Greatly simplify the resampling routine using the fact it processes

exactly one block.

2 files changed, 21 insertions, 54 deletions

diff --git a/usr.bin/sndiod/dsp.c b/usr.bin/sndiod/dsp.c
index 794e43ebffc..d0446f10793 100644
--- a/usr.bin/sndiod/dsp.c
+++ b/usr.bin/sndiod/dsp.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dsp.c,v 1.12 2016/10/27 04:37:47 ratchov Exp $	*/
+/*	$OpenBSD: dsp.c,v 1.13 2018/06/08 06:21:56 ratchov Exp $	*/
 /*
  * Copyright (c) 2008-2012 Alexandre Ratchov <alex@caoua.org>
  *
@@ -200,21 +200,26 @@ aparams_native(struct aparams *par)
 /*
  * resample the given number of frames
  */
-int
+void
 resamp_do(struct resamp *p, adata_t *in, adata_t *out, int todo)
 {
 	unsigned int nch;
 	adata_t *idata;
 	unsigned int oblksz;
-	unsigned int ifr;
 	int s, ds, diff;
 	adata_t *odata;
 	unsigned int iblksz;
-	unsigned int ofr;
 	unsigned int c;
 	adata_t *ctxbuf, *ctx;
 	unsigned int ctx_start;
 
+#ifdef DEBUG
+	if (todo % p->iblksz != 0) {
+		log_puts("resamp_do: partial blocks not supported\n");
+		panic();
+	}
+#endif
+
 	/*
 	 * Partially copy structures into local variables, to avoid
 	 * unnecessary indirections; this also allows the compiler to
@@ -222,30 +227,16 @@ resamp_do(struct resamp *p, adata_t *in, adata_t *out, int todo)
 	 */
 	idata = in;
 	odata = out;
-	diff = p->diff;
+	diff = p->oblksz;
 	iblksz = p->iblksz;
 	oblksz = p->oblksz;
 	ctxbuf = p->ctx;
 	ctx_start = p->ctx_start;
 	nch = p->nch;
-	ifr = todo;
-	ofr = oblksz;
 
-	/*
-	 * Start conversion.
-	 */
-#ifdef DEBUG
-	if (log_level >= 4) {
-		log_puts("resamp: copying ");
-		log_puti(todo);
-		log_puts(" frames, diff = ");
-		log_putu(diff);
-		log_puts("\n");
-	}
-#endif
 	for (;;) {
-		if (diff < 0) {
-			if (ifr == 0)
+		if (diff >= oblksz) {
+			if (todo == 0)
 				break;
 			ctx_start ^= 1;
 			ctx = ctxbuf + ctx_start;
@@ -253,43 +244,21 @@ resamp_do(struct resamp *p, adata_t *in, adata_t *out, int todo)
 				*ctx = *idata++;
 				ctx += RESAMP_NCTX;
 			}
-			diff += oblksz;
-			ifr--;
-		} else if (diff > 0) {
-			if (ofr == 0)
-				break;
+			diff -= oblksz;
+			todo--;
+		} else {
 			ctx = ctxbuf;
 			for (c = nch; c > 0; c--) {
-				s = ctx[ctx_start];
-				ds = ctx[ctx_start ^ 1] - s;
+				s = ctx[ctx_start ^ 1];
+				ds = ctx[ctx_start] - s;
 				ctx += RESAMP_NCTX;
 				*odata++ = s + ADATA_MULDIV(ds, diff, oblksz);
 			}
-			diff -= iblksz;
-			ofr--;
-		} else {
-			if (ifr == 0 || ofr == 0)
-				break;
-			ctx = ctxbuf + ctx_start;
-			for (c = nch; c > 0; c--) {
-				*odata++ = *ctx;
-				ctx += RESAMP_NCTX;
-			}
-			ctx_start ^= 1;
-			ctx = ctxbuf + ctx_start;
-			for (c = nch; c > 0; c--) {
-				*ctx = *idata++;
-				ctx += RESAMP_NCTX;
-			}
-			diff -= iblksz;
-			diff += oblksz;
-			ifr--;
-			ofr--;
+			diff += iblksz;
 		}
 	}
-	p->diff = diff;
+
 	p->ctx_start = ctx_start;
-	return oblksz - ofr;
 }
 
 /*
@@ -303,7 +272,6 @@ resamp_init(struct resamp *p, unsigned int iblksz,
 
 	p->iblksz = iblksz;
 	p->oblksz = oblksz;
-	p->diff = 0;
 	p->nch = nch;
 	p->ctx_start = 0;
 	for (i = 0; i < NCHAN_MAX * RESAMP_NCTX; i++)
diff --git a/usr.bin/sndiod/dsp.h b/usr.bin/sndiod/dsp.h
index e5647b23ceb..3b75a13680f 100644
--- a/usr.bin/sndiod/dsp.h
+++ b/usr.bin/sndiod/dsp.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dsp.h,v 1.6 2016/10/20 05:29:55 ratchov Exp $	*/
+/*	$OpenBSD: dsp.h,v 1.7 2018/06/08 06:21:56 ratchov Exp $	*/
 /*
  * Copyright (c) 2012 Alexandre Ratchov <alex@caoua.org>
  *
@@ -115,7 +115,6 @@ struct resamp {
 	unsigned int ctx_start;
 	adata_t ctx[NCHAN_MAX * RESAMP_NCTX];
 	unsigned int iblksz, oblksz;
-	int diff;
 	int nch;
 };
 
@@ -146,7 +145,7 @@ int aparams_strtoenc(struct aparams *, char *);
 int aparams_enctostr(struct aparams *, char *);
 int aparams_native(struct aparams *);
 
-int resamp_do(struct resamp *, adata_t *, adata_t *, int);
+void resamp_do(struct resamp *, adata_t *, adata_t *, int);
 void resamp_init(struct resamp *, unsigned int, unsigned int, int);
 void enc_do(struct conv *, unsigned char *, unsigned char *, int);
 void enc_sil_do(struct conv *, unsigned char *, int);