Review at https://gerrit.osmocom.org/4110
SI2q: cleanup UARFCN addition
* fix comment typo
* constify parameter
* move try-add-adjust routine into separate function to facilitate
further modifications
* remove excessive checks and unnecessary return values
Change-Id: Ia72f848dec40723510ca56868e08081804227d47
Related: OS#2357
---
M src/libbsc/rest_octets.c
M src/libbsc/system_information.c
2 files changed, 44 insertions(+), 55 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/osmo-bsc refs/changes/10/4110/1
diff --git a/src/libbsc/rest_octets.c b/src/libbsc/rest_octets.c
index 866734b..1b3b1a9 100644
--- a/src/libbsc/rest_octets.c
+++ b/src/libbsc/rest_octets.c
@@ -232,7 +232,7 @@
}
/* Estimate how many bits it'll take to append single FDD UARFCN */
-static inline int append_utran_fdd_length(uint16_t u, int *sc, size_t sc_len,
size_t length)
+static inline int append_utran_fdd_length(uint16_t u, const int *sc, size_t
sc_len, size_t length)
{
uint8_t chan_list[16] = { 0 };
int tmp[sc_len], f0;
@@ -274,18 +274,42 @@
return 21 + range1024_p(length);
}
-/* Append multiple FDD UARFCNs */
-static inline int append_uarfcns(struct bitvec *bv, struct gsm_bts *bts,
uint8_t budget)
+static inline int try_adding_uarfcn(struct bitvec *bv, struct gsm_bts *bts,
uint16_t uarfcn,
+ uint8_t num_sc, uint8_t start_pos, uint8_t
budget)
{
- const uint16_t *u = bts->si_common.data.uarfcn_list, *sc =
bts->si_common.data.scramble_list;
- int i, j, k, rc, st = 0, a[bts->si_common.uarfcn_length];
+ int i, k, rc, a[bts->si_common.uarfcn_length];
+
+ if (budget < 23)
+ return -ENOMEM;
+
+ /* copy corresponding Scrambling Codes: range encoder make in-place
modifications */
+ for (i = start_pos, k = 0; i < num_sc; a[k++] =
bts->si_common.data.scramble_list[i++]);
+
+ /* estimate bit length requirements */
+ rc = append_utran_fdd_length(uarfcn, a, bts->si_common.uarfcn_length,
k);
+ if (rc < 0)
+ return rc; /* range encoder failure */
+
+ if (budget - rc <= 0)
+ return -ENOMEM; /* we have ran out of budget in current SI2q */
+
+ /* compute next offset */
+ bts->u_offset += k;
+
+ return budget - append_utran_fdd(bv, uarfcn, a, k);
+}
+
+/* Append multiple FDD UARFCNs */
+static inline void append_uarfcns(struct bitvec *bv, struct gsm_bts *bts,
uint8_t budget)
+{
+ const uint16_t *u = bts->si_common.data.uarfcn_list;
+ int i, rem = budget - 7, st = 0; /* account for constant bits right
away */
uint16_t cu = u[bts->u_offset]; /* caller ensures that length is
positive */
- uint8_t rem = budget - 7, offset_diff; /* account for constant bits
right away */
OSMO_ASSERT(budget <= SI2Q_MAX_LEN);
if (budget <= 7)
- return -ENOMEM;
+ return;
/* 3G Neighbour Cell Description */
bitvec_set_bit(bv, 1);
@@ -299,53 +323,24 @@
/* No Bandwidth_FDD */
bitvec_set_bit(bv, 0);
- for (i = bts->u_offset; i < bts->si_common.uarfcn_length; i++) {
- offset_diff = 0;
- for (j = st, k = 0; j < i; j++) {
- a[k++] = sc[j]; /* copy corresponding SCs */
- offset_diff++; /* compute proper offset step */
- }
+ for (i = bts->u_offset; i <= bts->si_common.uarfcn_length; i++)
if (u[i] != cu) { /* we've reached new UARFCN */
- rc = append_utran_fdd_length(cu, a,
bts->si_common.uarfcn_length, k);
- if (rc < 0) { /* estimate bit length requirements */
- return rc;
- }
+ rem = try_adding_uarfcn(bv, bts, cu, i, st, rem);
+ if (rem < 0)
+ break;
- if (rem - rc <= 0)
- break; /* we have ran out of budget in current
SI2q */
- else {
- rem -= append_utran_fdd(bv, cu, a, k);
- bts->u_offset += offset_diff;
- }
- cu = u[i];
- st = i; /* update start position */
+ if (i < bts->si_common.uarfcn_length) {
+ cu = u[i];
+ st = i;
+ } else
+ break;
}
- }
-
- if (rem > 22) { /* add last UARFCN not covered by previous cycle if it
could possibly fit into budget */
- offset_diff = 0;
- for (i = st, k = 0; i < bts->si_common.uarfcn_length; i++) {
- a[k++] = sc[i];
- offset_diff++;
- }
- rc = append_utran_fdd_length(cu, a,
bts->si_common.uarfcn_length, k);
- if (rc < 0) {
- return rc;
- }
-
- if (rem - rc >= 0) {
- rem -= append_utran_fdd(bv, cu, a, k);
- bts->u_offset += offset_diff;
- }
- }
/* stop bit - end of Repeated UTRAN FDD Neighbour Cells */
bitvec_set_bit(bv, 0);
/* UTRAN TDD Description */
bitvec_set_bit(bv, 0);
-
- return 0;
}
/* generate SI2quater rest octets: 3GPP TS 44.018 ยง 10.5.2.33b */
@@ -389,15 +384,9 @@
bitvec_set_bit(&bv, 0);
rc = SI2Q_MAX_LEN - (bv.cur_bit + 3);
- if (rc > 0 && bts->si_common.uarfcn_length - bts->u_offset > 0) {
- rc = append_uarfcns(&bv, bts, rc);
- if (rc < 0) {
- LOGP(DRR, LOGL_ERROR, "SI2quater [%u/%u]: failed to
append %zu UARFCNs due to range encoding "
- "failure: %s\n",
- bts->si2q_index, bts->si2q_count,
bts->si_common.uarfcn_length, strerror(-rc));
- return rc;
- }
- } else /* No 3G Neighbour Cell Description */
+ if (rc > 0 && bts->si_common.uarfcn_length - bts->u_offset > 0)
+ append_uarfcns(&bv, bts, rc);
+ else /* No 3G Neighbour Cell Description */
bitvec_set_bit(&bv, 0);
/* No 3G Measurement Parameters Description */
diff --git a/src/libbsc/system_information.c b/src/libbsc/system_information.c
index c9da4b2..1dd91a0 100644
--- a/src/libbsc/system_information.c
+++ b/src/libbsc/system_information.c
@@ -182,7 +182,7 @@
int rc = make_si2quaters(bts, true);
uint8_t num = bts->si2q_index + 1; /* number of SI2quater messages */
- /* N. B: si2q_num() should NEVER be called during actualSI2q rest
octets generation
+ /* N. B: si2q_num() should NEVER be called during actual SI2q rest
octets generation
we're not re-entrant because of the following code: */
bts->u_offset = 0;
bts->e_offset = 0;
--
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Gerrit-MessageType: newchange
Gerrit-Change-Id: Ia72f848dec40723510ca56868e08081804227d47
Gerrit-PatchSet: 1
Gerrit-Project: osmo-bsc
Gerrit-Branch: master
Gerrit-Owner: Max <[email protected]>
