfile *gz;
+    Data_Get_Struct(obj, struct gzfile, gz);
+    return gzfile_reader_get_unused(gz);
+}
+
+static VALUE
+rb_gzreader_read(argc, argv, obj)
+    int argc;
+    VALUE *argv;
+    VALUE obj;
+{
+    struct gzfile *gz = get_gzfile(obj);
+    VALUE vlen;
+    int len;
+
+    rb_scan_args(argc, argv, "01", &vlen);
+    if (NIL_P(vlen)) {
+	return gzfile_read_all(gz);
+    }
+
+    len = NUM2INT(vlen);
+    if (len < 0) {
+	rb_raise(rb_eArgError, "negative length %d given", len);
+    }
+    return gzfile_read(gz, len);
+}
+
+static VALUE
+rb_gzreader_getc(obj)
+    VALUE obj;
+{
+    struct gzfile *gz = get_gzfile(obj);
+    VALUE dst;
+
+    dst = gzfile_read(gz, 1);
+    if (!NIL_P(dst)) {
+	dst = INT2FIX(RSTRING(dst)->ptr[0]);
+    }
+    return dst;
+}
+
+static VALUE
+rb_gzreader_readchar(obj)
+    VALUE obj;
+{
+    VALUE dst;
+    dst = rb_gzreader_getc(obj);
+    if (NIL_P(dst)) {
+	rb_raise(rb_eEOFError, "End of file reached");
+    }
+    return dst;
+}
+
+static VALUE
+rb_gzreader_each_byte(obj)
+    VALUE obj;
+{
+    VALUE c;
+    while (!NIL_P(c = rb_gzreader_getc(obj))) {
+	rb_yield(c);
+    }
+    return Qnil;
+}
+
+static VALUE
+rb_gzreader_ungetc(obj, ch)
+    VALUE obj, ch;
+{
+    struct gzfile *gz = get_gzfile(obj);
+    gzfile_ungetc(gz, NUM2CHR(ch));
+    return Qnil;
+}
+
+static void
+gzreader_skip_linebreaks(gz)
+    struct gzfile *gz;
+{
+    VALUE str;
+    char *p;
+    int n;
+
+    while (gz->z.buf_filled == 0) {
+	if (GZFILE_IS_FINISHED(gz)) return;
+	gzfile_read_more(gz);
+    }
+    n = 0;
+    p = RSTRING(gz->z.buf)->ptr;
+
+    while (n++, *(p++) == '\n') {
+	if (n >= gz->z.buf_filled) {
+	    str = zstream_detach_buffer(&gz->z);
+	    gz->crc = crc32(gz->crc, RSTRING(str)->ptr,
+			    RSTRING(str)->len);
+	    while (gz->z.buf_filled == 0) {
+		if (GZFILE_IS_FINISHED(gz)) return;
+		gzfile_read_more(gz);
+	    }
+	    n = 0;
+	    p = RSTRING(gz->z.buf)->ptr;
+	}
+    }
+
+    str = zstream_shift_buffer(&gz->z, n - 1);
+    gz->crc = crc32(gz->crc, RSTRING(str)->ptr, RSTRING(str)->len);
+}
+
+static VALUE
+gzreader_gets(argc, argv, obj)
+    int argc;
+    VALUE *argv;
+    VALUE obj;
+{
+    struct gzfile *gz = get_gzfile(obj);
+    VALUE rs, dst;
+    char *rsptr, *p;
+    long rslen, n;
+    int rspara;
+
+    if (argc == 0) {
+	rs = rb_rs;
+    }
+    else {
+	rb_scan_args(argc, argv, "1", &rs);
+	if (!NIL_P(rs)) {
+	    Check_Type(rs, T_STRING);
+	}
+    }
+
+    if (NIL_P(rs)) {
+	dst = gzfile_read_all(gz);
+	if (!NIL_P(dst)) gz->lineno++;
+	return dst;
+    }
+
+    if (RSTRING(rs)->len == 0) {
+	rsptr = "\n\n";
+	rslen = 2;
+	rspara = 1;
+    } else {
+	rsptr = RSTRING(rs)->ptr;
+	rslen = RSTRING(rs)->len;
+	rspara = 0;
+    }
+
+    if (rspara) {
+	gzreader_skip_linebreaks(gz);
+    }
+
+    while (gz->z.buf_filled < rslen) {
+	if (ZSTREAM_IS_FINISHED(&gz->z)) {
+	    if (gz->z.buf_filled > 0) gz->lineno++;
+	    return gzfile_read(gz, rslen);
+	}
+	gzfile_read_more(gz);
+    }
+
+    n = rslen;
+    p = RSTRING(gz->z.buf)->ptr;
+    for (;;) {
+	if (n > gz->z.buf_filled) {
+	    if (ZSTREAM_IS_FINISHED(&gz->z)) break;
+	    gzfile_read_more(gz);
+	    p = RSTRING(gz->z.buf)->ptr + n - rslen;
+	}
+	if (memcmp(p, rsptr, rslen) == 0) break;
+	p++, n++;
+    }
+
+    gz->lineno++;
+    dst = gzfile_read(gz, n);
+    if (rspara) {
+	gzreader_skip_linebreaks(gz);
+    }
+
+    return dst;
+}
+
+static VALUE
+rb_gzreader_gets(argc, argv, obj)
+    int argc;
+    VALUE *argv;
+    VALUE obj;
+{
+    VALUE dst;
+    dst = gzreader_gets(argc, argv, obj);
+    if (!NIL_P(dst)) {
+	rb_lastline_set(dst);
+    }
+    return dst;
+}
+
+static VALUE
+rb_gzreader_readline(argc, argv, obj)
+    int argc;
+    VALUE *argv;
+    VALUE obj;
+{
+    VALUE dst;
+    dst = rb_gzreader_gets(argc, argv, obj);
+    if (NIL_P(dst)) {
+	rb_raise(rb_eEOFError, "End of file reached");
+    }
+    return dst;
+}
+
+static VALUE
+rb_gzreader_each(argc, argv, obj)
+    int argc;
+    VALUE *argv;
+    VALUE obj;
+{
+    VALUE str;
+    while (!NIL_P(str = gzreader_gets(argc, argv, obj))) {
+	rb_yield(str);
+    }
+    return obj;
+}
+
+static VALUE
+rb_gzreader_readlines(argc, argv, obj)
+    int argc;
+    VALUE *argv;
+    VALUE obj;
+{
+    VALUE str, dst;
+    dst = rb_ary_new();
+    while (!NIL_P(str = gzreader_gets(argc, argv, obj))) {
+	rb_ary_push(dst, str);
+    }
+    return dst;
+}
+
+#endif /* GZIP_SUPPORT */
+
+
+void Init_zlib()
+{
+    VALUE mZlib, cZStream, cDeflate, cInflate;
+#if GZIP_SUPPORT
+    VALUE cGzipFile, cGzipWriter, cGzipReader;
+#endif
+
+    mZlib = rb_define_module("Zlib");
+
+    cZError = rb_define_class_under(mZlib, "Error", rb_eStandardError);
+    cStreamEnd    = rb_define_class_under(mZlib, "StreamEnd", cZError);
+    cNeedDict     = rb_define_class_under(mZlib, "NeedDict", cZError);
+    cDataError    = rb_define_class_under(mZlib, "DataError", cZError);
+    cStreamError  = rb_define_class_under(mZlib, "StreamError", cZError);
+    cMemError     = rb_define_class_under(mZlib, "MemError", cZError);
+    cBufError     = rb_define_class_under(mZlib, "BufError", cZError);
+    cVersionError = rb_define_class_under(mZlib, "VersionError", cZError);
+
+    rb_define_module_function(mZlib, "zlib_version", rb_zlib_version, 0);
+    rb_define_module_function(mZlib, "adler32", rb_zlib_adler32, -1);
+    rb_define_module_function(mZlib, "crc32", rb_zlib_crc32, -1);
+    rb_define_module_function(mZlib, "crc_table", rb_zlib_crc_table, 0);
+
+    rb_define_const(mZlib, "VERSION", rb_str_new2(RUBY_ZLIB_VERSION));
+    rb_define_const(mZlib, "ZLIB_VERSION", rb_str_new2(ZLIB_VERSION));
+
+    cZStream = rb_define_class_under(mZlib, "ZStream", rb_cObject);
+    rb_undef_alloc_func(cZStream);
+    rb_define_method(cZStream, "avail_out", rb_zstream_avail_out, 0);
+    rb_define_method(cZStream, "avail_out=", rb_zstream_set_avail_out, 0);
+    rb_define_method(cZStream, "avail_in", rb_zstream_avail_in, 0);
+    rb_define_method(cZStream, "total_in", rb_zstream_total_in, 0);
+    rb_define_method(cZStream, "total_out", rb_zstream_total_out, 0);
+    rb_define_method(cZStream, "data_type", rb_zstream_data_type, 0);
+    rb_define_method(cZStream, "adler", rb_zstream_adler, 0);
+    rb_define_method(cZStream, "finished?", rb_zstream_finished_p, 0);
+    rb_define_method(cZStream, "stream_end?", rb_zstream_finished_p, 0);
+    rb_define_method(cZStream, "closed?", rb_zstream_closed_p, 0);
+    rb_define_method(cZStream, "ended?", rb_zstream_closed_p, 0);
+    rb_define_method(cZStream, "close", rb_zstream_end, 0);
+    rb_define_method(cZStream, "end", rb_zstream_end, 0);
+    rb_define_method(cZStream, "reset", rb_zstream_reset, 0);
+    rb_define_method(cZStream, "finish", rb_zstream_finish, 0);
+    rb_define_method(cZStream, "flush_next_in", rb_zstream_flush_next_in, 0);
+    rb_define_method(cZStream, "flush_next_out", rb_zstream_flush_next_out, 0);
+
+    rb_define_const(mZlib, "BINARY", INT2FIX(Z_BINARY));
+    rb_define_const(mZlib, "ASCII", INT2FIX(Z_ASCII));
+    rb_define_const(mZlib, "UNKNOWN", INT2FIX(Z_UNKNOWN));
+
+    cDeflate = rb_define_class_under(mZlib, "Deflate", cZStream);
+    rb_define_singleton_method(cDeflate, "deflate", rb_deflate_s_deflate, -1);
+    rb_define_alloc_func(cDeflate, rb_deflate_s_allocate);
+    rb_define_method(cDeflate, "initialize", rb_deflate_initialize, -1);
+    rb_define_method(cDeflate, "clone", rb_deflate_clone, 0);
+    rb_define_method(cDeflate, "deflate", rb_deflate_deflate, -1);
+    rb_define_method(cDeflate, "<<", rb_deflate_addstr, 1);
+    rb_define_method(cDeflate, "flush", rb_deflate_flush, -1);
+    rb_define_method(cDeflate, "params", rb_deflate_params, 2);
+    rb_define_method(cDeflate, "set_dictionary", rb_deflate_set_dictionary, 1);
+
+    cInflate = rb_define_class_under(mZlib, "Inflate", cZStream);
+    rb_define_singleton_method(cInflate, "inflate", rb_inflate_s_inflate, 1);
+    rb_define_alloc_func(cInflate, rb_inflate_s_allocate);
+    rb_define_method(cInflate, "initialize", rb_inflate_initialize, -1);
+    rb_define_method(cInflate, "inflate", rb_inflate_inflate, 1);
+    rb_define_method(cInflate, "<<", rb_inflate_addstr, 1);
+    rb_define_method(cInflate, "sync", rb_inflate_sync, 1);
+    rb_define_method(cInflate, "sync_point?", rb_inflate_sync_point_p, 0);
+    rb_define_method(cInflate, "set_dictionary", rb_inflate_set_dictionary, 1);
+
+    rb_define_const(mZlib, "NO_COMPRESSION", INT2FIX(Z_NO_COMPRESSION));
+    rb_define_const(mZlib, "BEST_SPEED", INT2FIX(Z_BEST_SPEED));
+    rb_define_const(mZlib, "BEST_COMPRESSION", INT2FIX(Z_BEST_COMPRESSION));
+    rb_define_const(mZlib, "DEFAULT_COMPRESSION",
+		    INT2FIX(Z_DEFAULT_COMPRESSION));
+
+    rb_define_const(mZlib, "FILTERED", INT2FIX(Z_FILTERED));
+    rb_define_const(mZlib, "HUFFMAN_ONLY", INT2FIX(Z_HUFFMAN_ONLY));
+    rb_define_const(mZlib, "DEFAULT_STRATEGY", INT2FIX(Z_DEFAULT_STRATEGY));
+
+    rb_define_const(mZlib, "MAX_WBITS", INT2FIX(MAX_WBITS));
+    rb_define_const(mZlib, "DEF_MEM_LEVEL", INT2FIX(DEF_MEM_LEVEL));
+    rb_define_const(mZlib, "MAX_MEM_LEVEL", INT2FIX(MAX_MEM_LEVEL));
+
+    rb_define_const(mZlib, "NO_FLUSH", INT2FIX(Z_NO_FLUSH));
+    rb_define_const(mZlib, "SYNC_FLUSH", INT2FIX(Z_SYNC_FLUSH));
+    rb_define_const(mZlib, "FULL_FLUSH", INT2FIX(Z_FULL_FLUSH));
+    rb_define_const(mZlib, "FINISH", INT2FIX(Z_FINISH));
+
+#if GZIP_SUPPORT
+    id_write = rb_intern("write");
+    id_read = rb_intern("read");
+    id_flush = rb_intern("flush");
+    id_seek = rb_intern("seek");
+    id_close = rb_intern("close");
+
+    cGzipFile = rb_define_class_under(mZlib, "GzipFile", rb_cObject);
+    cGzError = rb_define_class_under(cGzipFile, "Error", cZError);
+
+    cNoFooter = rb_define_class_under(cGzipFile, "NoFooter", cGzError);
+    cCRCError = rb_define_class_under(cGzipFile, "CRCError", cGzError);
+    cLengthError = rb_define_class_under(cGzipFile,"LengthError",cGzError);
+
+    cGzipWriter = rb_define_class_under(mZlib, "GzipWriter", cGzipFile);
+    cGzipReader = rb_define_class_under(mZlib, "GzipReader", cGzipFile);
+    rb_include_module(cGzipReader, rb_mEnumerable);
+
+    rb_define_singleton_method(cGzipFile, "wrap", rb_gzfile_s_wrap, -1);
+    rb_undef_alloc_func(cGzipFile);
+    rb_define_method(cGzipFile, "to_io", rb_gzfile_to_io, 0);
+    rb_define_method(cGzipFile, "crc", rb_gzfile_crc, 0);
+    rb_define_method(cGzipFile, "mtime", rb_gzfile_mtime, 0);
+    rb_define_method(cGzipFile, "level", rb_gzfile_level, 0);
+    rb_define_method(cGzipFile, "os_code", rb_gzfile_os_code, 0);
+    rb_define_method(cGzipFile, "orig_name", rb_gzfile_orig_name, 0);
+    rb_define_method(cGzipFile, "comment", rb_gzfile_comment, 0);
+    rb_define_method(cGzipReader, "lineno", rb_gzfile_lineno, 0);
+    rb_define_method(cGzipReader, "lineno=", rb_gzfile_set_lineno, 1);
+    rb_define_method(cGzipWriter, "mtime=", rb_gzfile_set_mtime, 1);
+    rb_define_method(cGzipWriter, "orig_name=", rb_gzfile_set_orig_name,1);
+    rb_define_method(cGzipWriter, "comment=", rb_gzfile_set_comment, 1);
+    rb_define_method(cGzipFile, "close", rb_gzfile_close, 0);
+    rb_define_method(cGzipFile, "finish", rb_gzfile_finish, 0);
+    rb_define_method(cGzipFile, "closed?", rb_gzfile_closed_p, 0);
+    rb_define_method(cGzipReader, "eof", rb_gzfile_eof_p, 0);
+    rb_define_method(cGzipReader, "eof?", rb_gzfile_eof_p, 0);
+    rb_define_method(cGzipFile, "sync", rb_gzfile_sync, 0);
+    rb_define_method(cGzipFile, "sync=", rb_gzfile_set_sync, 1);
+    rb_define_method(cGzipReader, "pos", rb_gzfile_total_out, 0);
+    rb_define_method(cGzipWriter, "pos", rb_gzfile_total_in, 0);
+    rb_define_method(cGzipReader, "tell", rb_gzfile_total_out, 0);
+    rb_define_method(cGzipWriter, "tell", rb_gzfile_total_in, 0);
+
+    rb_define_singleton_method(cGzipWriter, "open", rb_gzwriter_s_open,-1);
+    rb_define_alloc_func(cGzipWriter, rb_gzwriter_s_allocate);
+    rb_define_method(cGzipWriter, "initialize", rb_gzwriter_initialize,-1);
+    rb_define_method(cGzipWriter, "flush", rb_gzwriter_flush, -1);
+    rb_define_method(cGzipWriter, "write", rb_gzwriter_write, 1);
+    rb_define_method(cGzipWriter, "putc", rb_gzwriter_putc, 1);
+    rb_define_method(cGzipWriter, "<<", rb_gzwriter_addstr, 1);
+    rb_define_method(cGzipWriter, "printf", rb_gzwriter_printf, -1);
+    rb_define_method(cGzipWriter, "print", rb_gzwriter_print, -1);
+    rb_define_method(cGzipWriter, "puts", rb_gzwriter_puts, -1);
+
+    rb_define_singleton_method(cGzipReader, "open", rb_gzreader_s_open,-1);
+    rb_define_alloc_func(cGzipReader, rb_gzreader_s_allocate);
+    rb_define_method(cGzipReader, "initialize", rb_gzreader_initialize, 1);
+    rb_define_method(cGzipReader, "rewind", rb_gzreader_rewind, 0);
+    rb_define_method(cGzipReader, "unused", rb_gzreader_unused, 0);
+    rb_define_method(cGzipReader, "read", rb_gzreader_read, -1);
+    rb_define_method(cGzipReader, "getc", rb_gzreader_getc, 0);
+    rb_define_method(cGzipReader, "readchar", rb_gzreader_readchar, 0);
+    rb_define_method(cGzipReader, "each_byte", rb_gzreader_each_byte, 0);
+    rb_define_method(cGzipReader, "ungetc", rb_gzreader_ungetc, 1);
+    rb_define_method(cGzipReader, "gets", rb_gzreader_gets, -1);
+    rb_define_method(cGzipReader, "readline", rb_gzreader_readline, -1);
+    rb_define_method(cGzipReader, "each", rb_gzreader_each, -1);
+    rb_define_method(cGzipReader, "readlines", rb_gzreader_readlines, -1);
+
+    rb_define_const(mZlib, "OS_CODE", INT2FIX(OS_CODE));
+    rb_define_const(mZlib, "OS_MSDOS", INT2FIX(OS_MSDOS));
+    rb_define_const(mZlib, "OS_AMIGA", INT2FIX(OS_AMIGA));
+    rb_define_const(mZlib, "OS_VMS", INT2FIX(OS_VMS));
+    rb_define_const(mZlib, "OS_UNIX", INT2FIX(OS_UNIX));
+    rb_define_const(mZlib, "OS_ATARI", INT2FIX(OS_ATARI));
+    rb_define_const(mZlib, "OS_OS2", INT2FIX(OS_OS2));
+    rb_define_const(mZlib, "OS_MACOS", INT2FIX(OS_MACOS));
+    rb_define_const(mZlib, "OS_TOPS20", INT2FIX(OS_TOPS20));
+    rb_define_const(mZlib, "OS_WIN32", INT2FIX(OS_WIN32));
+
+    rb_define_const(mZlib, "OS_VMCMS", INT2FIX(OS_VMCMS));
+    rb_define_const(mZlib, "OS_ZSYSTEM", INT2FIX(OS_ZSYSTEM));
+    rb_define_const(mZlib, "OS_CPM", INT2FIX(OS_CPM));
+    rb_define_const(mZlib, "OS_QDOS", INT2FIX(OS_QDOS));
+    rb_define_const(mZlib, "OS_RISCOS", INT2FIX(OS_RISCOS));
+    rb_define_const(mZlib, "OS_UNKNOWN", INT2FIX(OS_UNKNOWN));
+
+#endif /* GZIP_SUPPORT */
+}