diff options
Diffstat (limited to 'src/bits.c')
| -rw-r--r-- | src/bits.c | 48 |
1 files changed, 48 insertions, 0 deletions
@@ -61,6 +61,54 @@ int osmo_ubit2pbit(pbit_t *out, const ubit_t *in, unsigned int num_bits) return outptr - out; } +/*! \brief Shift unaligned input to octet-aligned output + * \param[out] out output buffer, unaligned + * \param[in] in input buffer, octet-aligned + * \param[in] num_nibbles number of nibbles + */ +void osmo_nibble_shift_right(uint8_t *out, const uint8_t *in, + unsigned int num_nibbles) +{ + unsigned int i, num_whole_bytes = num_nibbles / 2; + if (!num_whole_bytes) + return; + + /* first byte: upper nibble empty, lower nibble from src */ + out[0] = (in[0] >> 4); + + /* bytes 1.. */ + for (i = 1; i < num_whole_bytes; i++) + out[i] = ((in[i - 1] & 0xF) << 4) | (in[i] >> 4); + + /* shift the last nibble, in case there's an odd count */ + i = num_whole_bytes; + if (num_nibbles & 1) + out[i] = ((in[i - 1] & 0xF) << 4) | (in[i] >> 4); + else + out[i] = (in[i - 1] & 0xF) << 4; +} + +/*! \brief Shift unaligned input to octet-aligned output + * \param[out] out output buffer, octet-aligned + * \param[in] in input buffer, unaligned + * \param[in] num_nibbles number of nibbles + */ +void osmo_nibble_shift_left_unal(uint8_t *out, const uint8_t *in, + unsigned int num_nibbles) +{ + unsigned int i, num_whole_bytes = num_nibbles / 2; + if (!num_whole_bytes) + return; + + for (i = 0; i < num_whole_bytes; i++) + out[i] = ((in[i] & 0xF) << 4) | (in[i + 1] >> 4); + + /* shift the last nibble, in case there's an odd count */ + i = num_whole_bytes; + if (num_nibbles & 1) + out[i] = (in[i] & 0xF) << 4; +} + /*! \brief convert unpacked bits to soft bits * \param[out] out output buffer of soft bits * \param[in] in input buffer of unpacked bits |