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-rw-r--r--include/osmocom/core/bits.h45
1 files changed, 45 insertions, 0 deletions
diff --git a/include/osmocom/core/bits.h b/include/osmocom/core/bits.h
new file mode 100644
index 0000000..8d4a078
--- /dev/null
+++ b/include/osmocom/core/bits.h
@@ -0,0 +1,45 @@
+#ifndef _OSMO_BITS_H
+#define _OSMO_BITS_H
+
+#include <stdint.h>
+
+typedef uint8_t sbit_t; /* soft bit (-127...127) */
+typedef uint8_t ubit_t; /* unpacked bit (0 or 1) */
+typedef uint8_t pbit_t; /* packed bis (8 bits in a byte) */
+
+/*
+ NOTE on the endianess of pbit_t:
+ Bits in a pbit_t are ordered MSB first, i.e. 0x80 is the first bit.
+ Bit i in a pbit_t array is array[i/8] & (1<<(7-i%8))
+*/
+
+/* determine how many bytes we would need for 'num_bits' packed bits */
+static inline unsigned int osmo_pbit_bytesize(unsigned int num_bits)
+{
+ unsigned int pbit_bytesize = num_bits / 8;
+
+ if (num_bits % 8)
+ pbit_bytesize++;
+
+ return pbit_bytesize;
+}
+
+/* convert unpacked bits to packed bits, return length in bytes */
+int osmo_ubit2pbit(pbit_t *out, const ubit_t *in, unsigned int num_bits);
+
+/* convert packed bits to unpacked bits, return length in bytes */
+int osmo_pbit2ubit(ubit_t *out, const pbit_t *in, unsigned int num_bits);
+
+/* convert unpacked bits to packed bits (extended options but slower),
+ * return length in bytes (max written ofs of output buffer + 1) */
+int osmo_ubit2pbit_ext(pbit_t *out, unsigned int out_ofs,
+ const ubit_t *in, unsigned int in_ofs,
+ unsigned int num_bits, int lsb_mode);
+
+/* convert packed bits to unpacked bits (extended options but slower),
+ * return length in bytes (max written ofs of output buffer + 1) */
+int osmo_pbit2ubit_ext(ubit_t *out, unsigned int out_ofs,
+ const pbit_t *in, unsigned int in_ofs,
+ unsigned int num_bits, int lsb_mode);
+
+#endif