Class: Zlib::Inflate
Relationships & Source Files | |
Super Chains via Extension / Inclusion / Inheritance | |
Class Chain:
self,
ZStream
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Instance Chain:
self,
ZStream
|
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Inherits: |
Zlib::ZStream
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Defined in: | ext/zlib/zlib.c, ext/zlib/zlib.c |
Overview
Zlib:Inflate is the class for decompressing compressed data. Unlike Deflate, an instance of this class is not able to duplicate (clone, dup) itself.
Class Method Summary
-
.inflate(string)
Decompresses
string
. -
.new(window_bits = Zlib::MAX_WBITS)
constructor
Creates a new inflate stream for decompression.
Instance Attribute Summary
-
#sync_point? ⇒ Boolean
readonly
Quoted verbatim from original documentation:
ZStream - Inherited
#avail_out | Returns number of bytes of free spaces in output buffer. |
#avail_out= | Allocates |
#closed? | Alias for ZStream#ended?. |
#ended? | Returns true if the stream is closed. |
#finished? | Returns true if the stream is finished. |
#stream_end? | Alias for ZStream#finished?. |
Instance Method Summary
-
#<<(string)
Inputs
string
into the inflate stream just like #inflate, but returns theInflate
object itself. -
#add_dictionary(string)
Provide the inflate stream with a dictionary that may be required in the future.
-
#inflate(deflate_string) ⇒ String
Inputs
deflate_string
into the inflate stream and returns the output from the stream. -
#set_dictionary(dic)
Sets the preset dictionary and returns
string
. -
#sync(string)
Inputs
string
into the end of input buffer and skips data until a full flush point can be found.
ZStream - Inherited
#adler | Returns the adler-32 checksum. |
#avail_in | Returns bytes of data in the input buffer. |
#close | Alias for ZStream#end. |
#data_type | Guesses the type of the data which have been inputed into the stream. |
#end | Closes the stream. |
#finish | Finishes the stream and flushes output buffer. |
#flush_next_in, | |
#flush_next_out | Flushes output buffer and returns all data in that buffer. |
#reset | Resets and initializes the stream. |
#total_in | Returns the total bytes of the input data to the stream. |
#total_out | Returns the total bytes of the output data from the stream. |
Constructor Details
.new(window_bits = Zlib::MAX_WBITS)
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
Class Method Details
Zlib.inflate(string)
.inflate(string)
Decompresses string
. Raises a 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
Instance Attribute Details
#sync_point? ⇒ Boolean
(readonly)
Quoted verbatim from original documentation:
What is this?
:)
Instance Method Details
#<<(string)
Inputs string
into the inflate stream just like #inflate, but returns the Inflate
object itself. The output from the stream is preserved in output buffer.
#add_dictionary(string)
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.
#inflate(deflate_string) ⇒ String
#inflate(deflate_string) {|chunk| ... } ⇒ nil
String
#inflate(deflate_string) {|chunk| ... } ⇒ nil
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 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 NeedDict exception if a preset dictionary is needed to decompress. Set the dictionary by #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 .new
#set_dictionary(dic)
Sets the preset dictionary and returns string
. This method is available just only after a NeedDict exception was raised. See zlib.h for details.
#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.