diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/bitvec.c | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/src/bitvec.c b/src/bitvec.c index 00ae1505..a92fd716 100644 --- a/src/bitvec.c +++ b/src/bitvec.c @@ -570,4 +570,44 @@ void bitvec_shiftl(struct bitvec *bv, unsigned n) bv->cur_bit -= n; } +/*! \brief Add given array to bitvec + * \param[in,out] bv bit vector to work with + * \param[in] array elements to be added + * \param[in] array_len length of array + * \param[in] dry_run indicates whether to return number of bits required + * instead of adding anything to bv for real + * \param[in] num_bits number of bits to consider in each element of array + * \returns number of bits necessary to add array elements if dry_run is true, + * 0 otherwise (only in this case bv is actually changed) + * + * N. B: no length checks are performed on bv - it's caller's job to ensure + * enough space is available - for example by calling with dry_run = true first. + * + * Useful for common pattern in CSN.1 spec which looks like: + * { 1 < XXX : bit (num_bits) > } ** 0 + * which means repeat any times (between 0 and infinity), + * start each repetition with 1, mark end of repetitions with 0 bit + * see app. note in 3GPP TS 24.007 ยง B.2.1 Rule A2 + */ +unsigned int bitvec_add_array(struct bitvec *bv, const uint32_t *array, + unsigned int array_len, bool dry_run, + unsigned int num_bits) +{ + unsigned i, bits = 1; /* account for stop bit */ + for (i = 0; i < array_len; i++) { + if (dry_run) { + bits += (1 + num_bits); + } else { + bitvec_set_bit(bv, 1); + bitvec_set_uint(bv, array[i], num_bits); + } + } + + if (dry_run) + return bits; + + bitvec_set_bit(bv, 0); /* stop bit - end of the sequence */ + return 0; +} + /*! @} */ |