Zirak · December 12, 2015 01:28
diff --git a/usage.md b/usage.md
diff --git a/xzf.py b/xzf.py
 #!/usr/bin/python
 #XTRACT ZE FILES!!!

 import subprocess

 #header => tar flag map
 #you can find these with something along the lines of:
 # hexdump -n 16 -C file
 #(execute in console, of course)
 headers = {
    #nothing
    b'' : '',

    #gzip
    # http://www.onicos.com/staff/iz/formats/gzip.html
    b'\x1f\x8b' : '--gzip',

    #bzip2
    # http://bzip.org/1.0.5/bzip2-manual-1.0.5.html
    #   (look for BZ_DATA_ERROR_MAGIC)
    b'BZ' : '--bzip2',
    #we assume bzip2, even though bzip1 files begin with BZ as well (the
    # distinction is in the 3rd byte, h in bzip2, 0 in bzip1)

    #TODO: check the following

    #xz
    # http://tukaani.org/xz/xz-file-format.txt
    #  (look for Header Magic Bytes)
    b'\xfd7zXZ\x00' : '--xz',
 }

 def xtract_ze_files (fn, extra_flags):
    tar_flag = get_tar_flag(fn)

    command = [
        'tar',

        tar_flag,
        extra_flags,
        '-xf',

        fn ]

    return subprocess.call(command)

 #grabs the header, which is really the leading bytes of a file, depending on
 # the longest header we have in stock.
 #once you have that, go over our fine list of possible headers, find possible
 # matches. I say matches in plural because files may begin with the same bytes,
 # but diverge later on.
 #now we basically find the best match - that's the longest header in the result,
 #  naturally indicating the best match, most header chars matched file beginning
 def get_tar_flag (fn):
    magic = get_header(fn)
    #python3's filter returns an iterator instead of a list. we can't handle
    # that nicely to work for both versions, so here we just extract the
    # filter functionality
    possible_heads = [k for k in headers.keys() if magic.startswith(k)]
    #default
    possible_heads.append('');

    return headers[max(possible_heads, key=len)]

 def get_header (fn):
    longest = max(len(h) for h in headers)

    with open(fn, 'rb') as file:
        return file.read(longest)

 if __name__ == '__main__':
    import os, sys

    status = xtract_ze_files(
        os.path.abspath(sys.argv[1]),
        ' '.join(sys.argv[2:]))

    sys.exit(status)
	#!/usr/bin/python
	#XTRACT ZE FILES!!!

	import subprocess

	#header => tar flag map
	#you can find these with something along the lines of:
	# hexdump -n 16 -C file
	#(execute in console, of course)
	headers = {
	#nothing
	b'' : '',

	#gzip
	# http://www.onicos.com/staff/iz/formats/gzip.html
	b'\x1f\x8b' : '--gzip',

	#bzip2
	# http://bzip.org/1.0.5/bzip2-manual-1.0.5.html
	# (look for BZ_DATA_ERROR_MAGIC)
	b'BZ' : '--bzip2',
	#we assume bzip2, even though bzip1 files begin with BZ as well (the
	# distinction is in the 3rd byte, h in bzip2, 0 in bzip1)

	#TODO: check the following

	#xz
	# http://tukaani.org/xz/xz-file-format.txt
	# (look for Header Magic Bytes)
	b'\xfd7zXZ\x00' : '--xz',
	}

	def xtract_ze_files (fn, extra_flags):
	tar_flag = get_tar_flag(fn)

	command = [
	'tar',

	tar_flag,
	extra_flags,
	'-xf',

	fn ]

	return subprocess.call(command)

	#grabs the header, which is really the leading bytes of a file, depending on
	# the longest header we have in stock.
	#once you have that, go over our fine list of possible headers, find possible
	# matches. I say matches in plural because files may begin with the same bytes,
	# but diverge later on.
	#now we basically find the best match - that's the longest header in the result,
	# naturally indicating the best match, most header chars matched file beginning
	def get_tar_flag (fn):
	magic = get_header(fn)
	#python3's filter returns an iterator instead of a list. we can't handle
	# that nicely to work for both versions, so here we just extract the
	# filter functionality
	possible_heads = [k for k in headers.keys() if magic.startswith(k)]
	#default
	possible_heads.append('');

	return headers[max(possible_heads, key=len)]

	def get_header (fn):
	longest = max(len(h) for h in headers)

	with open(fn, 'rb') as file:
	return file.read(longest)

	if __name__ == '__main__':
	import os, sys

	status = xtract_ze_files(
	os.path.abspath(sys.argv[1]),
	' '.join(sys.argv[2:]))

	sys.exit(status)
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