tbf: Replace static casts by calls to as_ul_tbf/as_dl_tbf

Currently casts from gprs_rlcmac_tbf to gprs_rlcmac_ul_tbf and
gprs_rlcmac_dl_tbf are done by using static_cast. This doesn't provide
protection against converting a gprs_rlcmac_ul_tbf pointer to a
gprs_rlcmac_dl_tbf pointer and vice versa.

This commit provides two functions as_ul_tbf and as_dl_tbf, that
behave similar like dynamic_cast but use the direction field instead
of RTTI.

Sponsored-by: On-Waves ehf

1 files changed, 17 insertions, 0 deletions

diff --git a/src/tbf.h b/src/tbf.h
index a3a2eeba..190101bf 100644
--- a/src/tbf.h
+++ b/src/tbf.h
@@ -452,6 +452,23 @@ inline enum gprs_rlcmac_tbf_direction reverse(enum gprs_rlcmac_tbf_direction dir
 	return (enum gprs_rlcmac_tbf_direction)
 		((int)GPRS_RLCMAC_UL_TBF - (int)dir + (int)GPRS_RLCMAC_DL_TBF);
 }
+
+inline gprs_rlcmac_ul_tbf *as_ul_tbf(gprs_rlcmac_tbf *tbf)
+{
+	if (tbf && tbf->direction == GPRS_RLCMAC_UL_TBF)
+		return static_cast<gprs_rlcmac_ul_tbf *>(tbf);
+	else
+		return NULL;
+}
+
+inline gprs_rlcmac_dl_tbf *as_dl_tbf(gprs_rlcmac_tbf *tbf)
+{
+	if (tbf && tbf->direction == GPRS_RLCMAC_DL_TBF)
+		return static_cast<gprs_rlcmac_dl_tbf *>(tbf);
+	else
+		return NULL;
+}
+
 #endif
 
 #ifdef __cplusplus