codec_mapping: add amr flags

These flags are redundant, the aim is to speed up comparisons of AMR
fmtp when traversing a long list of codec variants. It can skip a lot of
repetitive strcmp and fmtp string parsing when used by a loop.

Change-Id: Ic2c9b4983b5374621e02389900e3622faa29cad9

include/osmocom/msc/codec_mapping.h

@@ -37,6 +37,14 @@ struct codec_mapping {
 	/* If applicable, indicator whether this codec can work on a GERAN half-rate lchan, or whether full-rate is
 	 * required. Leave zero when this codec does not apply to GERAN. */
 	enum codec_frhr frhr;
+	/* Shortcut flags for AMR: there are a lot of entries with sdp.subtype_name = "AMR". These AMR related flags
+	 * duplicate the state of sdp.subtype_name and sdp.fmtp, in order to speed up some codec iterations. */
+	struct {
+		/* true iff sdp.subtype_name = "AMR". */
+		bool is_amr;
+		/* true iff is_amr and sdp.fmtp contains "octet-align=1". */
+		bool is_octet_aligned;
+	} amr;
 };
 
 const struct codec_mapping *codec_mapping_next(const struct codec_mapping *c);

src/libmsc/codec_mapping.c

@@ -136,6 +136,10 @@ static const struct codec_mapping codec_map[] = {
 		}, \
 		.perm_speech = GSM0808_PERM_FR3, \
 		.frhr = CODEC_FRHR_FR, \
+		.amr = { \
+			.is_amr = true, \
+			.is_octet_aligned = IS_OA, \
+		}, \
 	}
 
 #define AMR_HR(IS_OA, FMTP, SPEECH_CODEC_CFG) \
@@ -158,6 +162,10 @@ static const struct codec_mapping codec_map[] = {
 		}, \
 		.perm_speech = GSM0808_PERM_HR3, \
 		.frhr = CODEC_FRHR_HR, \
+		.amr = { \
+			.is_amr = true, \
+			.is_octet_aligned = IS_OA, \
+		}, \
 	}
 
 	/* AMR rates as in 3GPP TS 28.062, Table 7.11.3.1.3-2; gsm0808_speech_codec.cfg is a bitmask of Sn bits: