class

Compress::BZ2::Writer

A write-only IO object to compress data in the bzip2 format.

Instances of this class wrap another IO object. When you write to this instance, it compresses the data and writes it to the underlying IO.

NOTE: unless created with a block, close must be invoked after all data has been written to a BZ2::Writer instance.

Example: compress a file

require "bz2"

File.open("./file.txt", "r") do |input_file|
  File.open("./file.bz2", "w") do |output_file|
    Compress::BZ2::Writer.open(output_file) do |bz2|
      IO.copy(input_file, bz2)
    end
  end
end

Constructors

new(output : IO, block_size100k : Int32 = 9, work_factor : Int32 = 0, sync_close : Bool = false)

Creates an instance of BZ2::Writer. close must be invoked after all data has been written.

block_size100k controls the compressor's block size in units of 100kB (1..9, default 9 - the highest compression). work_factor (0..250, default 0 meaning bzlib's own default of 30) only affects how the compressor behaves on highly repetitive data - it never affects the decompressor.

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new(filename : String, block_size100k : Int32 = 9, work_factor : Int32 = 0)

Creates a new writer to the given filename.

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Class methods

open(io : IO, block_size100k : Int32 = 9, work_factor : Int32 = 0, sync_close : Bool = false, &)

Creates a new writer to the given io, yields it to the given block, and closes it at the end.

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open(filename : String, block_size100k : Int32 = 9, work_factor : Int32 = 0, &)

Creates a new writer to the given filename, yields it to the given block, and closes it at the end.

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Instance methods

Closes this writer. Must be invoked after all data has been written.

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closed?

Returns true if this IO is closed.

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flush

See IO#flush.

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read(slice : Bytes)

Always raises IO::Error because this is a write-only IO.

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sync_close=(sync_close : Bool)

If #sync_close? is true, closing this IO will close the underlying IO.

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sync_close?

If #sync_close? is true, closing this IO will close the underlying IO.

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write(slice : Bytes) : Nil

See IO#write.

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