gsm: add gsm48_mnc_from_str() and gsm48_mnc_cmp(), for 3-digit MNC
gsm48_mnc_from_str() preserves leading zeros in the string and is useful for
VTY config parsing.
gsm48_mnc_cmp() will be used by osmo-sgsn.git
Change-Id: Ib7176b1d65a03b76f41f94bc9d3293a8a07d24c6
---
M include/osmocom/gsm/gsm48.h
M src/gsm/gsm48.c
M src/gsm/libosmogsm.map
3 files changed, 63 insertions(+), 0 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/libosmocore refs/changes/63/6663/2
diff --git a/include/osmocom/gsm/gsm48.h b/include/osmocom/gsm/gsm48.h
index 9d312c2..37c421d 100644
--- a/include/osmocom/gsm/gsm48.h
+++ b/include/osmocom/gsm/gsm48.h
@@ -63,3 +63,7 @@
void gsm48_mcc_mnc_to_bcd2(uint8_t *bcd_dst, uint16_t mcc, uint16_t mnc, bool
mnc_3_digits);
void gsm48_mcc_mnc_from_bcd(uint8_t *bcd_src, uint16_t *mcc, uint16_t *mnc);
void gsm48_mcc_mnc_from_bcd2(uint8_t *bcd_src, uint16_t *mcc, uint16_t *mnc,
bool *mnc_3_digits);
+
+int gsm48_mnc_from_str(const char *mnc_str, uint16_t *mnc, bool *mnc_3_digits);
+
+int gsm48_mnc_cmp(uint16_t a_mnc, bool a_mnc_3_digits, uint16_t b_mnc, bool
b_mnc_3_digits);
diff --git a/src/gsm/gsm48.c b/src/gsm/gsm48.c
index 122f7ea..be2a976 100644
--- a/src/gsm/gsm48.c
+++ b/src/gsm/gsm48.c
@@ -530,6 +530,63 @@
}
}
+/* Convert string to MNC, detecting 3-digit MNC with leading zeros.
+ * Return mnc_3_digits as false if the MNC's most significant digit is encoded
as 0xF, true
+ * otherwise; i.e. true if MNC > 99 or if it is represented with leading zeros
instead of 0xF.
+ * \param mnc_str[in] String representation of an MNC, with or without
leading zeros.
+ * \param mnc[out] MNC result buffer, or NULL.
+ * \param[out] mnc_3_digits Result buffer for 3-digit flag, or NULL.
+ * \returns zero on success, -EINVAL in case of surplus characters, negative
errno in case of conversion
+ * errors.
+ */
+int gsm48_mnc_from_str(const char *mnc_str, uint16_t *mnc, bool *mnc_3_digits)
+{
+ uint16_t _mnc = 0;
+ bool _mnc_3_digits = false;
+ char *endptr;
+ int rc = 0;
+
+ if (!mnc_str || !isdigit(mnc_str[0])) {
+ /* return invalid, but give strtol a shot anyway, for callers
that don't want to be
+ * strict */
+ rc = -EINVAL;
+ }
+ errno = 0;
+ _mnc = strtol(mnc_str, &endptr, 10);
+ if (errno)
+ rc = -errno;
+ else if (*endptr)
+ rc = -EINVAL;
+ _mnc_3_digits = strlen(mnc_str) > 2;
+
+ if (mnc)
+ *mnc = _mnc;
+ if (mnc_3_digits)
+ *mnc_3_digits = _mnc_3_digits;
+ return rc;
+}
+
+/* Compare two MNC with three-digit flag.
+ * The mnc_3_digits flags passed in only have an effect if the MNC are < 100,
i.e. if they would amount
+ * to a change in leading zeros in a BCD representation. An MNC >= 100 implies
three digits, and the flag
+ * is actually ignored.
+ * \param a_mnc[in] "Left" side MNC.
+ * \param a_mnc_3_digits[in] "Left" side three-digits flag.
+ * \param b_mnc[in] "Right" side MNC.
+ * \param b_mnc_3_digits[in] "Right" side three-digits flag.
+ * \returns 0 if the MNC are equal, -1 if a < b or a shorter, 1 if a > b or a
longer. */
+int gsm48_mnc_cmp(uint16_t a_mnc, bool a_mnc_3_digits, uint16_t b_mnc, bool
b_mnc_3_digits)
+{
+ if (a_mnc < b_mnc)
+ return -1;
+ if (a_mnc > b_mnc)
+ return 1;
+ /* a_mnc == b_mnc, but same amount of leading zeros? */
+ if (a_mnc < 100 && a_mnc_3_digits != b_mnc_3_digits)
+ return a_mnc_3_digits ? 1 : -1;
+ return 0;
+}
+
/*! Encode TS 04.08 Location Area Identifier, legacy implementation.
* Instead use gsm48_generate_lai2(), which is capable of three-digit MNC with
leading zeros.
* \param[out] caller-provided memory for output
diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map
index 917eab2..9e3de75 100644
--- a/src/gsm/libosmogsm.map
+++ b/src/gsm/libosmogsm.map
@@ -272,6 +272,8 @@
osmo_mcc_mnc_name;
osmo_mcc_mnc_name2;
osmo_rai_name;
+gsm48_mnc_from_str;
+gsm48_mnc_cmp;
gsm48_chan_mode_names;
gsm_chan_t_names;
gsm48_pdisc_names;
--
To view, visit https://gerrit.osmocom.org/6663
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Gerrit-MessageType: newpatchset
Gerrit-Change-Id: Ib7176b1d65a03b76f41f94bc9d3293a8a07d24c6
Gerrit-PatchSet: 2
Gerrit-Project: libosmocore
Gerrit-Branch: master
Gerrit-Owner: Neels Hofmeyr <nhofm...@sysmocom.de>
