mirror of https://gerrit.osmocom.org/libosmocore
99 lines
2.3 KiB
C
99 lines
2.3 KiB
C
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#include <stdint.h>
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#include <osmocom/core/bits.h>
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/* convert unpacked bits to packed bits, return length in bytes */
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int osmo_ubit2pbit(pbit_t *out, const ubit_t *in, unsigned int num_bits)
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{
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unsigned int i;
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uint8_t curbyte = 0;
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pbit_t *outptr = out;
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for (i = 0; i < num_bits; i++) {
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uint8_t bitnum = 7 - (i % 8);
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curbyte |= (in[i] << bitnum);
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if(i % 8 == 7){
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*outptr++ = curbyte;
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curbyte = 0;
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}
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}
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/* we have a non-modulo-8 bitcount */
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if (i % 8)
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*outptr++ = curbyte;
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return outptr - out;
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}
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/* convert packed bits to unpacked bits, return length in bytes */
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int osmo_pbit2ubit(ubit_t *out, const pbit_t *in, unsigned int num_bits)
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{
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unsigned int i;
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ubit_t *cur = out;
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ubit_t *limit = out + num_bits;
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for (i = 0; i < (num_bits/8)+1; i++) {
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pbit_t byte = in[i];
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*cur++ = (byte >> 7) & 1;
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if (cur >= limit)
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break;
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*cur++ = (byte >> 6) & 1;
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if (cur >= limit)
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break;
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*cur++ = (byte >> 5) & 1;
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if (cur >= limit)
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break;
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*cur++ = (byte >> 4) & 1;
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if (cur >= limit)
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break;
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*cur++ = (byte >> 3) & 1;
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if (cur >= limit)
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break;
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*cur++ = (byte >> 2) & 1;
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if (cur >= limit)
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break;
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*cur++ = (byte >> 1) & 1;
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if (cur >= limit)
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break;
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*cur++ = (byte >> 0) & 1;
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if (cur >= limit)
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break;
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}
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return cur - out;
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}
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/* convert unpacked bits to packed bits (extended options but slower),
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* return length in bytes (max written ofs of output buffer + 1) */
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int osmo_ubit2pbit_ext(pbit_t *out, unsigned int out_ofs,
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const ubit_t *in, unsigned int in_ofs,
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unsigned int num_bits, int lsb_mode)
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{
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int i, op, bn;
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for (i=0; i<num_bits; i++) {
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op = out_ofs + i;
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bn = lsb_mode ? (op&7) : (7-(op&7));
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if (in[in_ofs+i])
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out[op>>3] |= 1 << bn;
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else
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out[op>>3] &= ~(1 << bn);
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}
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return ((out_ofs + num_bits - 1) >> 3) + 1;
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}
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/* convert packed bits to unpacked bits (extended options but slower),
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* return length in bytes (max written ofs of output buffer + 1) */
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int osmo_pbit2ubit_ext(ubit_t *out, unsigned int out_ofs,
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const pbit_t *in, unsigned int in_ofs,
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unsigned int num_bits, int lsb_mode)
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{
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int i, ip, bn;
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for (i=0; i<num_bits; i++) {
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ip = in_ofs + i;
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bn = lsb_mode ? (ip&7) : (7-(ip&7));
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out[out_ofs+i] = !!(in[ip>>3] & (1<<bn));
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}
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return out_ofs + num_bits;
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}
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