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#include <stdint.h>
#include <osmocom/core/bits.h>
/*! \addtogroup bits
* @{
*/
/*! \file bits.c
* \brief Osmocom bit level support code
*/
/*! \brief convert unpacked bits to packed bits, return length in bytes
* \param[out] out output buffer of packed bits
* \param[in] in input buffer of unpacked bits
* \param[in] num_bits number of bits
*/
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 % 8 == 7){
*outptr++ = curbyte;
curbyte = 0;
}
}
/* we have a non-modulo-8 bitcount */
if (i % 8)
*outptr++ = curbyte;
return outptr - out;
}
/*! \brief convert packed bits to unpacked bits, return length in bytes
* \param[out] out output buffer of unpacked bits
* \param[in] in input buffer of packed bits
* \param[in] num_bits number of bits
*/
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;
}
/*! \brief convert unpacked bits to packed bits (extended options)
* \param[out] out output buffer of packed bits
* \param[in] out_ofs offset into output buffer
* \param[in] in input buffer of unpacked bits
* \param[in] in_ofs offset into input buffer
* \param[in] num_bits number of bits
* \param[in] lsb_mode Encode bits in LSB orde instead of MSB
* \returns length in bytes (max written offset 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)
{
int i, op, bn;
for (i=0; i<num_bits; i++) {
op = out_ofs + i;
bn = lsb_mode ? (op&7) : (7-(op&7));
if (in[in_ofs+i])
out[op>>3] |= 1 << bn;
else
out[op>>3] &= ~(1 << bn);
}
return ((out_ofs + num_bits - 1) >> 3) + 1;
}
/*! \brief convert packed bits to unpacked bits (extended options)
* \param[out] out output buffer of unpacked bits
* \param[in] out_ofs offset into output buffer
* \param[in] in input buffer of packed bits
* \param[in] in_ofs offset into input buffer
* \param[in] num_bits number of bits
* \param[in] lsb_mode Encode bits in LSB orde instead of MSB
* \returns length in bytes (max written offset 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)
{
int i, ip, bn;
for (i=0; i<num_bits; i++) {
ip = in_ofs + i;
bn = lsb_mode ? (ip&7) : (7-(ip&7));
out[out_ofs+i] = !!(in[ip>>3] & (1<<bn));
}
return out_ofs + num_bits;
}
/*! }@ */
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