89 lines
3.0 KiB
Python
89 lines
3.0 KiB
Python
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import argparse
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import os
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from compress import compress_data
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class ApplicationError(Exception):
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pass
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def read_input_file(input_name, skip):
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try:
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with open(input_name, "rb") as ifp:
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# determine input size
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ifp.seek(0, os.SEEK_END)
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input_size = ifp.tell()
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ifp.seek(0, os.SEEK_SET)
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if input_size == 0:
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raise ApplicationError("Empty input file")
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if skip >= input_size:
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raise ApplicationError("Skip value exceeds input file size")
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input_data = bytearray(input_size)
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read_count = ifp.readinto(input_data)
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if read_count != input_size:
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raise ApplicationError("Cannot read input file")
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except FileNotFoundError:
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print(f"Error: Cannot access input file {input_name}")
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exit(1)
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except ApplicationError as e:
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print(f"Error: {e}")
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exit(1)
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return input_data
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def write_output_file(output_name, output_data):
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with open(output_name, "wb") as ofp:
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ofp.write(output_data)
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ofp.close()
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def write_summary(backwards_mode, delta, input_data, output_data, skip):
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text_backwards = " backwards" if backwards_mode else ""
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initial_size = len(input_data) - skip
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output_size = len(output_data)
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print(
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f"File compressed{text_backwards} from {initial_size} to {output_size} bytes! (delta {delta})")
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def main():
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parser = argparse.ArgumentParser(
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description='pyZX0 v2.2: Python port of ZX0 compressor by Einar Saukas for the same version.')
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parser.add_argument('-f', action='store_true', help='Force overwrite of output file', dest='forced_mode')
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parser.add_argument('-c', action='store_true', help='Classic file format (v1.*)', dest='classic_mode')
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parser.add_argument('-b', action='store_true', help='Compress backwards', dest='backwards_mode')
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parser.add_argument('-q', action='store_true', help='Quick non-optimal compression', dest='quick_mode')
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parser.add_argument('-s', type=int, help='Skip first N bytes of input file', dest='skip')
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parser.add_argument('input_name', type=str, help='Input file')
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parser.add_argument('output_name', type=str, nargs='?', help='Output file')
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args = parser.parse_args()
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forced_mode = args.forced_mode
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classic_mode = args.classic_mode
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backwards_mode = args.backwards_mode
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quick_mode = args.quick_mode
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skip = args.skip if args.skip else 0
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output_name = args.output_name if args.output_name else args.input_name + ".zx0"
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input_data = read_input_file(args.input_name, skip)
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if not forced_mode and os.path.exists(output_name):
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raise ApplicationError(f"Already existing output file {output_name}")
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output_data, delta = compress_data(input_data, skip, backwards_mode, classic_mode, quick_mode)
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write_output_file(output_name, output_data)
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write_summary(backwards_mode, delta, input_data, output_data, skip)
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return 0
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if __name__ == "__main__":
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main()
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