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io::uncompress::base(3pm) [osx man page]

IO::Uncompress::Base(3pm)				 Perl Programmers Reference Guide				 IO::Uncompress::Base(3pm)

NAME
IO::Uncompress::Base - Base Class for IO::Uncompress modules SYNOPSIS
use IO::Uncompress::Base ; DESCRIPTION
This module is not intended for direct use in application code. Its sole purpose if to to be sub-classed by IO::Uncompress modules. SEE ALSO
Compress::Zlib, IO::Compress::Gzip, IO::Uncompress::Gunzip, IO::Compress::Deflate, IO::Uncompress::Inflate, IO::Compress::RawDeflate, IO::Uncompress::RawInflate, IO::Compress::Bzip2, IO::Uncompress::Bunzip2, IO::Compress::Lzma, IO::Uncompress::UnLzma, IO::Compress::Xz, IO::Uncompress::UnXz, IO::Compress::Lzop, IO::Uncompress::UnLzop, IO::Compress::Lzf, IO::Uncompress::UnLzf, IO::Uncompress::AnyInflate, IO::Uncompress::AnyUncompress IO::Compress::FAQ File::GlobMapper, Archive::Zip, Archive::Tar, IO::Zlib AUTHOR
This module was written by Paul Marquess, pmqs@cpan.org. MODIFICATION HISTORY
See the Changes file. COPYRIGHT AND LICENSE
Copyright (c) 2005-2012 Paul Marquess. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. perl v5.16.2 2012-10-25 IO::Uncompress::Base(3pm)

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Compress::Raw::Bzip2(3pm)				User Contributed Perl Documentation				 Compress::Raw::Bzip2(3pm)

NAME
Compress::Raw::Bzip2 - Low-Level Interface to bzip2 compression library SYNOPSIS
use Compress::Raw::Bzip2 ; my ($bz, $status) = new Compress::Raw::Bzip2 [OPTS] or die "Cannot create bzip2 object: $bzerno "; $status = $bz->bzdeflate($input, $output); $status = $bz->bzflush($output); $status = $bz->bzclose($output); my ($bz, $status) = new Compress::Raw::Bunzip2 [OPTS] or die "Cannot create bunzip2 object: $bzerno "; $status = $bz->bzinflate($input, $output); my $version = Compress::Raw::Bzip2::bzlibversion(); DESCRIPTION
"Compress::Raw::Bzip2" provides an interface to the in-memory compression/uncompression functions from the bzip2 compression library. Although the primary purpose for the existence of "Compress::Raw::Bzip2" is for use by the "IO::Compress::Bzip2" and "IO::Compress::Bunzip2" modules, it can be used on its own for simple compression/uncompression tasks. Compression ($z, $status) = new Compress::Raw::Bzip2 $appendOutput, $blockSize100k, $workfactor; Creates a new compression object. If successful, it will return the initialised compression object, $z and a $status of "BZ_OK" in a list context. In scalar context it returns the deflation object, $z, only. If not successful, the returned compression object, $z, will be undef and $status will hold the a bzip2 error code. Below is a list of the valid options: $appendOutput Controls whether the compressed data is appended to the output buffer in the "bzdeflate", "bzflush" and "bzclose" methods. Defaults to 1. $blockSize100k To quote the bzip2 documentation blockSize100k specifies the block size to be used for compression. It should be a value between 1 and 9 inclusive, and the actual block size used is 100000 x this figure. 9 gives the best compression but takes most memory. Defaults to 1. $workfactor To quote the bzip2 documentation This parameter controls how the compression phase behaves when presented with worst case, highly repetitive, input data. If compression runs into difficulties caused by repetitive data, the library switches from the standard sorting algorithm to a fallback algorithm. The fallback is slower than the standard algorithm by perhaps a factor of three, but always behaves reasonably, no matter how bad the input. Lower values of workFactor reduce the amount of effort the standard algorithm will expend before resorting to the fallback. You should set this parameter carefully; too low, and many inputs will be handled by the fallback algorithm and so compress rather slowly, too high, and your average-to-worst case compression times can become very large. The default value of 30 gives reasonable behaviour over a wide range of circumstances. Allowable values range from 0 to 250 inclusive. 0 is a special case, equivalent to using the default value of 30. Defaults to 0. $status = $bz->bzdeflate($input, $output); Reads the contents of $input, compresses it and writes the compressed data to $output. Returns "BZ_RUN_OK" on success and a "bzip2" error code on failure. If "appendOutput" is enabled in the constructor for the bzip2 object, the compressed data will be appended to $output. If not enabled, $output will be truncated before the compressed data is written to it. $status = $bz->bzflush($output); Flushes any pending compressed data to $output. Returns "BZ_RUN_OK" on success and a "bzip2" error code on failure. $status = $bz->bzclose($output); Terminates the compressed data stream and flushes any pending compressed data to $output. Returns "BZ_STREAM_END" on success and a "bzip2" error code on failure. Example Uncompression ($z, $status) = new Compress::Raw::Bunzip2 $appendOutput, $consumeInput, $small, $verbosity, $limitOutput; If successful, it will return the initialised uncompression object, $z and a $status of "BZ_OK" in a list context. In scalar context it returns the deflation object, $z, only. If not successful, the returned uncompression object, $z, will be undef and $status will hold the a bzip2 error code. Below is a list of the valid options: $appendOutput Controls whether the compressed data is appended to the output buffer in the "bzinflate", "bzflush" and "bzclose" methods. Defaults to 1. $consumeInput $small To quote the bzip2 documentation If small is nonzero, the library will use an alternative decompression algorithm which uses less memory but at the cost of decompressing more slowly (roughly speaking, half the speed, but the maximum memory requirement drops to around 2300k). Defaults to 0. $limitOutput The "LimitOutput" option changes the behavior of the "$i->bzinflate" method so that the amount of memory used by the output buffer can be limited. When "LimitOutput" is used the size of the output buffer used will either be the 16k or the amount of memory already allocated to $output, whichever is larger. Predicting the output size available is tricky, so don't rely on getting an exact output buffer size. When "LimitOutout" is not specified "$i->bzinflate" will use as much memory as it takes to write all the uncompressed data it creates by uncompressing the input buffer. If "LimitOutput" is enabled, the "ConsumeInput" option will also be enabled. This option defaults to false. $verbosity This parameter is ignored. Defaults to 0. $status = $z->bzinflate($input, $output); Uncompresses $input and writes the uncompressed data to $output. Returns "BZ_OK" if the uncompression was successful, but the end of the compressed data stream has not been reached. Returns "BZ_STREAM_END" on successful uncompression and the end of the compression stream has been reached. If "consumeInput" is enabled in the constructor for the bunzip2 object, $input will have all compressed data removed from it after uncompression. On "BZ_OK" return this will mean that $input will be an empty string; when "BZ_STREAM_END" $input will either be an empty string or will contain whatever data immediately followed the compressed data stream. If "appendOutput" is enabled in the constructor for the bunzip2 object, the uncompressed data will be appended to $output. If not enabled, $output will be truncated before the uncompressed data is written to it. Misc my $version = Compress::Raw::Bzip2::bzlibversion(); Returns the version of the underlying bzip2 library. Constants The following bzip2 constants are exported by this module BZ_RUN BZ_FLUSH BZ_FINISH BZ_OK BZ_RUN_OK BZ_FLUSH_OK BZ_FINISH_OK BZ_STREAM_END BZ_SEQUENCE_ERROR BZ_PARAM_ERROR BZ_MEM_ERROR BZ_DATA_ERROR BZ_DATA_ERROR_MAGIC BZ_IO_ERROR BZ_UNEXPECTED_EOF BZ_OUTBUFF_FULL BZ_CONFIG_ERROR SEE ALSO
Compress::Zlib, IO::Compress::Gzip, IO::Uncompress::Gunzip, IO::Compress::Deflate, IO::Uncompress::Inflate, IO::Compress::RawDeflate, IO::Uncompress::RawInflate, IO::Compress::Bzip2, IO::Uncompress::Bunzip2, IO::Compress::Lzma, IO::Uncompress::UnLzma, IO::Compress::Xz, IO::Uncompress::UnXz, IO::Compress::Lzop, IO::Uncompress::UnLzop, IO::Compress::Lzf, IO::Uncompress::UnLzf, IO::Uncompress::AnyInflate, IO::Uncompress::AnyUncompress IO::Compress::FAQ File::GlobMapper, Archive::Zip, Archive::Tar, IO::Zlib The primary site for the bzip2 program is http://www.bzip.org. See the module Compress::Bzip2 AUTHOR
This module was written by Paul Marquess, pmqs@cpan.org. MODIFICATION HISTORY
See the Changes file. COPYRIGHT AND LICENSE
Copyright (c) 2005-2012 Paul Marquess. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. perl v5.14.2 2012-04-29 Compress::Raw::Bzip2(3pm)
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