Harald Welte | 2230c13 | 2011-01-19 10:10:16 +0100 | [diff] [blame] | 1 | |
| 2 | #include <stdint.h> |
| 3 | |
Pablo Neira Ayuso | 8341934 | 2011-03-22 16:36:13 +0100 | [diff] [blame] | 4 | #include <osmocom/core/bits.h> |
Harald Welte | 2230c13 | 2011-01-19 10:10:16 +0100 | [diff] [blame] | 5 | |
Harald Welte | ba6988b | 2011-08-17 12:46:48 +0200 | [diff] [blame] | 6 | /*! \addtogroup bits |
| 7 | * @{ |
| 8 | */ |
| 9 | |
| 10 | /*! \file bits.c |
| 11 | * \brief Osmocom bit level support code |
| 12 | */ |
| 13 | |
| 14 | |
| 15 | /*! \brief convert unpacked bits to packed bits, return length in bytes |
| 16 | * \param[out] out output buffer of packed bits |
| 17 | * \param[in] in input buffer of unpacked bits |
| 18 | * \param[in] num_bits number of bits |
| 19 | */ |
Harald Welte | 2230c13 | 2011-01-19 10:10:16 +0100 | [diff] [blame] | 20 | int osmo_ubit2pbit(pbit_t *out, const ubit_t *in, unsigned int num_bits) |
| 21 | { |
| 22 | unsigned int i; |
| 23 | uint8_t curbyte = 0; |
| 24 | pbit_t *outptr = out; |
| 25 | |
| 26 | for (i = 0; i < num_bits; i++) { |
| 27 | uint8_t bitnum = 7 - (i % 8); |
| 28 | |
| 29 | curbyte |= (in[i] << bitnum); |
| 30 | |
Christian Vogel | c7f84e9 | 2011-01-22 22:48:37 +0100 | [diff] [blame] | 31 | if(i % 8 == 7){ |
Harald Welte | 2230c13 | 2011-01-19 10:10:16 +0100 | [diff] [blame] | 32 | *outptr++ = curbyte; |
| 33 | curbyte = 0; |
| 34 | } |
| 35 | } |
| 36 | /* we have a non-modulo-8 bitcount */ |
| 37 | if (i % 8) |
| 38 | *outptr++ = curbyte; |
| 39 | |
| 40 | return outptr - out; |
| 41 | } |
| 42 | |
Harald Welte | ba6988b | 2011-08-17 12:46:48 +0200 | [diff] [blame] | 43 | /*! \brief convert packed bits to unpacked bits, return length in bytes |
| 44 | * \param[out] out output buffer of unpacked bits |
| 45 | * \param[in] in input buffer of packed bits |
| 46 | * \param[in] num_bits number of bits |
| 47 | */ |
Harald Welte | 2230c13 | 2011-01-19 10:10:16 +0100 | [diff] [blame] | 48 | int osmo_pbit2ubit(ubit_t *out, const pbit_t *in, unsigned int num_bits) |
| 49 | { |
| 50 | unsigned int i; |
| 51 | ubit_t *cur = out; |
| 52 | ubit_t *limit = out + num_bits; |
| 53 | |
| 54 | for (i = 0; i < (num_bits/8)+1; i++) { |
| 55 | pbit_t byte = in[i]; |
| 56 | *cur++ = (byte >> 7) & 1; |
| 57 | if (cur >= limit) |
| 58 | break; |
| 59 | *cur++ = (byte >> 6) & 1; |
| 60 | if (cur >= limit) |
| 61 | break; |
| 62 | *cur++ = (byte >> 5) & 1; |
| 63 | if (cur >= limit) |
| 64 | break; |
| 65 | *cur++ = (byte >> 4) & 1; |
| 66 | if (cur >= limit) |
| 67 | break; |
| 68 | *cur++ = (byte >> 3) & 1; |
| 69 | if (cur >= limit) |
| 70 | break; |
| 71 | *cur++ = (byte >> 2) & 1; |
| 72 | if (cur >= limit) |
| 73 | break; |
| 74 | *cur++ = (byte >> 1) & 1; |
| 75 | if (cur >= limit) |
| 76 | break; |
| 77 | *cur++ = (byte >> 0) & 1; |
| 78 | if (cur >= limit) |
| 79 | break; |
| 80 | } |
| 81 | return cur - out; |
| 82 | } |
Sylvain Munaut | aeb1077 | 2011-01-21 12:22:30 +0100 | [diff] [blame] | 83 | |
Harald Welte | ba6988b | 2011-08-17 12:46:48 +0200 | [diff] [blame] | 84 | /*! \brief convert unpacked bits to packed bits (extended options) |
| 85 | * \param[out] out output buffer of packed bits |
| 86 | * \param[in] out_ofs offset into output buffer |
| 87 | * \param[in] in input buffer of unpacked bits |
| 88 | * \param[in] in_ofs offset into input buffer |
| 89 | * \param[in] num_bits number of bits |
| 90 | * \param[in] lsb_mode Encode bits in LSB orde instead of MSB |
| 91 | * \returns length in bytes (max written offset of output buffer + 1) |
| 92 | */ |
Sylvain Munaut | aeb1077 | 2011-01-21 12:22:30 +0100 | [diff] [blame] | 93 | int osmo_ubit2pbit_ext(pbit_t *out, unsigned int out_ofs, |
| 94 | const ubit_t *in, unsigned int in_ofs, |
| 95 | unsigned int num_bits, int lsb_mode) |
| 96 | { |
| 97 | int i, op, bn; |
| 98 | for (i=0; i<num_bits; i++) { |
| 99 | op = out_ofs + i; |
| 100 | bn = lsb_mode ? (op&7) : (7-(op&7)); |
| 101 | if (in[in_ofs+i]) |
| 102 | out[op>>3] |= 1 << bn; |
| 103 | else |
| 104 | out[op>>3] &= ~(1 << bn); |
| 105 | } |
| 106 | return ((out_ofs + num_bits - 1) >> 3) + 1; |
| 107 | } |
| 108 | |
Harald Welte | ba6988b | 2011-08-17 12:46:48 +0200 | [diff] [blame] | 109 | /*! \brief convert packed bits to unpacked bits (extended options) |
| 110 | * \param[out] out output buffer of unpacked bits |
| 111 | * \param[in] out_ofs offset into output buffer |
| 112 | * \param[in] in input buffer of packed bits |
| 113 | * \param[in] in_ofs offset into input buffer |
| 114 | * \param[in] num_bits number of bits |
| 115 | * \param[in] lsb_mode Encode bits in LSB orde instead of MSB |
| 116 | * \returns length in bytes (max written offset of output buffer + 1) |
| 117 | */ |
Sylvain Munaut | aeb1077 | 2011-01-21 12:22:30 +0100 | [diff] [blame] | 118 | int osmo_pbit2ubit_ext(ubit_t *out, unsigned int out_ofs, |
| 119 | const pbit_t *in, unsigned int in_ofs, |
| 120 | unsigned int num_bits, int lsb_mode) |
| 121 | { |
| 122 | int i, ip, bn; |
| 123 | for (i=0; i<num_bits; i++) { |
| 124 | ip = in_ofs + i; |
| 125 | bn = lsb_mode ? (ip&7) : (7-(ip&7)); |
| 126 | out[out_ofs+i] = !!(in[ip>>3] & (1<<bn)); |
| 127 | } |
| 128 | return out_ofs + num_bits; |
| 129 | } |
Harald Welte | ba6988b | 2011-08-17 12:46:48 +0200 | [diff] [blame] | 130 | |
| 131 | /*! }@ */ |