si: Partially implement the range encoding for the SI.
I saw the old copy of the "Appendix J" code too late and I have
discovered some quirks and I am more familar with my implementation.
Most noticable 'w' only needs to be as big as the input arfcn but
requires the 'w' to be initialized. The power_of_2 implementation
differs as well (mine matches the output of wirehsark).
The f0 could be chosen in a better way but right now picking
the lower bound is the easiest. It is not clear if to use
modulo if the range is chosen in the middle. This can be improved
in the future. Right now I have no bit fiddling for range128, 256
and 1024 as I was running out of time.
diff --git a/openbsc/tests/si/si_test.c b/openbsc/tests/si/si_test.c
new file mode 100644
index 0000000..16f6ea3
--- /dev/null
+++ b/openbsc/tests/si/si_test.c
@@ -0,0 +1,156 @@
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <openbsc/arfcn_range_encode.h>
+
+#include <osmocom/core/utils.h>
+
+#define DBG(...)
+
+#define VERIFY(res, cmp, wanted) \
+ if (!(res cmp wanted)) { \
+ printf("ASSERT failed: %s:%d Wanted: %d %s %d\n", \
+ __FILE__, __LINE__, res, # cmp, wanted); \
+ }
+
+
+static int freqs1[] = {
+ 12, 70, 121, 190, 250, 320, 401, 475, 520, 574, 634, 700, 764, 830, 905, 980
+};
+
+static int freqs2[] = {
+ 402, 460, 1, 67, 131, 197, 272, 347,
+};
+
+static int freqs3[] = {
+ 68, 128, 198, 279, 353, 398, 452,
+
+};
+
+static int w_out[] = {
+ 122, 2, 69, 204, 75, 66, 60, 70, 83, 3, 24, 67, 54, 64, 70, 9,
+};
+
+static int range128[] = {
+ 1, 1 + 127,
+};
+
+static int range256[] = {
+ 1, 1 + 128,
+};
+
+static int range512[] = {
+ 1, 1+ 511,
+};
+
+
+static void test_arfcn_filter()
+{
+ int arfcns[50], i, res, f0_included;
+ for (i = 0; i < ARRAY_SIZE(arfcns); ++i)
+ arfcns[i] = (i + 1) * 2;
+
+ /* check that the arfcn is taken out. f0_included is only set for Range1024 */
+ f0_included = 24;
+ res = range_enc_filter_arfcns(ARFCN_RANGE_512, arfcns, ARRAY_SIZE(arfcns),
+ arfcns[0], &f0_included);
+ VERIFY(res, ==, ARRAY_SIZE(arfcns) - 1);
+ VERIFY(f0_included, ==, 0);
+ for (i = 0; i < res; ++i)
+ VERIFY(arfcns[i], ==, ((i+2) * 2) - (2+1));
+
+ /* check with range1024 */
+ for (i = 0; i < ARRAY_SIZE(arfcns); ++i)
+ arfcns[i] = (i + 1) * 2;
+ res = range_enc_filter_arfcns(ARFCN_RANGE_1024, arfcns, ARRAY_SIZE(arfcns),
+ arfcns[0], &f0_included);
+ VERIFY(res, ==, ARRAY_SIZE(arfcns) - 1);
+ VERIFY(f0_included, ==, 1);
+ for (i = 0; i < res; ++i)
+ VERIFY(arfcns[i], ==, ((i + 2) * 2) - 1);
+
+ /* check with range1024, not included */
+ for (i = 0; i < ARRAY_SIZE(arfcns); ++i)
+ arfcns[i] = (i + 1) * 2;
+ res = range_enc_filter_arfcns(ARFCN_RANGE_1024, arfcns, ARRAY_SIZE(arfcns),
+ 11, &f0_included);
+ VERIFY(res, ==, ARRAY_SIZE(arfcns));
+ VERIFY(f0_included, ==, 0);
+ for (i = 0; i < res; ++i)
+ VERIFY(arfcns[i], ==, ((i + 1) * 2) - 1);
+}
+
+static void test_print_encoding()
+{
+ int rc;
+ int w[17];
+ uint8_t chan_list[16];
+ memset(chan_list, 0x23, sizeof(chan_list));
+
+ for (rc = 0; rc < ARRAY_SIZE(w); ++rc)
+ switch (rc % 3) {
+ case 0:
+ w[rc] = 0xAAAA;
+ break;
+ case 1:
+ w[rc] = 0x5555;
+ break;
+ case 2:
+ w[rc] = 0x9696;
+ break;
+ }
+
+ rc = range_enc_range512(chan_list, 0x96, w);
+ VERIFY(rc, ==, 0);
+
+ printf("Range512: %s\n", osmo_hexdump(chan_list, ARRAY_SIZE(chan_list)));
+}
+
+int main(int argc, char **argv)
+{
+ int ws[(sizeof(freqs1)/sizeof(freqs1[0]))];
+ int i, f0 = 0xFFFFFF;
+
+ memset(&ws[0], 0x23, sizeof(ws));
+
+ i = range_enc_find_index(1023, freqs1, ARRAY_SIZE(freqs1));
+ printf("Element is: %d => freqs[i] = %d\n", i, freqs1[i]);
+ VERIFY(i, ==, 2);
+
+ i = range_enc_find_index(511, freqs2, ARRAY_SIZE(freqs2));
+ printf("Element is: %d => freqs[i] = %d\n", i, freqs2[i]);
+ VERIFY(i, ==, 2);
+
+ i = range_enc_find_index(511, freqs3, ARRAY_SIZE(freqs3));
+ printf("Element is: %d => freqs[i] = %d\n", i, freqs3[i]);
+ VERIFY(i, ==, 0);
+
+ i = range_enc_arfcns(1023, freqs1, ARRAY_SIZE(freqs1), ws, 0);
+ VERIFY(i, ==, 0);
+
+ for (i = 0; i < sizeof(freqs1)/sizeof(freqs1[0]); ++i) {
+ printf("w[%d]=%d\n", i, ws[i]);
+ VERIFY(ws[i], ==, w_out[i]);
+ }
+
+ i = range_enc_determine_range(range128, ARRAY_SIZE(range128), &f0);
+ VERIFY(i, ==, ARFCN_RANGE_128);
+ VERIFY(f0, ==, 1);
+
+ i = range_enc_determine_range(range256, ARRAY_SIZE(range256), &f0);
+ VERIFY(i, ==, ARFCN_RANGE_256);
+ VERIFY(f0, ==, 1);
+
+ i = range_enc_determine_range(range512, ARRAY_SIZE(range512), &f0);
+ VERIFY(i, ==, ARFCN_RANGE_512);
+ VERIFY(f0, ==, 1);
+
+
+ test_arfcn_filter();
+ test_print_encoding();
+
+ return 0;
+}