rawlz4.py

#Licensed under the 3-Clause BSD License
#Copyright 2021, Martin Wendt
#Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
#
#1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
#
#2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
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#3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
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#THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
#TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
#CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
#PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
#LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
#SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#======================================================
#This script simply crops out the bare lz4 data load and adds a 16bit size header
import sys
filename=sys.argv[1]
basename=filename[:-4]
header=11
tail=8 #because of endmarker 0,0,0,0 and chechksum
data=open(filename,'rb').read()[header:-tail]
output=open(basename+'prep.dat','wb')   
size16 = len(data)
size_lsb = size16 & 0xff
size_msb = size16 >> 8
size = [size_lsb, size_msb]
databytes=bytearray(size)
output.write(databytes)

databytes=bytearray(data)
output.write(databytes)