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lvm2/libdm/datastruct/bitset.c

258 lines
5.3 KiB
C

/*
* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
*
* This file is part of the device-mapper userspace tools.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU Lesser General Public License v.2.1.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libdm/misc/dmlib.h"
#include <ctype.h>
/* FIXME: calculate this. */
#define INT_SHIFT 5
dm_bitset_t dm_bitset_create(struct dm_pool *mem, unsigned num_bits)
{
unsigned n = (num_bits / DM_BITS_PER_INT) + 2;
size_t size = sizeof(int) * n;
dm_bitset_t bs;
if (mem)
bs = dm_pool_zalloc(mem, size);
else
bs = dm_zalloc(size);
if (!bs)
return NULL;
*bs = num_bits;
return bs;
}
void dm_bitset_destroy(dm_bitset_t bs)
{
dm_free(bs);
}
int dm_bitset_equal(dm_bitset_t in1, dm_bitset_t in2)
{
int i;
for (i = (in1[0] / DM_BITS_PER_INT) + 1; i; i--)
if (in1[i] != in2[i])
return 0;
return 1;
}
void dm_bit_and(dm_bitset_t out, dm_bitset_t in1, dm_bitset_t in2)
{
int i;
for (i = (in1[0] / DM_BITS_PER_INT) + 1; i; i--)
out[i] = in1[i] & in2[i];
}
void dm_bit_union(dm_bitset_t out, dm_bitset_t in1, dm_bitset_t in2)
{
int i;
for (i = (in1[0] / DM_BITS_PER_INT) + 1; i; i--)
out[i] = in1[i] | in2[i];
}
static int _test_word(uint32_t test, int bit)
{
uint32_t tb = test >> bit;
return (tb ? ffs(tb) + bit - 1 : -1);
}
static int _test_word_rev(uint32_t test, int bit)
{
uint32_t tb = test << (DM_BITS_PER_INT - 1 - bit);
return (tb ? bit - clz(tb) : -1);
}
int dm_bit_get_next(dm_bitset_t bs, int last_bit)
{
int bit, word;
uint32_t test;
last_bit++; /* otherwise we'll return the same bit again */
/*
* bs[0] holds number of bits
*/
while (last_bit < (int) bs[0]) {
word = last_bit >> INT_SHIFT;
test = bs[word + 1];
bit = last_bit & (DM_BITS_PER_INT - 1);
if ((bit = _test_word(test, bit)) >= 0)
return (word * DM_BITS_PER_INT) + bit;
last_bit = last_bit - (last_bit & (DM_BITS_PER_INT - 1)) +
DM_BITS_PER_INT;
}
return -1;
}
int dm_bit_get_prev(dm_bitset_t bs, int last_bit)
{
int bit, word;
uint32_t test;
last_bit--; /* otherwise we'll return the same bit again */
/*
* bs[0] holds number of bits
*/
while (last_bit >= 0) {
word = last_bit >> INT_SHIFT;
test = bs[word + 1];
bit = last_bit & (DM_BITS_PER_INT - 1);
if ((bit = _test_word_rev(test, bit)) >= 0)
return (word * DM_BITS_PER_INT) + bit;
last_bit = (last_bit & ~(DM_BITS_PER_INT - 1)) - 1;
}
return -1;
}
int dm_bit_get_first(dm_bitset_t bs)
{
return dm_bit_get_next(bs, -1);
}
int dm_bit_get_last(dm_bitset_t bs)
{
return dm_bit_get_prev(bs, bs[0] + 1);
}
/*
* Based on the Linux kernel __bitmap_parselist from lib/bitmap.c
*/
dm_bitset_t dm_bitset_parse_list(const char *str, struct dm_pool *mem,
size_t min_num_bits)
{
unsigned a, b;
int c, old_c, totaldigits, ndigits, nmaskbits;
int at_start, in_range;
dm_bitset_t mask = NULL;
const char *start = str;
size_t len;
scan:
len = strlen(str);
totaldigits = c = 0;
nmaskbits = 0;
do {
at_start = 1;
in_range = 0;
a = b = 0;
ndigits = totaldigits;
/* Get the next value or range of values */
while (len) {
old_c = c;
c = *str++;
len--;
if (isspace(c))
continue;
/* A '\0' or a ',' signal the end of a value or range */
if (c == '\0' || c == ',')
break;
/*
* whitespaces between digits are not allowed,
* but it's ok if whitespaces are on head or tail.
* when old_c is whilespace,
* if totaldigits == ndigits, whitespace is on head.
* if whitespace is on tail, it should not run here.
* as c was ',' or '\0',
* the last code line has broken the current loop.
*/
if ((totaldigits != ndigits) && isspace(old_c))
goto_bad;
if (c == '-') {
if (at_start || in_range)
goto_bad;
b = 0;
in_range = 1;
at_start = 1;
continue;
}
if (!isdigit(c))
goto_bad;
b = b * 10 + (c - '0');
if (!in_range)
a = b;
at_start = 0;
totaldigits++;
}
if (ndigits == totaldigits)
continue;
/* if no digit is after '-', it's wrong */
if (at_start && in_range)
goto_bad;
if (!(a <= b))
goto_bad;
if (b >= nmaskbits)
nmaskbits = b + 1;
while ((a <= b) && mask) {
dm_bit_set(mask, a);
a++;
}
} while (len && c == ',');
if (!mask) {
if (min_num_bits && (nmaskbits < min_num_bits))
nmaskbits = min_num_bits;
if (!(mask = dm_bitset_create(mem, nmaskbits)))
goto_bad;
str = start;
goto scan;
}
return mask;
bad:
if (mask) {
if (mem)
dm_pool_free(mem, mask);
else
dm_bitset_destroy(mask);
}
return NULL;
}
#if defined(GNU_SYMVER)
/*
* Maintain backward compatibility with older versions that did not
* accept a 'min_num_bits' argument to dm_bitset_parse_list().
*/
DM_EXPORT_SYMBOL(dm_bitset_parse_list, 1_02_129)
dm_bitset_t dm_bitset_parse_list_v1_02_129(const char *str, struct dm_pool *mem);
dm_bitset_t dm_bitset_parse_list_v1_02_129(const char *str, struct dm_pool *mem)
{
return dm_bitset_parse_list(str, mem, 0);
}
#endif