1 files changed, 122 insertions, 0 deletions
diff --git a/lib/decoding/osmocom/core/bits.h b/lib/decoding/osmocom/core/bits.h
new file mode 100644
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+++ b/lib/decoding/osmocom/core/bits.h
@@ -0,0 +1,122 @@
+/*! \file bits.h
+ *  Osmocom bit level support code.
+ *
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <stddef.h>
+
+#include <osmocom/core/bit16gen.h>
+#include <osmocom/core/bit32gen.h>
+#include <osmocom/core/bit64gen.h>
+
+/*! \defgroup bits soft, unpacked and packed bits
+ *  @{
+ * \file bits.h */
+
+/*! soft bit with value (-127...127), as commonly used in
+ * communications receivers such as [viterbi] decoders */
+typedef int8_t  sbit_t;
+
+/*! unpacked bit (0 or 1): 1 bit per byte */
+typedef uint8_t ubit_t;
+
+/*! packed bits (8 bits in a byte).
+ *  NOTE on the endian-ness of \ref pbit_t:
+ *  - Bits in a \ref pbit_t are ordered MSB first, i.e. 0x80 is the first bit.
+ *  - Bit i in a \ref pbit_t array is array[i/8] & (1<<(7-i%8)) */
+typedef uint8_t pbit_t;
+
+/*! determine how many bytes we would need for \a num_bits packed bits
+ *  \param[in] num_bits Number of packed bits
+ *  \returns number of bytes needed for \a 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;
+}
+
+int osmo_ubit2pbit(pbit_t *out, const ubit_t *in, unsigned int num_bits);
+
+int osmo_pbit2ubit(ubit_t *out, const pbit_t *in, unsigned int num_bits);
+
+void osmo_nibble_shift_right(uint8_t *out, const uint8_t *in,
+			     unsigned int num_nibbles);
+void osmo_nibble_shift_left_unal(uint8_t *out, const uint8_t *in,
+				 unsigned int num_nibbles);
+
+void osmo_ubit2sbit(sbit_t *out, const ubit_t *in, unsigned int num_bits);
+void osmo_sbit2ubit(ubit_t *out, const sbit_t *in, unsigned int num_bits);
+
+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);
+
+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);
+
+#define OSMO_BIN_SPEC "%d%d%d%d%d%d%d%d"
+#define OSMO_BIN_PRINT(byte)  \
+  (byte & 0x80 ? 1 : 0), \
+  (byte & 0x40 ? 1 : 0), \
+  (byte & 0x20 ? 1 : 0), \
+  (byte & 0x10 ? 1 : 0), \
+  (byte & 0x08 ? 1 : 0), \
+  (byte & 0x04 ? 1 : 0), \
+  (byte & 0x02 ? 1 : 0), \
+  (byte & 0x01 ? 1 : 0)
+
+#define OSMO_BIT_SPEC "%c%c%c%c%c%c%c%c"
+#define OSMO_BIT_PRINT_EX(byte, ch)		\
+  (byte & 0x80 ? ch : '.'), \
+  (byte & 0x40 ? ch : '.'), \
+  (byte & 0x20 ? ch : '.'), \
+  (byte & 0x10 ? ch : '.'), \
+  (byte & 0x08 ? ch : '.'), \
+  (byte & 0x04 ? ch : '.'), \
+  (byte & 0x02 ? ch : '.'), \
+  (byte & 0x01 ? ch : '.')
+
+#define OSMO_BIT_PRINT(byte)  OSMO_BIT_PRINT_EX(byte, '1')
+
+/* BIT REVERSAL */
+
+/*! bit-reversal mode for osmo_bit_reversal() */
+enum osmo_br_mode {
+	/*! reverse all bits in a 32bit dword */
+	OSMO_BR_BITS_IN_DWORD	= 31,
+	/*! reverse byte order in a 32bit dword */
+	OSMO_BR_BYTES_IN_DWORD	= 24,
+	/*! reverse bits of each byte in a 32bit dword */
+	OSMO_BR_BITS_IN_BYTE	= 7,
+	/*! swap the two 16bit words in a 32bit dword */
+	OSMO_BR_WORD_SWAP	= 16,
+};
+
+uint32_t osmo_bit_reversal(uint32_t x, enum osmo_br_mode k);
+
+uint32_t osmo_revbytebits_32(uint32_t x);
+
+uint32_t osmo_revbytebits_8(uint8_t x);
+
+void osmo_revbytebits_buf(uint8_t *buf, int len);
+
+/*! left circular shift
+ *  \param[in] in The 16 bit unsigned integer to be rotated
+ *  \param[in] shift Number of bits to shift \a in to, [0;16] bits
+ *  \returns shifted value
+ */
+static inline uint16_t osmo_rol16(uint16_t in, unsigned shift)
+{
+	return (in << shift) | (in >> (16 - shift));
+}
+
+/*! @} */