[BITS] introduce new packed/unpacked bit conversion routines
diff --git a/src/bits.c b/src/bits.c
new file mode 100644
index 0000000..fb3c722
--- /dev/null
+++ b/src/bits.c
@@ -0,0 +1,65 @@
+
+#include <stdint.h>
+
+#include <osmocore/bits.h>
+
+/* convert unpacked bits to packed bits, return length in bytes */
+int osmo_ubit2pbit(pbit_t *out, const ubit_t *in, unsigned int num_bits)
+{
+ unsigned int i;
+ uint8_t curbyte = 0;
+ pbit_t *outptr = out;
+
+ for (i = 0; i < num_bits; i++) {
+ uint8_t bitnum = 7 - (i % 8);
+
+ curbyte |= (in[i] << bitnum);
+
+ if (i > 0 && i % 8 == 0) {
+ *outptr++ = curbyte;
+ curbyte = 0;
+ }
+ }
+ /* we have a non-modulo-8 bitcount */
+ if (i % 8)
+ *outptr++ = curbyte;
+
+ return outptr - out;
+}
+
+/* convert packed bits to unpacked bits, return length in bytes */
+int osmo_pbit2ubit(ubit_t *out, const pbit_t *in, unsigned int num_bits)
+{
+ unsigned int i;
+ ubit_t *cur = out;
+ ubit_t *limit = out + num_bits;
+
+ for (i = 0; i < (num_bits/8)+1; i++) {
+ pbit_t byte = in[i];
+ *cur++ = (byte >> 7) & 1;
+ if (cur >= limit)
+ break;
+ *cur++ = (byte >> 6) & 1;
+ if (cur >= limit)
+ break;
+ *cur++ = (byte >> 5) & 1;
+ if (cur >= limit)
+ break;
+ *cur++ = (byte >> 4) & 1;
+ if (cur >= limit)
+ break;
+ *cur++ = (byte >> 3) & 1;
+ if (cur >= limit)
+ break;
+ *cur++ = (byte >> 2) & 1;
+ if (cur >= limit)
+ break;
+ *cur++ = (byte >> 1) & 1;
+ if (cur >= limit)
+ break;
+ *cur++ = (byte >> 0) & 1;
+ if (cur >= limit)
+ break;
+ }
+ return cur - out;
+}