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easy7zip/DOC/Methods.txt
Tino Reichardt ef790b5209 Update to 7-Zip 17.01 Beta from Igor Pavlov
- Minor speed optimization for LZMA2 (xz and 7z) multi-threading compression.
  7-Zip now uses additional memory buffers for multi-block LZMA2 compression.
  CPU utilization was slightly improved.
- 7-zip now creates multi-block xz archives by default. Block size can be
  specified with -ms[Size]{m|g} switch.
- xz decoder now can unpack random block from multi-block xz archives.  7-Zip
  File Manager now can open nested multi-block xz archives (for example,
  image.iso.xz) without full unpacking of xz archive.
- 7-Zip now can create zip archives from stdin to stdout.
- 7-Zip command line: @listfile now doesn't work after -- switch.  Use
  -i@listfile before -- switch instead.

fixed bugs:
- 7-Zip could add unrequired alternate file streams to WIM archives, for
  commands that contain filename wildcards and -sns switch.
- 7-Zip 17.00 beta crashed for commands that write anti-item to 7z archive.
- 7-Zip 17.00 beta ignored "Use large memory pages" option.
2017-08-28 16:40:24 +02:00

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7-Zip method IDs for 7z and xz archives
---------------------------------------
Version: 17.01
Date: 2017-05-27
Each compression or crypto method in 7z is associated with unique binary value (ID).
The length of ID in bytes is arbitrary but it can not exceed 63 bits (8 bytes).
xz and 7z formats use same ID map.
If you want to add some new ID, you have two ways:
1) Write request for allocating IDs to 7-Zip developers.
2) Generate 8-bytes ID:
3F ZZ ZZ ZZ ZZ ZZ MM MM
3F - Prefix for random IDs (1 byte)
ZZ ZZ ZZ ZZ ZZ - Developer ID (5 bytes). Use real random bytes.
MM MM - Method ID (2 bytes)
You can notify 7-Zip developers about your Developer ID / Method ID.
Note: Use new ID, if old codec can not decode data encoded with new version.
List of defined IDs
-------------------
00 - Copy
03 - Delta
04 - BCJ (x86)
05 - PPC (big-endian)
06 - IA64
07 - ARM (little-endian)
08 - ARMT (little-endian)
09 - SPARC
21 - LZMA2
02.. - Common
03 [Swap]
- 2 Swap2
- 4 Swap4
03.. - 7z
01 -
01 - LZMA
03 - [Branch Codecs]
01 - [x86 Codecs]
03 - BCJ
1B - BCJ2 (4 packed streams)
02 -
05 - PPC (big-endian)
03 -
01 - Alpha
04 -
01 - IA64
05 -
01 - ARM (little-endian)
06 -
05 - M68 (big-endian)
07 -
01 - ARMT (little-endian)
08 -
05 - SPARC
04 -
01 - PPMD
7F -
01 - experimental method.
04.. - Misc codecs
00 - Reserved
01 - [Zip]
00 - Copy (not used. Use {00} instead)
01 - Shrink
06 - Implode
08 - Deflate
09 - Deflate64
0A - Imploding
0C - BZip2 (not used. Use {040202} instead)
0E - LZMA (LZMA-zip)
5F - xz
60 - Jpeg
61 - WavPack
62 - PPMd (PPMd-zip)
63 - wzAES
02 -
02 - BZip2
03 - [Rar]
01 - Rar1
02 - Rar2
03 - Rar3
05 - Rar5
04 - [Arj]
01 - Arj(1,2,3)
02 - Arj4
05 - [Z]
06 - [Lzh]
07 - Reserved for 7z
08 - [Cab]
09 - [NSIS]
01 - DeflateNSIS
02 - BZip2NSIS
F7 - External codecs (that are not included to 7-Zip)
0x xx - reserved
10 xx - reserved (LZHAM)
01 - LZHAM
11 xx - reserved (Tino Reichardt)
01 - ZSTD
02 - BROTLI
04 - LZ4
05 - LZ5
06 - LIZARD
06.. - Crypto
F0 - Ciphers without hashing algo
01 - [AES]
0x - AES-128
4x - AES-192
8x - AES-256
Cx - AES
x0 - ECB
x1 - CBC
x2 - CFB
x3 - OFB
x4 - CTR
F1 - Combine Ciphers
01 - [Zip]
01 - ZipCrypto (Main Zip crypto algo)
03 - [RAR]
02 -
03 - Rar29AES (AES-128 + modified SHA-1)
07 - [7z]
01 - 7zAES (AES-256 + SHA-256)
---
End of document