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class Compress::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 "compress/gzip"

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

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

Defined in:

compress/gzip/writer.cr

Constructors

Class Method Summary

Instance Method Summary

Instance methods inherited from class IO

<self <<, close close, closed? closed?, each_byte(&) : Nil
each_byte each_byte
, each_char(&) : Nil
each_char each_char
, each_line(*args, **options, &block : String -> ) : Nil
each_line(*args, **options) each_line
, encoding : String encoding, flush flush, gets(delimiter : Char, limit : Int, chomp = false) : String?
gets(delimiter : Char, chomp = false) : String?
gets(chomp = true) : String?
gets(limit : Int, chomp = false) : String?
gets(delimiter : String, chomp = false) : String? gets
, gets_to_end : String gets_to_end, peek : Bytes? peek, pos pos, pos=(value) pos=, print(*objects : _) : Nil
print(obj) : Nil print
, printf(format_string, *args) : Nil
printf(format_string, args : Array | Tuple) : Nil printf
, puts(*objects : _) : Nil
puts : Nil
puts(obj) : Nil
puts(string : String) : Nil puts
, read(slice : Bytes) read, read_at(offset, bytesize, &) read_at, 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, seek(offset, whence : Seek = Seek::Set) seek, set_encoding(encoding : String, invalid : Symbol? = nil) set_encoding, skip(bytes_count : Int) : Nil skip, skip_to_end : Nil skip_to_end, tell tell, 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 class IO

copy(src, dst, limit : Int) : Int64
copy(src, dst) : Int64 copy
, pipe(read_blocking = false, write_blocking = false) : Tuple(IO::FileDescriptor, IO::FileDescriptor)
pipe(read_blocking = false, write_blocking = false, &) pipe
, same_content?(stream1 : IO, stream2 : IO) same_content?

Instance methods inherited from class Reference

==(other : self)
==(other : JSON::Any)
==(other : YAML::Any)
==(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

! : Bool !, !=(other) !=, !~(other) !~, ==(other) ==, ===(other : JSON::Any)
===(other : YAML::Any)
===(other) ===
, =~(other) =~, as(type : Class) as, as?(type : Class) as?, class class, dup dup, hash(hasher)
hash hash
, in?(*values : Object) : Bool
in?(collection) : Bool in?
, inspect : String
inspect(io : IO) : Nil inspect
, is_a?(type : Class) : Bool is_a?, itself itself, nil? : Bool nil?, not_nil! not_nil!, pretty_inspect(width = 79, newline = "\n", indent = 0) : String pretty_inspect, pretty_print(pp : PrettyPrint) : Nil pretty_print, responds_to?(name : Symbol) : Bool responds_to?, tap(&) tap, to_json(io : IO)
to_json to_json
, to_pretty_json(io : IO, indent : String = " ")
to_pretty_json(indent : String = " ") to_pretty_json
, to_s : String
to_s(io : IO) : Nil to_s
, to_yaml(io : IO)
to_yaml to_yaml
, try(&) try, unsafe_as(type : T.class) forall T unsafe_as

Class methods inherited from class Object

from_json(string_or_io, root : String)
from_json(string_or_io) from_json
, from_yaml(string_or_io : String | IO) from_yaml

Constructor Detail

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

Creates a new writer to the given io.

def self.new(filename : String, level = Compress::Gzip::DEFAULT_COMPRESSION)Source

Creates a new writer to the given filename.

Class Method Detail

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

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

def self.open(filename : String, level = Compress::Gzip::DEFAULT_COMPRESSION, &)Source

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

Instance Method Detail

def closeSource

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

def closed? : BoolSource

Returns true if this writer is closed.

def flushSource

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

See IO#flush.

def header : Compress::Gzip::HeaderSource

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.

def read(slice : Bytes)Source

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

def sync_close=(sync_close)Source

Whether to close the enclosed IO when closing this writer.

def sync_close? : BoolSource

Whether to close the enclosed IO when closing this writer.

def write(slice : Bytes) : NilSource

See IO#write.

© 2012–2020 Manas Technology Solutions.
Licensed under the Apache License, Version 2.0.
https://crystal-lang.org/api/0.35.1/Compress/Gzip/Writer.html