add osmo_bcd2str()

Add a standalone bcd-to-string conversion function with generic parameters.
Add a regression test in utils_test.c.

So far there is no single universal implementation that converts a BCD to a
string. I could only find gsm48_mi_to_string(), which also interprets
surrounding bytes, MI type and TMSI as non-BCD value.

The idea is to use this function from gsm48_mi_to_string() and similar
implementations in subsequent commits.

Root cause: in osmo-msc, I want to have an alternative MI-to-string function
for composing an FSM name, which needs the BCD part of gsm48_mi_to_string() but
not the TMSI part.

Change-Id: I86b09d37ceef33331c1a56046a5443127d6c6be0

1 files changed, 29 insertions, 0 deletions

diff --git a/tests/utils/utils_test.ok b/tests/utils/utils_test.ok
index 3ea8ec6a..65e32ed2 100644
--- a/tests/utils/utils_test.ok
+++ b/tests/utils/utils_test.ok
@@ -80,6 +80,35 @@ Testing BCD conversion
 	val=0xe, expected=E, found=E
 	val=0xf, expected=F, found=F
 
+Testing bcd to string conversion
+- BCD-input='1a 32 54 76 98 f0' nibbles=[1..11[ str_size=64
+  rc=10
+  -> "1234567890"
+- BCD-input='1a 32 a4 cb 9d f0' nibbles=[1..11[ str_size=64
+  rc=-22
+  -> "1234ABCD90"
+- BCD-input='1a 32 a4 cb 9d f0' nibbles=[1..11[ str_size=64
+  rc=10
+  -> "1234ABCD90"
+- BCD-input='1a 32 54 76 98 f0' nibbles=[1..12[ str_size=64
+  rc=-22
+  -> "1234567890F"
+- BCD-input='1a 32 54 76 98 f0' nibbles=[1..12[ str_size=64
+  rc=11
+  -> "1234567890F"
+- BCD-input='1a 32 54 76 98 f0' nibbles=[0..12[ str_size=64
+  rc=12
+  -> "A1234567890F"
+- BCD-input='1a 32 54 76 98 f0' nibbles=[1..12[ str_size=5
+  rc=11
+  -> "1234"
+- BCD-input='' nibbles=[1..1[ str_size=64
+  rc=0
+  -> ""
+- zero output buffer
+  bcd2str(NULL, ...) -> -12
+  bcd2str(dst, 0, ...) -> -12
+
 Testing string escaping
 - all chars from 0 to 255 in batches of 16:
 "\0\1\2\3\4\5\6\a\b\t\n\v\f\r\14\15"