[clisp-list] writing binary files

[Daniel S. <dv...@ea...>]

Sam,

Perhaps a dumb question.  I should probably have learned
this in some obvious reverence.

I wrote a sound-generation program that makes .AIF files.
I write the sound samples sequentionally into the file with this ...

(defmacro write-integer (n outfil &optional (nbytes 2) &aux stash)
   (dotimes (i (1- nbytes)) (push (list 'ash n (* -8 (1+ i))) stash))
   `(progn ,@(mapcar (lambda (x) `(write-byte (logand ,x 255) ,outfil))
                     (reverse (cons n stash)))))

It writes integers of nbytes into a binary file.

In order to do rescaling, I want to write binary files of floating-point
numbers, ... and fast.  Put differently, I want to #'logand and #'ash
the bits of floating-point numbers.

The CL floating-point conversion functions don’t quite do the job.
They will break it up into <sign exponent mantissa>.
I want something like #'float-as-integer, and then something to
undo that on reading it back in.

-- devious dan