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Alexander Hanel Python aPlib option for decompressing data with no headers.

Created by Alexander Hanel
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File aplib.py Added

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+################################################################################
+# quick hack for using aplib (http://www.ibsensoftware.com/products_aPLib.html)
+# put aplib.dll in %PATH% or same dir as this script
+# on *nix it might require LD_LIBRARY_PATH set depending on where libaplib.so is
+#
+# 20161001 - added 'dnh' option to decompress data with no aplib header - alexander hanel 
+
+import os
+from ctypes import *
+
+################################################################################
+
+__all__ = [ 'pack', 'pack_safe', 'depack', 'depack_safe', 'CB_COMPRESS']
+
+################################################################################
+
+if os.name == 'nt':
+    CB_COMPRESS = WINFUNCTYPE(c_uint, c_uint, c_uint, c_uint, c_void_p)
+    _aplib = windll.aplib
+else:
+    CB_COMPRESS = CFUNCTYPE(c_uint, c_uint, c_uint, c_uint, c_void_p)
+    # might require LD_LIBRARY_PATH set
+    _aplib = CDLL("libaplib.so")    
+
+def _ratio(inpos, insize):
+    return (inpos * 100) / insize
+
+def _cbCompress(insize, inpos, outpos, cbparam):
+    print "compressed %u -> %u bytes (%u%% done)" % \
+        ( inpos, outpos, _ratio(inpos, insize))
+    return 1
+
+_cbCompressFunc = CB_COMPRESS(_cbCompress)
+
+################################################################################
+
+def pack(src, cb=None):
+
+    srclen = len(src)
+    if srclen <= 0:
+        raise ValueError('Invalid input.')
+
+    dstlen = _aplib.aP_max_packed_size(srclen)
+    dst = create_string_buffer(dstlen)
+    wrkmem = create_string_buffer(_aplib.aP_workmem_size(srclen))
+
+    dstlen = _aplib.aP_pack(src, dst, srclen, wrkmem, cb, 0)
+
+    if dstlen == -1:
+        raise ValueError('Compression error.')
+        
+    return buffer(dst, 0, dstlen)
+
+def pack_safe(src, cb=None):
+
+    srclen = len(src)
+    if srclen <= 0:
+        raise ValueError('Invalid input.')
+
+    dstlen = _aplib.aP_max_packed_size(srclen)
+    dst = create_string_buffer(dstlen)
+    wrkmem = create_string_buffer(_aplib.aP_workmem_size(srclen))
+
+    dstlen = _aplib.aPsafe_pack(src, dst, srclen, wrkmem, cb, 0)
+
+    if dstlen == -1:
+        raise ValueError('Compression error.')
+        
+    return buffer(dst, 0, dstlen)
+
+################################################################################
+
+def depack(src, dstlen):
+
+    srclen = len(src)
+    if srclen <= 0 or dstlen <= 0:
+        raise ValueError('Invalid input.')
+    
+    dst = create_string_buffer(dstlen)
+
+    dstlen = _aplib.aP_depack_asm_safe(src, srclen, dst, dstlen)
+       
+    if dstlen == -1:
+        raise ValueError('Decompression error.')
+    
+    return buffer(dst, 0, dstlen)
+
+def depack_safe(src):
+
+    srclen = len(src)
+    if srclen <= 0:
+        raise ValueError('Invalid input.')
+    
+    dstlen = _aplib.aPsafe_get_orig_size(src)
+    dst = create_string_buffer(dstlen)
+
+    dstlen = _aplib.aPsafe_depack(src, srclen, dst, dstlen)
+       
+    if dstlen == -1:
+        raise ValueError('Decompression error.')
+    
+    return buffer(dst, 0, dstlen)
+
+def depack_no_header(src):
+    # uses aP_depack_asm_fast to decompress buffer
+    srclen = len(src)
+    # probably could allocate less but don't really care 
+    dstlen = 50 * srclen
+    if srclen <= 0 or dstlen <= 0:
+        raise ValueError('Invalid input.')
+    
+    dst = create_string_buffer(dstlen)
+
+    dstlen = _aplib.aP_depack_asm_fast(src, dst)
+       
+    if dstlen == -1:
+        raise ValueError('Decompression error.')
+    
+    return buffer(dst, 0, dstlen)
+
+################################################################################
+
+if __name__ == "__main__":
+    import optparse
+
+    parser = optparse.OptionParser(
+        usage='%prog [-h] [-v] -m c|d infile outfile'
+        )
+    parser.add_option(
+        '-m', '--mode',
+        action="store",
+        type="string", 
+        dest='mode',
+        help='c for compress, d for decompress')
+    parser.add_option(
+        '-v', '--verbose',
+        action="store_true",
+        dest='verbose')
+
+    options, args = parser.parse_args()
+    if not options.mode in ['c', 'd', 'dnh']:
+        parser.error('You must give a valid --mode')
+    if not len(args) == 2:
+        parser.error('You must give in- and outfile')
+
+    infile = args[0]
+    outfile = args[1]
+
+    src = open(infile, 'rb').read()
+
+    if options.mode == 'c':
+        print "Compressing '%s' to '%s'" % (infile, outfile)
+        if options.verbose:
+            dst = pack_safe(src, _cbCompressFunc)
+        else:
+            print "called"
+            dst = pack_safe(src)
+        open(outfile, 'wb').write(dst)
+        print "Compressed '%s' from %u to %u bytes (%u%%)" \
+                % (infile, len(src), len(dst), _ratio(len(dst), len(src)))
+    elif options.mode == 'd':
+        print "Decompressing '%s' to '%s'" % (infile, outfile)
+        dst = depack_safe(src)
+        open(outfile, 'wb').write(dst)
+        print "Decompressed '%s' from %u to %u bytes (%u%%)" \
+                % (infile, len(src), len(dst), _ratio(len(dst), len(src)))
+    elif options.mode == 'dnh':
+        print "Decompressing '%s' to '%s'" % (infile, outfile)
+        dst = depack_no_header(src)
+        open(outfile, 'wb').write(dst)
+        print "Decompressed '%s' from %u to %u bytes (%u%%)" \
+                % (infile, len(src), len(dst), _ratio(len(dst), len(src)))
+
+################################################################################
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