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audacity/lib-src/libnyquist/nyquist/tran/fromarraystream.alg
2015-04-07 22:10:17 -05:00

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(FRMASTRM-ALG
(NAME "fromarraystream")
(ARGUMENTS ("time_type" "t0") ("rate_type" "sr") ("LVAL" "src"))
(SUPPORT-FUNCTIONS "
/* IMPLEMENTATION NOTE:
* The src argument is an XLisp object that returns either an
* array of samples or NIL. The output of ifft is simply the
* concatenation of the samples taken from the array. Later,
* an ifft will be plugged in and this will return overlapped
* adds of the ifft's.
*/
#include \"samples.h\"
")
(SAMPLE-RATE "sr")
(STATE
("long" "index" "0") ; samples index
("long" "length" "0"); samples length
("LVAL" "array" "NULL")
("LVAL" "src" "src")
("sample_type *" "samples" "NULL;"))
(OUTER-LOOP "
if (susp->src == NULL) {
out: togo = 0; /* indicate termination */
break; /* we're done */
}
if (susp->index >= susp->length) {
long i;
susp->index = 0;
susp->array = xleval(cons(s_send, cons(susp->src, consa(s_next))));
susp->index = 0;
if (susp->array == NULL) {
susp->src = NULL;
goto out;
} else if (!vectorp(susp->array)) {
xlerror(\"array expected\", susp->array);
} else if (susp->samples == NULL) {
/* assume arrays are all the same size as first one;
now that we know the size, we just have to do this
first allocation.
*/
susp->length = getsize(susp->array);
if (susp->length < 1) xlerror(\"array has no elements\", susp->array);
susp->samples =
(sample_type *) calloc(susp->length,
sizeof(sample_type));
} else if (getsize(susp->array) != susp->length) {
xlerror(\"arrays must all be the same length\", susp->array);
}
/* at this point, we have a new array and a place to put samples */
for (i = 0; i < susp->length; i++) {
LVAL elem = getelement(susp->array, i);
if (ntype(elem) != FLONUM) {
xlerror(\"flonum expected\", elem);
}
susp->samples[i] = (sample_type) getflonum(elem);
}
susp->array = NULL; /* free the array */
}
togo = min(togo, susp->length - susp->index);
")
(INNER-LOOP "output = samples[index++]")
(CONSTANT "length" "samples" "array" "src")
(TERMINATE COMPUTED)
(FINALIZATION " free(susp->samples);\n")
)