From cbe7f5735635c9661dc66840657d271d1f418766 Mon Sep 17 00:00:00 2001
From: Vadim Yanitskiy <axilirator@gmail.com>
Date: Mon, 19 Jun 2017 05:41:49 +0700
Subject: [PATCH] core/conv/viterbi.c: delete reset_decoder()

Currently this implementation exposes nothing than
osmo_conv_decode_acc(), so it wasn't possible to call
reset_decoder() from outside.

The method itself was used to initialize accumulated
path metrics and the starting state of encoder. Now
this code is moved to generate_trellis().

Moreover, setting accumulated path metrics inside
existing loop is a bit faster that calling memset().

Change-Id: I8f17cebf468cf0106927ccee091cfb2896649cb2
---
 src/viterbi.c | 33 +++++++++++++--------------------
 1 file changed, 13 insertions(+), 20 deletions(-)

diff --git a/src/viterbi.c b/src/viterbi.c
index 957408402..7777f9632 100644
--- a/src/viterbi.c
+++ b/src/viterbi.c
@@ -413,10 +413,21 @@ static struct vtrellis *generate_trellis(const struct osmo_conv_code *code)
 			rc = gen_state_info(&trellis->vals[i],
 				i, outputs, code);
 		}
+
+		if (rc < 0)
+			goto fail;
+
+		/* Set accumulated path metrics to zero */
+		trellis->sums[i] = 0;
 	}
 
-	if (rc < 0)
-		goto fail;
+	/**
+	 * For termination other than tail-biting, initialize the zero state
+	 * as the encoder starting state. Initialize with the maximum
+	 * accumulated sum at length equal to the constraint length.
+	 */
+	if (code->term != CONV_TERM_TAIL_BITING)
+		trellis->sums[0] = INT8_MAX * code->N * code->K;
 
 	return trellis;
 
@@ -425,22 +436,6 @@ fail:
 	return NULL;
 }
 
-/* Reset decoder
- * Set accumulated path metrics to zero. For termination other than
- * tail-biting, initialize the zero state as the encoder starting state.
- * Initialize with the maximum accumulated sum at length equal to the
- * constraint length.
- */
-static void reset_decoder(struct vdecoder *dec, int term)
-{
-	int ns = dec->trellis->num_states;
-
-	memset(dec->trellis->sums, 0, sizeof(int16_t) * ns);
-
-	if (term != CONV_TERM_TAIL_BITING)
-		dec->trellis->sums[0] = INT8_MAX * dec->n * dec->k;
-}
-
 static void _traceback(struct vdecoder *dec,
 	unsigned state, uint8_t *out, int len)
 {
@@ -641,8 +636,6 @@ static int conv_decode(struct vdecoder *dec, const int8_t *seq,
 {
 	int8_t depunc[dec->len * dec->n];
 
-	reset_decoder(dec, term);
-
 	if (punc) {
 		depuncture(seq, punc, depunc, dec->len * dec->n);
 		seq = depunc;