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Last change
on this file since 793 was 793, checked in by andi.b@gmx.net, 11 years ago |
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wpa_supplicant: initial import of wpa_supplicant2.2
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Property svn:eol-style
set to
native
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File size:
1.4 KB
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| 1 | /*
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| 2 | * Bitfield
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| 3 | * Copyright (c) 2013, Jouni Malinen <j@w1.fi>
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| 4 | *
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| 5 | * This software may be distributed under the terms of the BSD license.
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| 6 | * See README for more details.
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| 7 | */
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| 8 |
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| 9 | #include "includes.h"
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| 10 |
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| 11 | #include "common.h"
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| 12 | #include "bitfield.h"
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| 13 |
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| 14 |
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| 15 | struct bitfield {
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| 16 | u8 *bits;
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| 17 | size_t max_bits;
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| 18 | };
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| 19 |
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| 20 |
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| 21 | struct bitfield * bitfield_alloc(size_t max_bits)
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| 22 | {
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| 23 | struct bitfield *bf;
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| 24 |
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| 25 | bf = os_zalloc(sizeof(*bf) + (max_bits + 7) / 8);
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| 26 | if (bf == NULL)
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| 27 | return NULL;
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| 28 | bf->bits = (u8 *) (bf + 1);
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| 29 | bf->max_bits = max_bits;
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| 30 | return bf;
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| 31 | }
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| 32 |
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| 33 |
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| 34 | void bitfield_free(struct bitfield *bf)
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| 35 | {
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| 36 | os_free(bf);
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| 37 | }
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| 38 |
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| 39 |
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| 40 | void bitfield_set(struct bitfield *bf, size_t bit)
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| 41 | {
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| 42 | if (bit >= bf->max_bits)
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| 43 | return;
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| 44 | bf->bits[bit / 8] |= BIT(bit % 8);
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| 45 | }
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| 46 |
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| 47 |
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| 48 | void bitfield_clear(struct bitfield *bf, size_t bit)
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| 49 | {
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| 50 | if (bit >= bf->max_bits)
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| 51 | return;
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| 52 | bf->bits[bit / 8] &= ~BIT(bit % 8);
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| 53 | }
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| 54 |
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| 55 |
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| 56 | int bitfield_is_set(struct bitfield *bf, size_t bit)
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| 57 | {
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| 58 | if (bit >= bf->max_bits)
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| 59 | return 0;
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| 60 | return !!(bf->bits[bit / 8] & BIT(bit % 8));
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| 61 | }
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| 62 |
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| 63 |
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| 64 | static int first_zero(u8 val)
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| 65 | {
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| 66 | int i;
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| 67 | for (i = 0; i < 8; i++) {
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| 68 | if (!(val & 0x01))
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| 69 | return i;
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| 70 | val >>= 1;
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| 71 | }
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| 72 | return -1;
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| 73 | }
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| 74 |
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| 75 |
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| 76 | int bitfield_get_first_zero(struct bitfield *bf)
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| 77 | {
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| 78 | size_t i;
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| 79 | for (i = 0; i <= (bf->max_bits + 7) / 8; i++) {
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| 80 | if (bf->bits[i] != 0xff)
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| 81 | break;
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| 82 | }
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| 83 | if (i > (bf->max_bits + 7) / 8)
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| 84 | return -1;
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| 85 | i = i * 8 + first_zero(bf->bits[i]);
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| 86 | if (i >= bf->max_bits)
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| 87 | return -1;
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| 88 | return i;
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| 89 | }
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