[SciPy-User] AT&T format

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[SciPy-User] AT&T format

Slavin, Jonathan
​Have you looked at the python library struct?  I don't know anything about the AT&T format but I have been able to read Fortran unformatted data using it.  It depends on knowing the number of padding bytes on each line, etc.  Anyways, could be useful.

Jon​

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Excellent.

We are working with DSP32C legacy data, and of course it is not a
native type. The original C code is no longer available so this is
our numpy implementation...
Might there be a "better" method to support the AT&T format?

def dsp32c_to_float(bytes):
   dsp32c_array = np.frombuffer(bytes, np.int32)
   signed = dsp32c_array & 0x80000000 > 0
   exponent = (dsp32c_array & 0x000000ff) << 23
   mantissa = (dsp32c_array & 0x7fffffff) >> 8
   mantissa[signed] = 0x80000000 + ~mantissa[signed]
   ieee_array = exponent + mantissa
   float_array = ieee_array.view('f')
   return float_array

Of course if anyone out there has a stashed copy of dsptools.c
void ieeetodspf( float *x);
void dspftoieee( float *x);
http://www.symres.com/files/legacy/mandsp.pdf
it would go a long way...





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Jonathan D. Slavin                 Harvard-Smithsonian CfA
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