87 lines
3.4 KiB
Python
Executable file
87 lines
3.4 KiB
Python
Executable file
#!/usr/bin/python
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'''
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@author - e
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@date - 9/3/2013
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'''
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import sys
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import argparse
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import struct
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# Magic number and line ending bits in the PNG header
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pngFixedHeader = "\x89\x50\x4e\x47\x0d\x0a" + "\x1a\x0a"
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# A colorful reference image (3 chunks)
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imageData = "\x00\x00\x00\x0d\x49\x48\x44\x52\x00\x00\x00\x80\x00\x00\x00\x44\x08\x02\x00\x00\x00\xc6\x25\xaa\x3e"+\
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"\x00\x00\x00\xc2\x49\x44\x41\x54\x78\x5e\xed\xd4\x81\x06\xc3\x30\x14\x40\xd1\xb7\x34\xdd\xff\xff\x6f\xb3\x74\x56\xea\x89\x12\x6c\x28\x73\xe2\xaa\x34\x49\x03\x87\xd6\xfe\xd8\x7b\x89\xbb\x52\x8d\x3b\x87\xfe\x01\x00\x80\x00\x00\x10\x00\x00\x02\x00\x40\x00\x00\x08\x00\x00\x01\x00\x20\x00\x00\x04\x00\x80\x00\x00\x10\x00\x00\x02\x00\x40\x00\x00\x08\x00\x00\x01\x00\x20\x00\x00\x00\xd4\x5e\x6a\x64\x4b\x94\xf5\x98\x7c\xd1\xf4\x92\x5c\x5c\x3e\xcf\x9c\x3f\x73\x71\x58\x5f\xaf\x8b\x79\x5b\xee\x96\xb6\x47\xeb\xf1\xea\xd1\xce\xb6\xe3\x75\x3b\xe6\xb9\x95\x8d\xc7\xce\x03\x39\xc9\xaf\xc6\x33\x93\x7b\x66\x37\xcf\xab\xbf\xf9\xc9\x2f\x08\x80\x00\x00\x10\x00\x00\x02\x00\x40\x00\x00\x08\x00\x00\x01\x00\x20\x00\x00\x04\x00\x80\x00\x00\x10\x00\x00\x02\x00\x40\x00\x00\x08\x00\x00\x01\x00\x20\x00\x00\x8c\x37\xdb\x68\x03\x20\xfb\xed\x96\x65\x00\x00\x00\x00\x49\x45\x4e\x44\xae\x42\x60\x82"
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# Reference image if we want to write data
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fakeimage = pngFixedHeader+imageData
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# A simple routine to search from the start of an assumed valid PNG file, and find the IEND block
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# indicating the end of a file.
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def findLastChunk(infile):
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# Assume inital offset of PNG fixed header
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with open(infile, "rb") as f:
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ckStart=len(pngFixedHeader);
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while f.read(1) != "":
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f.seek(ckStart)
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# Find the length of the current chunk
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ckSize = struct.unpack(">i", f.read(4))[0]
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# Get the type of the cunk
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ckType = f.read(4)
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# From the size compute the start of the next chunk
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ckStart=(ckStart+8+ckSize+4);
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# Uncomment to retreve chunk data and CRC
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#ckDat = f.read(ckSize)
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#ckCrc = f.read(4)
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# If we're at the end of a chunk, return the end of the chunk
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if ckType == "IEND":
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break;
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# Return the index to the trailing data.
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return ckStart
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def pngit(infile, outfile, nowrite=0):
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outcounter = 0
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with open(outfile, "wb") as theoutf:
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with open(infile, "rb") as f:
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if nowrite == 0:
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theoutf.write(fakeimage)
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else:
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f.seek(nowrite)
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byte = f.read(1)
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while byte != "":
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theoutf.write(byte)
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byte = f.read(1)
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def unpngit(infile, outfile):
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dataStart = findLastChunk(infile)
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pngit(infile, outfile, dataStart)
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if __name__ == '__main__':
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parser = argparse.ArgumentParser(description='Process some integers.')
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parser.add_argument('-i', '--input', help='the input file you want to perform a png or unpng operation on.')
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parser.add_argument('-o', '--output', help='the output file after the png or unpng operation.')
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parser.add_argument('-u', '--unpng', action='store_true', help='use this flag to unpng a file that looks like a png file')
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args = parser.parse_args()
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if (not (args.input or args.output)):
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print "Usage:"
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print "\tpython pnger.py -i <from_file> -o <to_file> [optional] -u"
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print "Example:"
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print "\tpython pnger.py -i NSASecrets.txt -o NSASecrets.png"
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print "\tpython pnger.py -i example.cpp -o ireallyenjoycarpeting.png"
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print "\tpython pnger.py -i example.png -o example.cpp --unpng"
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else:
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if args.unpng:
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unpngit(args.input, args.output)
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else:
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pngit(args.input, args.output)
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