The Ruby/zlib version string.
The string which represents the version of zlib.h
Represents binary data as guessed by deflate.
Represents text data as guessed by deflate.
NOTE: The underlying constant Z_ASCII was deprecated in favor of Z_TEXT in zlib 1.2.2. New applications should not use this constant.
Represents text data as guessed by deflate.
Represents an unknown data type as guessed by deflate.
No compression, passes through data untouched. Use this for appending pre-compressed data to a deflate stream.
Fastest compression level, but with with lowest space savings.
Slowest compression level, but with the best space savings.
Default compression level which is a good trade-off between space and time
Deflate strategy for data produced by a filter (or predictor). The effect of FILTERED is to force more Huffman codes and less string matching; it is somewhat intermediate between DEFAULT_STRATEGY and HUFFMAN_ONLY. Filtered data consists mostly of small values with a somewhat random distribution.
Deflate strategy which uses Huffman codes only (no string matching).
Deflate compression strategy designed to be almost as fast as HUFFMAN_ONLY, but give better compression for PNG image data.
Deflate strategy which prevents the use of dynamic Huffman codes, allowing for a simpler decoder for specialized applications.
Default deflate strategy which is used for normal data.
The maximum size of the zlib history buffer. Note that zlib allows larger values to enable different inflate modes. See Zlib::Inflate.new for details.
The default memory level for allocating zlib deflate compression state.
The maximum memory level for allocating zlib deflate compression state.
NO_FLUSH is the default flush method and allows deflate to decide how much data to accumulate before producing output in order to maximize compression.
The SYNC_FLUSH method flushes all pending output to the output buffer and the output is aligned on a byte boundary. Flushing may degrade compression so it should be used only when necessary, such as at a request or response boundary for a network stream.
Flushes all output as with SYNC_FLUSH, and the compression state is reset so that decompression can restart from this point if previous compressed data has been damaged or if random access is desired. Like SYNC_FLUSH, using FULL_FLUSH too often can seriously degrade compression.
Processes all pending input and flushes pending output.
The OS code of current host
OS code for MSDOS hosts
OS code for Amiga hosts
OS code for VMS hosts
OS code for UNIX hosts
OS code for Atari hosts
OS code for OS2 hosts
OS code for Mac OS hosts
OS code for TOPS-20 hosts
OS code for Win32 hosts
OS code for VM OS hosts
OS code for Z-System hosts
OS code for CP/M hosts
OS code for QDOS hosts
OS code for RISC OS hosts
OS code for unknown hosts
This module provides access to the zlib library. Zlib is designed to be a portable, free, general-purpose, legally unencumbered – that is, not covered by any patents – lossless data-compression library for use on virtually any computer hardware and operating system.
The zlib compression library provides in-memory compression and decompression functions, including integrity checks of the uncompressed data.
The zlib compressed data format is described in RFC 1950, which is a wrapper around a deflate stream which is described in RFC 1951.
The library also supports reading and writing files in gzip (.gz) format with an interface similar to that of IO. The gzip format is described in RFC 1952 which is also a wrapper around a deflate stream.
The zlib format was designed to be compact and fast for use in memory and on communications channels. The gzip format was designed for single-file compression on file systems, has a larger header than zlib to maintain directory information, and uses a different, slower check method than zlib.
See your system's zlib.h for further information about zlib
Sample usage
Using the wrapper to compress strings with default parameters is quite simple:
require "zlib"
data_to_compress = File.read("don_quixote.txt")
puts "Input size: #{data_to_compress.size}"
#=> Input size: 2347740
data_compressed = Zlib::Deflate.deflate(data_to_compress)
puts "Compressed size: #{data_compressed.size}"
#=> Compressed size: 887238
uncompressed_data = Zlib::Inflate.inflate(data_compressed)
puts "Uncompressed data is: #{uncompressed_data}"
#=> Uncompressed data is: The Project Gutenberg EBook of Don Quixote...
Class tree
(if you have GZIP_SUPPORT)