OpenEuphoria

Let's talk about zip files

• Posted by ghaberek (admin) Feb 21, 2022
• 2062 views

Another thing I'm working on and have half-completed (along with structs and hashes) is zip files. I've got miniz implemented in the backend and I'm exposing its API to the frontend via a sequence of pointers and define_c_func/proc.

Question is: what does a good, simple, Euphoria-like zip API look like? Let's discuss! (For reference, the miniz archive API lives here: miniz_zip.h) I'm thinking that a zip file library is basically a combination of two things: file system (dirs/files, names/sizes, etc.) and file I/O (open/close, read/write, etc.).

With that, the typical operations are going to be: creating zip files, inspecting zip files, and extracting zip files. So to start with, here's what I propose. (There will be additional routines for doing more advanced things with zip files, but I think this covers most use cases).

Zip file routines

include std/zip.e 
 
--** 
-- Open a zip file for reading or writing. 
public function zip_open( sequence filename, sequence mode, integer flags=0, atom archive_start=0, atom archive_size=0 ) 
 
--** 
-- Close (and if writing, finalize) a zip file. 
public function zip_close( atom zip, integer finalize=TRUE ) 
 
--** 
-- Add an entry to a zip file. 
public function zip_add( atom zip, sequence source_name, sequence archive_name="", integer flags=ZIP_DEFAULT_COMPRESSION, sequence comment="" ) 
 
--** 
-- Extract an entry from a zip file. 
public function zip_extract( atom zip, sequence archive_name, sequence destination_name="", integer flags=0 ) 
 
--** 
-- Locate an entry in a zip file. 
public function zip_find( atom zip, sequence filename, integer flags=0, sequence comment="" ) 
 
--** 
-- List the entries in a zip file, filtered by an optional pattern. 
public function zip_dir( atom zip, sequence pattern="" ) 

Creating zip files

include std/zip.e 
 
-- open zip file for writing 
atom zip = zip_open( "test.zip", "w" ) 
 
-- add entry using its base name "file1.txt" 
zip_add( zip, "path/to/file1.txt" ) 
 
-- add entry using specific name "path/file2.txt" 
zip_add( zip, "path/to/file2.txt", "path/file2.txt" ) 
 
-- add entry using its base name and no compression 
zip_add( zip, "path/to/file3.txt",, ZIP_NO_COMPRESSION ) 
 
-- finalize (write directory) and close the zip file 
zip_close( zip ) 

Inspecting zip files

include std/zip.e 
 
-- open zip file for reading 
atom zip = zip_open( "test.zip", "r" ) 
 
-- find a specific file (returns ordinal number or -1 if not found) 
? zip_find( zip, "file3.txt" ) 
 
-- list all entries, with optional wildcard (same input/output as dir()) 
sequence files = zip_dir( zip ) 
for i = 1 to length( files ) do 
    printf( 1, "name: \"%s\", size: %d bytes\n", {files[i][D_NAME],files[i][D_SIZE]} ) 
end for 
 
-- close the zip file 
zip_close( zip ) 

Extracting zip files

include std/zip.e 
 
-- open zip file for reading 
atom zip = zip_open( "test.zip", "r" ) 
 
-- extract the entry (and its path) to the current directory 
zip_extract( zip, "path/file2.txt" ) 
 
-- extract the entry to a specific destination (to ignore path) 
zip_extract( zip, "path/file2.txt", "file.txt" ) 
 
-- close the zip file 
zip_close( zip ) 

Thoughts, comments, opinions?

-Greg