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PODetermine how many files are in a zip
 

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  1. PODetermine how many files are in a zip
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    <p>I am trying to read a zip file (in python 2.7.2) by reading each of the bytes. I am able to get through the local file headers and the data. However I am stuck when trying to read the Central file header.</p> <p>This helps alot <a href="http://en.wikipedia.org/wiki/File:ZIP-64_Internal_Layout.svg" rel="nofollow">http://en.wikipedia.org/wiki/File:ZIP-64_Internal_Layout.svg</a></p> <p>I dont know how to find out how many items there are in the archive so I can switch to formating the central file header or how else to know how to switch from formating file to the central file header.</p> <p>This is what I have right now -</p> <pre><code>import sys def main(debug=0,arg_file=''): if debug==2: print "- Opening %s" % arg_file with open(arg_file) as archive: if debug==2: print "- Reading %s" % arg_file bytes = archive.read() if debug==2: print "-------------Binary-------------" print bytes #Read file headers end = 0 while end != bytes.__len__(): print end end = process_sub_file(debug,end,bytes) def process_sub_file(debug,startbytes, bytes): header = bytes[startbytes + 0] + bytes[startbytes + 1] + bytes[startbytes + 2] + bytes[startbytes + 3] version = bytes[startbytes + 4] + bytes[startbytes + 5] flags = bytes[startbytes + 6] + bytes[startbytes + 7] comp_method = bytes[startbytes + 8] + bytes[startbytes + 9] mod_time = bytes[startbytes + 10] + bytes[startbytes + 11] mod_date = bytes[startbytes + 12] + bytes[startbytes + 13] crc = bytes[startbytes + 14] + bytes[startbytes + 15] + bytes[startbytes + 16] + bytes[startbytes + 17] comp_size_bytes = bytes[startbytes + 18] + bytes[startbytes + 19] + bytes[startbytes + 20] + bytes[startbytes + 21] comp_size = ord(comp_size_bytes[0]) + ord(comp_size_bytes[1]) + ord(comp_size_bytes[2]) + ord(comp_size_bytes[3]) uncomp_size_bytes = bytes[startbytes + 22] + bytes[startbytes + 23] + bytes[startbytes + 24] + bytes[startbytes + 25] uncomp_size = ord(uncomp_size_bytes[0]) + ord(uncomp_size_bytes[1]) + ord(uncomp_size_bytes[2]) + ord(uncomp_size_bytes[3]) name_len_bytes = bytes[startbytes + 26] + bytes[startbytes + 27] name_len = int(ord(name_len_bytes[0])+ord(name_len_bytes[1])) extra_len_bytes = bytes[startbytes + 28] + bytes[startbytes + 29] extra_len = int(ord(extra_len_bytes[0])+ord(extra_len_bytes[1])) file_name = "" for i in range(name_len): file_name = file_name + bytes[startbytes + 30 + i] extra_field = "" for i in range(extra_len): file_name = file_name + bytes[startbytes + 30 + name_len + i] data = "" for i in range(comp_size): data = data + bytes[startbytes + 30 + name_len + extra_len + i] if debug&gt;=1: print "-------------Header-------------" print "Header Signature: %s" % header print "Version: %s" % version print "Flags: %s" % flags print "Compression Method: %s" % comp_method print "Modification Time: %s" % (ord(mod_time[0]) + ord(mod_time[1])) print "Modification Date: %s" % (ord(mod_date[0]) + ord(mod_time[1])) print "CRC-32: %s" % crc print "Compressed Size: %s" % comp_size print "Uncompressed Size: %s" % uncomp_size print "File Name Length: %s" % name_len print "Extra Field Length: %s" % extra_len print "File Name: %s" % file_name print "Extra Field: %s" % extra_field print "Data:\n%s" % data return startbytes + 30 + name_len + extra_len + comp_size </code></pre>
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    1. PTQuestion
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    1. USEric Sauer
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
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      1. PODetermine how many files are in a zip
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      1. VTUpMod
    1. COIs there a reason you're not using the built in `zipfile` module?
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      1. PODetermine how many files are in a zip
      1. USlazy1
    2. COI am attempting to analyze/find malformed/malicious zips and I need to check the file header manually (unfortunatly)
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      1. PODetermine how many files are in a zip
      1. USEric Sauer
    3. COA bit unrelated, but for all this bit processing - see the `struct` module.
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      1. PODetermine how many files are in a zip
      1. USlazy1
 

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