Have IAX2 optimize the codec translation path just like chan_sip does it. If

the caller's codec is in our codec list, move it to the top to avoid transcoding.

(closes issue #10500)
Reported by: stevedavies
Patches:
      iax-prefer-current-codec.patch uploaded by stevedavies (license 184)
      iax-prefer-current-codec.1.4.patch uploaded by stevedavies (license 184)
Tested by: stevedavies, pj, sheldonh


git-svn-id: http://svn.digium.com/svn/asterisk/branches/1.4@99004 f38db490-d61c-443f-a65b-d21fe96a405b

1 files changed, 37 insertions, 1 deletions

diff --git a/main/frame.c b/main/frame.c
index 88f6b4e76..9ac309fa3 100644
--- a/main/frame.c
+++ b/main/frame.c
@@ -1149,7 +1149,7 @@ void ast_codec_pref_remove(struct ast_codec_pref *pref, int format)
 /*! \brief Append codec to list */
 int ast_codec_pref_append(struct ast_codec_pref *pref, int format)
 {
-	int x, newindex = -1;
+	int x, newindex = 0;
 
 	ast_codec_pref_remove(pref, format);
 
@@ -1172,6 +1172,42 @@ int ast_codec_pref_append(struct ast_codec_pref *pref, int format)
 	return x;
 }
 
+/*! \brief Prepend codec to list */
+void ast_codec_pref_prepend(struct ast_codec_pref *pref, int format, int only_if_existing)
+{
+	int x, newindex = 0;
+
+	/* First step is to get the codecs "index number" */
+	for (x = 0; x < ARRAY_LEN(AST_FORMAT_LIST); x++) {
+		if (AST_FORMAT_LIST[x].bits == format) {
+			newindex = x + 1;
+			break;
+		}
+	}
+	/* Done if its unknown */
+	if (!newindex)
+		return;
+
+	/* Now find any existing occurrence, or the end */
+	for (x = 0; x < 32; x++) {
+		if (!pref->order[x] || pref->order[x] == newindex)
+			break;
+	}
+
+	if (only_if_existing && !pref->order[x])
+		return;
+
+	/* Move down to make space to insert - either all the way to the end,
+	   or as far as the existing location (which will be overwritten) */
+	for (; x > 0; x--) {
+		pref->order[x] = pref->order[x - 1];
+		pref->framing[x] = pref->framing[x - 1];
+	}
+
+	/* And insert the new entry */
+	pref->order[0] = newindex;
+	pref->framing[0] = 0; /* ? */
+}
 
 /*! \brief Set packet size for codec */
 int ast_codec_pref_setsize(struct ast_codec_pref *pref, int format, int framems)