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/*
twarp.c:
Copyright (C) 1991 Barry Vercoe, John ffitch
This file is part of Csound.
The Csound Library is free software; you can redistribute it
and/or modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
Csound is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with Csound; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
02110-1301 USA
*/
#include "csoundCore.h" /* TWARP.C */
typedef struct {
MYFLT betbas;
MYFLT durslp;
MYFLT durbas;
MYFLT timbas;
} TSEG;
int realtset(CSOUND *, SRTBLK *);
MYFLT realt(CSOUND *, MYFLT);
void twarp(CSOUND *csound) /* time-warp a score section acc to T-statement */
{
SRTBLK *bp;
MYFLT absp3;
MYFLT endtime;
int negp3;
if (UNLIKELY((bp = csound->frstbp) == NULL)) /* if null file, */
return;
while (bp->text[0] != 't') /* or cannot find a t, */
if (UNLIKELY((bp = bp->nxtblk) == NULL))
return; /* we are done */
bp->text[0] = 'w'; /* else mark the t used */
if (!realtset(csound, bp)) /* and init the t-array */
return; /* (done if t0 60 or err) */
bp = csound->frstbp;
negp3 = 0;
do {
switch (bp->text[0]) { /* else warp all timvals */
case 'i':
absp3 = bp->newp3;
if (UNLIKELY(absp3 < 0)) {
absp3 = -absp3;
negp3++;
}
endtime = bp->newp2 + absp3;
bp->newp2 = realt(csound, bp->newp2);
bp->newp3 = realt(csound, endtime) - bp->newp2;
if (negp3) {
bp->newp3 = -bp->newp3;
negp3--;
}
break;
case 'a':
endtime = bp->newp2 + bp->newp3;
bp->newp2 = realt(csound, bp->newp2);
bp->newp3 = realt(csound, endtime) - bp->newp2;
break;
case 'f':
case 'q':
bp->newp2 = realt(csound, bp->newp2);
break;
case 't':
case 'w':
break;
case 's':
case 'e':
if (bp->pcnt > 0)
bp->newp2 = realt(csound, bp->p2val);
break;
default:
csound->Message(csound, Str("twarp: illegal opcode\n"));
break;
}
} while ((bp = bp->nxtblk) != NULL);
}
int realtset(CSOUND *csound, SRTBLK *bp)
{
char *p;
char c;
MYFLT tempo, betspan, durbas, avgdur, stof(CSOUND *, char *);
TSEG *tp, *prvtp;
TSEG *tseg = (TSEG*)csound->tseg;
csound->tseg =
tseg = (TSEG*)csound->ReAlloc(csound,
tseg, (1+bp->pcnt/2) * sizeof(TSEG));
//tplim = &tseg[(bp->pcnt/2)];
//csound->tseglen = 1+bp->pcnt/2;
tp = (TSEG*) (csound->tpsave = tseg);
if (UNLIKELY(bp->pcnt < 2))
goto error1;
p = bp->text; /* first go to p1 */
p += 2;
if (UNLIKELY((tp->betbas = stof(csound, p)) != 0)) /* betbas1 must be zero */
goto error1;
while ((c = *p++) != SP) {}
if (UNLIKELY((tempo = stof(csound, p)) <= 0)) /* durbas = 60/tempo */
goto error2;
if (bp->pcnt == 2 && tempo == FL(60.0)) /* just t0 60 means done */
return(0);
tp->durbas = FL(60.0)/tempo;
tp->timbas = FL(0.0); /* timbas1 = 0 */
while ((c = *p++) != SP && c != LF) {}
while (c != LF) { /* for each time-tempo pair: */
prvtp = tp;
++tp;
tp->betbas = stof(csound, p); /* betbas = time */
while ((c = *p++) != SP && c != LF) {}
if (UNLIKELY(c == LF))
goto error1;
if (UNLIKELY((tempo = stof(csound, p)) <= 0)) /* get tempo */
goto error2;
if ((betspan = tp->betbas - prvtp->betbas) <= 0) {
if (UNLIKELY(betspan < 0)) /* if time = lastime */
goto error1;
tp--; /* overwrit prvdurbas*/
tp->durbas = FL(60.0)/tempo; /* with 60/tempo */
goto align; /* and reloop */
}
tp->durbas = durbas = FL(60.0)/tempo; /* else this durbas */
avgdur = (durbas + prvtp->durbas)*FL(0.5);
tp->timbas = avgdur*betspan + prvtp->timbas; /* set timbas*/
prvtp->durslp = (avgdur - prvtp->durbas)/betspan;/* prvdurslp*/
align:
while ((c = *p++) != SP && c != LF) {}
}
tp->durslp = FL(0.0); /* clear last durslp */
++tp;
tp->betbas = FL(9223372036854775807.0); /* and cap with large betval */
return(1);
error1:
csound->Message(csound,Str("twarp: t has extra or disordered beat value\n"));
return(0);
error2:
csound->Message(csound,Str("twarp: t has non-positive tempo\n"));
return(0);
}
MYFLT realt(CSOUND *csound, MYFLT srctim)
{
TSEG *tp;
MYFLT diff;
tp = (TSEG*) csound->tpsave;
while (srctim >= (tp+1)->betbas)
tp++;
while ((diff = srctim - tp->betbas) < FL(0.0))
tp--;
csound->tpsave = tp;
return ((tp->durslp * diff + tp->durbas) * diff + tp->timbas);
}
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