sndiod: Use the channel mapping code of aucat

For now sndiod uses only a subset of the available channel mappings.
It gives the same result as the previous one, but having the same
in both programs makes code review and testing easier.

diff --git a/usr.bin/sndiod/dsp.c b/usr.bin/sndiod/dsp.c
index f3420d1..2aa1cb1 100644 (file)
--- a/usr.bin/sndiod/dsp.c
+++ b/usr.bin/sndiod/dsp.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: dsp.c,v 1.20 2024/04/22 11:07:42 ratchov Exp $        */
+/*     $OpenBSD: dsp.c,v 1.21 2024/04/22 14:11:35 ratchov Exp $        */
 /*
  * Copyright (c) 2008-2012 Alexandre Ratchov <alex@caoua.org>
  *
@@ -834,33 +834,35 @@ cmap_init(struct cmap *p,
     int imin, int imax, int isubmin, int isubmax,
     int omin, int omax, int osubmin, int osubmax)
 {
-       int cmin, cmax;
-
-       cmin = -NCHAN_MAX;
-       if (osubmin > cmin)
-               cmin = osubmin;
-       if (omin > cmin)
-               cmin = omin;
-       if (isubmin > cmin)
-               cmin = isubmin;
-       if (imin > cmin)
-               cmin = imin;
-
-       cmax = NCHAN_MAX;
-       if (osubmax < cmax)
-               cmax = osubmax;
-       if (omax < cmax)
-               cmax = omax;
-       if (isubmax < cmax)
-               cmax = isubmax;
-       if (imax < cmax)
-               cmax = imax;
-
-       p->ostart = cmin - omin;
-       p->onext = omax - cmax;
-       p->istart = cmin - imin;
-       p->inext = imax - cmax;
-       p->nch = cmax - cmin + 1;
+       int inch, onch, nch;
+
+       /*
+        * Ignore channels outside of the available sets
+        */
+       if (isubmin < imin)
+               isubmin = imin;
+       if (isubmax > imax)
+               isubmax = imax;
+       if (osubmin < omin)
+               osubmin = omin;
+       if (osubmax > omax)
+               osubmax = omax;
+
+       /*
+        * Shrink the input or the output subset to make both subsets of
+        * the same size
+        */
+       inch = isubmax - isubmin + 1;
+       onch = osubmax - osubmin + 1;
+       nch = (inch < onch) ? inch : onch;
+       isubmax = isubmin + nch - 1;
+       osubmax = osubmin + nch - 1;
+
+       p->ostart = osubmin - omin;
+       p->onext = omax - osubmax;
+       p->istart = isubmin - imin;
+       p->inext = imax - isubmax;
+       p->nch = nch;
 #ifdef DEBUG
        if (log_level >= 3) {
                log_puts("cmap: nch = ");