Rojj Rojj - 1 year ago 140
Ruby Question

Ruby - Unpack irregular binary string

I have an irregular binary file that has been produced by an external program.

The beginning of the file looks like this


As you can see, it has a repetitive pattern:

  • String (unspecified length)

  • tab (\t)

  • 6 floats

  • Repeat

In the ASCII version the first three elements would constitute a line:

mct_terrain_material 2.814988e+01 1.279283e+01 0.000000e+00 0.000000e+00 0.000000e+00 -1.000000e+00
FrontColor 2.814988e+01 2.571460e+01 2.437201e+00 0.000000e+00 9.986295e-01 5.233596e-02

There is no newline in the binary version.

I know how to unpack strings with only one type. In that case I would do:


My first idea was to use
and then build one by one starting the unpacking from the second element, but I think that there should be a more elegant solution.

Any idea?

Answer Source

Could you try something along the lines of:

while string = file.gets("\t") # separator instead of \n
  binary =*4) # or whatever size of the float is
  floats = binary.unpack('F*') # or however you unpack this to array
  # do whatever with string and floats
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