ref: 9211d95a76975169ee7b71fc74582e5707e3fa04
dir: /tangled/vardelay.c/
#line 18 "vardelay.org" #include <math.h> #include <stdlib.h> #define SK_VARDELAY_PRIV #include "vardelay.h" #line 57 "vardelay.org" void sk_vardelay_init(sk_vardelay *vd, int sr, SKFLT *buf, unsigned long sz) { #line 92 "vardelay.org" vd->sr = sr; #line 112 "vardelay.org" if (sz < 4) { vd->buf = NULL; vd->buf = 0; } else { vd->buf = buf; vd->sz = sz; } #line 135 "vardelay.org" vd->prev = 0; #line 156 "vardelay.org" vd->writepos = 0; #line 185 "vardelay.org" sk_vardelay_delay(vd, ((SKFLT)sz / sr) * 0.5); #line 213 "vardelay.org" sk_vardelay_feedback(vd, 0); #line 61 "vardelay.org" } #line 169 "vardelay.org" void sk_vardelay_delay(sk_vardelay *vd, SKFLT delay) { vd->delay = delay; } #line 198 "vardelay.org" void sk_vardelay_feedback(sk_vardelay *vd, SKFLT feedback) { vd->feedback = feedback; } #line 225 "vardelay.org" SKFLT sk_vardelay_tick(sk_vardelay *vd, SKFLT in) { SKFLT out; SKFLT dels; SKFLT f; long i; SKFLT s[4]; unsigned long n[4]; SKFLT a, b, c, d; out = 0; #line 254 "vardelay.org" if (vd->buf == NULL || vd->sz == 0) return 0; #line 225 "vardelay.org" #line 261 "vardelay.org" vd->buf[vd->writepos] = in + vd->prev * vd->feedback; #line 225 "vardelay.org" #line 274 "vardelay.org" dels = vd->delay * vd->sr; i = floor(dels); f = i - dels; i = vd->writepos - i; #line 225 "vardelay.org" #line 299 "vardelay.org" if ((f < 0.0) || (i < 0)) { /* flip fractional component */ f = f + 1.0; /* go backwards one sample */ i = i - 1; while (i < 0) i += vd->sz; } else while(i >= vd->sz) i -= vd->sz; #line 225 "vardelay.org" #line 313 "vardelay.org" /* x(n) */ n[1] = i; /* x(n + 1) */ if (i == (vd->sz - 1)) n[2] = 0; else n[2] = n[1] + 1; /* x(n - 1) */ if (i == 0) n[0] = vd->sz - 1; else n[0] = i - 1; if (n[2] == vd->sz - 1) n[3] = 0; else n[3] = n[2] + 1; { int j; for (j = 0; j < 4; j++) s[j] = vd->buf[n[j]]; } #line 225 "vardelay.org" #line 338 "vardelay.org" { SKFLT tmp[2]; d = ((f * f) - 1) * 0.1666666667; tmp[0] = (f + 1.0) * 0.5; tmp[1] = 3.0 * d; a = tmp[0] - 1.0 - d; c = tmp[0] - tmp[1]; b = tmp[1] - f; } #line 225 "vardelay.org" #line 358 "vardelay.org" out = (a*s[0] + b*s[1] + c*s[2] + d*s[3]) * f + s[1]; #line 225 "vardelay.org" #line 366 "vardelay.org" vd->writepos++; if (vd->writepos == vd->sz) vd->writepos = 0; #line 225 "vardelay.org" #line 375 "vardelay.org" vd->prev = out; #line 245 "vardelay.org" return out; } #line 18 "vardelay.org"