IO/Compress/Gzip.pm

100             # Modification time defaults to now.
327 data to files or buffer as defined in RFC 1952.
337 A top-level function, C<gzip>, is provided to carry out
357 The parameter, C<$input_filename_or_reference>, is used to define the
367 assumed to be a filename. This file will be opened for reading and the
388 The complete array will be walked to ensure that it only
409 If you do not want to use these defaults they can be overridden by
415 The parameter C<$output_filename_or_reference> is used to control the
424 assumed to be a filename.  This file will be opened for writing and the
425 compressed data will be written to it.
430 compressed data will be written to it.  The string '-' can be used as
463 When C<$input_filename_or_reference> maps to multiple files/buffers and
471 are (for the most part) identical to those used with the OO interface defined in the
478 This option applies to any input or output data streams to
485 This parameter defaults to 0.
500 If C<Append> is enabled, all compressed data will be append to the end of
502 compressed data is written to it.
508 data is written to it.
512 If C<Append> is enabled, the filehandle will be positioned to the end of
513 the file via a call to C<seek> before any compressed data is
514 written to it.  Otherwise the file pointer will not be moved.
518 When C<Append> is specified, and set to true, it will I<append> all compressed
519 data to the output data stream.
521 So when the output is a filehandle it will carry out a seek to the eof
524 appended to the existing buffer.
526 Conversely when C<Append> is not specified, or it is present and is set to
534 Defaults to 0.
545 The code reads data from STDIN, compresses it, and writes the compressed data to STDOUT.
557 data to the file C<file1.txt.gz>.
567 =head3 Reading from a Filehandle and writing to an in-memory buffer
570 compressed data to a buffer, C<$buffer>.
595 and if you want to compress each file one at a time, this will do the trick
624 For example, to write to a compressed file/buffer you can use either of
630 The mandatory parameter C<$output> is used to control the destination
637 If the C<$output> parameter is a simple scalar, it is assumed to be a
639 will be written to it.
644 written to it.
670 This parameter defaults to 0.
683 will be append to the end of C<$output>. Otherwise C<$output> will be
684 cleared before any data is written to it.
690 truncated before any compressed data is written to it.
694 If C<$output> is a filehandle, the file pointer will be positioned to the
695 end of the file via a call to C<seek> before any compressed data is written
696 to it.  Otherwise the file pointer will not be moved.
700 This parameter defaults to 0.
704 This option is used to compress input data and append it to an existing
708 It is a fatal error to attempt to use this option when C<$output> is not an
717 This module needs to have been built with zlib 1.2.1 or better to work. A
727 This parameter defaults to 0.
750 Defines the strategy used to tune the compression. Use one of the symbolic
771 be ignored if this parameter is set to 1.
773 This parameter defaults to 0.
779 By default, no comment field is written to the gzip file.
802 Sets the MTIME field in the gzip header to $number.
804 This field defaults to the time the C<IO::Compress::Gzip> object was created
810 header. It is used to signal that the data stored in the gzip file/buffer
817 When true this parameter will set the FLG.FHCRC bit to 1 in the gzip header
818 and set the CRC16 header field to the CRC of the complete gzip header
821 B<Note> that gzip files created with the C<HeaderCRC> flag set to 1 cannot
824 you want to maximize the portability of your gzip files.
826 This parameter defaults to 0.
833 If not specified, this parameter defaults to the OS code of the Operating
839 This parameter allows additional metadata to be stored in the ExtraField in
879 Sets the XFL byte in the gzip header to C<$value>.
884 If C<< Level => Z_BEST_SPEED >> has been specified then XFL is set to 2.
885 If C<< Level => Z_BEST_COMPRESSION >> has been specified then XFL is set to 4.
886 Otherwise XFL is set to 0.
891 to ensure they are compliant with RFC1952.
917 it must conform to the sub-field structure as defined in RFC 1952.
922 checked in each subfield to ensure that it does not contain the reserved
944 multiple embedded nulls. The string written to the gzip header will
945 consist of the characters up to, but not including, the first embedded
1023 Flushes any pending compressed data to the output file/buffer.
1060 that it is only legal to seek forward in the output file/buffer.
1061 It is a fatal error to attempt to seek backward.
1063 Empty parts of the file/buffer will have NULL (0x00) bytes written to them.
1083 Returns true if the object currently refers to a opened file/buffer.
1098 B<Note> that the special variable C<$|> B<cannot> be used to set or
1129 variable with the reference to the object going out of scope). The
1135 Therefore, if you want your scripts to be able to run on all versions
1230 General feedback/questions/bug reports should be sent to