Zlib::GzipReader - Ruby Core Documentation 1.8.7

Inheritance: < Zlib::GzipFile < Object
Included Modules: Enumerable

Zlib::GzipReader is the class for reading a gzipped file. GzipReader should be used an IO, or -IO-lie, object.

  Zlib::GzipReader.open('hoge.gz') {|gz|
    print gz.read
  }

  File.open('hoge.gz') do |f|
    gz = Zlib::GzipReader.new(f)
    print gz.read
    gz.close
  end

  # TODO: test these.  Are they equivalent?  Can GzipReader.new take a
  # block?

Method Catalogue

The following methods in Zlib::GzipReader are just like their counterparts in IO, but they raise Zlib::Error or Zlib::GzipFile::Error exception if an error was found in the gzip file.

Be careful of the footer of the gzip file. A gzip file has the checksum of pre-compressed data in its footer. GzipReader checks all uncompressed data against that checksum at the following cases, and if it fails, raises Zlib::GzipFile::NoFooter, Zlib::GzipFile::CRCError, or Zlib::GzipFile::LengthError exception.

When an reading request is received beyond the end of file (the end of compressed data). That is, when Zlib::GzipReader#read, Zlib::GzipReader#gets, or some other methods for reading returns nil.
When Zlib::GzipFile#close method is called after the object reaches the end of file.
When Zlib::GzipReader#unused method is called after the object reaches the end of file.

The rest of the methods are adequately described in their own documentation.

Methods

Class

Visibility	Signature
public	new (p1)
public	open (...)

Instance

Visibility	Signature
public	each (...)
public	each_byte ()
public	each_line (...)
public	eof ()
public	eof? ()
public	getc ()
public	gets (...)
public	lineno ()
public	lineno= (p1)
public	pos ()
public	read (...)
public	readchar ()
public	readline (...)
public	readlines (...)
public	rewind ()
public	tell ()
public	ungetc (p1)
public	unused ()

Class Method Detail

Zlib::GzipReader.new(io)

Creates a GzipReader object associated with io. The GzipReader object reads gzipped data from io, and parses/decompresses them. At least, io must have a read method that behaves same as the read method in IO class.

If the gzip file header is incorrect, raises an Zlib::GzipFile::Error exception.

Zlib::GzipReader.open(filename) {|gz| ... }

Opens a file specified by filename as a gzipped file, and returns a GzipReader object associated with that file. Further details of this method are in Zlib::GzipReader.new and ZLib::GzipReader.wrap.

Instance Method Detail

each(...)

See Zlib::GzipReader documentation for a description.

each_byte()

See Zlib::GzipReader documentation for a description.

each_line(...)

See Zlib::GzipReader documentation for a description.

eof()

???

eof?()

???

getc()

See Zlib::GzipReader documentation for a description.

gets(...)

See Zlib::GzipReader documentation for a description.

lineno()

???

lineno=(p1)

???

pos()

???

read(...)

See Zlib::GzipReader documentation for a description.

readchar()

See Zlib::GzipReader documentation for a description.

readline(...)

See Zlib::GzipReader documentation for a description.

readlines(...)

See Zlib::GzipReader documentation for a description.

rewind()

Resets the position of the file pointer to the point created the GzipReader object. The associated IO object needs to respond to the seek method.

tell()

???

ungetc(p1)

See Zlib::GzipReader documentation for a description.

unused()

Returns the rest of the data which had read for parsing gzip format, or nil if the whole gzip file is not parsed yet.