jz_board addition

README.md

@@ -4,4 +4,6 @@ A zlib based file compression utility for circuitpython
 
 ## Important note
 
-This utility will not be able to compress files on boards, you will have to use it on a host computer to compress files with.
+This utility will not be able to compress files on boards, you will have to use it on a host computer to compress files with.<br />
+<br />
+For extracting file on a board, you are recommended to use the "_board" mpy versions, however the full one should work just fine.

jz_board.py

@@ -0,0 +1,53 @@
+from zlib import decompress
+from gc import collect
+from sys import exit
+from os import getcwd, chdir
+
+VERSION = "1.0-board"
+
+def decompress(filee, directory="."):
+    print(f"Decompressing {filee} into {directory if directory != '.' else 'the current directory'}")
+    with open(filee,"rb") as inpf:
+        dataa = inpf.read()
+        inpf.close()
+        del inpf
+    olddir = getcwd()
+    chdir(directory)
+    unz = decompress(dataa)
+    del dataa
+    collect()
+    collect()
+    ctlstr = str(unz[:unz.find(bytes("|eocf","utf-8"),0)],"utf-8")
+    ctlarr = ctlstr.split()
+    offset = unz.find(bytes("|eocf","utf-8"),0)+5
+
+    for i in range(0, int(len(ctlarr)), 2): # skipping over len
+        fname = ctlarr[i]
+        lco = int(ctlarr[i+1])
+        print(f"Extracting: {fname} ({str(lco)} bytes)")
+        try:
+            with open(fname,"wb") as fout:
+                fout.write(unz[offset:offset+lco])
+                fout.flush()
+                fout.close()
+                del fout
+        except OSError:
+            print("Error: Could not write file")
+            exit(1)
+        offset += lco
+        del lco, fname
+        collect()
+        collect()
+    del unz
+    chdir(olddir)
+    del olddir
+    exit(0)
+
+def help():
+    print(f"""
+        About: jz file compression module, board edition.
+               Version: {VERSION} - Author: Bill Sideris (bill88t)
+               This project is licenced under the MIT licence.
+        Usage: jz.decompress(\"jz_archive_name\")
+    """)
+    exit(0)