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(SAMPLER-ALG
(NAME "sampler")
(ARGUMENTS ("sound_type" "s") ("double" "step") ("double" "loop_start")
("rate_type" "sr") ("double" "hz") ("time_type" "t0")
("sound_type" "s_fm") ("long" "npoints"))
(TABLE "s")
(NOT-IN-INNER-LOOP "s")
(STATE
("double" "loop_to" "loop_start * s->sr")
("table_type" "the_table" "sound_to_table(s)")
("sample_type *" "table_ptr" "susp->the_table->samples")
("double" "table_len" "susp->the_table->length;")
("double" "phase" "0.0")
("double" "ph_incr" "(s->sr / sr) * hz / step_to_hz(step);
s_fm->scale = (sample_type) (s_fm->scale * (susp->ph_incr / hz));
/* make sure parameters are ok
* the table must have samples
* the loop_start must be before the end of the table
* ph_incr must be positive
* sr should be positive
*/
{ long index = (long) susp->loop_to;
double frac = susp->loop_to - index;
if (susp->the_table->length <= 1) {
xlfail(\"sampler table length <= 1\");
}
if (index > round(susp->table_len) - 2 ||
index < 0) {
xlfail(\"sampler loop start not within samples\");
}
if (susp->ph_incr <= 0) {
xlfail(\"sampler phase increment <= 0\");
}
if (sr <= 0) {
xlfail(\"sampler sample rate <= 0\");
}
/* copy interpolated start to last entry */
susp->table_ptr[round(susp->table_len)] =
(sample_type) (susp->table_ptr[index] * (1.0 - frac) +
susp->table_ptr[index + 1] * frac);}")
)
(ALWAYS-SCALE s_fm)
(STEP-FUNCTION s_fm)
(TERMINATE (MIN s_fm))
(LOGICAL-STOP (MIN s_fm))
(INNER-LOOP-LOCALS " long table_index;
double x1;
")
(INNER-LOOP "table_index = (long) phase;
x1 = table_ptr[table_index];
output = (sample_type) (x1 + (phase - table_index) *
(table_ptr[table_index + 1] - x1));
phase += ph_incr + s_fm;
while (phase > table_len) phase -= (table_len - loop_to);
/* watch out for negative frequencies! */
if (phase < 0) phase = 0")
(CONSTANT "ph_incr" "table_len" "table_ptr" "loop_to")
(SAMPLE-RATE "sr")
(FINALIZATION " table_unref(susp->the_table);\n")
)
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