mirror of
https://github.com/cookiengineer/audacity
synced 2025-05-04 17:49:45 +02:00
93 lines
3.3 KiB
Plaintext
93 lines
3.3 KiB
Plaintext
(IFFT-ALG
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(NAME "ifft")
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(ARGUMENTS ("time_type" "t0") ("rate_type" "sr") ("LVAL" "src"))
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(SUPPORT-FUNCTIONS "
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/* IMPLEMENTATION NOTE:
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* The src argument is an XLisp object that returns either an
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* array of samples or NIL. The output of ifft is simply the
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* concatenation of the samples taken from the array. Later,
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* an ifft will be plugged in and this will return overlapped
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* adds of the ifft's.
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*/
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#include \"samples.h\"
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/* IFFT code goes here */
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")
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(SAMPLE-RATE "sr")
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(STATE
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("long" "index" "0") ; samples index
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("long" "length" "0"); samples length
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("LVAL" "array" "NULL")
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("LVAL" "src" "src")
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("sample_type *" "samples" "NULL"))
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(OUTER-LOOP "
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if (susp->src == NULL) {
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out: togo = 0; /* indicate termination */
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break; /* we're done */
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}
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if (susp->index >= susp->length) {
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long i;
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susp->index = 0;
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susp->array = xleval(cons(s_send, cons(susp->src, consa(s_next))));
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susp->index = 0;
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if (susp->array == NULL) {
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susp->src = NULL;
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goto out;
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} else if (!vectorp(susp->array)) {
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xlerror(\"array expected\", susp->array);
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} else if (susp->samples == NULL) {
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/* assume arrays are all the same size as first one;
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now that we know the size, we just have to do this
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first allocation.
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*/
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susp->length = getsize(susp->array);
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if (susp->length < 1) xlerror(\"array has no elements\", susp->array);
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susp->samples =
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(sample_type *) calloc(susp->length,
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sizeof(sample_type));
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} else if (getsize(susp->array) != susp->length) {
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xlerror(\"arrays must all be the same length\", susp->array);
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}
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/* at this point, we have a new array and a place to put samples */
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for (i = 0; i < susp->length; i++) {
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LVAL elem = getelement(susp->array, i);
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if (ntype(elem) != FLONUM) {
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xlerror(\"flonum expected\", elem);
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}
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susp->samples[i] = (sample_type) getflonum(elem);
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}
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susp->array = NULL; /* free the array */
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/* here is where the IFFT and windowing should take place */
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/*
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temp_fft = (double *) malloc (susp->length * sizeof(double));
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if (temp_fft == 0) return;
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big_samples = (double *) malloc (susp->length * sizeof(double));
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if (big_samples == 0) return;
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for (i = 0; i < susp->length; i++) {
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big_samples[i] = (double) susp->samples[i];
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}
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rp = rfftw_create_plan(susp->length, FFTW_COMPLEX_TO_REAL, FFTW_ESTIMATE);
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rfftw_one(rp, big_samples, temp_fft);
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rfftw_destroy_plan(rp);
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free(big_samples);
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for (i = 0; i < susp->length; i++) {
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setelement(result, i, cvflonum(temp_fft[i]));
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}
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free (temp_fft);
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*/
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}
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togo = min(togo, susp->length - susp->index);
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")
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(INNER-LOOP "output = samples[index++];")
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(CONSTANT "length" "samples" "array" "src")
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(TERMINATE COMPUTED)
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(FINALIZATION " free(susp->samples);
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")
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)
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