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https://github.com/onox/dcf-ada
An Ada 2012 library for document container files
https://github.com/onox/dcf-ada
ada archiving dcf dcf-ada zip
Last synced: 14 days ago
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An Ada 2012 library for document container files
- Host: GitHub
- URL: https://github.com/onox/dcf-ada
- Owner: onox
- License: mit
- Created: 2019-05-11T21:11:51.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2022-07-31T13:14:59.000Z (over 2 years ago)
- Last Synced: 2024-07-31T20:40:55.243Z (3 months ago)
- Topics: ada, archiving, dcf, dcf-ada, zip
- Language: Ada
- Size: 1.3 MB
- Stars: 6
- Watchers: 4
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
Awesome Lists containing this project
- awesome-ada - dcf-ada - An Ada 2012 library for document container files (Based on [zip-ada]). (Libraries / Compression)
README
[](https://alire.ada.dev/crates/dcf.html)
[](https://alire.ada.dev/crates/zipdcf.html)
[](https://github.com/onox/dcf-ada/blob/master/LICENSE)
[](https://github.com/onox/dcf-ada/releases/latest)
[](https://libera.chat)
[](https://gitter.im/ada-lang/Lobby)
# dcf-ada
An Ada 2012 library for document container files, a Zip-based archive files
with some limitations:
* Only the "store" (uncompressed) and "deflate" ([RFC 1951][url-deflate])
compression methods can be used
* Archives cannot be encrypted or contain digital signatures
* Archives cannot be split into multiple files
This library is based on the [Zip-Ada][url-zip-ada] library, with extensive
modifications:
* Binary and Windows-specific files have been removed with [The BFG Repo Cleaner][url-bfg]
* Reformatted code to Ada default style guide
* Removed obsolescent features and implementation-defined extensions
* All packages except one that uses `Ada.Calendar` are preelaborated
* Removed unneeded features
* Removed lots of duplicated code and simplified the API, reducing SLOC from 12k to 4.5k
## Usage
Before the archived files in a document container file can be queried
or extracted, the archive first needs to be opened and loaded:
```ada
Archive_Stream : aliased DCF.Streams.File_Zipstream := DCF.Streams.Open (Archive_Name);
Info : DCF.Zip.Zip_Info;
```
Then load the archive by calling `DCF.Zip.Load (Info, Archive_Stream)`.
While the `Info` and `Archive_Stream` objects are in scope, the files
can be visited in order to extract them.
### Visiting archived files in a document container file
Files can be extracted by visiting over all the archived files in the
archive and then extracting each of them:
```ada
procedure Visit_File (File : DCF.Zip.Archived_File) is
begin
Ada.Text_IO.Put_Line ("Visiting " & File.Name);
end Visit_File;
procedure Visit_All_Files is new DCF.Zip.Traverse (Visit_File);
procedure Visit_One_File is new DCF.Zip.Traverse_One_File (Visit_File);
```
Call `Visit_All_Files (Info)` to visit all files. To extract a single
file, call `Visit_One_File (Info, "my-file.txt")` instead.
### Querying an archived file
A `File` object of type `Archived_File` can be queried:
* `Name` returns the name (path) of the file
* `Compressed_Size` gives the compressed size
* `Uncompressed_Size` gives the uncompressed size
* `Date_Time` returns the modification date and time
* `Compressed` returns True if compressed with the "deflate" algorithm
and False if stored uncompressed
* `Encrypted` returns True if the file is encrypted and False otherwise.
Note that encryption is prohibited and not supported, thus these files
cannot be decrypted and extracted
* `CRC_32` returns the CRC code. This number can be printed with
`DCF.Zip.CRC.Image`
### Extracting an archived file
While visiting an archived file, the file can be extracted using a
`Stream_Writer` object. First create the file and then write to it:
```ada
declare
File_Stream : aliased DCF.Streams.File_Zipstream := DCF.Streams.Create (File.Name);
Stream_Writer : DCF.Unzip.Streams.Stream_Writer (File_Stream'Access);
begin
DCF.Unzip.Streams.Extract
(Destination => Stream_Writer,
Archive_Info => Info,
File => File,
Verify_Integrity => False);
end;
```
If you want to extract to a `Stream_Element_Array`, use `DCF.Streams.Array_Zipstream`:
```ada
declare
Byte_Stream : aliased DCF.Streams.Array_Zipstream (My_Element_Array'Access);
Stream_Writer : DCF.Unzip.Streams.Stream_Writer (Byte_Stream'Access);
begin
```
If you want to verify the integrity of the file without extracting it, set
`Verify_Integrity` to `True` and use `null` in the discriminant of `Stream_Writer`.
Note that you should verify that `File.Name` is a valid path and sanitize
it before attempting to create and write to the file.
## Dependencies
In order to build the library, you need to have:
* An Ada 2012 compiler
* [Alire][url-alire] and `make`
## Using the library
Use the library in your crates as follows:
```
alr with dcf
```
## Installing the tools
Some tools to compress or decompress document container files can be build with:
```
$ make
$ make PREFIX=~/.local install
```
## Thanks
Much thanks to @zertovitch for the Zip-Ada project.
## Contributing
Please read the [contributing guidelines][url-contributing] before opening
issues or pull requests.
## License
This library is distributed under the terms of the [MIT License][url-mit].
The first line of each Ada file should contain an SPDX license identifier
tag that refers to this license:
SPDX-License-Identifier: MIT
[url-alire]: https://alire.ada.dev/
[url-bfg]: https://rtyley.github.io/bfg-repo-cleaner
[url-contributing]: /CONTRIBUTING.md
[url-deflate]: https://tools.ietf.org/html/rfc1951
[url-mit]: https://opensource.org/licenses/mit
[url-zip-ada]: https://unzip-ada.sourceforge.net