Version 61

Gautier de Montmollin — Sat, 15 Mar 2025 09:11:02 -0000

🆕 Changes in this release:

BZip2 encoder: improved performance by reducing possible entropy codings chosen by brute-force.
BZip2 encoder: added segmentation of blocks for heterogeneous data.

Version 60

Gautier de Montmollin — Sun, 17 Nov 2024 11:12:08 -0000

New feature: added compression for the BZip2 format for .bz2 and .zip files or streams.

Note that Zip-Ada .zip archive creation with the "preselection_2" mode now tops (or rather, bottoms ;-) in terms of compressed size) 7-Zip for both Calgary (*) and Canterbury benchmarks, for the .zip format and even the .7z format. More details here.

(*) File names need extensions: .txt, .c, .lsp, .pas

Version 59

Gautier de Montmollin — Sat, 25 May 2024 19:30:12 -0000

New features:

UnZip.Streams: added Set_Index & Index subprograms for inward streams from Zip archives.
Zip.Create: added procedure Add_Empty_Folder

Version 58

Gautier de Montmollin — Sat, 27 Aug 2022 07:47:57 -0000

New feature in version 58 (as frozen in rev. 922): Support for Zip_64 archives. The Zip_64 format extension is needed when there are more than more than 65535 entries or more than 4 GiB data for a single entry's compressed or uncompressed size, or for a whole archive.

Some research with LZMA...

Gautier de Montmollin — Sat, 28 Nov 2020 19:57:32 -0000

A rare case where Zip-Ada's LZMA encoder is much better than LZMA SDK's. Rare but still interesting, and with, on Zip-Ada's side, standard LZMA parameters (no specific tuning for that file):

The compressed size with current public revision (rev.#882) of Zip-Ada is slightly worse (42,559 bytes).

The file is part of the classic Canterbury Corpus compression benchmark data set.

Version 57

Gautier de Montmollin — Sat, 03 Oct 2020 19:42:16 -0000

Changes in '57', 02-Oct-2020 [rev. 799]:

UnZip: fixed bad decoding case for the Shrink (LZW) format,
on some data compressed only by PKZIP up to v.1.10,
release date 1990-03-15.
Zip.Create: added Zip_Entry_Stream_Type for doing output
streaming into Zip archives.
Zip.Compress: Preselection method detects Audacity files (.aup, .au)
and compresses them better.

Version 56

Gautier de Montmollin — Sat, 03 Oct 2020 19:41:42 -0000

Changes in '56', 17-Jan-2020 [rev. 780]:

Zip: the Zip_info type is now controlled (no need to call Delete;
additionally, clones are done correctly).
UnZip.Streams: added Size and Name functions for Zipped_File_Type.
LZ77: added nice simple LZ77 compressor by Rich Geldreich, Jr.
(Tools) Added Zip_Dir_List.
Some refactoring was needed for -gnatwh warning switch (warnings for
hiding declarations). Subprogram Create in package Zip.Create
was renamed to Create_Archive.
Adapted to -gnatytc style checks.
Better names for some exceptions (the old names
can be still used); better exception messages.

Preselection method for Audacity files

Gautier de Montmollin — Wed, 23 Sep 2020 14:01:34 -0000

Latest commit (rev. 796) adds a stronger and faster compression specifically for Audacity files (.aud, .au) for hot backups of audio editing projects.
More about it in this article.

Zip-Ada (and Trained Compression) presented at FOSDEM 2019

Gautier de Montmollin — Wed, 06 Feb 2019 14:53:26 -0000

Presentation is available as PDF and PPT.

Version 55

Gautier de Montmollin — Thu, 22 Nov 2018 13:26:06 -0000

Zip-Ada v.55

Changes in '55', 22-Nov-2018:

Zip_Streams: ZS_Size_Type is now 64-bit signed, enabling Zip.Create
to capture archive size overflows in Zip_32 mode.
Zip.Create raises Zip_Capacity_Exceeded when archive creation exceeds
the Zip_32 format's capacity: 4GB total size, 65,535 entries.
Zip.Create is now using an Ada 2005+'s Containers's Hashed Maps;
creation is much faster on Zip archives with many entries.
(Tools) ReZip has a new option for working only with its own internal
compression algorithms - those provided by Zip.Compress.
This option is useful if external tools are not available.
New Trained_Compression package: generic streaming encoder-decoder
engine with the capability of training the engine with data known
in advance, in order to achieve better compression. Not Zip-related.
Minimum required Ada version is now Ada 2005 (was Ada 95 before).

Zip-Ada Web site: http://unzip-ada.sf.net

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