class Gzip::Writer

Overview

A write-only IO object to compress data in the gzip 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 Gzip::Writer instance.

Example: compress a file

require "gzip"

File.write("file.txt", "abc")

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

Included Modules

Defined in:

gzip/writer.cr

Constructors

Class Method Summary

Instance Method Summary

Instance methods inherited from module IO

<<(obj) : self <<, close close, closed? closed?, each_byte
each_byte(&block) : Nil
each_byte
, each_char(&block) : Nil
each_char
each_char
, each_line(*args, **options, &block) : Nil
each_line(*args, **options)
each_line
, encoding : String encoding, flush flush, gets(limit : Int, chomp = false) : String?
gets(delimiter : Char, chomp = false) : String?
gets(delimiter : String, chomp = false) : String?
gets(chomp = true) : String?
gets(delimiter : Char, limit : Int, chomp = false) : String?
gets
, gets_to_end : String gets_to_end, peek : Bytes? peek, print(*objects : _) : Nil
print(obj) : Nil
print
, printf(format_string, args : Array | Tuple) : Nil
printf(format_string, *args) : Nil
printf
, puts(*objects : _) : Nil
puts : Nil
puts(obj) : Nil
puts(string : String) : Nil
puts
, read(slice : Bytes) read, read_byte : UInt8? read_byte, read_bytes(type, format : IO::ByteFormat = IO::ByteFormat::SystemEndian) read_bytes, read_char : Char? read_char, read_fully(slice : Bytes) read_fully, read_fully?(slice : Bytes) read_fully?, read_line(*args, **options) : String read_line, read_string(bytesize : Int) : String read_string, read_utf8(slice : Bytes) read_utf8, read_utf8_byte read_utf8_byte, rewind rewind, set_encoding(encoding : String, invalid : Symbol? = nil) set_encoding, skip(bytes_count : Int) : Nil skip, skip_to_end : Nil skip_to_end, tty? : Bool tty?, write(slice : Bytes) : Nil write, write_byte(byte : UInt8) write_byte, write_bytes(object, format : IO::ByteFormat = IO::ByteFormat::SystemEndian) write_bytes, write_utf8(slice : Bytes) write_utf8

Class methods inherited from module IO

copy(src, dst, limit : Int)
copy(src, dst)
copy
, pipe(read_blocking = false, write_blocking = false)
pipe(read_blocking = false, write_blocking = false, &block)
pipe

Instance methods inherited from class Reference

==(other : self)
==(other)
==
, dup dup, hash(hasher) hash, inspect(io : IO) : Nil inspect, object_id : UInt64 object_id, pretty_print(pp) : Nil pretty_print, same?(other : Reference)
same?(other : Nil)
same?
, to_s(io : IO) : Nil to_s

Constructor methods inherited from class Reference

new new

Instance methods inherited from class Object

!=(other) !=, !~(other) !~, ==(other) ==, ===(other : JSON::Any)
===(other : YAML::Any)
===(other)
===
, =~(other) =~, class class, dup dup, hash(hasher)
hash
hash
, inspect(io : IO)
inspect
inspect
, itself itself, not_nil! not_nil!, pretty_inspect(width = 79, newline = "\n", indent = 0) : String pretty_inspect, pretty_print(pp : PrettyPrint) : Nil pretty_print, tap(&block) tap, to_json(io : IO)
to_json
to_json
, to_pretty_json(indent : String = " ")
to_pretty_json(io : IO, indent : String = " ")
to_pretty_json
, to_s
to_s(io : IO)
to_s
, to_yaml(io : IO)
to_yaml
to_yaml
, try(&block) try, unsafe_as(type : T.class) forall T unsafe_as

Constructor methods inherited from class Object

from_json(string_or_io, root : String) : self
from_json(string_or_io) : self
from_json
, from_yaml(string_or_io) : self from_yaml

Constructor Detail

def self.new(io : IO, level = Gzip::DEFAULT_COMPRESSION, sync_close = false) #

Creates a new writer to the given io.


[View source]
def self.new(filename : String, level = Gzip::DEFAULT_COMPRESSION) #

Creates a new writer to the given filename.


[View source]

Class Method Detail

def self.open(io : IO, level = Gzip::DEFAULT_COMPRESSION, sync_close = false, &block) #

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


[View source]
def self.open(filename : String, level = Gzip::DEFAULT_COMPRESSION, &block) #

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


[View source]

Instance Method Detail

def close #

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


[View source]
def closed? : Bool #

Returns true if this writer is closed.


[View source]
def flush #

Flushes data, forcing writing the gzip header if no data has been written yet.

See IO#flush.


[View source]
def header : Gzip::Header #

The header to write to the gzip stream. It will be written just before the first write to this writer. Changes to the header after the first write are ignored.


[View source]
def read(slice : Bytes) #

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


[View source]
def sync_close=(sync_close) #

Whether to close the enclosed IO when closing this writer.


[View source]
def sync_close? : Bool #

Whether to close the enclosed IO when closing this writer.


[View source]
def write(slice : Bytes) : Nil #

[View source]