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Compress::Raw::Bzip2.3
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.\" -*- mode: troff; coding: utf-8 -*- .\" Automatically generated by Pod::Man 5.01 (Pod::Simple 3.43) .\" .\" Standard preamble: .\" ======================================================================== .de Sp \" Vertical space (when we can't use .PP) .if t .sp .5v .if n .sp .. .de Vb \" Begin verbatim text .ft CW .nf .ne \\$1 .. .de Ve \" End verbatim text .ft R .fi .. .\" \*(C` and \*(C' are quotes in nroff, nothing in troff, for use with C<>. .ie n \{\ . ds C` "" . ds C' "" 'br\} .el\{\ . ds C` . ds C' 'br\} .\" .\" Escape single quotes in literal strings from groff's Unicode transform. .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" .\" If the F register is >0, we'll generate index entries on stderr for .\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index .\" entries marked with X<> in POD. Of course, you'll have to process the .\" output yourself in some meaningful fashion. .\" .\" Avoid warning from groff about undefined register 'F'. .de IX .. .nr rF 0 .if \n(.g .if rF .nr rF 1 .if (\n(rF:(\n(.g==0)) \{\ . if \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} . \} .\} .rr rF .\" ======================================================================== .\" .IX Title "Compress::Raw::Bzip2 3" .TH Compress::Raw::Bzip2 3 2023-06-02 "perl v5.38.0" "Perl Programmers Reference Guide" .\" For nroff, turn off justification. Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH NAME Compress::Raw::Bzip2 \- Low\-Level Interface to bzip2 compression library .SH SYNOPSIS .IX Header "SYNOPSIS" .Vb 1 \& use Compress::Raw::Bzip2 ; \& \& my ($bz, $status) = new Compress::Raw::Bzip2 [OPTS] \& or die "Cannot create bzip2 object: $bzerno\en"; \& \& $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\en"; \& \& $status = $bz\->bzinflate($input, $output); \& \& my $version = Compress::Raw::Bzip2::bzlibversion(); .Ve .SH DESCRIPTION .IX Header "DESCRIPTION" \&\f(CW\*(C`Compress::Raw::Bzip2\*(C'\fR provides an interface to the in-memory compression/uncompression functions from the bzip2 compression library. .PP Although the primary purpose for the existence of \f(CW\*(C`Compress::Raw::Bzip2\*(C'\fR is for use by the \f(CW\*(C`IO::Compress::Bzip2\*(C'\fR and \f(CW\*(C`IO::Compress::Bunzip2\*(C'\fR modules, it can be used on its own for simple compression/uncompression tasks. .SH Compression .IX Header "Compression" .ie n .SS "($z, $status) = new Compress::Raw::Bzip2 $appendOutput, $blockSize100k, $workfactor;" .el .SS "($z, \f(CW$status\fP) = new Compress::Raw::Bzip2 \f(CW$appendOutput\fP, \f(CW$blockSize100k\fP, \f(CW$workfactor\fP;" .IX Subsection "($z, $status) = new Compress::Raw::Bzip2 $appendOutput, $blockSize100k, $workfactor;" Creates a new compression object. .PP If successful, it will return the initialised compression object, \f(CW$z\fR and a \f(CW$status\fR of \f(CW\*(C`BZ_OK\*(C'\fR in a list context. In scalar context it returns the deflation object, \f(CW$z\fR, only. .PP If not successful, the returned compression object, \f(CW$z\fR, will be \&\fIundef\fR and \f(CW$status\fR will hold the a \fIbzip2\fR error code. .PP Below is a list of the valid options: .ie n .IP \fR\fB$appendOutput\fR\fB\fR 5 .el .IP \fR\f(CB$appendOutput\fR\fB\fR 5 .IX Item "$appendOutput" Controls whether the compressed data is appended to the output buffer in the \f(CW\*(C`bzdeflate\*(C'\fR, \f(CW\*(C`bzflush\*(C'\fR and \f(CW\*(C`bzclose\*(C'\fR methods. .Sp Defaults to 1. .ie n .IP \fR\fB$blockSize100k\fR\fB\fR 5 .el .IP \fR\f(CB$blockSize100k\fR\fB\fR 5 .IX Item "$blockSize100k" To quote the bzip2 documentation .Sp .Vb 4 \& 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. .Ve .Sp Defaults to 1. .ie n .IP \fR\fB$workfactor\fR\fB\fR 5 .el .IP \fR\f(CB$workfactor\fR\fB\fR 5 .IX Item "$workfactor" To quote the bzip2 documentation .Sp .Vb 7 \& This parameter controls how the compression phase behaves when \& presented with worst case, highly repetitive, input data. If \& compression runs into difficulties caused by repetitive data, the \& library switches from the standard sorting algorithm to a fallback \& algorithm. The fallback is slower than the standard algorithm by \& perhaps a factor of three, but always behaves reasonably, no matter how \& bad the input. \& \& Lower values of workFactor reduce the amount of effort the standard \& algorithm will expend before resorting to the fallback. You should set \& this parameter carefully; too low, and many inputs will be handled by \& the fallback algorithm and so compress rather slowly, too high, and \& your average\-to\-worst case compression times can become very large. The \& default value of 30 gives reasonable behaviour over a wide range of \& circumstances. \& \& Allowable values range from 0 to 250 inclusive. 0 is a special case, \& equivalent to using the default value of 30. .Ve .Sp Defaults to 0. .ie n .SS "$status = $bz\->bzdeflate($input, $output);" .el .SS "\f(CW$status\fP = \f(CW$bz\fP\->bzdeflate($input, \f(CW$output\fP);" .IX Subsection "$status = $bz->bzdeflate($input, $output);" Reads the contents of \f(CW$input\fR, compresses it and writes the compressed data to \f(CW$output\fR. .PP Returns \f(CW\*(C`BZ_RUN_OK\*(C'\fR on success and a \f(CW\*(C`bzip2\*(C'\fR error code on failure. .PP If \f(CW\*(C`appendOutput\*(C'\fR is enabled in the constructor for the bzip2 object, the compressed data will be appended to \f(CW$output\fR. If not enabled, \f(CW$output\fR will be truncated before the compressed data is written to it. .ie n .SS "$status = $bz\->bzflush($output);" .el .SS "\f(CW$status\fP = \f(CW$bz\fP\->bzflush($output);" .IX Subsection "$status = $bz->bzflush($output);" Flushes any pending compressed data to \f(CW$output\fR. .PP Returns \f(CW\*(C`BZ_RUN_OK\*(C'\fR on success and a \f(CW\*(C`bzip2\*(C'\fR error code on failure. .ie n .SS "$status = $bz\->bzclose($output);" .el .SS "\f(CW$status\fP = \f(CW$bz\fP\->bzclose($output);" .IX Subsection "$status = $bz->bzclose($output);" Terminates the compressed data stream and flushes any pending compressed data to \f(CW$output\fR. .PP Returns \f(CW\*(C`BZ_STREAM_END\*(C'\fR on success and a \f(CW\*(C`bzip2\*(C'\fR error code on failure. .SS Example .IX Subsection "Example" .SH Uncompression .IX Header "Uncompression" .ie n .SS "($z, $status) = new Compress::Raw::Bunzip2 $appendOutput, $consumeInput, $small, $verbosity, $limitOutput;" .el .SS "($z, \f(CW$status\fP) = new Compress::Raw::Bunzip2 \f(CW$appendOutput\fP, \f(CW$consumeInput\fP, \f(CW$small\fP, \f(CW$verbosity\fP, \f(CW$limitOutput\fP;" .IX Subsection "($z, $status) = new Compress::Raw::Bunzip2 $appendOutput, $consumeInput, $small, $verbosity, $limitOutput;" If successful, it will return the initialised uncompression object, \f(CW$z\fR and a \f(CW$status\fR of \f(CW\*(C`BZ_OK\*(C'\fR in a list context. In scalar context it returns the deflation object, \f(CW$z\fR, only. .PP If not successful, the returned uncompression object, \f(CW$z\fR, will be \&\fIundef\fR and \f(CW$status\fR will hold the a \fIbzip2\fR error code. .PP Below is a list of the valid options: .ie n .IP \fR\fB$appendOutput\fR\fB\fR 5 .el .IP \fR\f(CB$appendOutput\fR\fB\fR 5 .IX Item "$appendOutput" Controls whether the compressed data is appended to the output buffer in the \&\f(CW\*(C`bzinflate\*(C'\fR, \f(CW\*(C`bzflush\*(C'\fR and \f(CW\*(C`bzclose\*(C'\fR methods. .Sp Defaults to 1. .ie n .IP \fR\fB$consumeInput\fR\fB\fR 5 .el .IP \fR\f(CB$consumeInput\fR\fB\fR 5 .IX Item "$consumeInput" .PD 0 .ie n .IP \fR\fB$small\fR\fB\fR 5 .el .IP \fR\f(CB$small\fR\fB\fR 5 .IX Item "$small" .PD To quote the bzip2 documentation .Sp .Vb 4 \& If small is nonzero, the library will use an alternative decompression \& algorithm which uses less memory but at the cost of decompressing more \& slowly (roughly speaking, half the speed, but the maximum memory \& requirement drops to around 2300k). .Ve .Sp Defaults to 0. .ie n .IP \fR\fB$limitOutput\fR\fB\fR 5 .el .IP \fR\f(CB$limitOutput\fR\fB\fR 5 .IX Item "$limitOutput" The \f(CW\*(C`LimitOutput\*(C'\fR option changes the behavior of the \f(CW\*(C`$i\->bzinflate\*(C'\fR method so that the amount of memory used by the output buffer can be limited. .Sp When \f(CW\*(C`LimitOutput\*(C'\fR is used the size of the output buffer used will either be the 16k or the amount of memory already allocated to \f(CW$output\fR, whichever is larger. Predicting the output size available is tricky, so don't rely on getting an exact output buffer size. .Sp When \f(CW\*(C`LimitOutout\*(C'\fR is not specified \f(CW\*(C`$i\->bzinflate\*(C'\fR will use as much memory as it takes to write all the uncompressed data it creates by uncompressing the input buffer. .Sp If \f(CW\*(C`LimitOutput\*(C'\fR is enabled, the \f(CW\*(C`ConsumeInput\*(C'\fR option will also be enabled. .Sp This option defaults to false. .ie n .IP \fR\fB$verbosity\fR\fB\fR 5 .el .IP \fR\f(CB$verbosity\fR\fB\fR 5 .IX Item "$verbosity" This parameter is ignored. .Sp Defaults to 0. .ie n .SS "$status = $z\->bzinflate($input, $output);" .el .SS "\f(CW$status\fP = \f(CW$z\fP\->bzinflate($input, \f(CW$output\fP);" .IX Subsection "$status = $z->bzinflate($input, $output);" Uncompresses \f(CW$input\fR and writes the uncompressed data to \f(CW$output\fR. .PP Returns \f(CW\*(C`BZ_OK\*(C'\fR if the uncompression was successful, but the end of the compressed data stream has not been reached. Returns \f(CW\*(C`BZ_STREAM_END\*(C'\fR on successful uncompression and the end of the compression stream has been reached. .PP If \f(CW\*(C`consumeInput\*(C'\fR is enabled in the constructor for the bunzip2 object, \&\f(CW$input\fR will have all compressed data removed from it after uncompression. On \f(CW\*(C`BZ_OK\*(C'\fR return this will mean that \f(CW$input\fR will be an empty string; when \f(CW\*(C`BZ_STREAM_END\*(C'\fR \f(CW$input\fR will either be an empty string or will contain whatever data immediately followed the compressed data stream. .PP If \f(CW\*(C`appendOutput\*(C'\fR is enabled in the constructor for the bunzip2 object, the uncompressed data will be appended to \f(CW$output\fR. If not enabled, \&\f(CW$output\fR will be truncated before the uncompressed data is written to it. .SH Misc .IX Header "Misc" .ie n .SS "my $version = \fBCompress::Raw::Bzip2::bzlibversion()\fP;" .el .SS "my \f(CW$version\fP = \fBCompress::Raw::Bzip2::bzlibversion()\fP;" .IX Subsection "my $version = Compress::Raw::Bzip2::bzlibversion();" Returns the version of the underlying bzip2 library. .SH Constants .IX Header "Constants" The following bzip2 constants are exported by this module .PP .Vb 3 \& 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 .Ve .SH SUPPORT .IX Header "SUPPORT" General feedback/questions/bug reports should be sent to <https://github.com/pmqs/Compress\-Raw\-Bzip2/issues> (preferred) or <https://rt.cpan.org/Public/Dist/Display.html?Name=Compress\-Raw\-Bzip2>. .SH "SEE ALSO" .IX Header "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::Lzip, IO::Uncompress::UnLzip, IO::Compress::Lzop, IO::Uncompress::UnLzop, IO::Compress::Lzf, IO::Uncompress::UnLzf, IO::Compress::Zstd, IO::Uncompress::UnZstd, IO::Uncompress::AnyInflate, IO::Uncompress::AnyUncompress .PP IO::Compress::FAQ .PP File::GlobMapper, Archive::Zip, Archive::Tar, IO::Zlib .PP The primary site for the bzip2 program is <https://sourceware.org/bzip2/>. .PP See the module Compress::Bzip2 .SH AUTHOR .IX Header "AUTHOR" This module was written by Paul Marquess, \f(CW\*(C`pmqs@cpan.org\*(C'\fR. .SH "MODIFICATION HISTORY" .IX Header "MODIFICATION HISTORY" See the Changes file. .SH "COPYRIGHT AND LICENSE" .IX Header "COPYRIGHT AND LICENSE" Copyright (c) 2005\-2023 Paul Marquess. All rights reserved. .PP This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.