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/*
This file is taken from the Linux kernel and minimally adapted for use in userspace
*/
/*
* lib/bitmap.c
* Helper functions for bitmap.h.
*
* This source code is licensed under the GNU General Public License,
* Version 2. See the file COPYING for more details.
*/
#include "config.h"
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include "bitmap.h"
#include "non-atomic.h"
/*
* bitmaps provide an array of bits, implemented using an an
* array of unsigned longs. The number of valid bits in a
* given bitmap does _not_ need to be an exact multiple of
* BITS_PER_LONG.
*
* The possible unused bits in the last, partially used word
* of a bitmap are 'don't care'. The implementation makes
* no particular effort to keep them zero. It ensures that
* their value will not affect the results of any operation.
* The bitmap operations that return Boolean (bitmap_empty,
* for example) or scalar (bitmap_weight, for example) results
* carefully filter out these unused bits from impacting their
* results.
*
* These operations actually hold to a slightly stronger rule:
* if you don't input any bitmaps to these ops that have some
* unused bits set, then they won't output any set unused bits
* in output bitmaps.
*
* The byte ordering of bitmaps is more natural on little
* endian architectures. See the big-endian headers
* include/asm-ppc64/bitops.h and include/asm-s390/bitops.h
* for the best explanations of this ordering.
*/
int __bitmap_empty(const unsigned long *bitmap, int bits)
{
int k, lim = bits/BITS_PER_LONG;
for (k = 0; k < lim; ++k)
if (bitmap[k])
return 0;
if (bits % BITS_PER_LONG)
if (bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
return 0;
return 1;
}
int __bitmap_full(const unsigned long *bitmap, int bits)
{
int k, lim = bits/BITS_PER_LONG;
for (k = 0; k < lim; ++k)
if (~bitmap[k])
return 0;
if (bits % BITS_PER_LONG)
if (~bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
return 0;
return 1;
}
int __bitmap_weight(const unsigned long *bitmap, int bits)
{
int k, w = 0, lim = bits/BITS_PER_LONG;
for (k = 0; k < lim; k++)
w += hweight_long(bitmap[k]);
if (bits % BITS_PER_LONG)
w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
return w;
}
int __bitmap_equal(const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits)
{
int k, lim = bits/BITS_PER_LONG;
for (k = 0; k < lim; ++k)
if (bitmap1[k] != bitmap2[k])
return 0;
if (bits % BITS_PER_LONG)
if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
return 0;
return 1;
}
void __bitmap_complement(unsigned long *dst, const unsigned long *src, int bits)
{
int k, lim = bits/BITS_PER_LONG;
for (k = 0; k < lim; ++k)
dst[k] = ~src[k];
if (bits % BITS_PER_LONG)
dst[k] = ~src[k] & BITMAP_LAST_WORD_MASK(bits);
}
/*
* __bitmap_shift_right - logical right shift of the bits in a bitmap
* @dst - destination bitmap
* @src - source bitmap
* @nbits - shift by this many bits
* @bits - bitmap size, in bits
*
* Shifting right (dividing) means moving bits in the MS -> LS bit
* direction. Zeros are fed into the vacated MS positions and the
* LS bits shifted off the bottom are lost.
*/
void __bitmap_shift_right(unsigned long *dst,
const unsigned long *src, int shift, int bits)
{
int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
unsigned long mask = (1UL << left) - 1;
for (k = 0; off + k < lim; ++k) {
unsigned long upper, lower;
/*
* If shift is not word aligned, take lower rem bits of
* word above and make them the top rem bits of result.
*/
if (!rem || off + k + 1 >= lim)
upper = 0;
else {
upper = src[off + k + 1];
if (off + k + 1 == lim - 1 && left)
upper &= mask;
}
lower = src[off + k];
if (left && off + k == lim - 1)
lower &= mask;
dst[k] = upper << (BITS_PER_LONG - rem) | lower >> rem;
if (left && k == lim - 1)
dst[k] &= mask;
}
if (off)
memset(&dst[lim - off], 0, off*sizeof(unsigned long));
}
/*
* __bitmap_shift_left - logical left shift of the bits in a bitmap
* @dst - destination bitmap
* @src - source bitmap
* @nbits - shift by this many bits
* @bits - bitmap size, in bits
*
* Shifting left (multiplying) means moving bits in the LS -> MS
* direction. Zeros are fed into the vacated LS bit positions
* and those MS bits shifted off the top are lost.
*/
void __bitmap_shift_left(unsigned long *dst,
const unsigned long *src, int shift, int bits)
{
int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
for (k = lim - off - 1; k >= 0; --k) {
unsigned long upper, lower;
/*
* If shift is not word aligned, take upper rem bits of
* word below and make them the bottom rem bits of result.
*/
if (rem && k > 0)
lower = src[k - 1];
else
lower = 0;
upper = src[k];
if (left && k == lim - 1)
upper &= (1UL << left) - 1;
dst[k + off] = lower >> (BITS_PER_LONG - rem) | upper << rem;
if (left && k + off == lim - 1)
dst[k + off] &= (1UL << left) - 1;
}
if (off)
memset(dst, 0, off*sizeof(unsigned long));
}
void __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits)
{
int k;
int nr = BITS_TO_LONGS(bits);
for (k = 0; k < nr; k++)
dst[k] = bitmap1[k] & bitmap2[k];
}
void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits)
{
int k;
int nr = BITS_TO_LONGS(bits);
for (k = 0; k < nr; k++)
dst[k] = bitmap1[k] | bitmap2[k];
}
void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits)
{
int k;
int nr = BITS_TO_LONGS(bits);
for (k = 0; k < nr; k++)
dst[k] = bitmap1[k] ^ bitmap2[k];
}
void __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits)
{
int k;
int nr = BITS_TO_LONGS(bits);
for (k = 0; k < nr; k++)
dst[k] = bitmap1[k] & ~bitmap2[k];
}
int __bitmap_intersects(const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits)
{
int k, lim = bits/BITS_PER_LONG;
for (k = 0; k < lim; ++k)
if (bitmap1[k] & bitmap2[k])
return 1;
if (bits % BITS_PER_LONG)
if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
return 1;
return 0;
}
/*
* Bitmap printing & parsing functions: first version by Bill Irwin,
* second version by Paul Jackson, third by Joe Korty.
*/
#define CHUNKSZ 32
#define nbits_to_hold_value(val) fls(val)
#define unhex(c) (isdigit(c) ? (c - '0') : (toupper(c) - 'A' + 10))
#define BASEDEC 10 /* fancier cpuset lists input in decimal */
/**
* bitmap_scnprintf - convert bitmap to an ASCII hex string.
* @buf: byte buffer into which string is placed
* @buflen: reserved size of @buf, in bytes
* @maskp: pointer to bitmap to convert
* @nmaskbits: size of bitmap, in bits
*
* Exactly @nmaskbits bits are displayed. Hex digits are grouped into
* comma-separated sets of eight digits per set.
*/
int bitmap_scnprintf(char *buf, unsigned int buflen,
const unsigned long *maskp, int nmaskbits)
{
int i, word, bit, len = 0;
unsigned long val;
const char *sep = "";
int chunksz;
uint32_t chunkmask;
int first = 1;
chunksz = nmaskbits & (CHUNKSZ - 1);
if (chunksz == 0)
chunksz = CHUNKSZ;
i = ALIGN(nmaskbits, CHUNKSZ) - CHUNKSZ;
for (; i >= 0; i -= CHUNKSZ) {
chunkmask = ((1ULL << chunksz) - 1);
word = i / BITS_PER_LONG;
bit = i % BITS_PER_LONG;
val = (maskp[word] >> bit) & chunkmask;
if (val!=0 || !first || i==0) {
len += snprintf(buf+len, buflen-len, "%s%0*lx", sep,
(chunksz+3)/4, val);
sep = ",";
first = 0;
}
chunksz = CHUNKSZ;
}
return len;
}
/**
* __bitmap_parse - convert an ASCII hex string into a bitmap.
* @buf: pointer to buffer containing string.
* @buflen: buffer size in bytes. If string is smaller than this
* then it must be terminated with a \0.
* @is_user: location of buffer, 0 indicates kernel space
* @maskp: pointer to bitmap array that will contain result.
* @nmaskbits: size of bitmap, in bits.
*
* Commas group hex digits into chunks. Each chunk defines exactly 32
* bits of the resultant bitmask. No chunk may specify a value larger
* than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value
* then leading 0-bits are prepended. %-EINVAL is returned for illegal
* characters and for grouping errors such as "1,,5", ",44", "," and "".
* Leading and trailing whitespace accepted, but not embedded whitespace.
*/
int __bitmap_parse(const char *buf, unsigned int buflen,
int is_user __attribute((unused)), unsigned long *maskp,
int nmaskbits)
{
int c, old_c, totaldigits, ndigits, nchunks, nbits;
uint32_t chunk;
bitmap_zero(maskp, nmaskbits);
nchunks = nbits = totaldigits = c = 0;
do {
chunk = ndigits = 0;
/* Get the next chunk of the bitmap */
while (buflen) {
old_c = c;
c = *buf++;
buflen--;
if (isspace(c))
continue;
/*
* If the last character was a space and the current
* character isn't '\0', we've got embedded whitespace.
* This is a no-no, so throw an error.
*/
if (totaldigits && c && isspace(old_c))
return 0;
/* A '\0' or a ',' signal the end of the chunk */
if (c == '\0' || c == ',')
break;
if (!isxdigit(c))
return -EINVAL;
/*
* Make sure there are at least 4 free bits in 'chunk'.
* If not, this hexdigit will overflow 'chunk', so
* throw an error.
*/
if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1))
return -EOVERFLOW;
chunk = (chunk << 4) | unhex(c);
ndigits++; totaldigits++;
}
if (ndigits == 0)
return -EINVAL;
if (nchunks == 0 && chunk == 0)
continue;
__bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits);
*maskp |= chunk;
nchunks++;
nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ;
if (nbits > nmaskbits)
return -EOVERFLOW;
} while (buflen && c == ',');
return 0;
}
/**
* __bitmap_parselist - convert list format ASCII string to bitmap
* @buf: read nul-terminated user string from this buffer
* @buflen: buffer size in bytes. If string is smaller than this
* then it must be terminated with a \0.
* @is_user: location of buffer, 0 indicates kernel space
* @maskp: write resulting mask here
* @nmaskbits: number of bits in mask to be written
*
* Input format is a comma-separated list of decimal numbers and
* ranges. Consecutively set bits are shown as two hyphen-separated
* decimal numbers, the smallest and largest bit numbers set in
* the range.
*
* Returns 0 on success, -errno on invalid input strings.
* Error values:
* %-EINVAL: second number in range smaller than first
* %-EINVAL: invalid character in string
* %-ERANGE: bit number specified too large for mask
*/
int __bitmap_parselist(const char *buf, unsigned int buflen,
int is_user __attribute((unused)), unsigned long *maskp,
int nmaskbits)
{
int a, b, c, old_c, totaldigits;
int exp_digit, in_range;
totaldigits = c = 0;
bitmap_zero(maskp, nmaskbits);
do {
exp_digit = 1;
in_range = 0;
a = b = 0;
/* Get the next cpu# or a range of cpu#'s */
while (buflen) {
old_c = c;
c = *buf++;
buflen--;
if (isspace(c))
continue;
/*
* If the last character was a space and the current
* character isn't '\0', we've got embedded whitespace.
* This is a no-no, so throw an error.
*/
if (totaldigits && c && isspace(old_c))
return -EINVAL;
/* A '\0' or a ',' signal the end of a cpu# or range */
if (c == '\0' || c == ',')
break;
if (c == '-') {
if (exp_digit || in_range)
return -EINVAL;
b = 0;
in_range = 1;
exp_digit = 1;
continue;
}
if (!isdigit(c))
return -EINVAL;
b = b * 10 + (c - '0');
if (!in_range)
a = b;
exp_digit = 0;
totaldigits++;
}
if (!(a <= b))
return -EINVAL;
if (b >= nmaskbits)
return -ERANGE;
while (a <= b) {
set_bit(a, maskp);
a++;
}
} while (buflen && c == ',');
return 0;
}