Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 1 | /* bit vector utility routines */ |
| 2 | |
| 3 | /* (C) 2009 by Harald Welte <laforge@gnumonks.org> |
| 4 | * |
| 5 | * All Rights Reserved |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License as published by |
| 9 | * the Free Software Foundation; either version 2 of the License, or |
| 10 | * (at your option) any later version. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | * GNU General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License along |
| 18 | * with this program; if not, write to the Free Software Foundation, Inc., |
| 19 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | */ |
| 22 | |
Harald Welte | ba6988b | 2011-08-17 12:46:48 +0200 | [diff] [blame] | 23 | /*! \addtogroup bitvec |
| 24 | * @{ |
| 25 | */ |
| 26 | |
| 27 | /*! \file bitvec.c |
| 28 | * \brief Osmocom bit vector abstraction |
| 29 | */ |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 30 | |
| 31 | #include <errno.h> |
| 32 | #include <stdint.h> |
| 33 | |
Pablo Neira Ayuso | 8341934 | 2011-03-22 16:36:13 +0100 | [diff] [blame] | 34 | #include <osmocom/core/bitvec.h> |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 35 | |
| 36 | #define BITNUM_FROM_COMP(byte, bit) ((byte*8)+bit) |
| 37 | |
| 38 | static inline unsigned int bytenum_from_bitnum(unsigned int bitnum) |
| 39 | { |
| 40 | unsigned int bytenum = bitnum / 8; |
| 41 | |
| 42 | return bytenum; |
| 43 | } |
| 44 | |
| 45 | /* convert ZERO/ONE/L/H to a bitmask at given pos in a byte */ |
| 46 | static uint8_t bitval2mask(enum bit_value bit, uint8_t bitnum) |
| 47 | { |
| 48 | int bitval; |
| 49 | |
| 50 | switch (bit) { |
| 51 | case ZERO: |
| 52 | bitval = (0 << bitnum); |
| 53 | break; |
| 54 | case ONE: |
| 55 | bitval = (1 << bitnum); |
| 56 | break; |
| 57 | case L: |
| 58 | bitval = ((0x2b ^ (0 << bitnum)) & (1 << bitnum)); |
| 59 | break; |
| 60 | case H: |
| 61 | bitval = ((0x2b ^ (1 << bitnum)) & (1 << bitnum)); |
| 62 | break; |
| 63 | default: |
| 64 | return 0; |
| 65 | } |
| 66 | return bitval; |
| 67 | } |
| 68 | |
Harald Welte | ba6988b | 2011-08-17 12:46:48 +0200 | [diff] [blame] | 69 | /*! \brief check if the bit is 0 or 1 for a given position inside a bitvec |
| 70 | * \param[in] bv the bit vector on which to check |
| 71 | * \param[in] bitnr the bit number inside the bit vector to check |
| 72 | * \returns |
| 73 | */ |
Harald Welte | d9abf01 | 2010-03-06 11:28:49 +0100 | [diff] [blame] | 74 | enum bit_value bitvec_get_bit_pos(const struct bitvec *bv, unsigned int bitnr) |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 75 | { |
| 76 | unsigned int bytenum = bytenum_from_bitnum(bitnr); |
| 77 | unsigned int bitnum = 7 - (bitnr % 8); |
| 78 | uint8_t bitval; |
| 79 | |
| 80 | if (bytenum >= bv->data_len) |
| 81 | return -EINVAL; |
| 82 | |
| 83 | bitval = bitval2mask(ONE, bitnum); |
| 84 | |
| 85 | if (bv->data[bytenum] & bitval) |
| 86 | return ONE; |
| 87 | |
| 88 | return ZERO; |
| 89 | } |
| 90 | |
Harald Welte | ba6988b | 2011-08-17 12:46:48 +0200 | [diff] [blame] | 91 | /*! \brief check if the bit is L or H for a given position inside a bitvec |
| 92 | * \param[in] bv the bit vector on which to check |
| 93 | * \param[in] bitnr the bit number inside the bit vector to check |
| 94 | */ |
Andreas.Eversberg | 0ebd688 | 2010-05-09 09:36:54 +0000 | [diff] [blame] | 95 | enum bit_value bitvec_get_bit_pos_high(const struct bitvec *bv, |
| 96 | unsigned int bitnr) |
| 97 | { |
| 98 | unsigned int bytenum = bytenum_from_bitnum(bitnr); |
| 99 | unsigned int bitnum = 7 - (bitnr % 8); |
| 100 | uint8_t bitval; |
| 101 | |
| 102 | if (bytenum >= bv->data_len) |
| 103 | return -EINVAL; |
| 104 | |
| 105 | bitval = bitval2mask(H, bitnum); |
| 106 | |
Andreas.Eversberg | dc0ebdf | 2010-10-24 11:59:33 +0200 | [diff] [blame] | 107 | if ((bv->data[bytenum] & (1 << bitnum)) == bitval) |
Andreas.Eversberg | 0ebd688 | 2010-05-09 09:36:54 +0000 | [diff] [blame] | 108 | return H; |
| 109 | |
| 110 | return L; |
| 111 | } |
| 112 | |
Harald Welte | ba6988b | 2011-08-17 12:46:48 +0200 | [diff] [blame] | 113 | /*! \brief get the Nth set bit inside the bit vector |
| 114 | * \param[in] bv the bit vector to use |
| 115 | * \param[in] n the bit number to get |
| 116 | * \returns the bit number (offset) of the Nth set bit in \a bv |
| 117 | */ |
Harald Welte | d9abf01 | 2010-03-06 11:28:49 +0100 | [diff] [blame] | 118 | unsigned int bitvec_get_nth_set_bit(const struct bitvec *bv, unsigned int n) |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 119 | { |
| 120 | unsigned int i, k = 0; |
| 121 | |
| 122 | for (i = 0; i < bv->data_len*8; i++) { |
| 123 | if (bitvec_get_bit_pos(bv, i) == ONE) { |
| 124 | k++; |
| 125 | if (k == n) |
| 126 | return i; |
| 127 | } |
| 128 | } |
| 129 | |
| 130 | return 0; |
| 131 | } |
| 132 | |
Harald Welte | ba6988b | 2011-08-17 12:46:48 +0200 | [diff] [blame] | 133 | /*! \brief set a bit at given position in a bit vector |
| 134 | * \param[in] bv bit vector on which to operate |
Katerina Barone-Adesi | c28c6a0 | 2013-02-15 13:27:59 +0100 | [diff] [blame] | 135 | * \param[in] bitnr number of bit to be set |
Harald Welte | ba6988b | 2011-08-17 12:46:48 +0200 | [diff] [blame] | 136 | * \param[in] bit value to which the bit is to be set |
| 137 | */ |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 138 | int bitvec_set_bit_pos(struct bitvec *bv, unsigned int bitnr, |
| 139 | enum bit_value bit) |
| 140 | { |
| 141 | unsigned int bytenum = bytenum_from_bitnum(bitnr); |
| 142 | unsigned int bitnum = 7 - (bitnr % 8); |
| 143 | uint8_t bitval; |
| 144 | |
| 145 | if (bytenum >= bv->data_len) |
| 146 | return -EINVAL; |
| 147 | |
| 148 | /* first clear the bit */ |
| 149 | bitval = bitval2mask(ONE, bitnum); |
| 150 | bv->data[bytenum] &= ~bitval; |
| 151 | |
| 152 | /* then set it to desired value */ |
| 153 | bitval = bitval2mask(bit, bitnum); |
| 154 | bv->data[bytenum] |= bitval; |
| 155 | |
| 156 | return 0; |
| 157 | } |
| 158 | |
Harald Welte | ba6988b | 2011-08-17 12:46:48 +0200 | [diff] [blame] | 159 | /*! \brief set the next bit inside a bitvec |
| 160 | * \param[in] bv bit vector to be used |
| 161 | * \param[in] bit value of the bit to be set |
| 162 | */ |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 163 | int bitvec_set_bit(struct bitvec *bv, enum bit_value bit) |
| 164 | { |
| 165 | int rc; |
| 166 | |
| 167 | rc = bitvec_set_bit_pos(bv, bv->cur_bit, bit); |
| 168 | if (!rc) |
| 169 | bv->cur_bit++; |
| 170 | |
| 171 | return rc; |
| 172 | } |
| 173 | |
Harald Welte | ba6988b | 2011-08-17 12:46:48 +0200 | [diff] [blame] | 174 | /*! \brief get the next bit (low/high) inside a bitvec */ |
Andreas.Eversberg | 0ebd688 | 2010-05-09 09:36:54 +0000 | [diff] [blame] | 175 | int bitvec_get_bit_high(struct bitvec *bv) |
| 176 | { |
| 177 | int rc; |
| 178 | |
| 179 | rc = bitvec_get_bit_pos_high(bv, bv->cur_bit); |
| 180 | if (rc >= 0) |
| 181 | bv->cur_bit++; |
| 182 | |
| 183 | return rc; |
| 184 | } |
| 185 | |
Harald Welte | ba6988b | 2011-08-17 12:46:48 +0200 | [diff] [blame] | 186 | /*! \brief set multiple bits (based on array of bitvals) at current pos |
| 187 | * \param[in] bv bit vector |
| 188 | * \param[in] bits array of \ref bit_value |
| 189 | * \param[in] count number of bits to set |
| 190 | */ |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 191 | int bitvec_set_bits(struct bitvec *bv, enum bit_value *bits, int count) |
| 192 | { |
| 193 | int i, rc; |
| 194 | |
| 195 | for (i = 0; i < count; i++) { |
| 196 | rc = bitvec_set_bit(bv, bits[i]); |
| 197 | if (rc) |
| 198 | return rc; |
| 199 | } |
| 200 | |
| 201 | return 0; |
| 202 | } |
| 203 | |
Harald Welte | ba6988b | 2011-08-17 12:46:48 +0200 | [diff] [blame] | 204 | /*! \brief set multiple bits (based on numeric value) at current pos */ |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 205 | int bitvec_set_uint(struct bitvec *bv, unsigned int ui, int num_bits) |
| 206 | { |
| 207 | int i, rc; |
| 208 | |
| 209 | for (i = 0; i < num_bits; i++) { |
| 210 | int bit = 0; |
| 211 | if (ui & (1 << (num_bits - i - 1))) |
| 212 | bit = 1; |
| 213 | rc = bitvec_set_bit(bv, bit); |
| 214 | if (rc) |
| 215 | return rc; |
| 216 | } |
| 217 | |
| 218 | return 0; |
| 219 | } |
| 220 | |
Harald Welte | ba6988b | 2011-08-17 12:46:48 +0200 | [diff] [blame] | 221 | /*! \brief get multiple bits (based on numeric value) from current pos */ |
Andreas.Eversberg | 0ebd688 | 2010-05-09 09:36:54 +0000 | [diff] [blame] | 222 | int bitvec_get_uint(struct bitvec *bv, int num_bits) |
| 223 | { |
| 224 | int i; |
| 225 | unsigned int ui = 0; |
| 226 | |
| 227 | for (i = 0; i < num_bits; i++) { |
| 228 | int bit = bitvec_get_bit_pos(bv, bv->cur_bit); |
| 229 | if (bit < 0) |
| 230 | return bit; |
| 231 | if (bit) |
| 232 | ui |= (1 << (num_bits - i - 1)); |
| 233 | bv->cur_bit++; |
| 234 | } |
| 235 | |
| 236 | return ui; |
| 237 | } |
| 238 | |
Harald Welte | ba6988b | 2011-08-17 12:46:48 +0200 | [diff] [blame] | 239 | /*! \brief pad all remaining bits up to num_bits */ |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 240 | int bitvec_spare_padding(struct bitvec *bv, unsigned int up_to_bit) |
| 241 | { |
| 242 | unsigned int i; |
| 243 | |
| 244 | for (i = bv->cur_bit; i <= up_to_bit; i++) |
| 245 | bitvec_set_bit(bv, L); |
| 246 | |
| 247 | return 0; |
| 248 | } |
Pablo Neira Ayuso | 36bdf2c | 2011-03-28 19:24:19 +0200 | [diff] [blame] | 249 | |
Harald Welte | ba6988b | 2011-08-17 12:46:48 +0200 | [diff] [blame] | 250 | /*! \brief find first bit set in bit vector */ |
Pablo Neira Ayuso | 36bdf2c | 2011-03-28 19:24:19 +0200 | [diff] [blame] | 251 | int bitvec_find_bit_pos(const struct bitvec *bv, unsigned int n, |
| 252 | enum bit_value val) |
| 253 | { |
| 254 | unsigned int i; |
| 255 | |
| 256 | for (i = n; i < bv->data_len*8; i++) { |
| 257 | if (bitvec_get_bit_pos(bv, i) == val) |
| 258 | return i; |
| 259 | } |
| 260 | |
| 261 | return -1; |
| 262 | } |
Harald Welte | ba6988b | 2011-08-17 12:46:48 +0200 | [diff] [blame] | 263 | |
Sylvain Munaut | dca7d2c | 2012-04-18 21:53:23 +0200 | [diff] [blame] | 264 | /*! @} */ |