=begin # # zlib.rd.src # # Copyright (C) UENO Katsuhiro 2000-2003 # # $Id$ # = Ruby/zlib version 0.6.0 Ruby/zlib is an extension library to use zlib from Ruby. Ruby/zlib also provides the features for accessing gzipped files. You can modify or redistribute Ruby/zlib in the same manner of Ruby interpreter. The latest version of Ruby/zlib would be found at (()). Any comments and suggestions are always welcome. Please send them to ruby-list ML, ruby-ext ML, ruby-talk ML, or the author's mail address (()). This document is experimental and broken English version. If you find some mistakes or strange expressions (including kidding or unnatural ones) in this document, please let me know for my study. * (()) * (()) * (()) * (()) * (()) * (()) * (()) * (()) * (()) * (()) * (()) == Zlib Zlib is the module which provides the other features in zlib C library. See zlib.h for detail of each module function. === Module Functions: --- Zlib.zlib_version Returns the string which represents the version of zlib library. --- Zlib.adler32([string[, adler]]) Calculates Alder-32 checksum for ((|string|)), and returns updated value of ((|alder|)). If ((|string|)) is omitted, it returns the Adler-32 initial value. If ((|alder|)) is omitted, it assumes that the initial value is given to ((|alder|)). --- Zlib.crc32([string[, crc]]) Calculates CRC checksum for ((|string|)), and returns updated value of ((|crc|)). If ((|string|)) is omitted, it returns the CRC initial value. ((|crc|)) is omitted, it assumes that the initial value is given to ((|crc|)). --- Zlib.crc_table Returns the table for calculating CRC checksum as an array. === Constants: --- Zlib::VERSION The Ruby/zlib version string. --- Zlib::ZLIB_VERSION The string which represents the version of zlib.h. --- Zlib::BINARY --- Zlib::ASCII --- Zlib::UNKNOWN The integers representing data types which (()) method returns. --- Zlib::NO_COMPRESSION --- Zlib::BEST_SPEED --- Zlib::BEST_COMPRESSION --- Zlib::DEFAULT_COMPRESSION The integers representing compression levels which are an argument for (()), (()), and so on. --- Zlib::FILTERED --- Zlib::HUFFMAN_ONLY --- Zlib::DEFAULT_STRATEGY The integers representing compression methods which are an argument for (()) and (()). --- Zlib::DEF_MEM_LEVEL --- Zlib::MAX_MEM_LEVEL The integers representing memory levels which are an argument for (()), (()), and so on. --- Zlib::MAX_WBITS The default value of ((|windowBits|)) which is an argument for (()) and (()). --- Zlib::NO_FLUSH --- Zlib::SYNC_FLUSH --- Zlib::FULL_FLUSH --- Zlib::FINISH The integers to control the output of the deflate stream, which are an argument for (()) and so on. --- Zlib::OS_CODE --- Zlib::OS_MSDOS --- Zlib::OS_AMIGA --- Zlib::OS_VMS --- Zlib::OS_UNIX --- Zlib::OS_VMCMS --- Zlib::OS_ATARI --- Zlib::OS_OS2 --- Zlib::OS_MACOS --- Zlib::OS_ZSYSTEM --- Zlib::OS_CPM --- Zlib::OS_TOPS20 --- Zlib::OS_WIN32 --- Zlib::OS_QDOS --- Zlib::OS_RISCOS --- Zlib::OS_UNKNOWN The return values of (()) method. == Zlib::Error The superclass for all exceptions raised by Ruby/zlib. The following exceptions are defined as subclasses of Zlib::Error. These exceptions are raised when zlib library functions return with an error status. * Zlib::StreamEnd * Zlib::NeedDict * Zlib::DataError * Zlib::StreamError * Zlib::MemError * Zlib::BufError * Zlib::VersionError === SuperClass: * StandardError == Zlib::ZStream The abstract class for the stream which handles the compressed data. The operations are defined in the subclasses, (()) for compression, and (()) for decompression. An instance of Zlib::ZStream has one stream (struct zstream) and two variable-length buffers which associated to the input (next_in) of the stream and the output (next_out) of the stream. In this document, "input buffer" means the buffer for input, and "output buffer" means the buffer for output. Data inputed into an instance of Zlib::ZStream are temporally stored into the end of input buffer, and then data in input buffer are processed from the beginning of the buffer until no more output from the stream is produced (i.e. until avail_out > 0 after processing). During processing, output buffer is allocated and expanded automatically to hold all output data. Some particular instance methods consume the data in output buffer and return them as a String. Here is an ascii art for describing above: +================ an instance of Zlib::ZStream ================+ || || || +--------+ +-------+ +--------+ || || +--| output |<---------|zstream|<---------| input |<--+ || || | | buffer | next_out+-------+next_in | buffer | | || || | +--------+ +--------+ | || || | | || +===|======================================================|===+ | | v | "output data" "input data" If an error is occurred during processing input buffer, an exception which is a subclass of (()) is raised. At that time, both input and output buffer keeps their conditions at the time when the error is occurred. === SuperClass: * Object === Class Methods: --- Zlib::ZStream.new See (()) and (()). === Methods: --- Zlib::ZStream#avail_in Returns bytes of data in input buffer. Normally, returns 0. --- Zlib::ZStream#avail_out Returns bytes of free spaces in output buffer. Because the free spaces are allocated automatically, this method returns 0 normally. --- Zlib::ZStream#avail_out = size Allocates free spaces of ((|size|)) bytes in output buffer. If there are more than ((|size|)) bytes spaces in the buffer, the buffer is truncated. Because the free spaces are allocated automatically, you usually need not to use this method. --- Zlib::ZStream#flush_next_in Flushes input buffer and returns all data in that buffer. --- Zlib::ZStream#flush_next_out Flushes output buffer and returns all data in that buffer. --- Zlib::ZStream#total_in Returns the total bytes of the input data to the stream. --- Zlib::ZStream#total_out Returns the total bytes of the output data from the stream. --- Zlib::ZStream#data_type Guesses the type of the data which have been inputed into the stream. The returned value is either (()), (()), or (()). --- Zlib::ZStream#adler Returns the alder-32 checksum. --- Zlib::ZStream#reset Resets and initializes the stream. All data in both input and output buffer are discarded. --- Zlib::ZStream#finish Finishes the stream and flushes output buffer. See (()) and (()) for detail of the behavior. --- Zlib::ZStream#finished? --- Zlib::ZStream#stream_end? Returns true if the stream is finished. --- Zlib::ZStream#close --- Zlib::ZStream#end Closes the stream. All operations on the closed stream will raise an exception. --- Zlib::ZStream#closed? --- Zlib::ZStream#ended? Returns true if the stream closed. == Zlib::Deflate The class for compressing string data. === SuperClass: * (()) === Class Methods: --- Zlib::Deflate.deflate(string[, level]) Compresses ((|string|)). The avail values of ((|level|)) are (()), (()), (()), (()), and the integer from 0 to 9. This method is almost equivalent to the following code: def deflate(string, level) z = Zlib::Deflate.new(level) dst = z.deflate(string, Zlib::FINISH) z.close dst end --- Zlib::Deflate.new([level[, windowBits[, memlevel[, strategy]]]]) Creates a new deflate stream for compression. See zlib.h for details of each argument. If an argument is nil, the default value of that argument is used. === Methods: --- Zlib::Deflate#clone Duplicates the deflate stream. --- Zlib::Deflate#deflate(string[, flush]) Inputs ((|string|)) into the deflate stream and returns the output from the stream. Calling this method, both input and output buffer of the stream are flushed. If ((|string|)) is nil, this method finishes the stream, just like (()). The value of ((|flush|)) should be either (()), (()), (()), or (()). See zlib.h for details. --- Zlib::Deflate#<< string Inputs ((|string|)) into the deflate stream just like (()), but returns Zlib::Deflate object itself. The output from the stream is preserved in output buffer. --- Zlib::Deflate#flush([flush]) This method is equivalent to (({deflate('', ((|flush|)))})). If ((|flush|)) is omitted, (()) is used as ((|flush|)). This method is just provided for readability of your Ruby script. --- Zlib::Deflate#finish Finishes the stream. This method is equivalent to (({deflate('', Zlib::FINISH)})). --- Zlib::Deflate#params(level, strategy) Changes the parameters of the deflate stream. See zlib.h for details. The output from the stream by changing the params is preserved in output buffer. --- Zlib::Deflate#set_dictionary(string) Sets the preset dictionary and returns ((|string|)). This method is available just only after (()) or (()) method was called. See zlib.h for details. == Zlib::Inflate The class for decompressing compressed data. Unlike (()), an instance of this class is not able to duplicate (clone, dup) itself. === SuperClass: * (()) === Class Methods: --- Zlib::Inflate.inflate(string) Decompresses ((|string|)). Raises a (()) exception if a preset dictionary is needed for decompression. This method is almost equivalent to the following code: def inflate(string) zstream = Zlib::Inflate.new buf = zstream.inflate(string) zstream.finish zstream.close buf end --- Zlib::Inflate.new([windowBits]) Creates a new inflate stream for decompression. See zlib.h for details of the argument. If ((|windowBits|)) is nil, the default value is used. === Methods: --- Zlib::Inflate#inflate(string) Inputs ((|string|)) into the inflate stream and returns the output from the stream. Calling this method, both input and output buffer of the stream are flushed. If ((|string|)) is nil, this method finishes the stream, just like (()). Raises a (()) exception if a preset dictionary is needed to decompress. Set the dictionary by (()) and then call this method again with an empty string. --- Zlib::Inflate#<< string Inputs ((|string|)) into the inflate stream just like (()), but returns Zlib::Inflate object itself. The output from the stream is preserved in output buffer. --- Zlib::Inflate#finish Finishes the inflate stream and returns the garbage following the compressed data. Raises an exception if the stream is not finished (i.e. (()) doesn't returns true). The inflate stream finishes itself as soon as it meets the end code of the compressed data, you need not to call this method explicitly. However, this method is useful for checking whether the data is correctly ended or not. --- Zlib::Inflate#set_dictionary(string) Sets the preset dictionary and returns ((|string|)) This method is available just only after a (()) exception was raised. See zlib.h for details. --- Zlib::Inflate#sync(string) Inputs ((|string|)) into the end of input buffer and skips data until a full flush point can be found. If the point is found in the buffer, this method flushes the buffer and returns false. Otherwise it returns true and the following data of full flush point is preserved in the buffer. --- Zlib::Inflate#sync_point? What is this? == Zlib::GzipFile The abstruct class for handling a gzip formatted compressed file. The operations are defined in the subclasses, (()) for reading, and (()) for writing. GzipReader should be used with associating an instance of IO class (or an object which has the same methods as IO has). === SuperClass: * Object === Class Methods: --- Zlib::GzipFile.new(args...) See (()) and (()). --- Zlib::GzipFile.wrap(args...) {|gz| ... } See (()) and (()). --- Zlib::GzipFile.open(args...) {|gz| ... } See (()) and (()). === Methods: --- Zlib::GzipFile#closed? --- Zlib::GzipFile#to_io Same as IO. --- Zlib::GzipFile#close Closes the GzipFile object. This method calls close method of the associated IO object. Returns the associated IO object. --- Zlib::GzipFile#finish Closes the GzipFile object. Unlike (()), this method ((*never*)) calls close method of the associated IO object. Returns the associated IO object. --- Zlib::GzipFile#crc Returns CRC value of the uncompressed data. --- Zlib::GzipFile#level Returns compression level. --- Zlib::GzipFile#mtime Returns last modification time recorded in the gzip file header. --- Zlib::GzipFile#os_code Returns OS code number recorded in the gzip file header. --- Zlib::GzipFile#orig_name Returns original filename recorded in the gzip file header, or nil if original filename is not present. --- Zlib::GzipFile#comment Returns comments recorded in the gzip file header, or nil if the comments is not present. --- Zlib::GzipFile#sync --- Zlib::GzipFile#sync= flag Same as IO. If ((|flag|)) is true, the associated IO object must respond to flush method. While `sync' mode is true, the compression ratio decreases sharply. == Zlib::GzipFile::Error The superclass for all exceptions raised during processing a gzip file. The following exceptions are defined as subclasses of Zlib::GzipFile::Error. : Zlib::GzipFile::NoFooter Raised when gzip file footer has not found. : Zlib::GzipFile::CRCError Raised when the CRC checksum recorded in gzip file footer is not equivalent to CRC checksum of the actually uncompressed data. : Zlib::GzipFile::LengthError Raised when the data length recorded in gzip file footer is not equivalent to length of the actually uncompressed data. === SuperClass: * (()) == Zlib::GzipReader The class for reading a gzipped file. GzipReader should be used with associating an instance of IO class (or an object which has the same methods as IO has). Zlib::GzipReader.open('hoge.gz') {|gz| print gz.read } f = File.open('hoge.gz') gz = Zlib::GzipReader.new(f) print gz.read gz.close === SuperClass: * (()) === Included Modules: * Enumerable === Class Methods: --- 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 read method that behaves same as read method in IO class. If the gzip file header is incorrect, raises an (()) exception. --- Zlib::GzipReader.wrap(io) {|gz| ... } Creates a GzipReader object associated with ((|io|)), and executes the block with the newly created GzipReader object, just like File::open. The GzipReader object will be closed automatically after executing the block. If you want to keep the associated IO object opening, you may call (()) method in the block. --- Zlib::GzipReader.open(filename) --- 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 same as (()) and (()). === �᥽�å�: --- Zlib::GzipReader#eof --- Zlib::GzipReader#eof? Returns true if the object reaches the end of compressed data. Note that eof? does ((*not*)) return true when reaches the end of ((*file*)). --- Zlib::GzipReader#pos --- Zlib::GzipReader#tell Returns the total bytes of data decompressed until now. Not that it does ((*not*)) the position of file pointer. --- Zlib::GzipReader#each([rs]) --- Zlib::GzipReader#each_line([rs]) --- Zlib::GzipReader#each_byte([rs]) --- Zlib::GzipReader#gets([rs]) --- Zlib::GzipReader#getc --- Zlib::GzipReader#lineno --- Zlib::GzipReader#lineno= --- Zlib::GzipReader#read([length]) --- Zlib::GzipReader#readchar --- Zlib::GzipReader#readline([rs]) --- Zlib::GzipReader#readlines([rs]) --- Zlib::GzipReader#ungetc(char) Same as IO, but raises (()) or (()) exception if an error was found in the gzip file. Be careful of the footer of 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 failed, raises (()), (()), or (()) exception. * When an reading request is received beyond the end of file (the end of compressed data). That is, when (()), (()), or some other methods for reading returns nil. * When (()) method is called after the object reaches the end of file. * When (()) method is called after the object reaches the end of file. --- Zlib::GzipReader#rewind Resets the position of the file pointer to the point created the GzipReader object. The associated IO object need to respond to seek method. --- Zlib::GzipReader#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. == Zlib::GzipWriter The class for writing a gzipped file. GzipWriter should be used with associate with an instance of IO class (or an object which has the same methods as IO has). Zlib::GzipWriter.open('hoge.gz') {|gz| gz.write 'jugemu jugemu gokou no surikire...' } f = File.open('hoge.gz', 'w') gz = Zlib::GzipWriter.new(f) gz.write 'jugemu jugemu gokou no surikire...' gz.close NOTE: Due to the limitation in finalizer of Ruby, you must close explicitly GzipWriter object by (()) etc. Otherwise, GzipWriter should be not able to write gzip footer and generate broken gzip file. === SuperClass: * (()) === Class Methods: --- Zlib::GzipWriter.new(io[, level[, strategy]]) Creates a GzipWriter object associated with ((|io|)). ((|level|)) and ((|strategy|)) should be same as the arguments of (()). The GzipWriter object writes gzipped data to ((|io|)). At least, ((|io|)) must respond to write method that behaves same as write method in IO class. --- Zlib::GzipWriter.wrap(io[, level[, strategy]]) {|gz| ... } Creates a GzipWriter object associated with ((|io|)), and executes the block with the newly created GzipWriter object, just like File::open. The GzipWriter object will be closed automatically after executing the block. If you want to keep the associated IO object opening, you may call (()) method in the block. --- Zlib::GzipWriter.open(filename[, level[, strategy]]) --- Zlib::GzipWriter.open(filename[, level[, strategy]]) {|gz| ... } Opens a file specified by ((|filename|)) for writing gzip compressed data, and returns a GzipWriter object associated with that file. Further details of this method are same as (()) and (()). === Methods: --- Zlib::GzipWriter#close --- Zlib::GzipWriter#finish Closes the GzipFile object. This method calls close method of the associated IO object. Returns the associated IO object. See (()) and (()) for the difference between close and finish. ((*NOTE: Due to the limitation in finalizer of Ruby, you must close GzipWriter object explicitly. Otherwise, GzipWriter should be not able to write gzip footer and generate broken gzip file.*)) --- Zlib::GzipWriter#pos --- Zlib::GzipWriter#tell Returns the total bytes of data compressed until now. Note that it does ((*not*)) the position of file pointer. --- Zlib::GzipWriter#<< str --- Zlib::GzipWriter#putc(ch) --- Zlib::GzipWriter#puts(obj...) --- Zlib::GzipWriter#print(arg...) --- Zlib::GzipWriter#printf(format, arg...) --- Zlib::GzipWriter#write(str) Same as IO. --- Zlib::GzipWriter#flush([flush]) Flushes all the internal buffers of the GzipWriter object. The meaning of ((|flush|)) is same as one of the argument of (()). (()) is used if ((|flush|)) is omitted. It is no use giving ((|flush|)) (()). --- Zlib::GzipWriter#mtime= time Sets last modification time to be stored in the gzip file header. (()) exception will be raised if this method is called after writing method (like (())) was called. --- Zlib::GzipWriter#orig_name= filename Sets original filename to be stored in the gzip file header. (()) exception will be raised if this method is called after writing method (like (())) was called. --- Zlib::GzipWriter#comment= string Sets comments to be stored in the gzip file header. (()) exception will be raised if this method is called after writing method (like (())) was called. == Changes from 0.5 to 0.6 * New methods: * (()) * (()) * New constants: * (()) * (()) * (()) * (()) * (()) * (()) * (()) * Changed methods: * (()) now takes no block. Use (()) instead. * (()) now takes no argument. Use (()) instead. * Renamed methods: * Zlib.version is renamed to (()). * Changed constants: * (()) indicates the version of Ruby/zlib. The zlib.h version is now in (()). * Backward compatibility: * For backward compatibility for 0.5, the obsoleted methods and arguments are still available. * Obsoleted classes, methods, and constants for backward compatibility for 0.4 or earlier are removed. == Changes from 0.4 to 0.5 Almost all the code are rewritten. I hope all changes are enumerated below :-) * The names of almost classes and some methods are changed. All classes and constants are now defined under module (()). The obsoleted names are also available for backward compatibility. * Classes * Deflate -> (()) * Inflate -> (()) * Zlib::Gzip -> (()) * GzipReader -> (()) * GzipWriter -> (()) * Zlib::Gzip::Error -> (()) * Zlib::GzipReader::NoFooter -> (()) * Zlib::GzipReader::CRCError -> (()) * Zlib::GzipReader::LengthError -> (()) * Constants * Zlib::ZStream::BINARY -> (()) * Zlib::ZStream::ASCII -> (()) * Zlib::ZStream::UNKNOWN -> (()) * Zlib::Deflate::NO_COMPRESSION -> (()) * Zlib::Deflate::BEST_SPEED -> (()) * Zlib::Deflate::BEST_COMPRESSION -> (()) * Zlib::Deflate::DEFAULT_COMPRESSION -> (()) * Zlib::Deflate::FILTERED -> (()) * Zlib::Deflate::HUFFMAN_ONLY -> (()) * Zlib::Deflate::DEFAULT_STRATEGY -> (()) * Zlib::Deflate::MAX_WBITS -> (()) * Zlib::Deflate::DEF_MEM_LEVEL -> (()) * Zlib::Deflate::MAX_MEM_LEVEL -> (()) * Zlib::Deflate::NO_FLUSH -> (()) * Zlib::Deflate::SYNC_FLUSH -> (()) * Zlib::Deflate::FULL_FLUSH -> (()) * Zlib::Inflate::MAX_WBITS -> (()) * Zlib::GzipReader::OS_* -> (()) * Methods * Zlib::ZStream#flush_out -> (()) * Made buffer for input (next_in). * (()) returns nil after closing. * Now you are up to call (()) explicitly to avoid segv in finalizer. ((<[ruby-dev:11915]|URL:http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-dev/11915>)) * divided initialize from new. * remove sanity checks for arguments for deflateInit2 and inflateInit2. * adapted the behavior of (()) to Ruby-1.7. * Made all functions static. =end