rlc: Manage the received block bitmap in the ul_window

Added two methods to gprs_rlc_ul_window
* ssn() returns the starting sequence number
* update_rbb() returns an array of chars representing the state of the
  received   block bitmap. Each element is either 'I'nvalid or
  'R'eceived. The rbb is generated from v_n

rbb[63] relates to BSN ssn-1
...
rbb[0] relates to BSN ssn-64

2 files changed, 20 insertions, 0 deletions

diff --git a/src/rlc.cpp b/src/rlc.cpp
index 915da87f..4ee5f610 100644
--- a/src/rlc.cpp
+++ b/src/rlc.cpp
@@ -146,6 +146,18 @@ void gprs_rlc_v_n::reset()
 	memset(m_v_n, 0x0, sizeof(m_v_n));
 }
 
+/* Update the receive block bitmap */
+void gprs_rlc_ul_window::update_rbb(const gprs_rlc_v_n *v_n, char *rbb)
+{
+	int i;
+	for (i=0; i < ws(); i++) {
+		if (v_n->is_received(ssn()-1-i))
+			rbb[ws()-1-i] = 'R';
+		else
+			rbb[ws()-1-i] = 'I';
+	}
+}
+
 /* Raise V(R) to highest received sequence number not received. */
 void gprs_rlc_ul_window::raise_v_r(const uint16_t bsn, gprs_rlc_v_n *v_n)
 {
diff --git a/src/rlc.h b/src/rlc.h
index 0ecce407..d68afab8 100644
--- a/src/rlc.h
+++ b/src/rlc.h
@@ -89,8 +89,11 @@ struct gprs_rlc_ul_window {
 	const uint16_t v_r() const;
 	const uint16_t v_q() const;
 
+	const uint16_t ssn() const;
+
 	bool is_in_window(uint8_t bsn) const;
 
+	void update_rbb(const gprs_rlc_v_n *v_n, char *rbb);
 	void raise_v_r(int moves);
 	void raise_v_r(const uint16_t bsn, gprs_rlc_v_n *v_n);
 	uint16_t raise_v_q(gprs_rlc_v_n *v_n);
@@ -339,6 +342,11 @@ inline const uint16_t gprs_rlc_ul_window::v_q() const
 	return m_v_q;
 }
 
+inline const uint16_t gprs_rlc_ul_window::ssn() const
+{
+	return m_v_r;
+}
+
 inline void gprs_rlc_ul_window::raise_v_r(int moves)
 {
 	m_v_r = (m_v_r + moves) & mod_sns();