[PATCH] Refactor coding scheme assignment code

[msuraev]

From: Max <msur...@sysmocom.de>

Previously this code used too much copy-paste of boilerplate code which
is error-prone and hard to read. Factor out actual (M)CS assignment into
separate function and use it for both DL and UL cases in respective
mode.

Fixes: Coverity: CID 1351733
---
 src/gprs_ms.cpp | 65 +++++++++++++++++++++++++++++----------------------------
 1 file changed, 33 insertions(+), 32 deletions(-)

diff --git a/src/gprs_ms.cpp b/src/gprs_ms.cpp
index 78f03f8..c10c735 100644
--- a/src/gprs_ms.cpp
+++ b/src/gprs_ms.cpp
@@ -209,45 +209,46 @@ void GprsMs::stop_timer()
        unref();
 }

+inline static GprsCodingScheme assign_cs(GprsCodingScheme current, BTS *bts, 
bool uplink, GprsCodingScheme::Mode mode)
+{
+       GprsCodingScheme tmp = GprsCodingScheme::UNKNOWN;
+       struct gprs_rlcmac_bts * b = bts->bts_data();
+
+       if (GprsCodingScheme::GPRS == mode) {
+               if (!current.isGprs()) {
+                       tmp = GprsCodingScheme::getGprsByNum(uplink ? 
b->initial_cs_ul : b->initial_cs_dl);
+                       if (!tmp.isValid())
+                               return GprsCodingScheme::CS1;
+               }
+       } else {
+               if (!current.isEgprs()) {
+                       tmp = GprsCodingScheme::getEgprsByNum(uplink ? 
b->initial_mcs_ul : b->initial_mcs_dl);
+                       if (!tmp.isValid())
+                               return GprsCodingScheme::MCS1;
+               }
+       }
+
+    return tmp;
+}
+
 void GprsMs::set_mode(GprsCodingScheme::Mode mode)
 {
+       GprsCodingScheme tmp;
        m_mode = mode;

        if (!m_bts)
                return;

-       switch (m_mode) {
-       case GprsCodingScheme::GPRS:
-               if (!m_current_cs_ul.isGprs()) {
-                       m_current_cs_ul = GprsCodingScheme::getGprsByNum(
-                               m_bts->bts_data()->initial_cs_ul);
-                       if (!m_current_cs_ul.isValid())
-                               m_current_cs_ul = GprsCodingScheme::CS1;
-               }
-               if (!m_current_cs_dl.isGprs()) {
-                       m_current_cs_dl = GprsCodingScheme::getGprsByNum(
-                               m_bts->bts_data()->initial_cs_dl);
-                       if (!m_current_cs_dl.isValid())
-                               m_current_cs_dl = GprsCodingScheme::CS1;
-               }
-               break;
-
-       case GprsCodingScheme::EGPRS_GMSK:
-       case GprsCodingScheme::EGPRS:
-               if (!m_current_cs_ul.isEgprs()) {
-                       m_current_cs_ul = GprsCodingScheme::getEgprsByNum(
-                               m_bts->bts_data()->initial_mcs_ul);
-                       if (!m_current_cs_dl.isValid())
-                               m_current_cs_ul = GprsCodingScheme::MCS1;
-               }
-               if (!m_current_cs_dl.isEgprs()) {
-                       m_current_cs_dl = GprsCodingScheme::getEgprsByNum(
-                               m_bts->bts_data()->initial_mcs_dl);
-                       if (!m_current_cs_dl.isValid())
-                               m_current_cs_dl = GprsCodingScheme::MCS1;
-               }
-               break;
-       }
+       tmp = assign_cs(m_current_cs_ul, m_bts, true, mode);
+       if (tmp)
+               m_current_cs_ul = tmp;
+
+       tmp = assign_cs(m_current_cs_dl, m_bts, false, mode);
+       if (tmp)
+               m_current_cs_dl = tmp;
+
+       LOGP(DRLCMAC, LOGL_DEBUG, "MS IMSI=%s mode set to %s: UL=%s, DL=%s\n",
+               imsi(), tmp.modeName(mode), m_current_cs_ul.name(), 
m_current_cs_dl.name());
 }

 void GprsMs::attach_tbf(struct gprs_rlcmac_tbf *tbf)
-- 
2.7.1