===================================== Package "Bit::Vector" Version 5.3 ===================================== This package is available for download either from my web site at http://sb.fluomedia.org/download/ or from any CPAN (= "Comprehensive Perl Archive Network") mirror server: http://www.perl.com/CPAN/authors/id/STBEY/ The package consists of a C library (designed for maximum efficiency) which is the core of a Perl module (designed for maximum ease of use). The C library is specifically designed so that it can be used stand-alone, without Perl. Legal issues: ------------- This package with all its parts is Copyright (c) 1995, 1996, 1997, 1998 by Steffen Beyer. All rights reserved. This package is free software; you can redistribute it and/or modify it under the same terms as Perl itself, i.e., under the terms of the "Artistic License" or the "GNU General Public License". The C library at the core of this Perl module can additionally be redistributed and/or modified under the terms of the "GNU Library General Public License". Please refer to the files "Artistic.txt", "GNU_GPL.txt" and "GNU_LGPL.txt" in this distribution for details! Prerequisites: -------------- Perl version 5.000 or higher, and an ANSI C compiler (!) ^^^^^^ Installation: ------------- Please see the file "INSTALL.txt" in this distribution for instructions on how to install this package. Changes over previous versions: ------------------------------- Please refer to the file "CHANGES.txt" in this distribution for a detailed version history and instructions on how to upgrade existing applications. Documentation: -------------- The documentation to this package is included in POD format (= "Plain Old Documentation") in the file "Vector.pm" in this distribution, the human- readable markup-language standard for Perl documentation. By building this package, this documentation will automatically be converted into a man page, which will automatically be installed in your Perl tree for further reference in this process, where it can be accessed via the command "man Bit::Vector" (UNIX) or "perldoc Bit::Vector" (UNIX and Win32). If Perl is not available on your system, you can also read this documentation directly. What does it do: ---------------- This module is useful for a large range of different tasks: - For example for implementing sets and performing set operations (like union, difference, intersection, complement, check for subset relationship etc.), - as a basis for many efficient algorithms, for instance the "Sieve of Erathostenes" (for calculating prime numbers), (The complexities of the methods in this module are usually either O(1) or O(n/b), where "b" is the number of bits in a machine word on your system.) - for shift registers of arbitrary length (for example for cyclic redundancy checksums), - to calculate "look-ahead", "first" and "follow" character sets for parsers and compiler-compilers, - for graph algorithms, - for efficient storage and retrieval of status information, - for performing text synthesis ruled by boolean expressions, - for "big integer" arithmetic with arbitrarily large integers, - for manipulations of chunks of bits of arbitrary size, - for bitwise processing of audio CD wave files, - to convert formats of data files, and more. (A number of example applications is available from my web site at http://sb.fluomedia.org/download/.) A large number of import/export methods allow you to access individual bits, contiguous ranges of bits, machine words, arbitrary chunks of bits, lists (arrays) of chunks of bits or machine words and a whole bit vector at once (for instance for blockwrite/-read to and from a file). You can also import and export the contents of a bit vector in binary, hexadecimal and decimal representation as well as ".newsrc" style enumerations. Note that this module is specifically designed for efficiency, which is also the reason why its methods are implemented in C. To further increase execution speed, the module doesn't use bytes as its basic storage unit, but rather uses machine words, assuming that a machine word is the most efficiently handled size of all scalar types on all machines (that's what the ANSI C standard proposes and assumes anyway). In order to achieve this, it automatically determines the number of bits in a machine word on your system and then adjusts its internal configuration constants accordingly. The greater the size of this basic storage unit, the better the complexity (= execution speed) of the methods in this module, but also the greater the average waste of unused bits in the last word. The range of available methods is exceptionally large for this kind of library; in detail: Version() Word_Bits() Long_Bits() new() new_Hex() new_Bin() new_Dec() new_Enum() Shadow() Clone() Concat() Concat_List() Size() Resize() Copy() Empty() Fill() Flip() Primes() Reverse() Interval_Empty() Interval_Fill() Interval_Flip() Interval_Reverse() Interval_Scan_inc() Interval_Scan_dec() Interval_Copy() Interval_Substitute() is_empty() is_full() equal() Lexicompare() Compare() to_Hex() from_Hex() to_Bin() from_Bin() to_Dec() from_Dec() to_Enum() from_Enum() Bit_Off() Bit_On() bit_flip() bit_test() Bit_Copy() LSB() MSB() lsb() msb() rotate_left() rotate_right() shift_left() shift_right() Move_Left() Move_Right() Insert() Delete() increment() decrement() add() subtract() Negate() Absolute() Sign() Multiply() Divide() GCD() Block_Store() Block_Read() Word_Size() Word_Store() Word_Read() Word_List_Store() Word_List_Read() Word_Insert() Word_Delete() Chunk_Store() Chunk_Read() Chunk_List_Store() Chunk_List_Read() Index_List_Remove() Index_List_Store() Index_List_Read() Union() Intersection() Difference() ExclusiveOr() Complement() subset() Norm() Min() Max() Multiplication() Closure() Transpose() Important note: --------------- Note again that the C library at the core of this module ("BitVector.c") can also be used stand-alone (i.e., without Perl). To do so, simply link the output file "BitVector.o" (which is produced when you build this module or when you just compile "BitVector.c") with your application. Example applications: --------------------- See the module "Set::IntRange" for an easy-to-use module for sets of integers of arbitrary ranges. See the module "Math::MatrixBool" for an efficient implementation of boolean matrices and boolean matrix operations. (Both modules are also available from my web site or any CPAN server.) An application relying crucially on this "Bit::Vector" module is "Slice", a tool for generating different document versions out of a single master file, ruled by boolean expressions ("include english version of text plus examples but not ..."). (See also http://www.engelschall.com/sw/slice/.) This tool is itself part of another tool, "Website META Language" ("WML"), which allows you to generate and maintain large web sites. Among many other features, it allows you to define your own HTML tags which will be expanded either at generation or at run time, depending on your choice. (See also http://www.engelschall.com/sw/wml/.) Both tools are written by Ralf S. Engelschall. Credits: -------- Please refer to the file "CREDITS.txt" in this distribution for a list of contributors. Author's note: -------------- If you have any questions, suggestions or need any assistance, please let me know! I would in fact be glad to receive any kind of feedback from you! I hope you will find this module beneficial. Yours, -- Steffen Beyer http://sb.fluomedia.org/ "There is enough for the need of everyone in this world, but not for the greed of everyone." - Mahatma Gandhi