class Gzip::Reader

Overview

A read-only IO object to decompress data in the gzip format.

Instances of this class wrap another IO object. When you read from this instance instance, it reads data from the underlying IO, decompresses it, and returns it to the caller.

NOTE A gzip stream can contain zero or more members. If it contains no members, #header will be nil. If it contains one or more members, only the first header will be recorded here. This is because gzipping multiple members is not common as one usually combines gzip with tar. If, however, multiple members are present then reading from this reader will return the concatenation of all the members.

Example: decompress a gzip file

require "gzip"

File.write("file.gzip", Bytes[31, 139, 8, 0, 0, 0, 0, 0, 0, 3, 75, 76, 74, 6, 0, 194, 65, 36, 53, 3, 0, 0, 0])

string = File.open("file.gzip") do |file|
  Gzip::Reader.open(file) do |gzip|
    gzip.gets_to_end
  end
end
string # => "abc"

Included Modules

Defined in:

gzip/reader.cr

Constructors

Class Method Summary

Instance Method Summary

Instance methods inherited from module IO::Buffered

close : Nil close, flush flush, flush_on_newline=(flush_on_newline) flush_on_newline=, flush_on_newline? flush_on_newline?, peek : Bytes? peek, read(slice : Bytes) read, read_buffering=(read_buffering) read_buffering=, read_buffering? read_buffering?, rewind rewind, sync=(sync) sync=, sync? sync?, unbuffered_close unbuffered_close, unbuffered_flush unbuffered_flush, unbuffered_read(slice : Bytes) unbuffered_read, unbuffered_rewind unbuffered_rewind, unbuffered_write(slice : Bytes) unbuffered_write, write(slice : Bytes) write

Instance methods inherited from class IO

<<(obj) : self <<, close close, closed? closed?, each_byte(&block) : Nil
each_byte 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(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 : UNDERSCORE) : Nil
print(obj) : Nil print, printf(format_string, *args) : Nil
printf(format_string, args : Array | Tuple) : Nil printf, puts(*objects : UNDERSCORE) : Nil
puts : Nil
puts(obj) : Nil
puts(string : String) : Nil puts, read(slice : Bytes) read, read_at(offset, bytesize, &block) 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)
copy(src, dst) copy, pipe(read_blocking = false, write_blocking = false) : Tuple(IO::FileDescriptor, IO::FileDescriptor)
pipe(read_blocking = false, write_blocking = false, &block) pipe

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

!=(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 : String | IO) : self from_yaml

Constructor Detail

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

Creates a new reader from the given io.


[View source]
def self.new(filename : String) #

Creates a new reader from the given filename.


[View source]

Class Method Detail

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

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


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

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


[View source]

Instance Method Detail

def closed? : Bool #

Returns true if this reader is closed.


[View source]
def header : Header? #

Returns the first header in the gzip stream, if any.


[View source]
def sync_close=(sync_close) #

Whether to close the enclosed IO when closing this reader.


[View source]
def sync_close? : Bool #

Whether to close the enclosed IO when closing this reader.


[View source]
def unbuffered_close #

Closes this reader.


[View source]
def unbuffered_flush #

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

See IO#read.


[View source]
def unbuffered_rewind #

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

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


[View source]