Near jump, near call, conditional near jump targets are split out and compressed separately in another stream. BCJ2 is an improvement on BCJ, adding additional x86 jump/call instruction processing. BCJ2 - Pre-processor for 32-bit x86 executables.Normalise target addresses of near jumps and calls from relative distances to absolute destinations. BCJ - Converter for 32-bit x86 executables.For x86, this means that near jumps, calls and conditional jumps (but not short jumps and conditional jumps) are converted from the machine language "jump 1655 bytes backwards" style notation to normalized "jump to address 5554" style notation. The LZMA SDK comes with the BCJ / BCJ2 preprocessor included, so that later stages are able to achieve greater compression: For x86, ARM, PowerPC (PPC), IA64 and ARM Thumb processors, jump targets are normalized before compression by changing relative position into absolute values. PPMd – Dmitry Shkarin's 2002 PPMdH (PPMII/cPPMII) with small changes: PPMII is an improved version of the 1984 PPM compression algorithm (prediction by partial matching).Ī suite of recompression tools called AdvanceCOMP contains a copy of the DEFLATE encoder from the 7-Zip implementation these utilities can often be used to further compress the size of existing gzip, ZIP, PNG, or MNG files.Bzip2 uses two reversible transformations BWT, then Move to front with Huffman coding for symbol reduction (the actual compression element). Bzip2 – The standard Burrows-Wheeler transform algorithm.it provides the following advantages: better compression ratio for data than can't be compressed, better multithreading support. The LZ stage is followed by entropy coding using a Markov chain based range coder and binary trees. LZMA – A variation of the LZ77 algorithm, using a sliding dictionary up to 4 GB in length for duplicate string elimination.
The following compression methods are currently defined: The format's open architecture allows additional future compression methods to be added to the standard.
#WHAT IS .7Z FILE EXTENSION ARCHIVE#
Compression and encryption of archive headers.Support for solid compression, where multiple files of like type are compressed within a single stream, in order to exploit the combined redundancy inherent in similar files.Large file support (up to approximately 16 exabytes).High compression ratios (depending on the compression method used).Open, modular architecture which allows any compression, conversion, or encryption method to be stacked.The 7z format provides the following main features: