Zlib:Inflate is the class for decompressing compressed data. Unlike Zlib::Deflate, an instance of this class is not able to duplicate (clone, dup) itself.

Class Methods

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

See also Zlib.deflate

Creates a new inflate stream for decompression. window_bits sets the size of the history buffer and can have the following values:

0

Have inflate use the window size from the zlib header of the compressed stream.

(8..15)

Overrides the window size of the inflate header in the compressed stream. The window size must be greater than or equal to the window size of the compressed stream.

Greater than 15

Add 32 to window_bits to enable zlib and gzip decoding with automatic header detection, or add 16 to decode only the gzip format (a Zlib::DataError will be raised for a non-gzip stream).

(-8..-15)

Enables raw deflate mode which will not generate a check value, and will not look for any check values for comparison at the end of the stream.

This is for use with other formats that use the deflate compressed data format such as zip which provide their own check values.

Example

open "compressed.file" do |compressed_io|
  zi = Zlib::Inflate.new(Zlib::MAX_WBITS + 32)

  begin
    open "uncompressed.file", "w+" do |uncompressed_io|
      uncompressed_io << zi.inflate(compressed_io.read)
    end
  ensure
    zi.close
  end
end
Instance Methods

Same as IO.

Provide the inflate stream with a dictionary that may be required in the future. Multiple dictionaries may be provided. The inflate stream will automatically choose the correct user-provided dictionary based on the stream’s required dictionary.

Inputs deflate_string into the inflate stream and returns the output from the stream. Calling this method, both the input and the output buffer of the stream are flushed. If string is nil, this method finishes the stream, just like Zlib::ZStream#finish.

If a block is given consecutive inflated chunks from the deflate_string are yielded to the block and nil is returned.

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 to flush the stream:

inflater = Zlib::Inflate.new

begin
  out = inflater.inflate compressed
rescue Zlib::NeedDict
  # ensure the dictionary matches the stream's required dictionary
  raise unless inflater.adler == Zlib.adler32(dictionary)

  inflater.set_dictionary dictionary
  inflater.inflate ''
end

# ...

inflater.close

See also Zlib::Inflate.new

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.

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.

Quoted verbatim from original documentation:

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