isdn: Add V.110 encoder/decoder
V.110 defines a B-channel protocol for transmission of synchronous and
asynchronous serial data of V-series interfaces via terminal adapters
over ISDN.
Let's add (unoptimized but easy to debug) functions for encoding and
decoding of V.110 frames for various bit-rates.
Related: OS#1572
Change-Id: I1b5fd3847d3bfb0a0f763e0574893962ec699680
diff --git a/tests/v110/test_ra1.c b/tests/v110/test_ra1.c
new file mode 100644
index 0000000..775ec4b
--- /dev/null
+++ b/tests/v110/test_ra1.c
@@ -0,0 +1,71 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <unistd.h>
+
+#include <osmocom/core/bits.h>
+#include <osmocom/isdn/v110.h>
+
+
+static void test_ra1(enum osmo_v100_sync_ra1_rate rate)
+{
+ int user_rate = osmo_v110_sync_ra1_get_user_data_rate(rate);
+ int user_data_chunk_bits = osmo_v110_sync_ra1_get_user_data_chunk_bitlen(rate);
+ struct osmo_v110_decoded_frame fr;
+ ubit_t user_bits[48];
+ ubit_t bits[80];
+ unsigned int i;
+ int rc;
+
+ printf("\n======= User data rate %u\n", user_rate);
+
+ /* we abuse the fact that ubit_t is 8bit so we can actually
+ * store integer values to clearly identify which bit ends up where */
+ memset(user_bits, 0xFE, sizeof(user_bits));
+ for (i = 0; i < user_data_chunk_bits; i++)
+ user_bits[i] = 101 + i;
+
+ printf("user_bits: ");
+ for (i = 0; i < user_data_chunk_bits; i++)
+ printf("%03d ", user_bits[i]);
+ printf("\n");
+
+ /* generate the decoded v.110 frame */
+ memset(&fr, 0, sizeof(fr));
+ rc = osmo_v110_sync_ra1_user_to_ir(rate, &fr, user_bits, user_data_chunk_bits);
+ OSMO_ASSERT(rc == 0);
+
+ /* run encoder and dump to stdout */
+ memset(bits, 0xff, sizeof(bits));
+ osmo_v110_encode_frame(bits, sizeof(bits), &fr);
+ printf("dumping %u encoded bits in V.110 frame:\n", user_data_chunk_bits);
+ osmo_v110_ubit_dump(stdout, bits, sizeof(bits));
+
+ /* run decoder on what we just encoded */
+ memset(&fr, 0, sizeof(fr));
+ osmo_v110_decode_frame(&fr, bits, sizeof(bits));
+ printf("dumping re-decoded V.110 frame:\n");
+ printf("E-bits: %s\n", osmo_hexdump(fr.e_bits, sizeof(fr.e_bits)));
+ printf("S-bits: %s\n", osmo_hexdump(fr.s_bits, sizeof(fr.s_bits)));
+
+ /* re-encode and dump again 'expout' will match it. */
+ memset(user_bits, 0xff, sizeof(user_bits));
+ rc = osmo_v110_sync_ra1_ir_to_user(rate, user_bits, sizeof(user_bits), &fr);
+ if (rc != user_data_chunk_bits) {
+ fprintf(stderr, "ERROR: adapt_ir_to_user() returned %d, expected %u\n", rc,
+ user_data_chunk_bits);
+ exit(23);
+ }
+ fprintf(stdout, "re-decoded user bits: ");
+ for (i = 0; i < user_data_chunk_bits; i++)
+ printf("%03d ", user_bits[i]);
+ printf("\n");
+}
+
+
+int main(int argc, char **argv)
+{
+ for (int i = 0; i < _NUM_OSMO_V110_SYNC_RA1; i++)
+ test_ra1(i);
+}
+